Is a stock Tri Z 250 really that slow????

[Darius1502]

Hey Guys,

Just wondering...I am rebuilding an 86 Tri Z (as you may know). I have never ridden it and have heard the R and Tecate were faster. I have a YZ 400F (fourstroke motocross) and a Quadzilla (500cc two stroke).

I have also owned a KTM 250cc motocross...tell me:

How fast or slow is the Tri Z 250? Has anyone owned both an '85 and an '86 and if so is the '86 much faster?

[J.D.]

I dunno about this, but I'll give some comments. I do believe an 86 is faster, since it has the 6 speed tranny. My Z only goes 55 tops right now, but I'm running 12/44 gears with 22 inchers. I plan to put a front sprocket up to 14, so I should be able to go 65 after that, I also want to put a 42 rear sprocket on, I'm not real concerned about accelaration, I want top speed because most of my riding area is always 50+ mph. R's and Tecates are both more powerful and faster. The Tri-Z is like the crappiest of the 3, but still not a bad machine in my opinion. If I remember correctly I think an 86 or 85 R came stock going 85 mph, that's pretty damn fast.

[MR ATC]

they don't call them " Yamadog" for nothing...jk seriously out of the 3 250cc 2 strokes they are the least powerful and slower but they dose not mean they are bad. yamaha was just playing catch up to Honda & Kawasaki when the Tri-Z first appered. it is still one of the top performing 3 wheelers.

[Wickedfinger]

I don't know what Z's you guys are riding, but my '86 was and still remains probably the fastest ATV I've ever owned - faster than any of my ATC250R's ('85, '83, '82 - all stock except for pipes and a wiseco or two), faster than my '91 LT250R (R&R racing prepped motor, pipe), or my old '85 LT250R (ported, pipe, wiesco), or my '87 Banshee (DG piped), and maybe even faster than my highly modded '96 400L sport. Yeah the engine was match ported to the overbore piston, had the twin boost port, and I ran a DG pipe ..... but she was a beast. I'm sure TimSr would like to weigh in on this discussion.

[TimSr]

I dont much care what the magazines say, or how armchair engineers interpret what theyve read in the magazines. If you can ride my Z, and then tell me with a straight face that its slow, then Ive certainly got to see whatever you're riding!

Between the 85 and 86, if you are talking drag race or MX, I prefer the 85 gearbox. The 86 gears seem to be closer together, requiring more shifting than the motor deems necessary which costs to much time. I prefer the closer gears in the 86 for normal offroad riding.

[md1985250r]

YEARS AGO A BUDDY OF MINE HAD A TRI-Z,,BORED 2 OVER AFTER HE RAN STRAIGHT GAS IN IT....HE STILL COULDN'T HANG WITH MY STOCK 85 250R

[Dynofox]

I don't think my Z is slow by any means. It kills everything I ride with (warriors and blasters :-D ). I'd like to run it against some 400ex's, I don't see any reason my Z wouldn't take them. BTW i'm running a full dg system and boyesen reeds.

[CHAINSAW]

I have an 86 completely stock.. even has the original tires on it still (original bore, reeds, air filter, everything) . They are pretty fast... I mean its just as fast as any quad being released today. I love mine for the wheelie riding and jumping.. those things were made to jump!

You wont see a whole lot of fast Tri Z's because you cant find any aftermarket performance parts anymore. Other then a pipe, and that only helps a little bit. You wont be dissapointed by any means, and if you are.. Ill buy it. I love Z's

[Billy Golightly]

Call me crazy (Won't be the first time) but when my Z was running, it knocked the socks off of any atv I've ever owned before. It made mince meat out of my TRX250R in the excelleration department. I don't doubt that the R was a little bit faster overall, but thats mostly gearing. When I had it on the road (One of the very, very few times) I could lift the front wheel in ALL 5 gears with very little effort. My dad was also following me in the F-250, and he said he was doing over 70 and I was a loooong ways ahead of him. I'm not doubting the motor had some work done to it, but the exhaust was stock, and so was all the wacky airbox setup. I can't imagine one setup with the YZ250 powervalve setup + some porting and a good pipe like the LRD I have.

[Darius1502]

thanks guys...I appreciate the feedback. Hey chainsaw...can I see some pics of your Tri Z?

[CHAINSAW]

http://www.geocities.com/midwesttrikers/chainsrides.html

[Bill X_R]

I'm not much on changing the look of stock bikes...but Chainsaw, that is one bad ass lookin "R"


I dont care if that is a new 60 $ headlight....PAINT IT TO MATCH!!

[denn]

If any of you follow ebay you might remember a month or so ago, there was a 250cc shootout from an old newpaper called the ATV NEWS for 86 being sold on there. This was the most thorough shootout I have ever seen and I have the dirtwheels and 3&4 wheel action ones also. They had clocked all three bikes, the top speeds were as follows TRI-Z 70mph, 250R 68mph and the tecate 58mph. They had printed everything, like the gear ratio of each gear, number of teeth, and how fast each bike went in each gear. The degree of rake and trail for each bike. Everything technical about those bikes is listed. Here's my favorite part!! The TRI-Z was the winner of the shootout. They tested each bike on actual motorcross tracks and flattracks and the TRI-Z had the fastest times and was the best handling. Not like dirtwheels and the others that test everthing in sand as if everyone lives around the corner from GLAMIS! They said the motor had the most useful powerband out of the three meaning it had something to offer in each stage from low, mid and top. I will gladly make copies and send them out to whoever wants one. It is a three page article and really the most interesting one I have ever read regardless if the TRI-Z won or not. I would also like to add as a current owner of 3 Tri-z's . That the 85 tri-z was a piece of crap compared to the 86. The engine in the 86 has a broader powerband and the suspension is completly different. It is extremelly difficult to bottom the front of the 86 tri-z. Most people give tri-z's a bad rap cause of the 85. Most people can't get ahold of a refined 86Z. They really are a totally different bike.
Let me know if anyone wants a copy of the article. My email is NICNAV@Peoplepc.com.

Thanks Denn

[Wickedfinger]

Dude, float me a copy of that article: Tejas10@aol.com - Billygoat and Howdy - you should put that up in the magazines section. No problems with the copyright stuff - the mag dosnt exist anymore.

[Darius1502]

My MINT 1986 Tri Z project just go a shot in the arm!

Wow....thats really interesting. I will have to review the article...but its good to see another viewpoint. I know Dirt Wheels and 3 Wheel Action were always very biased toward Honda.

Also most people dont realize that powerbands with a narrow RPM range are horrible for motocross and supercross conditions. Thats why the Yamaha YZ 250 has been the top supercross bike for 3 plus years...its not has fast as the Honda but has the most usable power.

Well since I am waiting on my axle I will post some pics of perhaps the most 'underrated' 3 wheeler of 1986. Its also interesting that since that was the last year of the ATC 250R and the Tri Z, the Tri Z never go a chance to get the word out more. Also if you look at the numbers...you just don't find alot of 1986 models....I mean for every 4 '85 models you might see one '86 model.

Here are some pics!!

[Darius1502]

And another!!!!!!!!!!!11

[Darius1502]

one more!!!!!!!!1

[Darius1502]

Best for last!!!!!!....my project!

I am getting so sick of waiting on my axle, sometimes I just want to say,

"where the HELL is my AXLE B#TCH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" :twisted:

[Jeb]

My opinion as an owner. :-D

I love my ol' yellar 85 Tri-Z. Just because it's an 85 it's definitely not crap. But it's not stock. I have the tank switched out, a bill's pipe, CT Silencer, Clamp-on UNI filter, boyessen reeds, 14 tooth front sprocket, +2 West Coast Swingarm, 18x11-8 Turf Tamers on stock rims out back and a few other odd's & ends. It doesn't have allot of top speed, but it gets there quick and has plenty of power. I don't have an extended axle for it, but I do run the stock rims turned around and sometimes I run spacers. The suspension is in great shape, it's pretty much an MX trike, though I do not race MX.

I'm also an 84 & 86 Tecate owner. I don't care what shootout says what, It may have a faster top speed but the stock Tri-Z cannot outhandle or out motor the stock Tecate. It especially cannot out handle an 86 Tecate. Even with the mods my 85 Z has it will not handle as well as my Stock 86 KXT. My 84 KXT had comparable mods (swingarm, axle, pipe, etc) and it would out handle the Z too. They just slide and corner allot better.

I'm not going to discuss the Z motor because any motor can have a little magic breathed into it. All that take is dollars. My problem with the Z is it's handling. I believe the problems lie in chassis geometry. I also believe Yamaha tried to correct it as much as possible when they released the 86 by installing bigger forks, a lower-profile front tire, and slightly smaller, lower profile rear tires. I think these were all great changes. My next mod and probably the last I will do to my Z will be a smaller diameter front tire. I've also thought about picking up an 86 front end. I know some of the problem with 85 has got to be fork flex. I want to try the tire switch first. I've come to realize I'll never get it to match the handeling of the 86 Tecate. But that's ok, it's still one of the greatest sport ATVs of all time. You can't go wrong with a Tri-Z, which ever year you have.

[MR ATC]

there may be a good reason that ATVnews is no longer around. if they though a TRI-Z was that fast and 250R and Tecate that slow they must have been smoking some wacky trailprotrailprotrailprotrailpro. i've never been a BIG fan of magazine shootouts for one simple reason the winner always seems to be the one with the most ads in that particular magazine. what i do rely on is actual experiance. in 85/86 i was riding and racing against all these machines. now i try not to promote such activity but also during this time my friends and i also liked to play with the local cops. so what dose all this have to do with it...based on actual riding/racing and radar gun results the tecate is the fastest followed by the 250R,350X,TRI-Z, and finally 86 200X. the day a stock TRI-Z is faster then a stock Tecate or 250R is the day i trade 3 wheels for 4

[TimSr]

I couldnt have said it better Jeb!

As far as 86's handling any better than 85's, yes, the changed tire sizes work better, but since tire selection is matter of basic setup, I dont consider that a better handling trike. The bigger forks are stronger, but they have the same rake, and same length, so again, they have no effect on handling. Stiffer spring in the 86? Maybe it does, but again, they are sprung for the riders weight, which is also a matter of basic setup, and a lighter spring is better for a lighter rider. If stiffer= better, than an ATC110 has the best suspension of all. For a 150-160 lb rider, the stock 85 Z has excellent front suspension. For a 170 lb guy like me, the 86 might be better, or you drop in a set of $80 progressive rate springs from DK. I see no engineering changes between 85 and 86 that affect handling at all. They simply put a little more thought into basic setup.

Without changing frame geometry the Z will never corner like the R or the T3, which is what we usually mean by "handling", but the longer wheelbase is a handling asset for jumping, and straight lining.

All awesome machines, but top speed is Soooooo irrelevant. How fast you can do 0-50 is the name of the game. I dont know where the heck all these guys are riding at 60 or 70 mph, but my guess is Ive rarely, if ever hit 50 on a race track, and I cant remember the last time I found a field big enough to wind any of my two strokers all the way out. The drag strip at haspin ends before I can be totally topped out on my Z,even with its super low gearing. Geez, I had an old Honda CB175 twin that would do 75. Does that mean its "faster"?

Once again, if you can ride my Z, which has no major modifications, puch teh throttle and shift through the gears, and tell me its noticeably slower than whatever youve got, then I am dying to see what you are riding.

[Darius1502]

Tim,

You could have said it better...you could have your information correct! You are flat out wrong about the rake being the same. The rake on the 86 Tri Z was pulled in .05 degress to .22 degrees.

I do think the Tri Z in 1986 was a better bike than the 1985 model. Do you think the 85 250R was better than the 86...get real...its called refinement.

Also the 85 has very little preload adjustment on the rear shock. The 86 has tons.

But lets get to some real details. Here are the changes:

1) Smaller intake port area
2) 6 speed transmission
3) bigger airbox intake tract (thats why the coolant resevoir is on the left side on the engine in '86)
4) completely different jetting on the 32 mm Mikuni carb
5) Smaller front tire
6) Rake pulled in .05 degrees (with the smaller tire this adds to a shorter rake of 1.02 down from 1.4 inches
7) Lower profile Dunlop 21X11X9 inch tires
8) 39mm telscopic forks (verus 35mm)
9) Close to one inch more travel up front (10 inches)
10) Increased travel at the rear of 1.2 inches for a total of 9.3 inches
11) Increased compression and rebound damping adjustments
12) Red and White color scheme
13) New piston shape
14) Revised porting for more power

Well thats all I could see from the old tests and such...in the end the bike will handle alot better than a stock 85....don't you think Yamaha was aware of all of this and made changes to the 86 model.

I just thought this information would be helpful. I think both years are fine machines....I just always wanted an '86 so I jumped at the project.

Now everyone just enjoy thier machines (no matter what year) and lets look at that article!

[denn]

My apoligies to anyone who owns an 85 tri-z. I shouldn't say they are crap. I own 2 of them myself, but the 86 really is a big improvement. Mr. ATC all of the mods you want to do to your 85, as you know are stock on the 86 model. Also nobody said that the tri-z would out motor anything. They said it was most useful. The shootout even said the tecate had the strongest most powerful motor. It just doesn't have as high as a top speed. 6 speeds vs. 5. Even dirt wheels said it when talking about the 250R and tecate in a drag race"The honda comes close but doesn't have the screaming top end of the green machine, BUT the honda also has an extra COG that the tecate doesn't" A drag race is not telling anything about top end. As far as handling, eveything I have ever read said the tri-z is a little tougher to slide cause even in 86 it had 21 inch tires that were a bit flexy. You are able to get around that by just a little more leaning. I am going to send a copy of the ATV NEWS to the board and let them post it in the mag section so everyone can read it. One last thing, how many people who own tecates and 250r's also own a complete 86 TRI-Z, not an 85 with 86 forks and an 85 with the 6 speed and so on.

Thanks Denn

[MR ATC]

My apoligies to anyone who owns an 85 tri-z. I shouldn't say they are crap. I own 2 of them myself, but the 86 really is a big improvement. Mr. ATC all of the mods you want to do to your 85, as you know are stock on the 86 model.

Thanks Denn
i think you have me confused with someone else Denn. i don't own a TRI-Z

[denn]

Sorry I ment Jeb not mr atc and all those improvements in the 86 that are listed above are RIGHT ON. Not one was missed. THANKS

Denn

[MR ATC]

[quote="TimSr"]I couldnt have said it better Jeb!

Once again, if you can ride my Z, which has no major modifications, puch teh throttle and shift through the gears, and tell me its noticeably slower than whatever youve got, then I am dying to see what you are riding.[/quote

Tim i seem to remember a surprise on your face at haspin last year after riding Mik6's Tecate...and it wasn't even running right ;) ;) ;)

[TimSr]

Darius, Ill stand corrected on the rake. I did not think they changed it, as its not noticeable to the eye, but even a little would sure be helpful. I guess if people are looking for handling improvements, and 86 frame would be alot more helpful than the front end. I had one and sold it because I couldnt see any difference.

I also started thinking of all the things that get replaced over the years, and how I take some of them for granted. I had heard of porting changes, but apparently Yamaha used the 86 verson of cylinder as the standard replacement for both years. Same with the piston. Both years are the same part number, but then I wonder if anyone actually has a stock piston (or a yamaha one) any more! Same with rear shock. I have not seen a working TriZ shock for years, and often wondered if any still exist. Denn makes a good point, and i guess the fact is there are probably very few stock 85's or 86's to ever make a comparison, especially when so many of the revisions are parts often replaced through normal wear.

[TimSr]

MrATC, I was very please and impressed with his Tecate, but I cant say anything about it really surprised me. It certainly had better cornering capability than my Z, which I expected, and when you turned it on, it ripped, which I too expected, but I did not get off it thinking the Z seemed slow afterwards. A very fine machine, but the Z is certainly worthy to feast at the same table. Last time my Z was literally falling apart, but its since gone through total rebuild and been restored to its former glory so I look forward to seeing how close I can hang with it on the strip this year. Also, Im hoping I can find some people to run a little MX for fun this year!

[MR ATC]

Tim, thats one thing i missed out on last year was getting to race you on a mx track but with your Z having its problems we did not get the chance. I only wish i had a trike going for this year's event if things work out i may keep a trike and be there at the next one. we still have a bet i believe... ;) ;) ;)

[ATCs Reborn]

MR ATC, no ofense bud, but if you have that order correct, you're smokin a little wacky stuff yourself. there's no way in he!! the 350x is faster than the tri-z. i won't say it's faster than the r or t3, but c'mon, you gotta have that backwards right? i have 2 350x's now and they are officially my favorite machine, but i'd never try and convince anyone that either my stocker or my cammed, piped, high compression pistoned one would ever run a z.
anyways, i've owned all the 2 strokers and though i don't know what was inside the engine on my z, on the outside all it had was a cobra silencer and my z was the fastest 2 stroke i've ever owned. granted the r's and t3's i owned were the 85's and i'm sure the 86-87 tecate would have blew the doors off my z. all i know is when i had my z i was about 240lbs and it would eat up everything in sight including the ever popular piped, k&n'ed, boyesen, etc. banshees with little under 200lb riders.
my 2 cents,
steve

[MR ATC]

top speed yes its correct...how fast they acheive that top speed is differant.

[ATCs Reborn]

oh alright, i always get confused when you guys use top speed to compare machines!!!! LOL
sorry bout that,
steve

[Jeb]

Concerning the Tri-Z Frames,

I think those rake angle numbers are wrong. Unless I'm mistaken rake of a motorcycle frame is measured by the angle of a line through the center of the steering head off of a line perpendicular to the ground as the complete unit sets on a flat surface. If the rake of a tri-z frame was .22, the forks would be nearly verticle???? I think that should be 22 degrees of rake. Also a change of .05 degrees would mean very small difference on the actual trail. surely they meant 1/2 degree or .5 degrees. I guess I shouldn't say they are wrong, but I question the location of the decimal.

Correct me if I'm wrong, but I thought you could change the rake of a motorcycle (or 3 wheeler) front fork by raising or lowering the front and rear ends, either by changing tire sizes, suspension heights (slide forks in tubes or lower rear shock), or any way that changes the angle of the forks as the machine sets on flat ground. Changing the rake effects the trail which is what effects handling. The more trail the better the straight line stability and the less trail the better the cornering. Now the actual steering head angle is a fixed dimension from some point on the frame. If I'm right, the 86 Z RAKE could have been changed 1/2 degree by the differences in the Tire sizes meaning the actual STEERING HEAD ANGLE could have been left the same as the 85. Based on stock tire sizes the rear axle on the 86 got 1/2" closer to the ground and the front axle got 1" closer. In other words as a bone stock 85 Z with 22" rear tires and 25" front tire sets next to a bone stock 86 Z with 21" rear tires and a 23" inch front tire they could have the same steering head angle but different rake angles do to the way each sets on the ground. The 86 axles are lower in the front 1" and lower in the rear 1/2" which changes the angle of the rake of the forks and reduces the trail without changing steering head angle.

OMG, i've gone cross-eyed.... :D

Anyway I hope that makes a little bit o' sense! I guess my real question is could Yamaha have changed the claimed factory rake between the 85 & 86 Tri-Z with out changing the actual steering head angle of the frame???? Only way to tell is measure the steering head angle of a bare 86 tri-z frame and then measure a bare 85 frame the same way and compare ( a 1/2 degree difference will not be obvious upon visual inspection). If the frames end up being identicle except for coolant tank placement then an 85 can be easily modified to have the same rake by changing the wheels, tires, shock and forks to the 86 variety and should handle just like it. :-D

[denn]

Alright this is dragging on way to far. I own a MINT stock 85 tri-z 250 and a MINT stock 86 tri-z 250. All the parts a factory (shock, forks wheels tires etc.) The specs that darius gave are 100% correct. They did change the rake to excatly those numbers and the rest of it is also true. How they changed it I don't know. I've looked closely at both frames and never really saw a difference myself, but how can you accurately tell a degree by looking. The 2 bikes sit totally different and they feel totally different. They handle totally different and the motor is totally different. If you look at an 85 cylinder the part number is 38W and an 86 is 38W01. The powerband is longer and it pulls harder and has more top end to the powerband. The suspension is 10 times better and you can jump a hell of alot higher without bottoming out. I recommend everyone who has an 85 tri-z or any other bike and is curious about the difference try and find someone to let you ride there 86 or build one if you have the time and access to the parts.

Thanks Denn

[J.D.]

One of the improvements Yamaha needed to do was change the gas tank and air filter to traditional spots, that would have improved the Tri-Z exactly 86.98252 percent. Plus it would be less of a hassle having to remove the seat just to fill up on gas, that's bs. People like me who go riding and want to fill up at the pump have a harder time than just removing a cap, you gotta take off the seat, blah blah. BORING. I do love my Tri-Z though, and for 360 bucks in running cond. you cannot complain a bit. LONG LIVE TRI-Z's!!

[Darius1502]

Jeb...great analysis. I am in Houston, Texas...where are you at?

The dunes I was talking about are not Monahans.....but are just North of Monahans. Its basically the same sand. They reside in town called Kermit Texas. A ton of fun and very little restrictions as its a city park.

[Darius1502]

Denn,

I am also rebuilding my 86...I guess that's why I started this troublesome issue.

I would love to see your MINT '86. Please, Please post a pic of both!!!!!

Welcome to the board....

As far as mine I am waiting on an axle and some chrome from the shop. One thing I did do is get some Banshee Raptor hubs and swap my rear wheels and tires for Banshee 20 inchers.

Would love to see your Tri Z!! Here is a pic of mine

[Wickedfinger]

I don't think this thread has gone on too long in the least ... I think its very interesting and informative and its quickly becoming one of the all time great ones - worthy of trophy status - I might go out and buy another '86 Z now. Again though, I really think (for the umteenth time now) that this arguments basic core centers around the difference between fast vs quick. All three trikes had just about the same horsepower numbers, it was all in the stock gearing and to a lesser extent their piping - ATC250R 13/39 gearing, Tecate-3 13/37 and suprise suprise the Tri-Z 13/44! - thats why your top speeds are so different. This is the same discussion everyone gets into involving T-4's, TRX250R's and LT-R's - yes we all know the LT-R's were geared way too low at the output shaft and ran out of grunt on the top end when compared to the others, so what - they are great woods machines and a lousy $12 sprocket will change that top speed number real quick (assuming the chain and rear sprocket are in good shape). I think this holds true for the Z as well. ... I think Tim has a great point too in that "What the hell really is stock anymore anyway".

[TimSr]

Im thrilled that a discussion has lasted this long and still remained civil and intelligent. You folks have restored my faith that intelligent life does exist here!

I started thinking about it, and realized that since 1990 when I got my Z, the only things left of my original Z (which was not original then) are the frame, forks, front wheel and front brake assembly, carb and intake, gas tank, fuel pump, flywheel and cylinder which is on its 8th bore (after resleeving, of course). I just take for granted that I have an 85 Z with an 86 motor, when in fact I only have a giant cluster of parts from everybody elses aborted projects!

[200xer]

My 86 Z is stock except for the pipe. And I hung right with a brand new Banshee with FMF pipes in a short drag race. I also have BIG 22" tires on back, so acceleration was limited more than it should have been. I wouldn't call it slow by any means, but I haven't ridden a tecate or R, so they might be faster. It doesn't matter though as long as you're having fun. 8)

[Darius1502]

Tim,

You are right it has been a very interesting discussion...between this and my debates with MR ATC in the thread "Would you trade"...I wonder how I get myself into these situations.

Oh...I also promise I will stop posting pics of my project...I am just sick of waiting on my axle.

I would like see that ATV News Test. Also let me know if you guys want me to scan in any tests from the 80's on the Tri Z. I have both Dirt Wheels tests of the 85 and 86, plus the ATV News Tests...which are pretty detailed.

Maybe when I get my 86 running and can ride it for the 1st time I can give some real feedback.

Looking forward to more debate!

[Jeb]

I've been reading what little I could find on the internet about rake. Once again it's defined as the angle of the steering head off a line perpendicular to the ground. On most everything, the forks are held in an attitude parallel to the steering head, but moved forward a couple inches for more available steering lock. Some triple clamps increase rake by having a slight twist actually in the triple clamp. I don't believe this to be the case with the Z.

Take a look at my CAD sketch. I don't care what yamaha printed or dirtwheels printed. The 86 Tri-Z cannot have a .22 degree rake. It has to be 22 degrees. Unless yamaha measures rake differently. I also did some other sketchs that show the different tire combos change the rake .5 degree with out changing steering head angle. I used same wheelbase and some other assumptions which may not be the case. It does prove my own personal 85 Tri-Z has even MORE rake because I went to 18" tires out back. No wonder it doesnt corner as well. The added 2 inches on the W.C. Swingarm helped some. I need to try a 23" front Tire. And I still think the beefy 86 forks would help because of the flex of the skinny 85 forks. The 84/85 Tecate is the same way in the fork flex department.

Tri-Z Weight distribution is another issue in my opinion.

I agree 100% that the 86 tri-z is an improvement over 85. I just think you could set up an 85 to handle as good as an 86. But either or will never handle as good as an 86 Tecate or an 86 ATC 250R.

I know, useless info but it's been interesting research.

Darius, So your Houston area. I live west of Ft.Worth.

[TimSr]

Excellent research Jeb! I see this kind of stuff keeps you awake at night! "Rake" is almost self explanitary as to what it is, but that was a great catch on how its measured. It kind of reenforces my own personal belief that no earth shattering engineering design changes were made on the 86 model over the 85. Im still open minded, but am not convinced otherwise.

I concur with your observation about the 18" rear tires, though I believe you mean reducing rake (less of an angle) to cause worse handling. Last year at the fairs, I raced with 22" All Trax (which suck on the track) because the 18" Turf Tamers were even harder to corner with.

If you are correct in your method measurements, its no wonder I cant see any improvements in the 86. I run 22" rears, and slid the forks up over 2" so my Z probably has a lot more rake than a stock 86.

[Jeb]

Yes, I've wasted too much thought time on this! :-D In the grand scheme of things does it make a rats-@$$, no. :-D The engineering behind it is interesting to me.

I hope what I've come up with is right. I went to Kawasaki's web site and they list the different KX rakes in the 27 degree range. that's quite different from 22. I couldn't find rake measurement in the specs at yamaha's web site.
I wish someone could accurately measure the steering head angle between the 85 & 86 Frames. I could, but I don't have an 86. I'd just like to know if they really changed it or not.

[MR ATC]

one thing you may want to consider. triple clamps and steering stems can be changed to alter your rake without changing the steering neck on the frame. it's cheaper to manufacture these changes then to build a new frame jig.

[Wickedfinger]

Jeb, I'll tell ya, when I was putting together my "Frankenflyer Z" I had two almost complete Z's, an '85 and an '86. I set about building one good one from the bunch. I ended up using the '85 frame and swingarm with the '86 motor and Forks/trees with a bunch of other stuff mixed in. I only used the '85 frame because it was in much better shape than the '86. Now I swear at some point, I had both stripped frames together, side by side comparing them and their almost negligable little differences when I was trying to decide on which frame to use. I went over every little detail and I don't remember the head angle being any different - I usually notice little things like this. Darius, you just keep on posting those pictures of that beautiful Z project, no-one on here is going to complain about that - just take some different ones from time to time.

[Darius1502]

Now that is an awesome Z project...I just love that color combination...awesome job!

[Darius1502]

Here's my Z:


https://www.youtube.com/watch?v=afooV4IerlQ