New and need help with Tri-Z....

[Hooligans]

Let me start by saying this is my first 3 wheeler so bare with me. I just bought a 86 Tri-Z with a Banshee rear, shaved head, DG pipe, and a twist throttle conversion. My question..... this thing has not been started yet. How much compression should I feel when I try to start this? It doesnt feel like it takes much to start, compared to my 03 KX 250. I wondering if it needs a top end rebuild. I didnt get to work on it much due to getting home late but I was really curious about the compression. You can reach down with your hand and kick it over....

[Dustin87R]

Do you have a compression tester? If so run a test it should have around 160-180 psi.

[Hooligans]

I dont have a tester.... Im going to try to pick one up tomorrow. It just suprised me that I could do full compression with my hand....

[_brad_]

Definetly start with a compression test.

[Tri-ZNate]

Yeah sounds like either a rebuild is in order or a gasket got blown out because of the shaved head.

[Hooligans]

I appreciate all the help guys. Im going to do a compression test when I get home tonight. As for the shaved head, should I replace the head, or would a rebuild be fine?

[SYKO]

pm yamahondaman here on the boards and send him your head, hes the resident tri-z nutcase machinist, he did my head on my flat tracker 250r and I have never had a lic of problems from it.

[Mosh]

There are also Tri-z coolheads that were made.There are 2 left to sell.Interchangeable domes,for pump gas or race fuel and they use reuseable o-rings.No more 25 dollar head gaskets.Just another option for you.

[Hooligans]

Ok, just checked the compression...... ready for this..... 58PSI. So, now we know it needs a rebuild, I know there are a couple of options for the head, what is the recommended way to go. My plans for this is a straight dunes ATV. I'm not looking for stock power, Im going to be doing a full build on this.

[Hooligans]

Ok, heres what I got. I removed the head and found some pretty good damage. Something had dropped into the head and had a field day with the piston. In the pics, these are not shavings, these are dents and marks in the metal itself. Now, I was worried that there would be shavings in the bottom end so I drained the oil and found no shavings at all. Now there is no saying if there is damage or not. Where should I go from here?

http://i191.photobucket.com/albums/z186/dragginpan/3wheeler.jpg

http://i191.photobucket.com/albums/z186/dragginpan/head.jpg

http://i191.photobucket.com/albums/z186/dragginpan/head2.jpg

http://i191.photobucket.com/albums/z186/dragginpan/piston.jpg

http://i191.photobucket.com/albums/z186/dragginpan/piston2.jpg

[Yamahondaman]

HUMMMM .... how much was the Bike ? .. and like Mosh said ... the NEW ( Rare ) TRI-Z Cool Head's are NICE !! that looks like a Wiseco Piston .. what No's are on the Top .. they will tell you if it's .02-.08 Over and YES !!!!! ... that MESS is all in the Main Brg's... prolly the motor needs to be re-done

[Hooligans]

Ok, the piston is still a STD size piston. I paid $600.00 for the bike. I was told that it was a perfect runner. I was working all day yesterday so I sent my girl to get it and she didnt know what to look for. It sucks, but Im still happy that I have it.

Since we are talking a total motor redo now. Should I rebuild this motor, if so what are we looking at for a rough price? Or should I build another motor? This build probably wont get started for about a month but I would like to know where to start when its time.

[pickleweasel_00]

looking at the oil won't tell you much about the crankcase, it is seperate and sealed from the transmission:) being a two stroke, there won't (or shouldn't) be oil in the crankcase. And the cool heads are great! I have the 20cc dome on mine and running 110 torco and it gets with it!

[Eric250R]

Well, I wouldn't worry too much. Yes, that is fairly damaged, but if it was still running it's probably not all that bad. New head, new piston and rings, boring it is up to you. I probably would go just a step bigger to clean the cylinder up, but you may be able to get away with just honing it if the walls are not scratched up. No big deal really, just a good rebuild and let her rip. And Welcome to the club !!!!

[Mosh]

If you want to drag and or trail ride, this thing ,and do the motor right,,,Look into a Sprock Bigbore kit.For 6-700 bucks you can get a Sprock 310 bigbore kit for this baby with a coolhead.That includes Head, porting, piston kit, gaskets,and jug ready to go.You would just have to split the cases and rebuild the crank.That needs done anyway with all that damage, Like Yamahondaman and others said.
Oh yeah,,,They can be bored to a 330 cc motor.:naughty:

[NINJA]

from the looks of it the rings on that cashed piston haven't come apart which leads me to believe a.) they were there from a prior piston grenading, or b.) they rebuilt the top end after a piston went to hell and remaing pieces of ring were left in the crankcase to chew up the new piston and possibly crank and bearings. feel that crank, if it feels alright flush that crankcase out or split your cases if your paranoid like me. would be a shame to drop all those dead presidents on a sprock kit only to munch it up 5 minutes after assembly!

[Hooligans]

Ok, the bottom end is gone. Bearings are bad, crank is bad, so now that I'm in the bottom end, lets assume Im going with the 310 kit up top. What should I have done to the bottom end?

[NINJA]

Ok, the bottom end is gone. Bearings are bad, crank is bad, so now that I'm in the bottom end, lets assume Im going with the 310 kit up top. What should I have done to the bottom end?

you kinda lost me there dude, what exactly are you asking? and are you serious? is the bottom end really gone or is that sarcasm? cause i can't really tell by the tone of your voice.
if you're serious, you're gonna need a conrod kit and new mains and seals

[Mosh]

Ok, the bottom end is gone. Bearings are bad, crank is bad, so now that I'm in the bottom end, lets assume Im going with the 310 kit up top. What should I have done to the bottom end?Send A private message to (TRITecate350) a.k.a Sprock on here.He can set you up with the whole deal.Rebuilt crank,bearings new Rod the 310 top end, gaskets and seals.
There are other members on here too,Like Yamahondaman,SBLT500r,that do Tri-z engine work also,But sprock is the Bigbore guy and has easy access to the bottom end parts as well.

[Bryan Raffa]

grab right ahold of the rod,,,, if there is any up and down movement you need the crank rebuilt.. also grab ahold of the flywheel ...move it up and down if you feel any movement there you need main bearings..

[Hooligans]

grab right ahold of the rod,,,, if there is any up and down movement you need the crank rebuilt.. also grab ahold of the flywheel ...move it up and down if you feel any movement there you need main bearings..


If you grab the connecting rod and cycle it through you can hear a bad grinding noise in the lower end like the bearings are shot. The rod also has bad slop up and down. If you cycle the rod a few times through it starts to pull good size metal shaving out.

I appreciate all the help with this guys. I will keep everyone updated on this build.

[Bryan Raffa]

yes replace both,with seals.. if anything is in question in the bottom end replace it.. then you know you got a rock solid bottom end..good luck..I got two motors going together and I will do a step by step picture thred on how to do it..

[Hooligans]

I appreciate it Bryan. I PMed Sprock for a 310 kit and and full rebuild for the bottom end. I agree, if I just replace everything then I know I have a solid motor.

[Hooligans]

Ok guys.... I need some more help.

I cleaned up the bottom end to find a cracked case. All in all, pretty much the entire engine is trash.

So do I......?

1. Buy some used cases and start from scratch
2. Buy a complete YZ 250 motor and go that route.... if so what year motor is desired
3. YZ 490's are a dime a dozen around here and drop one of those in. I have heard that those motors have they're downfalls also.

[LonesomeTriZ]

Everything has pros and cons. There is never one perfect answer to anything. This rule is especially true when you modify something. Figure out the kind of riding you plan to do, the amount of upkeep you are prepared for, and what kind of budget you have to work with. Then you can make a rational decision.

[Hooligans]

Well, as for riding - strictly dunes. Not straight drag race but lots of dunes. My budget is always limited but at the same time Im not planning on this being done until next spring, so I have some time. Upkeep is not an issue either, I have plenty of time for that.

Here's what I was looking at. If I buy some cases and build a Z motor I was going to run a 310 kit. Im not sure as to what mods I would run on a YZ motor, I have heard there is a noticable difference in power allready. The 490 is just easy for me to find but I hear tuning is a bear and being air cooled is always a concern.

[Tri-ZNate]

I would run on a YZ motor, I have heard there is a noticeable difference in power allready.

Yep its a power valved Engine. I forget how much more horse it has Stock for Stock, probably around 8 more if I remember right

[LonesomeTriZ]

I have yet to ride in the dunes, so I have no advice on that. But I will reiterate what I said before. Decide what best fits your life style and go with it.