Tri z 250 upgrades

[honda3]

I just recently got this tri z for $400. It supposably needs a rod bearing and bored 20 over. While it is all disassembled I figured now would be the time to put some go fast goodies in it. I am looking for opinions on what some of the best things would be. I am open to hearing anything. Things such as extended axles and swingarms interest me if you have any aftermarket parts for sale pm me please. I am also curious on what the coolhead does. I will be doing some port and polishing. I plan to add the second boost port also. Also interested in larger carbs and what not. Any ideas appreciated. I plan to make it fast.

[Tri-Z 250]

Search for what parts interchange here on 3ww first. A banshee +2" is a good up grade. CST is for now the only close race tire you'll find in 23" front, doesn't mean you can't run a 25" for trails. Porting the 2nd window opens the top end and some say it can cause cracking from eventual fatigue. TT, drag, or oval may call for such mod but if it's for trail/fun or MX leave it a single side port to keep the bottom of the power range. You don't want a light switch power band in the woods. Pin the impeller the mod is here too. DG pipes are a basic up grade but you can get better with more money. Good luck

[Keepah Rolln]

What part of Maine?

[honda3]

Fort kent maine

[honda3]

Ok so maybe just a mild trail port and polish and keep the second port closed? I want to make it fast. This is going to be put in the garage and when my fiend thinks they have something fast I want to be able to pull it out of hiding and put a dent in their pride lol

[honda3]

i am also selling this unused cover for 30 plus shipping.

[honda3]

Anyone????

[this old rz]

I'm slowly making a list for a Tri z as well. As far as stock goes the mentioned "Yamaha wrench report" seems quite good. with the addition of newer carbs maybe PWK, and V force reeds the experience might be even better than it was back in the day,,it should be. Obviously a DG pipe will help a spec built custom pipe would be better but also a bit spendy $.
I've talked to KLEMM racing, He offers the 350cc big bore kit complete and installed for $1080 bucks..!!. IMO as far as performance goes..thats what Id do and plan too as soon as I'm ready. No replacement for displacement:. 100 ccs of xtra power!!!!!
I'm not up to date too much on a cool head for the Tri Z , but SPROCK racing seems to sell a billet head, if bought KLEMM could machine it to work good with his big bore kit between those two I think that's about as far as one can reasonably go at this point. FYI also a 1986 from what I have been told is substantially faster than a 1985, a lot of it has to do with the 86 having a 6 sp transmission, so 1st gear is a lot quicker out of the hole, then the 6th gear increases top speed I was told almost 15mph!!
Post anything you come across,as its help to other new owners & I'll do the same.

[honda3]

That is great info. Thanks

[El Camexican]

I’m not 100% sure, but I believe the 1st and last gear (be it 5th or 6th) are identical between the two years and that the added gear on the 1986 just tightened up the gaps a bit. As far as the 86 being faster at the top if it is it would likely be due to a larger carb. Again, I’m not 100% sure on this, but I believe the 85 came with a 34mm carb and that the 86 may have come with a 36mm.

Back to the original post, what exactly do you want to do with the trike? If it’s to be a dedicated racer then you want a YZ engine, or the 350cc kit, a reshaped combustion chamber, a 38mm carb and a custom made pipe. Lightening the stock stator would help too, but I have no idea if anyone does it.

If you just want to be a little faster than a stocker and to still be able to trail ride it don’t add the boost port (can cause a crack) just send it to a reputable porter like the aforementioned Mr. Sprock or a Jason Hall (on here) for a clean-up. Shave the head 0.020”, add a DG pipe and 36mm carb and a set of fiber reeds. The Cool Head looks sweet, but I keep hearing that you must use race fuel even with the pump gas chamber, so that’s a red light for me even though I may still yet convince myself that my 2mm higher exhaust port will lower compression enough to run it with pump gas. Again, Mr. Hall or Sprock should be able to guide you in this area.

Sadly you can’t trail ride the Worlds Fastest anything, so think about it and proceed accordingly.

[elvetost]

Hello!

I am also in the process of rebuilding my tri-z, new around here as well.

Could not agree more with El Camexican as far as the mods plan. Its what you wanna do with it that makes the plan..

My motor has been refreshed recently before I got it, so no plans to mod it soon, so I am trying to make sure that everything else works 100% while I eat the top end up.

I have read that there is a KX125 reed valve assembly (cant remember the year) so that is an alternative and will take a modern carb too, possibly a 38mm.

Anyways, will be following this build for sure. Good luck man!
Cheers,
Chris

[honda3]

I'm 15 and have 14 three wheelers now. Every once in a while I take then out of hiding and wash them then ride for bout 15 mins and put away till a few more months. I do not ride them on the trail. Be lucky if I ever put 20 hours on it, that's why I want it to be fast, so when I take it out I can beat my buddy's rides.

[badass350x]

yup Rise the exhaust port 2mm's,, extra boost port, window the piston, 38mm airstriker,,This is Halls work and it runs and runs waaayyy fast!

[El Camexican]

I'm 15 and have 14 three wheelers now.

You do realize these ones don't count

[honda3]

Haha come on now I'm down to 4. Haha I have a 86 200x, 85 tri-z, 85 250sx, 85 70, 85 zinger, 2 84 zingers, 2 84 70s, 83 alt 50, 83 200x, 83 tri moto 175, 82 200e, and a 80 185