Planet Minis

mo' tarded

This is a road race bike by the way....

Currently I'm running a ported TB race head (28/23), Tak K10 cam, 138 Tak cyl and +r piston with a 55mm stroker. For argumant sake, the intake is BBR swivel ported/matched to the head & carb with a pwk28. Pipe is the old two bros.

I'm curious if anyone knows how that would stack up against changing to:

The TB 143 V2 head & cyl, same intake and pipe, but with a custom 53mm crank to stay at 150cc.

Or staying with the 59mm bore/ 55mm stroke and just changing to the V2 head.

Something else? Just looking for every advantage I can get and still stay class legal.

Pros/cons... anybody have knowledge and not just opinion?

mo' tarded

Anybody?

I know it's technical and all.....

coletrain01

i think the new tb143 kit with a stroker would be good for you. i run the old style 143 with proted racehead and intake with 55mm stroker. fast and pulls hard around the corners

slide1in

new v2 w/motohp 150 kit.

Mxrider346

138 stroker + R One of the best to run in limited 150 class

357 Racing

Just get a V2 and maybe port it.

aedwards07

If you want the absolute best setup around go with the Kitaco 143 4V setup with the custom 52mm crank.Or you if you want a screamer go with a 165 scut setup with a +R head and then make a custom shorter crank.

slowracer

moto hp 150 kit
138 with a 55 stroker
you need either a +R or a V2 head for either setup

benjaidafufukil

Didn t he say 150cc limitation?

benjaidafufukil

I have a 138+R and a 55mm stroke + VM26 (Takegawa and Kitaco intake). I was wondering if I should stay with this setup and get the head ported or go to a 143 4 valve.

You seem to recommend my setup.. any reason? Will the porting of my +R really improve something? Will I need to get a bigger carb and intake?

Thx,

Ben

firepower354

Bigger bore, shorter stroke, more breathing, more gears thatz closer together.

slowracer

I thought I read that you had a old tb head not a +r.

you cant go wrong with the 4 valve.
I would rather have a bigger bore with a shorter crank

MX355

I have the MotoHP 150 V2 its rips forsure consider it.

w650gb500

138+R, ported head, S-35 cam, 55mm crank, big bore exhaust, VM-26 or PWK-28, close ratio 4-speed, inner rotor kit and billet output shaft. I ran this set-up on my roadrace/supermoto bike and it ripped! I've gone BIGGER now and I'm kinda disappointed at the performance compared to the old set-up.

Just my .02

Dan Lipperini Jr
Welcome to Racelabz, Your S2000 racing source - home of the fastest T3 S2000 Racecars

firepower354

Use the new 125-4V setup with a biger bore and custom J&E piston?

65.5 x 44.2 would be a sweet 149cc ripper.

mo' tarded

I'm glad to see this thread revived:

Bear with me... this is long winded.

It's descision time again. I have 2 races left this year. Since I started on the 4th race of the season, my chance at season final podium standing is out of the question.

Cash is tight right now, but I can pick up a +R head from a member. If I spend the cash now, I'll have to stick with the 138+r/55 stroke set-up for a while. Including next season when I'll be able to make every race.

Or I can wait till the offseason and pick up a 4 valve 143 set-up and destroke to a 53mm crank.

To complicate the matter more, several of the above responses mention closer ratio gearing. I looked at the CHP site and see two claims of note. First the 4v head claims to give 2500 more RPM to the powerband. And the close ratio trans has the following specs:
Stock transmission 4-speed: 1st-3.272, 2nd-1.937, 3rd-1.350, 4th-1.043
Takegawa 4-speed: 1st-2.623, 2nd-1.937, 3rd- 1.437, 4th- 1.300

Since I already run the 6disc clutch, and the smallest 39t sprocket I get on the KX65 hub, my gearing changes are limited to countersprocket changes. I can go up one from 15 to 16. Thats a change of .0625.

The close ratio 4sp reduces (shortens) the top end by 25% or so. But the 4v claim is I'll get that back with a higher reving engine (adds 2500rpm to the engine rev range). Plus, with the 4v making power in the higher revs, seems like a shorter geared bike would be a double advantage.

Money aside, it seems like the road race advantage would be a 4v head and the close ratio trans.

I'm running against 65 and 85cc two strokes. I can pull them now out of the corners and the first half of the long straights. But they pass me toward the end of the straights and I have to fight back through the twisties.

So finally the question !!!

Would the 4v close ratio set-up give me enough on the top-end without sacrificing the pull i have out of the corners?

slowracer

You can run the stock trans with the 4 valve and I dont think your torque is going to be very far off.
If you are going to de-stroke I would get the 160 4valve and de stroke it.

I would get a V2 head for the mean time to finish out the season.

Ditch the 65 hub and get something you can have more sprocket choices

sliding68

I had pretty much the same set up as you and.....the 143 4v roasted me down the straights.......If i had the cash id go to the 4v in a heart beat....now im curious to see what my 150+r is going to do next yr...(picked it all up pretty cheap).....