125-200cc Uptite 167

Walt
I know time is money but when you do the 144 test if you get time to whip off the PWK and compare it to the Mikuni it would be interesting to see a comparison .
As we have said before Id expect a little more top end from the Mikuni . Less mid range.
Dont really know as Ive never seen comparion on a 125/144

I am using the Mikuni for these tests. I would say that the pwk gives a little more on the bottom and the Mikuni has a little more on top. With the rm needle the mikuni is working very well for me. I am also using the fmf Fatty for all these tests. OBTW, I called fmf last Friday and they said they are still not able to supply the 150 pipe. They told me mid-January....maybe. I have re-mounted the 144 and made some road loops. Just leaves me wanting more on the bottom/mid compared to the 167. My 144 runs very good on the bottom/mid now compared to before I installed the CR ignition but still just isn't the same. Top end is a whole different story.

Has anyone tried a 35mm PWK ? I believe that most of these small bore bikes are way over carbed.

I'd say give it a shot and see what happens. One small carb for man, one giant leap for mods!

Most reed valved 175cc - 200cc bikes used 33, 34, and a few used 35mm carbs. Husky for some reason has tended for years to use 38mm carbs on 125cc bikes. I think it was a cost thing. They got a better price from Mikuni by ordering only 38mm carbs.

Would the 150 pipe work better for the 167 ? I'm assuming so ....

Kevin,

I imagine that it will. I don't think you are going to find a pipe that is perfect for the 167. The 150 pipe will be tuned to also increase HP at the top and the 167 is pretty much done where the 150 is making its peak hp. I wish I was a better sheet metal guy and I could build my own.

I think this 167 is going to be alot like the old IT175's vs Yz125's Yamaha's. The 125's revved to the moon but the IT's made a great luggable, smooth Harescramble bike. Am I right or wrong?

http://www.buildandclick.com/index.html

I'm tempted......

In 83 the cr 125 had Mikuni 38 went to 36 in 84 and back to 38 again
Riding a cr 125 with no issues with bog or hesitation or lag etc and heaps more grunt illustrated to to me that there is no issue with the size of the carb - more the ignition , flywheel side of things
Kelly has tried the 36mm PWK carb and didnt se any noticeable gains
that compensate for loss of top end

Darin,

I think the 167 falls inbetween those two. It still revs pretty well but definitely has a much more rideable low end/mid-range.

Mike,

There is free software that does the same thing.

http://vincentcrabtree.co.uk/ExpansionChamberDesigner.aspx

According to the above software the 167 really needs a larger/longer head pipe and larger longer stinger. Of course all the dimensions actually need to change some.

Thanks Wally! I love to play...

That's all right! There's always something out there for something! Might be fun to sit down some day with a pile of steel funnels, tin snips/box of bandaids, mig welder and plenty of water so you don't warp everything.

My goal some winter, is to build a life size gunslinger out of sheet metal like the ones I saw in Santa Fe, NM.

I still think this 167 is the ticket!

I remember a neighbor combining a PE175 top with a RM125 bottom. It was a good combo.

Slight OT, but in Australia there is a big untapped market for a good two stroke which suits the weekend warrior. At 250 is too powerful for most riders. 200 were not too popular...too wild.

It's all yours Husky.

I dont know if 200s were too wild ITs and KDX 200 werent -good linear power
KTM later on a little peaky maybe
KDX 200s were very popular around 1990 - won most enduros outright
Geoff Eldrgige - ADB favourite . Seeing some guys buying old ones . Thinking about it myself - good single track maker

Walt,

Did George open up your Transfer and Exhaust ports to compensate for the bigger bore? Is the 167 piston one ringy dingy or two?

Darin,

No porting work is done other than clean-up and chamfering. I am sure you could do some enlarging but I like the bottom/mid performance of the motor. The piston is a single ring but the ring is quite a bit larger than the 125/144 rings.

Walt,
I just happened to think of that. Lets say those ports are cut @ 15 degrees, so the bigger the bore the smaller your transfer and exhaust ports would be? So what would happen if you opened those ports back up to original size? Also, you have to send a stock head, correct? The EG, cut one won't work?

Darin,

I tried the EG head on mine just for giggles and while it does work it definitely doesn't run as well as using the stock head. The squish is set well for the stock head. The EG head lowers the compression by about 40 lbs too.

The only port that actually shrinks is the rear transfer. The rest have the same cross section. There is some room to open them up but I am not willing to mess with a good thing at this point. I just don't spend very much time on the very top where the extra breathing will really make a difference.