the xt225 forum solved the problem by using a TM33mm mikuni pumper....but the guy who sells them (or used to) highly modifies them, he cuts his own needles on a lathe and the cable mounts are custom cnc'd... factory TM's are way off for out little motors...
Other than that, Sebastian sells some alternative carbs in Europe at twparts dot com,...but I doubt they are dialed in specific
This will prolly start a pizzin contest, but here goes:
A TW200 displaces 196cc's. (roughly 12 cubic inches.
Let's say it operated at 100% volumetric efficiency (yeah, right). It's MAX air requirement would be 31 [email protected] 9,000 rpm. In the real world a stock TW prolly only needs about 25cfm.
A 33mm flatside flows about 100cfm, or 4 times the flow required for a stock TW, and 3 times the flow required for a theoretical "balls out" TW. The flatside also has some behavioral quirks which only make it suitable in certain situations.
It's way more complicated than this, and there's a case for a pumper carb, but few of us will ever be in that situation.
Just trying to save folks some heartache and cash. The little TK is capable of handling 99% of most folks' efforts to improve horsepower, which generally consist of aftermarket exhausts, airbox mods and rejetting to compensate.
Any 33mm carb will be bigger than necessary for a stock or nearly so 200cc TW engine. A 33 on a 350 tuned for torque seems about right.
... A 30mm pumper would probably be even better though.
I said a 33mm carb is bigger than necessary for a TW200. I didn't say it was too big.Lots of room behind a stock carb to modify a TW engine. A 33mm would simply allow more tweeking. I wonder what effect a 33mm would have on fuel efficiency?
General motors used 730cfm Quadrajets on engines as small as 283 cubic inches. Same carb used on 454s. Way more carb than all but the hairiest 283s could use. Worked good, though, because the design had a wider effective flow rate than virtually anything else on the market. No way you could run a Holley anywhere close to that flow rate on a 283 and have any low-speed throttle response.
Is there a 30mm pumper? That would be ideal for a moderately tweeked TW.
oh yeah...if the TK is a good and worthwhile swap then will ANY TK work or just certain years? i though they were all the same but i'm not very well versed on this issue so i'm looking to you guys for clarification. thanks again.