So over the winter im ordering a 351 kit from bill but im on the fence if i should get the pumper carb with it or wait to see how i like it on the stock carb. Any input both ways?

 

Pumper carb is a great mod but I'm glad I put it on after the 351. I felt better about spending the $$ after seeing what that one mod alone does.

 

I put in the 351 this spring and kept the stock carb but re-jetted it. Runs really strong but I don't know how it compares to a pumper.

 

I agree with IDRIDR. I'm a firm believer in the pumper carb...especially the TM36-68...but I think it's wise to tackle one big step at a time. The OEM carb requires minor tweaking to get in synch with the 351 kit. Get it broken in and ride it at least a little bit and get the feel for the larger displacement results. Then go for the pumper carb.

 

The pumper will change the bike, it depends what you want. It will make it more snappy and not as nice to ride around slowly or around town. If you don't do those things and you want snap, crackle and pop then got for it.

 

Guess ill just do the big bore first, sounds like the carb isn't for me

 

Since we are talking carbs, has anyone rode a new FI 250.
Do you think it has more snap on throttle than the CV model? It probably is tuned way lean, maybe that would help the snap.

For DS the CV is probably ok, for ST, not so much.

 

Not my experience at all...guess it depends on how you set it up....

 

Yeah, not mine either. I haven't found one booger on my experience with my TM36-68. I thought it might be too much carb for my 292cc KLX300 jug...it wasn't. I thought it might really hurt my fuel mileage...it didn't. I thought it might be a challenge to fit to the bike...it wasn't. I thought it might be difficult to get the jetting dialed in...it wasn't. I thought it might hurt my low end torque...it didn't.

My biggest issue was the fact that I had an Acerbis tank and had to cut the top half of the throttle for clearance...turned out to be quite easy. Otherwise it's been a total pleasure with this carb.

durielk, I have ridden a couple of WR250R's and the new Honda XL250...both FI. I was really disappointed with the Honda. It felt flat just about anywhere in the powerband. That may not have been the FI's fault. It may just be the overall setup of the whole bike. Not sure. I think my 1974 Kawasaki F7-175 2-stroke felt more powerful.

Now, on the two WR250R's, they both had the "full fix" of a programmer, pipe, airbox mod, and a couple of other things...no big bore. They screamed from mid-range on up to WOT. I know from other WR owners that this is fairly normal. While the WR is not flat or anemic at low rpm, the engine is really designed to haul at mid-range to high rpm. I'd like to see a dyno chart comparison of my KLX300 with all its mods...pipe, 36mm pumper carb, airbox mods, etc...to those two WR's I rode. I really think mine has more low end power, especially tractable power in loose conditions and for climbing. But from about 8000 rpm on, those WR's flat out haul. I know both of the guys who own those bikes. One of them had his bike geared for a short period where it would run an honest 90 mph by GPS...and get there fast.

 

I still run the CVK carb on my 351 with the exact same jets and needle settings as I did before the 351. No carb changes whatsoever. Runs great with slightly lower fuel economy but a lot more power. My last fill-up got me 63mpg. Was getting 70+ on the stock bore. Thinking about pulling some dyno runs just to see where my fuel:air ratio sits and experiment from there. I don't get easy throttle only wheelies but since I got used to clutch ups on the stock bore this is a non issue. I do not intend to get a pumper carb.