I have a Bill Blue pumper and I have to agree with the above, throttle response on the road can be jerky at low speeds, then again, when you want it, the response is certainly improved over the CVK.

Oh and no more starting issues, whoo hooo.

-Justin

 

Sounds like the squirt timing wasn't adjusted to suit the faster rate throttle. Probably best to have the stock rate throttle unless you're mxing with it though.

I don't get the rationale about sometimes not being able to keep-up with your riding buddies though. There's a lot more variables than the carb when you talk about that. The whole issue (IMHO) is whether or not the increased response suits your style. I'll never go back to the CVK, but everyone's different.

I've had one or two buds over here that went back to the CVK once they started riding on pavement because they felt the pumper was too sensitive, so I can definitely understand that part of it.

I just like the instant power and ability to loft the wheel much easier with throttle only.

 

RaceGass - I'll try to take a photo of my cable mount. It doesn't have that problem. The mount is held on a bracket with two rivets, that is then held to the carb body with two hex head bolts. The way it came, it was not a good fit, so I ground the two rivets out so I could place it better on the bracket which had several pre-drilled holes already.

 

I'm running a rejetted 36mm mikuni on my bigbore.

 

I hate to even suggest this, but aside from a few outliers it seems the common theme in these "pumper or not" threads is that folks that have the FCR35 or some variation of it (tremor38) love it, and folks that have the Mikuni could take it or leave it. I never rode with the Mikuni so I can't say for sure.

 

Instant throttle responce can be had w/o a pumper carb. It's called a Vortex quick throttle. It is the last thing i did power wise and i can now lift the front tire in the woops. It would not do this before the Vortex. IMO the best $30 spent on the KLX.

As far as cold starting is concerned, the easyist method i have come up with is simply leaning the bike over at a 45 degree angle for an instant and it fires right up.


KLXelent

 

[QUOTE=D

I don't get the rationale about sometimes not being able to keep-up with your riding buddies though. There's a lot more variables than the carb when you talk about that. The whole issue (IMHO) is whether or not the increased response suits your style. I'll never go back to the CVK, but everyone's different.

QUOTE]

Go ride in the dirt and you'll understand.

 

kbekus - that would be great. Thanks again for your help.

The instant response is exactly what I was looking for. To get out of critical situations with a blip of the wrist. No more waiting for the power to build up.

 

[QUOTE=lcpl0331;367738]And is that why most off road only bikes and MX machines come with pumper carbs if they haven't already went to fuel injection?

You're still not making sense.

 

There is a fundamental difference between how the "pumper" carb works compared to a CV carb.
Putting aside the accelerator pump, the slide on a CV carb rises and falls proportional to the amount of vacuum created by the engine, where as the slide in a pumper carb rises and falls proportional to the amount of throttle applied.
Crack open the throttle on a CV carb and you will need to wait for the vacuum to build and the slide to rise.
Do the same on a direct slide carb and the slide opens "immediately".
The accelerator pump gives you a "snap" right from the throttle stop, but even without this, a non vacuum carb will pull harder all the way to peak power.
There's more to be gained than just response.
Yes it will be more responsive but it will pull harder right through the rev range.
The bike will have more acceleration.

All of this applies to road use as well.
Back in my youth we pulled the CV carbs off and put on direct slide carbs.
All 4 of them.

If you you want smooth and economical, keep the CV.
If you want response and acceleration, go for a pumper.

IMHO it was the mod that most made me choose to keep the KLX.
The bike now accelerates out of corners better, and it also track up hills better.
We have all been in situation where a steep hill is killing the revs.
Once this happens on CV carb, you also kill fuel delivery and it can quickly spiral downwards. Frantic clutch and down shifts are your only way out.
But with a direct slide carb the fuel delivery is less affected and therefore it's easier to recover. Just hold a steady throttle.

As tremour says, the "serious" dirt bikes use them for a reason.
In line with what Nobrakes said, I think the FCR is better carb than the Mikuni.

I went with the Mikuni as I had a good feeling dealing with Bill Blue.
Even from here in Aus, Bill was onto it.
No other reason.
If I had been able to communicate with Jerry of FSW in the same time zone, I may have chosen the FCR.