big bore and new carb
 

Does Bill's new carb make that hard start go away... assuming its not the valves

If the problem is in the stock carb: yes.

I would almost guarantee the assumption that Bill's modded carb would remove the hard starting issue caused by the small starter jet in the OEM carb. That modded carb is a nice piece of work, and it will work great. But if you're thinking of going to it mainly because of the hard cold start issue with the OEM carb, why not just drill the starter jet? It's simple, cheap, and it works. If you have other starting issues, I'd suggest you get a handle on it before adding a new and different carb to the mix of issues you'd be trying to diagnose. Bill's carb is a great piece, and if you go for it, go for the right reasons.

Better power delivery, instantaneous throttle response. Starting isn't a problem.

A thread on TT has a fcr37 off a Yamaha yfz250 working on a klx300, probably work just as well on a big bore 330 or bigger. Checked eBay seen them for $160. I paid a lot more for a fcr35.

Guys thanks for the response. The reason why I would want to upgrade the carb is when I order the big bore kit.

I did drill that started just to .018', believe the bike starts but I roll on the throttle three times, then pull out the choke slow and she starts to fire... it takes several turns but it does fire up. I was thinking about getting the primer bulb for a quick fix until I get the new carb and big bore from bill.

Also sometimes when the motors warm it has an issue firing up until I choke it..... sounds like being to lean too me....?

KLXH, if you've drilled the starter jet, and you still have starting issues, I think you have something else going on that you're going to have to diagnose. It does sound somewhat like a lean condition if you have to use the choke even when warm...or maybe something like a low fuel level or such. IMO the starter bulb is unnecessary with a drilled starter jet. Try to figure out why it's happening. I can't keep up with everyone's jetting or overall setup here, so what's you're current setup?...jetting, pipe, totally stock, etc.

TNC - i did the 1st stage Dyno kit for full exhaust. I've also got the lid of the air box off, i have the fuel screw out 2.5 turns....i also took off the emissions crap. When I didnt drill the starter jet.... the condition was extremely worse.....

My first step would be to check the fuel level in the carb. If this is too low, you'll never be able to get rid of the problem by other means. Secondly I wonder if you have a partially plugged pilot jet. I got a partially plugged pilot toward the end of last fall. It would run but was harder to start, and it wasn't smooth during small throttle openings. I had to pull the jet, and I could see light through it, but it wasn't totally clear. This was a really subtle but aggravating condition.

On other thing, are your valves set properly? I'm sure you've read how tight valves can cause this too. One other issue, when you open the throttle with the choke on, you're actually diminishing the effectivness of the choke. Opening the throttle lowers vacuum and pulls less fuel up from the bowl. There's no accelerator pump on the OEM carb. Now, when the engine is hot, cracking the throttle can help, only because the engine needs a lower fuel to air ratio to start...similar to what a "hot start" button does on some bikes.

TNC to check the fuel level would I measure the height of the float..? i can clean it out with some carb cleaner... bike only has 250 miles on it and i always keep fresh gas and stablizer in it... tank full.

thanks for the explaination on the carb.. makes sense.

Check fuel level with a clear tube as shown below. Better than just float height in a dry carb. Level should be even with the top of the float bowl. The one shown below appears to be just a little above the float bowl.

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