30mm carb

[mb1134]

Looking for some input from the guys running 30mm pumper carbs with the riser and 30mm intake manifold. What kind of jetting are you running and what elevation are you at? I hooked mine up yesterday with a 42 pilot and 145 main. Rpms seem to be hanging when you let off the throttle. Adjusted the pilot screw out around 2 turns. If I try WOT it just seems to bog down. I got tired of the vacuum leaks and cracked manifolds, so I figured I would give this a try.

[mb1134]

No input?

[wildbob]

I had problems with mine, bogging, stalling, jetting and re-jetting. I found that the rubber connector from the intake to the carb had torn. When the buggy was still it kept together and didn't leak, but once i started moving it would flop all over. I cut a length of 1-1/4 radiator hose, loosend it up in boiling water and slipped it on the carb and intake. I think I'm running similar jetting at sea level, here in MA. It seems to rip...

[mb1134]

I don't believe the connector is bad. I believe I may be running too rich as Tom stated when I talked to him yesterday. I could see you running similar jets as you have the 4-valve head if I am running rich on the worked over big 2-valve. I would guess the 4-valve needs more gas then the 2-valve would? How do you like the 4-valve and where did you pick it up? I was thinking about getting one of those a while back but never did. I am currently waiting on my worked over Hammerhead 250 to come in from Tom at SYC. Hopefully this new buggy will settle my cravings for more power and I won't buy the 4-valve.

[wildbob]

Yeah, not sure when or how the connector ripped, as I had under 48 miles or so total on the buggy and less with the 30mm setup. I did notice that it still bogs a little in neutral, but under load seems to rip like crazy. I'm putting my problems down to that leak. I COULD NOT GET IT TO JET RIGHT. The crazy thing about the tear in the connector is that you couldn't see it from looking at it. spraying carb cleaner didn't get through, nothing. I was twisting the carb to get at the bowl and hadn't loosened the clamp enough and bingo there it was! Since I've eliminated the leaks she's running like a champ. I love the 4-valve and if you can find a source for the valve cover bolts I'll give you a brand new 4 valve head for FREE just missing one cover bolt. I got frustrated looking for them and just bought another head. Lemme know.. The head is a ruima, but also sold as Hoca.. I got it from provoscooter, but seeing as they took 6 months to get me the "included" long cylinder studs, I'd look elsewhere.

[mb1134]

Well an update on the tuning. Swapping the main jet down to a smaller jet made the WOT run better but the idle is bouncing around to about 2k rpm then settling dow to 7-800 then back up and holding anywhere from 1.2k to 2k. I tried a bigger pilot up to 45 for the hell of it. Having a hard time getting the buggy to start now that i went back to the electric choke from the manual one i was using. What color are the wires going to your electric choke Wildbob? I have 2 open plugs on mi e to choose from. Both have a green and a black wire i believe. One however goes down to a resistor that is bolted under the wire box. Any thoughts fellas? Will the manual choke off the 24mm carb work on the 30mm?

[wildbob]

couldn't put the pic in the pm but here's the kit

[wildbob]

I'll have to check the wires on my choke. but my idle went crazy too. rev waaay high then drop down. ordered a new choke, but never put it in. I went crazy checking for leaks until i had that torn connector starring me in the face..

[mb1134]

Looks good. I would have thought the head studs were longer?

[wildbob]

Ha! Thanks for reminding me.. I have the wrong studs in the box. Gotta open it back up and swap 'em out. I'm dropping it in the mail tomorrow.

[x-bird]

surging idle-- check your float level. may be too high. or vacuum leak.

[wildbob]

Yup, another thing I did was ditch the vacuum operated fuel petcock, installed a gravity feed and capped the the vac nipple on the intake.. I had all of the same symptoms until I found that leak..

[mb1134]

I checked and the rubber connector is perfectly fine. No issues whatsoever. I may have to look into the gravity feed. Funny thing is I swapped my 26mm carb back on and it idled fine.

[mb1134]

Ok so I put the 26mm carb back on and rejetted it to 42 pilot and 142 main. The engine idles and starts fine, but on WOT it starts cutting out and kicking back in. Doesn't sound as if it is backfiring. If I jump up to the 144 or 145 main it seems like the cutting out gets worse. What are your thoughts? Maybe running too rich?