Hey guys, im new to the atv scene been at wheeling for yrs tho. I got this quad off a buddy, i took the carb apart and gave it a thorough cleaning as per the manual. Re assembled it and the thing rips and runs great anything over an idle. BUT i gotta have it idled up to not backfire like a bugger. Im not sure where to go with it.

I checked the cam chain tension and timing marks, everything looks good there. But at idle speed i get lots of bumps back to the carb the odd hard pop. It had been sitting for years. Like 8 yrs lol.

Im tempted to drop 60 bucks on one of these zoom carbs to see if that helps. I did my best to clean the stuff out in there. I have the bottom screw set at two turns out, but what does the screw on the bottom/side of the bowl adjust, it ties into that tiny jet in the fuel bowl.

Any thoughts guys

 

Don't buy one of those cheap knock off carbs as they can cause more problems than what you have now.Some have the wrong jets,trash in the carbs from the factory. Get a good Shindy Japanese carb rebuild kit and retrace your steps on the carb and make sure all passage ways are clear.MOTO-4 BIG BEAR 350 4WD KODIAK 400 4WD SHINDY K&L CARBURETOR REBUILD KIT 18-4179 | eBay The screw at the bottom of the carb is the fuel screw or pilot screw as some call it. Controls fuel mainly for the low speed jet. 2-2.5 turns out is a normal base setting on most carbs.As it warms up you can fine tune the fuel mixture by slowly adjusting the screw out until it begins to stumble and then back in 1/2 turn. You may then need to adjust the idle speed screw for a steady idle.Also good if you know the float height setting from the service manual.https://www.tradebit.com/filedetail....service-manual You may have other problems but at least you can eliminate the carb off the list.

 

Thanks for the reply. I ordered that rebuild kit and ill avoid the cheapo carb. Do you know which way sets what on that bottom main screw? I turned it out 1/2 turn and it was worse, went back to two turns out. Same deal, screwed it in 1/2 turn amd the back firing minimized dramatically. On my holleys anything in goes leaner. Same on these?

 

Turning the screw in leans the mixture,out richens it up. Wait until you get the new carb kit. As the carb is now running crappy trying to start at a base of 2 turns may be too much/too little fuel to begin with. New parts include a new fuel screw,o-ring and washer along with the needle and seat,jet needle,etc.This should make a big difference when you adjust the fuel screw along with thoroughly cleaning and blowing out all orifices before you install the new parts.

 

Well i got the rebuild kit in and she runs great. Thanks for the link and assistance!

 

Hey on topic of screws,i cant find any info for the screw on the side of the fuel bowl. What does it adjust?

 

Float bowl drain screw. Item#22. Glad that the Shindy carb kit fixed you up. A lot better to rebuild a better quality Japanese carb than to give up and buy a cheap Chinese one.