Hello. My youngest son (8yr) has leukemia and ended up finding a deal on a 50cc and 90cc kazuma quads. At first I thought the 50 would be better but he actually fits on the 90 well. I was able to do some work on them and the 90 working good. Now as far as the 50 goes I can't seem to get that running. Got compression, got spark and got fuel. The thing just does not want to start. Sometimes it runs for a few seconds but it is rare. Even with starting fluid it should at least try and run for a few seconds but won't. Randomly ever so offer it will run for a few seconds and quit. Anybody have any suggestions to try?

Thanks
Jesse

 

sounds like a fuel delivery issue. now what was the compression gauge reading when you tested it? <90 psig? go ahead and clean the carb, remove the jets and clean them. also clean the needle valve/seat assembly area. clean or replace the air filter. let's start there. don't just spray cleaner in the carb, it ain't hard to disassemble the the carb. here's a quick video to help you. your carb probably ain't the same, but the principle is the same.

here's a kazuma link also for your records.

http://www.kidatvs.com/RedCat/kmx50_manual2.pdf

then maybe adjust the valves.

 

Thanks for the reply. The original guy that had the quad had the carb in pieces and messed it up. I tried one off an old dirt bike with the same results. But my biggest success was adjusting the valves. My original compression was 70 before valve adjustment. Did not check afterwards but if I did it right the valves were like a quarter inch off. Readjusted to .004. Now she starts everytime but runs at approx 3/4 throttle so it's really high and adjustment screws do nothing. It also has to be choked to run. When I looked up valve adjustment it said to line up the two straight lines. I seen the two lines but that was not tdc. It had another line with a "T" and another line with an"F" if I remember right. Think I'm getting close. Before it would only run a few seconds but usually wouldn't start 99% of the time. My valve adjustments I hope are right. Once I was at tdc on the the with the "T" I think I set the gap at .004 on both valves at the same time. If that is correct its a carb issue or one massive air leak which I don't see. I ordered a $20 carb off eBay and it should be here any day. Hoping its just the carb now. Does the valve adjustment sound right to you? Starts right up but extremely high idle and choked or it will die, no adjustments help. Thank much for the reply!
Jesse

 

that sounds right. now, the choke on is telling me that the carb is running with more fuel to it due to the fact that more air is ramming to it. sounds like a vacuum leak on the boot or flange or the O-Ring on the flange to at the carb to jug interface. high idle is probably cause it is sucking so much air and the choke is on sending more raw fuel to it. with the carb off, can you look inside and see if the slide is going up/down with the throttle cable? what's that needle set at on the notches for the slide? you can test for an intake boot vacuum leak 1 of 2 ways, get it running and spray ether/starting fluid around the area and if it revs up, it is sucking it inside in that area OR you can get it running and coat the area with a foam shaving cream which will "choke" the area off from sucking air and it should idle down until it sucks the lather into it. but sounds like a new carb will do the trick if the previous owner lost internal carb parts.

 

Got the new carb on and all is great now! Biggest issue was the valve clearance to start when it wouldn't run and the new carb allowed the quad carb to actually be adjusted. Sounds and runs good for now. Thanks for all the help!

Jesse

 

good deal. sorry we couldn't resurrect that old carb. sometimes it is better to replace it especially if it turns out to be a basket case.

 

Sure is and $19.95 shipped I think is a good deal. Love cheap parts!