Little less then a week ago I tried to fix a poogs syndrome, I removed the tank and checked the pet cock reassembled it and noticed a piece of the front carb wasn't plugged what I thought was not deep enough in the engine block, I removed one of the air intakes and put the carb in deeper. After taking it for a test spin I noticed it backfired like crazy around 5k rpm its so bad that the bike shocks with shots of power/no power when it does that (its mostly around 5k rpm) to fix this I just switched back to 4th gear and let it sit at 6k+ rpm until today where it did it even when driving slowly, the shocking is so bad you can't drive nicely when I pulled over I noticed the idle made jumps from 1k to 3k to below 500rpm for a while almost as if there isn't a good combusting. Shortly after it hit 0rpm and the engine shut down. Luckily I was at work and waited till I was done to see if it still had the problem. It didn't for about 5-10 min when I went off the highway to check it out, same problem. I waited a couple of minutes and drove home. Does any of you have any idea what this could be? Could it be clogged carb?
Edit: sorry for the crappy writing. I did this on my mobile phone
I had the boot come loose from what I guess was the constant vibration. Idle went crazy while I was sitting at a stop light. I was holding in the clutch and it jumped to 3.5k. I’d be lying if I said it didn’t scare me. I managed to reseat it without shutting the bike.
Try some water in a spray bottle, warm the engine fully and spray the boots while listening for changes in how it's running, and steam at the exhaust tips.
By shock I mean when driving you get a switch between power/no power about 10 times a second resulting in shocking acceleration/no acceleration, acceleration etc
I took it to mean a sudden burst of power, which points to dirty carb jets (but could easily be ignition), but the high rpm moments point to an air leak.
Should also check the vacuum line at the left carb, it should be dry at all times.
I noticed the vacuum line was sitting against the engine so it was melting. I think it's not melted all the way through though. I'll disassemble it to see. If not then that should not be the problem right
If it won't idle without throttle, crank the idle setting way up. Then spray it.
At this point I'm not sure if the high rev is caused by an air leak, or you're giving it throttle to make it idle, in turn hitting the main jet on the carb with the clogged pilot.
Classic clogged pilot goes like this - Won't idle, unless you crank the idle up. Low power on takeoff (one cyl. running), then it explodes with power as soon as the main jet kicks in, around 2500-3200 rpm.
Even with the idle cranked up, it will still explode with power when the main kicks in.
I wasn't giving throttle in the video to keep the idle going, if the video was a bit longer you would see it idling smoothly at 1k rpm, only after longer rides 20min+ whenever I stop at a stoplight what you see in the video also happens on low idle. But as soon as it cools down a bit (like in the video where it sat for 10min) it only does it at high revs. With a cooled engine it doesn't give a problem at all
I will try the sprayed bottle tomorrow, it's getting late here. What exactly should I look for?, a change in sound? And white smoke from the exhaust as water vapor? Also do I spray water on a boot as if the bike was fully assembled?
Edit: the video should be up again. Not sure if u have seen it already. I deleted it once and reuploaded it for better quality.
Not sure what's going on in the video. Ignition, ..maybe? Ignition parts do sometimes break down with heat, but still work when cold.
Could still be an air leak.
With the water spray, look for the idle to stumble, and steam out the back if you keep spraying. Do it with everything in place, spray around the clamps and boots on the engine side of the carbs.
Would letting someone adjust my carbs fix this? I replaced my airbox once which had a L turn for the air intake it also sputtered at high rpms. But once I switched back to my normal one it was fixed
The only adjustment I can think of that might help ... Carb synch. But I think it would also have to be a sticking slide along with one butterfly being open too far.
You can visually check the butterflies to see if they are set the same, and opening at the same time. Then also a lift test on the slides to check their action. Might need to be fully warmed up to see if one slide is sticking.
In the video... Does the rpm increase by itself? Or do you raise the rpm to the point where it begins surging?
Is there any kit for the vacuum valve?
I'll tear open my carb tomorrow or the day after to see if it's the valve. Just saw those things cost 100+ each and don't have the money for em
Do them one at a time, the needles are different sizes front/rear.
Should be able to get to them on the engine.
When you take the top off, try to see if the rubber is seated correctly all around, and there's a tab that lines up.
Pull the diaphragm, slide, and needle out together.
Gently flex the rubber in front of bright light to check for holes/cracks.
There are pairs of diaphragms on ebay at $50us per pair, but they come without slides. Some people say they're impossible to transfer the slides to, but there are websites that show how to do it. Haven't done it on this carb myself.
Edit: ''Should be able to get to them on the engine.'' Do you mean i can take them out with the carbs still stuck on the engine? I checked to be sure but it looks like its almost impossible to without taking the carbs out.
When you pull that out of the carb, there's also a long needle sticking through the slide. (don't mix the needles up)
There are Harley CVK40 slide/diap. at $20 each, but not sure if they fit.
Also, there's a lift test on the diaphragms. You lift the slide and let it drop. The slide should have resistance when dropping, and you should hear air wooshing from the diaph.
I opened my carb and saw gas in this piece its part of the rear carb. Is this suppose to be a vacuum? Or should gas be in here? The front one was dry and never seen gas in there.
Will airleaks for this problem only occur inside the carb upto the connection with the engine? If that's the case I might further inspect the carbs to see if I missed anything now that their out
Edit: I did found out that the rubber seal in the petcock has had its time, it continuesly let's out gas. Could this be the problem? With the seal I mean the one that let's through gas if a vacuum pulls on it (the middle tube from the petcock) , that one now let's through gasoline even without a vacuum(the seal)
It's not leaking the seal is just in a state of always vacuum if u know what I mean.
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