Posts
10
Joined
9/8/2018
Location
Clifton, NJ
US
So we rebuilt my friend and my own cause we split it in middle school, 91 RM125, man this thing needed a top end ?. So we have a Yamaha demo day today at Former Gotham Mt, and have a extra rider coming not for demo day but to ride who didn’t own a bike. So we got this one ready at beginning of week knowing he’s coming. Took the bike apart changed what needed to be changed, cleaned the carb, and all we do for Our own newer two smokes. Bike kicks and goes threw the gears and all. But the little fucker won’t hold a idle, it will ride but it’s a bitch to find that idle spot. My question is will this harm the bike and what would most likely be the problem? Like is the carb vacuuming itself? Or a air leak at the clamps? How would I diagnose these problems? Mostly can I ride the bike today? Would it harm the top end much? Literally need it for the day and that’s about it will disassemble again if I really have to.
Thank you and Ride Hard, have fun!!!
Thank you and Ride Hard, have fun!!!
I had a bike that wouldn't idle but ran great at 1/4 throttle on, it ended up being a stator going bad. Not enough juice at low rpms for the plug.
Good luck
Lastly ... i have to think it easily could be a crank seal after sitting that long.
Again best wishes for a fun day.
Might be electrical.
But I've found when a bike is put away, especially if the tank hasn't been drained, and the fuel in the carb hasn't been
cleared out by running it until dies, the gas left in there turns to a kinda gum at first. Then hardens to varnish.
Some of those passageways, especially the low idle ones, are real small. It's almost impossible to unclog them.
I mess with Vintage Honda 750s mostly now a days.
4 carbs per bike.
That all should be delivering the same amount of fuel at the same time, at all throttle positions.
Try getting that to happen when they have been sitting in a guy's garage, half full of gunk, for 30 years.
Look down the barrel of the carb, with the slide out. If there are any real small holes in the side, chances are idle passage is clogged.
Small guitar strings are good to try and pick that crap out, along with 100psi compressed air. Starting fluid is good for cutting that stuff. Some guys soak them for days in acetone to loosen the stuff up. I've heard of guys boiling them in a pot of water for a few hours to clear idle passages. And this one, you gotta be real careful, Tidy Boil toilet bowl cleaner, mixed with water, soak the carb in it for 10, 15 minutes. Too long and the carb will dissolve altogether.
Whatever, if there are small passages going from the inside of the slide|barrel, which end up somewhere in the float bowl area, you gotta get that stuff out.to get clean, adjustable idle.
Good luck dude.
The Shop
As mentioned above start with fresh premix & flush the tank / fuel lines as needed.
https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwj7gZa4-6vdA…
To check for air leaks,
Instead of spraying WD 40 all over and making a mess, use brake cleaner. Same method, same result, no mess.
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