I cant seem to narrow down the problem that Im having. The motor is running fine and i think i have close to 100 miles on this motor but after riding it for 20 mins and i go to pull the clutxh in and the motor sounds like im giving full throttle. I sealed the exhaust and mabifold wit gasket maker and put an O ring in the carb that connects to the manifold and an o ring behind the spring of the throttle. I dont know if i would still be having some sort of air leak. The c clip is at the 2nd from the top but would that be causing the engine to rev so high with the clutch pulled in? Also the motor seems to be working extra hard after 30 mins of riding sounding like i have some sort of knocking issue. If my issue is at the carb to manifold connection, what are you guys using to wrap it so no more leaks without any sort of melting?
motor revs really high with the clutch pulled in
- Thread starter dumpstercrusher
- Start date
Might have a bad crank seal if you cannot find the leak...this will also cause extra hot temps from a lean mixture
It sounds like the barrel is not closing as it should, remove the air filter and watch the barrel return. Tightening the top of a nt to tight will cause warping of the carb throat at the top. I had that happen to me, I ended up replacing the carb.
the motor does get extra hot. where is the crank seal at? i mean when i ran 16:1 i had oil comin out the screw where the magneto sits. Should i be extra worried? will the motor explode if i keep riding it? lol i do have another motor ready to go on but i want to run this motor till it fails before i start swapin it out.
i don think that would be the problem but i did think abiut switchin out the carb though
If fuel leaks from the magneto cover you have a seal leak, seals are not that hard to replace.
http://motorbicycling.com/picture.php?albumid=16&pictureid=4703
The picture above I found in another thread, biknut is the supplier. In the picture the magnet and coil have been removed.
http://motorbicycling.com/picture.php?albumid=16&pictureid=4703
The picture above I found in another thread, biknut is the supplier. In the picture the magnet and coil have been removed.
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Hiw do u go about replacing the seals? any special tools needed to replace? i have sockets, pliers, but nothing special as a once in a lifetine tool lol
maybe a pick (looks like a dentist pick, the seals resist pretty good and I can never seem to get pliers in there), a 14mm socket (for the magnet nut), a phillips (+) or flathead (-) screwdriver (depends what screws your coil uses, most can use either head) and a tiny bottle of superglue (you only need a drop). And whatever screwdriver to take off the magneto cover, obviously. And a hammer, maybe.
#1. Take off the cover
#2. Use your 14mm socket to remove the nut on top of the magnet (if you have a marker laying around, mark the top side of your magnet, they keyhole is off-center and putting it on with the magnet upside down will change your timing, potentially enough to prevent starting). You may need to jam something between the coil mount and the magnet to stop it from spinning while you unscrew this nut.
#3. Remove magnet
#4. Remove magneto coil (watch the wires! they're not very strong and can break easily, support it somehow or remove it completely for now).
#5. the plate under the magnet just pops off, it may be stuck the first time from the pressure of the screws just pry it off.
#6 pick that seal out, I used a hunting knife the last time (I didn't have a pick), but anything to get in there and pop it out will work.
#7 Replace seal with a new one, if you have any sealants like Seal-all, you can use it around the edge of the seal for some extra false-hope.
#8 Replace metal plate
#9 replace magnet coil
#10 Replace half-moon key on magnet shaft (use a dab of superglue, this is [in my experience] the most frustrating key to keep in place)
#11 replace magnet, marked side out, you may need to hammer it down, it should sit nearly flush with the coil mount, perhaps slightly lower. Make sure to match the half-moon key hole position, it'll be a really tight fight, thats why you use superglue
#12 replace nut
#13 test, and pray.
#1. Take off the cover
#2. Use your 14mm socket to remove the nut on top of the magnet (if you have a marker laying around, mark the top side of your magnet, they keyhole is off-center and putting it on with the magnet upside down will change your timing, potentially enough to prevent starting). You may need to jam something between the coil mount and the magnet to stop it from spinning while you unscrew this nut.
#3. Remove magnet
#4. Remove magneto coil (watch the wires! they're not very strong and can break easily, support it somehow or remove it completely for now).
#5. the plate under the magnet just pops off, it may be stuck the first time from the pressure of the screws just pry it off.
#6 pick that seal out, I used a hunting knife the last time (I didn't have a pick), but anything to get in there and pop it out will work.
#7 Replace seal with a new one, if you have any sealants like Seal-all, you can use it around the edge of the seal for some extra false-hope.
#8 Replace metal plate
#9 replace magnet coil
#10 Replace half-moon key on magnet shaft (use a dab of superglue, this is [in my experience] the most frustrating key to keep in place)
#11 replace magnet, marked side out, you may need to hammer it down, it should sit nearly flush with the coil mount, perhaps slightly lower. Make sure to match the half-moon key hole position, it'll be a really tight fight, thats why you use superglue
#12 replace nut
#13 test, and pray.
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Thanks man! ver y much appreciated! i do have thread sealant that i used on the screws for my carb n fuel lever. Should i use it? beneficial to put some in there? I guess since i got a new motor sittin in the basement ill replace the crank seal from that onto the motor im running now and jus buy a new one for the new motor. Comes in handy so i don have to wait long for shippin lol
Oil coming out the mag cover is a sure sign of a blown crank seal. Check the classic threads for repair info. It will require splitting the cases so you may as well replace the bearings too.
The case doesn't need to be split to replace crankshaft seals. They can be easily removed from the outside but the magneto rotor (magnet) and the small (primary) gear will have to be removed to gain access to the defective seals.
Tom
Tom
Oops! I automatically want to replace bearings anytime there are seal issues...
My bad.
But still, as long as you're in there....
well i took off the crank seal from the outside under the magnet from my old motor and boy was that falling apart on the underside. Took a couple pics so ill try to upload tomorrow. Old vs new. Hopefully that fixes my problem when i go to test it out
Before you test it, rotate the 10 tooth chain socket and watch the magneto rotor to check that it doesn't wobble and that it clears the coil when it turns.
Looks like the problem still persists. This time i let the bike idle and it starts to rev higher and then higher and then the bike moves forward without me touching it a lil bit and cuts off cuz of the clutch. its weird, if i move the clutch cable any more the bike would not start like the piston doesnt move so i left it where its at.
You made sure you don't have any air leaks? Mine would to the exact same thing when the carb cracked...
well its definitely an air leak. IIRC another member recommended getting some Carb cleaner and spraying where the possible culprits are and looking for bubbles while it's running. Is your new seal leaking oil as well? Either way replacing that seal will only help you. The most obvious places where an air leak could exist are where the manifold meets the jug, and the carb throat. If you're using any silicon tubing, there too. Basically any joint. Carb throat is usually it though, but an O-ring usually is enough to fix it. Are you sure your idle screw isnt too far in, or your throttle cable too tight and pulling the carb slide up? I wouldnt worry too much about the crank case or seals, as you saw with oil coming out, the air in the case itself will be pushing out because of its higher pressure. It'll be somewhere between the part of the carb where gas gets mixed (the jet/needle) and the jug itself. Perhaps an uneven gasket surface? playing with the clutch is how I remedied my air leak until I figured it out, but it's only a temporary solution, remember an air leak will make the motor run hotter which isnt a good thing.
i guess i can go ahead and try to seal off the carb to intake again since everywhere else i already sealed it. Will mass air flow cleaner work or do i "need" to use carb cleaner?
Either will work, spray around each connection till the engine rpm lowers. The liquid will seal a leak for a brief moment, don't use lubricant spray it will just dirty up the engine.
