Engine Overrevving! Tryed changing carb and throttle cable. STILL DIDNT WORK!Help.

[ecgoeken]

StrontiumEthics,
I was having this problem as well. i knew it had to be extra air getting into the mix but everything i did with the carb only helped very little to solve the problem. then i had an epiphany....what if extra air was getting into the combustion chamber through the connection between the intake manifold and cylinder head and totally bypassing the carb? i took the intake manifold off and discovered that the seal between that and the cylinder head was complete toast! i replaced the gasket and the bike has been running perfect. sounds like your problem is very similar. id bet your gasket is worn to bits.

 

[StrontiumEthics]

Nope! I tried replacing the intake gasket! and the same thing still happened. Guys I am back to square one. The same thing is happening. Its not the slide because I thoroughly check its multiply times today. Its not the carb I tried 2 different ones. Its not the seal by the mag, and its not the intake gasket. I'm going crazy Here!!

So these are the things I checked Please help me add to it

1. Intake Gasket
2. Carburator (Disassembled it)
3. Seal by Magneto
4. Carburator Barrel Slide
5. Throttle Cable

Tomorrow I am gonna check the space where the Carburetor and Manifold connect. After that I will be totally lost. Im about to just buy another engine!

 

[cabinfever1977]

Check:
1. sparkplug tightness
2. check headgasket
3. check all other engine gaskets
4. check muffler gasket
5. look over entire engine for holes
6. check seal behind magneto(not just the outside cover)
7. maybe a leaky seal in clutch cover,you may have to look inside and go exploring

goodluck

 

[210061741]

My guess would be the head gasket

 

[StrontiumEthics]

I dont believe its the head gasket because I would see oil comming out of it. I changed the sparkplug like 3 times and made sure that was tightened down. I dont believe the exhaust gasket is the problem. Since I have a jackshaft I am a little reluctant about removing the entire thing to get to the clutch but I guess i will have to.ugggg...... Any more suggestions?lol

 

[210061741]

Start it up and spray a little carb cleaner around all the sealing areas.
If it's sucking in air it'll suck in carb cleaner and rev up a bit.

all i can say is i have had neumerous problems with head gaskets leaking.
The machining is poor and you can only tighten the studs so much.

You wont nessessairly see oil coming out.
You might see a small discolored spot where it's leaking.

Other than that after all the work you have done so far i woulda just pulled the top end off and changed the gaskets anyway.

It's not that difficult to do and should only take an hour or 2.

The seals are prone to leaking as well.
I change the mainbearings with *** bearings that are sealed on both sides.
Pull the seal off of 1 side first. The open side is inside the cases.

Then put new seals in the engine case as well.

Yes this is getting into alot of work.

But for the time you have spent allready you coulda rebuilt it.

 

[StrontiumEthics]

The Carb cleaner is a really great idea, but Im afraid I cannot use it because the engine already revs up once it starts. I think im gonna just take it apart rebuild, relube,regasket. Its very anoying that it has to come to this but it might be the only thing left. I just want to make sure that I tackle As much stuff as I can without actually taking apart the engine. This is the second time I will probally be taking apart these engines, the first time wasnt so successful but I knew why.

 

[StrontiumEthics]

Now as for taking apart these engines. I need to know what the torque on the head bolts. Also, what things should I look for?

 

[Al.Fisherman]

Now as for taking apart these engines. I need to know what the torque on the head bolts. Also, what things should I look for?

I love these easy questions.....

http://www.motoredbikes.com/album.php?albumid=808

The torque for 8mm in these cast aluminum engines is a maximum of 204 inch pounds, although I use 150 inch pounds, without any issues whatsoever. ALL my hardware is grade 5 (8.8 metric). 6mm 50-60 inch pounds. All my studs are installed with lock tite and are secured by either nylon locking nuts or double nuted.

 

[210061741]

I will be tearing down an engine in the next day or 2 and i can take pics.
I kinda been planning on it anyway.

As far as torque im probably not the best person to ask.
I go by feel and make them as tight as i can without stripping the studs in the case.
I know how far i can go because i have stripped them out before.

I will try to give you a quick rundown of how i dissassemble the engine.
with it on the bike it might be a little easier.

#1 i remove the Head and pull the cylinder off if there is enough room.
This dosen't have to be done first. But gives more room to work if you want.

#2 remove the clutch Cover and the Magneto cover.

#3 Remove the magneto coil.

#4 loosen the bolt on the magneto magnet. Easiest to do with the chain on holding things from turning.

#5 remove the magneto magnet. You will need either a very small 2 jaw puller or a good pair of visegrips and some careful patience. If you cant get under the magnet with a puller grasp the magnet with the vise grips on the flat cutout portions.
Pull towards you and it will pop out and get stuck after moving a little. This is where the PITA comes into play. Carefully push and pull the magnet back and fourth as straight as possible. It's easy to bend the shaft so be careful. The Key gets stuck in the magnet and it wont come off until you work it loose. Thats what your doing pulling back and fourth. Do not pry at the magnet to get it off. Just pull back and forth eventually 5 or 10 minuets it will come off.

#6 loosen the large flat head screw in the little gear on the clutch side.
Be careful not to strip it and i would reccomend using an impact wrench to break it loose.
This is also good to do when the chain is still on holding things from turning.

#7 Pull in the clutch lever as far as you can and if you push the friction plate against the clutch you should be able to turn the star nut with your fingers. Remove the little screw if nessessary but if you get the clutch in enough you won't have to.
Then Remove the friction plate and the spring. And loosen the 19mm nut holding the clutch plate on.

#8 remove the sprocket cover and the clutch throw out pin.
With the chain still holding the sprocket Remove the 19mm nut and pull the sprocket off the shaft with the little 2 sided threaded puller.

#9 remove the 19mm nut from the clutch and pull the clutch with the puller.

#10 using the other side of the puller pull the little gear off the crankshaft.

#11 Using an impact driver the kind you hit with a hammer loosen all the case screws.
2 at the base of the cylinder on the top of the casees
3 under the clutch.
2 in the front motor mount.
and 1 on the bottom of the case.

#12 remove the engine from the bike.

#13 remove the 8 screws and then with a block of wood and a hammer very lightly tap the crankshaft end on the small gear side.
Hold only that half of the case when you do it and be prepared for the othe half of the engine to fall.
After the gasket lets loose a little you should be abel to pull the cases apart with your hands. Only tap as much as you have to.

your all done. Should take about an hour.

Clean everything get new crankcase seals and gaskets and replace the 6202 bearings with F.A.G 6202.2RSR.C3.J22R BEARINGS. tHERE ABOUT $10.00 EA AND COMMON AT MOST BEARING SUPPLY PLACES. These are high quality bearings.

Wouldn't be a bad idea to change the piston rings too.
When you put the cylinder back on make sure that the ring ends are lined up on the pins.
The pins in the piston go on the intake side of the motor.
Tha magneto magnet keyway will tip slightly toward the sprocket when put on the right way. If you flip the magnet the timing will be off.

Pay attention to all the washers and where they come from so you can put them back in the right spot.

Pull the seals off one side of the bearings that hold the crankshaft and put the sealed side facing out in the case.
The drive shaft bearings can be left sealed on both sides.

I normally put the new seals in the casese 1st....use a large enough socket that is perfect to the seal and carefully hammer or press them in.
When you go to re assemble the cases be very carful with the crankshaft.
Chamfer the ends of the crankshaft with a file on the bottom edges that will come through the seals.

be careful pushing the shaft through the seals. make sure the inside ring of the seals isn't pushing out. there is a little spring in that seal lip.