2 Stroke 94rm80 bogs/stalls 4th 5th gear

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Salanrm

Howdy. Got this RM 80 in a trade a couple weeks ago, fired and ran good and in good shape just needed new clutch and water pump gasket.

Got the parts yesterday and installed them allowing me to ride it for the first time.

It seemed to be going fine down the driveway in 2nd. Hit the road and all was well until I hit 5th gear, immediately it started bogging out and stalled. Fired right back up again but on the way back did the same thing in 4th this time. It's done that everytime I try to run down the road.

Now the bike runs great riding around our acre property in 1st through 3rd for about 10 minutes running around the house, then eventually does the same thing. Fires right back up and runs great again.

I tried cleaning the air filter and the carb. Took the carb out cleaned the jets and float bowl and sprayed cleaner throughout inside of carb.

Haven't had a chance to run it extensively yet as it was too late, but I think its still doing it.

What else could it be?
 
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PawPaw

Did you set the float level?
Did you inspect the carb vent lines as well as the fuel tank vent lines. If they are even partially clogged it will reduce the fuel flow under heavy flow requirements.
Also I would do an ohms test on the coil as it can be breaking down under load.
Also do a compression test. If it's a bit low then it will also loose power on top end.

Paw Paw
 
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Salanrm

OK I am starting to think maybe it's a leak somewhere as the idle does seem to go up and down at times, if it turns out to be a bad seal or something how hard would that be to fix. ?

About the carb vent lines, there is 2 valves on the carb, one on left side other on right side, right side has a hose from it left side never did, are these the vents?
 
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ossagp

yeah sounds like it. i would fill the tank, turn the gas off, put the gas can under the hose and dump fuel and see if it starts and stops first. the seals are easy, but you NEED a flywheel puller made for it. start it up and keep it running while you take the magneto side cover off. if it starts to idle up further you know the seal is bad. it may be bad anyway but that is a for sure thing.
 
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Salanrm

OK when leaning it back and forth a little it changes up and down, and will start to big out until given a little gas, and leaned back. Also just ran down the road a little and it only seemed to big out now when opening the throttle above half about 3/4 I guess, going to check the float I guess?
 
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Salanrm

Just bogging out and eventually dies. Not sputtering but bogging down, while leaning it back and forth it will sometimes start to idle higher and sometimes start to bog out and start to die till I give it more gas.

I don't understand how to actually adjust the float level on the carb, I can't see anything to adjust anything.
 
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ossagp

look over at allthingsmoto.com for a pictorial posted by a memeber who goes as faded. then you need to find the height yours is suposed to set at. in the meantime I would sure make sure you had full flow from the tank. what does the spark plug look like right after it dies? if you havent seen it, try going out and getting it to bog. shutdown and take a pic and post it is best.
 
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Salanrm

OK, already checked Petcock, had to drain the tank the other night, and fuel hose is good.

I've looked a few videos and pictorials for these things already, here's some pictures of the carb. Can't figure out hoe to acutalyy adjust the float, or remove the needle valve to set the clip. It's all one solid piece with the throttle cable going down into it with a spring.
 

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ossagp

pull the spring up towards that scerw down cap and get some of the cable exposed. with the spring up out of the slide you can see if there are screws holding the casting that the cable goes into. if so you may remove those, or see if you can get the cable out by pushing down out of the blind socket, and then flick the cable out through that slot.

as for the float setting you can priobably get really close by looking at the floats from the side and lifting them with your finger to where that brass tang that contacts the needle is just contacting it without compressing the spring. on that model the float mold lines should be level with the gasket surface of the carburetor body. you can bend that tang up or down to make that happen. while you are in there remove the float needle and make sure there is no dirt etc . once done you can blow through the fuel line with the float in the open or down position and move it to shutoff and see if you are getting a decent seal.

now what does the spark plug look like?
 
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Salanrm

Wet,

Still can't figure out how to get the needle out, throttle goes straight down inside the slide, has a green clip on the side of throttle cable down there but it don't budge,

Float adjustment, it's got a small metal lip coming out that rests against the edge is that what I need to bend?
 
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