Hi, I just bought my 2nd 1987 lt 80 for $50. As I was starting to clean it up, I noticed the fan cover had alot of oil on it. I didn't think anything of it, so I kept cleaning it up. Pulled off the carb and cleaned the jets then cleaned the tank and petcock. Put in a new battery and cranked her over and no go. Took a little carb clean and sprayed it and finally got her running. Seemed to idle good, but when riding it it kinda bogs or lacks power, especially compared to my other 87. Even after I have it running for a while and shut it off, it is a PITA to start (choke on, half throttle, and crank crank crank). Thought the plug may have been bad so I tried the one from the other bike, and cleaned carb again. then I noticed thin oil dripping from the bottom drain hole on the fan cover. Have no clue where its coming from (I already blocked off the oil pump and run premix). No significant oil in belt cover, just looks like old oil and burnt belt. Let the bike sit for a few hours and noticed fuel coming from the same hole on the fan cover. Found that my needle valve is missing the rubber tit so fuel was running in, but why out of the side? Crank seals? I thought it would rev high like a lean condition but it doesnt. Does a bad seal cause low compression? I am showing 92 which I believe is low. What should compression be? I have no prob tearing the motor down, I did my other one also. I just need an idea what to look for. I know what bad crank seals do to my banshee and blaster but I am not sure about the 80. Please help me! Thanks, Preston

 

Comp is a lil low (should be 120) and a bad seal won't cause that.
It's either leaking out the seal or the base gasket.
I'd replace the seals whem you have your motor down for a bore.

 

Thanks, am I able to pull the seals out without splitting the cases?

 

Yes.
You will need a puller for the flywheel tho.
You'll need to remove the front clutch for the left one.
Sounds like you could use a lil clutch maint while in there.
The seals pull out/push in. I coat them with a lil grease.
There is a lip on the seals. Install till the lip contacts the motor.

 

Thank you for the info!

 

Took it apart tonight and found that the right side crank seal was not even in the case. I checked it over and it looks good, actually it looks new.. I popped it back in and it is still tight and seals. I tried to start the bike and it fired right up (first crank even without the choke)! I know that I need to put a new top end on it but it may wait till later this summer. Has anyone had any luck advancing the timing on these? Any gains? Any disadvantages? Thanks, Preston

 

I advance the timing on my race motors but don't w/stock.