Went riding friday night. I wasnt on it hard, the bike backfires on it's way to dead stop, repeatedly. Checked the compression 55 on one 50 on the other. Time to start saving money for a new motor! Just bought it in November. Good thing it was dirt cheap.

 

Mmm 96" sidewinder...
Oops, sorry, was having a breakdown wet dream.
Sorry to hear about your loss, good luck on the rebuild

 

That sucks, I tore my bike down last winter to avoid a break-down. EVO's are pretty simple to work on, parts are cheap. If your rodbearings and end bearings are good, a top end rebuild is a breeze. Total cost for me was under 400 bucks, I did my own machinework, but thats not expensive anyway.

 

Just for giggles, check to see if you have adjustable pushrods. If you do then try readjusting them. Did this just start or has it been this way since you bought it. Was the engine warm and the throttle wide open when you did the compression test????? Next step is a leakdown test.

 

I agree with John, compression is darn low, sounds almost like valves are stuck open.

 

Since your compression is that low, but pretty equal between cylinders ...I am betting on inner cam bearing failure...which has allowed it to jump time. If you lucked out and it did not damage the case...it could be a pretty cheap fix...good luck and let us know what it was.

 

Checked the compression turning it over. Thing could d@mn well be a nasa rocket and Ive got no one to help show me how. But it,s never done this before. Seems like the valves got louder just before it happened.

 

If you feel up to the challenge, get the proper repair manual. a genuine used from ebay harley version if you please. Then open the pushrod covers and see what you see. If they have slop and they're not adjustables you'll need to delve into the cam chest. If they're adjustables that are out of adjustment that's a relatively easy fix.

Take your time, I know you're kinda freaking out right now, spring being right around the corner and all, but I'm betting it's relatively easy fix. Compression being almost even between the cylinders is a good indicator.

I've been there, my current bike had lowish compression I thought and I was ready to order a replacement motor until cooler heads on this site got me rethinking a few things... I replaced the cam, the carb and the pipe and it's running very well. Later on I'll pull the heads and get them ported and polished, maybe mill .050" off and she'll be just the way I wanted her. Thanks to these good folks I've still got the $6000 I was planning to spend on a new engine...

If you don't feel up to all of this, find a local indy mechanic, check some references, and see what he says.

 

i'm about in the same boat with an fxr i just got. this thing isn't a rat bike, it scares away the rats that might get near it, it's that bad. i just about got the motor pulled out, i was planning on sending it off and doing the harley remanufacture program. it costs $2395 and i can haul the motor up to the harley shop and in a couple of weeks i get basically a new motor. the welded up head from the hillbilly repair of a broken exhaust stud and all the other crap is going to be history. good luck with your motor. i will tear open the cam chest to peek in there along with the heads to see what the condition of the motor is in. if it's not looking bad inside, i'll do the top end rebuild with fresh heads and run it till she don't wanna go no more. the guys in here have been around the block with these motors, so i appreciate having access to their knowledge and advice.

 

yes im also greatfull for the great minds on here as well. i say do what you can to fix your motor! i hope its somthing simple!!