top end rebuild?

mistercl · Post by **mistercl** » Wed May 28, 2008 6:57 pm

So i just checked the compression of my 92 elite 50sr and i got about 70. i was reading through and ppl suggested a top end rebuild for low compression. can anyone tell me how and what i need to be able to do this? thanks

CharlotteSpreeRider · Post by **CharlotteSpreeRider** » Wed May 28, 2008 7:23 pm

At 70 PSI, the motor will not run at all. If your motor will run then your guage is incorrect. Top end rebuild requires a new head gasket, base gasket, piston rings and piston clips (about $40). Short version, you pull the head and cylinder off, take the piston off, take the piston rings off, then clean the everliving * out of the parts, hone the cylinder, check the piston to make sure you don't need a new one (major scoring or broken bits). Then you oil everything up with clean oil and put it back together with the new rings and gaskets. Theoretically, you don't even need to remove the engine from the bike to do it.

Bottom end rebuild is significantly more work as it requires all of the above plus removing the motor from the bike, pulling the flywheel (which is a REAL b****), spliting the crankcase halves, cleaning cleaning cleaning, etc. You only need to do that if you have problems with bearings or if the gasket between the crankcase halves has failed for some reason.

-aseigler

Dac · Post by **Dac** » Wed May 28, 2008 7:28 pm

remove the head, remove the cylinder, remove the piston.

check for any groves anywhere. There shouldn't be any. The inside of the cylinder and the piston should look complete smooth. Replace the rings with new ones from honda.
Reassemble.

New parts needed..
New set of rings- about $30
New base gasket- about $5

If there is any scratches in the cylinder take it somewhere and get it honed (Honed! not Bored!). If there is any problems with the piston, you can clean it up with some super fine sand paper.

CharlotteSpreeRider · Post by **CharlotteSpreeRider** » Wed May 28, 2008 8:47 pm

I end up getting so many cylinders honed, I'm looking at getting a hone so I can do it myself. I've done the research and the right idea is a 320 grit 41mm flex-hone using honing oil. It's gonna cost me about $35 shipped. I might pick up a lower grit for use on some of the more severely gouged cylinders I have lying around (followed up by the 320 grit). But 41mm is the right size.

-aseigler

chevyguyjay · Post by **chevyguyjay** » Thu May 29, 2008 3:48 am

.......dont forget about those crank seals lol.

gobucks · Post by **gobucks** » Thu May 29, 2008 2:03 pm

if my elite is getting about 75 psi and only goes about 20mph what do you think it will get after replacing rings and gaskets?

CharlotteSpreeRider · Post by **CharlotteSpreeRider** » Thu May 29, 2008 2:44 pm

If you were really at 75 PSI, I don't think the bike would go anywhere near that fast. As far as I've been made to understand, 90 PSI is the minimum to even get the thing to fire at all.

-aseigler

gobucks · Post by **gobucks** » Thu May 29, 2008 10:50 pm

yea, its been getting worse and worse, a few weeks ago i could go 25, now more recently it has gotten to the point where it goes like 15 and after a minute or two it dies, it also has trouble starting. does this sound like a compression problem?

what does a derestricted elite usually run at for a top speed?

Kenny_McCormic · Post by **Kenny_McCormic** » Thu May 29, 2008 11:16 pm

Sounds more like a carb problem.