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1980 xr500 compression release

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II have a 1980 XR500,  The compression release seems to need adjustment.  It could be that the cable is fully stretched but that is low on the list. 

The lever down by the kickstart is at the 11:00 position...correct?  It does not move as I kick it over several times.  Something wrong internally?  I cannot find pictures of it in the clymer manual.  Before I remove the side cover I would like to know what is inside.  Is there an internal adjustment?  Is this part trouble prone?   Up top on the cylinder head I can activate the compression lever and release compression so I know that works.

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I still have several of those engines.  I used mine for the most part in flattrack and ice racing applications,  and preferred running without the compression release mechanism in place.  There is an eccentric (cam) that contacts a mate on the kickstart mechanism at the shaft.  Other than that it looks a lot like any other kickstart mechanism.  If the cam wasn't in the clearanced position when the cover which contains the cam which is connected to the cable at the case,  when said case was put back on,  it catches the rest of the mechanism and breaks.  So if you are not getting any decompressing that is where to start.   Having to take the time to line those up each time that cover was off was part of why most race bikes didnt have those operational for long.   Backing it up on the compression stroke or simply holding the kick lever at the top of it's stroke until it just gets to tdc on the compression stroke and kicking it through produced much faster starts hot or cold for most of us.  You can adapt a handlebar lever to that engine easily since the parts are in the head.   If you go to something like bikebandit.com you ought to be able to find a schematic of the parts I am talking about.   I think I have a  manual that shows it somewhere.  

Edited by ossagp

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Thanks for the info.  I like the idea of backing the bike up till the piston is on tdc compression then kicking it through.  I'm used to the usual handlebar lever on british bikes so I can probably fabricate something.  

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22 hours ago, seattle gs said:

I'm used to the usual handlebar lever on british bikes so I can probably fabricate something.  

One of My old four strokes I used a bmx brake lever and cable to do this. It worked just fine.

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good idea.

Next question...is there any advantage of the 23" front wheel over a 21" ?  I would like to lower this bike a little since I am 5'7" .  changing to a 21 would drop the front end approx 1 1/2" and I could go a bit more by pushing the tubes up through the fork clamps.  which brings me to the rear shocks.  It currently has 17" shocks (rough measure) if I installed a pair of 15 " shocks would I run into problems such as the wheel hitting the rear fender at full compression?

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I'd do the 21 just because of tires, I believe it was a pretty common conversion back in the day.

The stock shock length seems to be 17.5, 15's would be pretty short, probably drop it around 3-3.5"once you account for the angle, and they only had about 7 1/2 inches of travel stock.

You may be better getting the seat re-shaped.

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