Mongrel '85 / '88 Motor Rebuild

madmcnish · Post by **madmcnish** » March 17th, 2009, 6:40 am

Hi guys,
Bought a complete '88 in really good condition and got a big pile of spares too.
Think I've got enough spares to build a second practice bike, but I've got a mix of parts from different years.
I've got 2 complete bottom ends - an '85 and an '88.
The '85 cases are useable, but the crank has a tight-spot.
The '88 cases are corroded at the waterpump and have a couple of chips around the countershaft sprocket area, but the internals are OK.
I was thinking of using the '88 crank in the '85 motor but will need to fit a 5mm cylinder spacer to compensate for the '88's longer rod length.
Alternatively, I could get the '85 crank refurbished.
To anyone who's done this before - what would be the preffered solution?
Does anyone have any photos showing repairs to damaged / corroded cases with which I could compare the damage to my cases?
If my '88 cases are repairable, I may try this instead of mixing the engine parts.
Repairing the cases (if possible) would be alot cheaper than buying replacement ones.
Are there differences in size of the swingarm bushes from '85 to '88?
The motor will be going into an '87/'88 frame once it's ready.
Cheers for any help.
Ross

madmcnish · Post by **madmcnish** » March 18th, 2009, 3:06 am

madmcnish · Post by **madmcnish** » March 18th, 2009, 3:08 am

Here's some photos of the complete '88.

http://i267.photobucket.com/albums/ii31 ... CR5001.jpg
http://i267.photobucket.com/albums/ii31 ... CR5002.jpg
http://i267.photobucket.com/albums/ii31 ... CR5003.jpg
http://i267.photobucket.com/albums/ii31 ... CR5004.jpg
http://i267.photobucket.com/albums/ii31 ... CR5005.jpg

BannedCR500Riders.com

Mongrel '85 / '88 Motor Rebuild

Mongrel '85 / '88 Motor Rebuild