Hi All

 

I have had my Beta for about three weeks now and am loving every moment.  I have a off-road history, but the trials fascination was finally getting too much.

 

I have gone through the bike systematically and have a wishlist of parts I am waiting on.  Trials is very rare in South Africa and spares is a big headache.

 

I have sourced a second hand air box as mine was pretty abused in its life.  I am waiting for new carb rubbers as well as the front manifold is showing cracks.

 

The issue I require help with is 'airleak' that seems to become more noticeable if I ride for +/- an hour.  The revs then almost don't drop at all.  The carb has been cleaned and the bike runs fine for the first while.  I have to ride +/- 3km to my playground, so the bike warms up reasonably quick.  I don't loose any oil, so I suspect the flywheel side seal is gone.

 

Do I need to split the motor to replace it?  Any idea why the bike gets worse after the hour period - I do have rest breaks in between?

 

Cheers

Good chance the main bearings are bad. Pull off the flywheel cover and grab the flywheel and check for play.

Good chance the main bearings are bad. Pull off the flywheel cover and grab the flywheel and check for play.

 

I really hope you are wrong

 

I removed an extra flywheel weight recently and everything felt good.

Find a Beta Rev3 manual, you'll find one on a beta importers website as a PDF file and check - reset the float height as stated in there.

 

The carb slopes forward slope due to how it's fitted and it very fussy to float level, too low and it'll lean out quickly, too high and the flood up going down hill.

Find a Beta Rev3 manual, you'll find one on a beta importers website as a PDF file and check - reset the float height as stated in there.

 

The carb slopes forward slope due to how it's fitted and it very fussy to float level, too low and it'll lean out quickly, too high and the flood up going down hill.

 

I found the 2003 manual, still hoping to get a 2001 manual somewhere.

 

The floats seems good as up and extreme down doesn't cause bogging down or revs racing.

 

I suspect the flywheel seal due to the time it takes to reoccur being constant.  If it was fuel, it could happen anytime. 

The combustion chamber and exhaust. ..full of carbon

The combustion chamber and exhaust. ..full of carbon

 

 

I did do a proper exhaust burn and repack.  It also seems intermittent.  When I had the exhaust off, I checked the top of the piston and it seemed clean enough.  Only stained brown.

I've had rev3s give symptoms of leanness and send me on wild goose chases only to discover the rectifier was at fault. ...

I stripped the bike down to the frame.  I found the carb slide cap and the cable guide quite worn.  This might be my issue.  Awaiting the parts now.

doubt it. ...usually compression issues, carbon build up, electrical components, or someone has messed with the bike

Just an update.  My fuelling issue was due to the reeds that were not sealing.  Replacing the slide cap only improved the issue by 50% before I replaced the reeds.