September 28, 201510 yr Hi everyone. So my friends son has a rev 3 200cc on a 2007 and its a lovely bike, loads of power and is ideal for him but he was on it yesterday when he and his dad started hearing a groany noise coming from the bottom end of the engine/gearbox. Now the day before we dropped and changed the milky gear oil because i said that should not look like that. Put fresh in and when it came back yeaterday it was exactly the same as we dropped it the day before. So i said it would be water getting in to cause this problem. So took the water pump of to see what lied beneath. This was what i found and knew that this had to be the problem. 1 them magnesium cases just corrode over time and 2 the water pump shaft seal will not be doing its job properly. So i thought the noise will be water in the oil causing moving parts not to be lubed properly. Am i right in thinking this. He has just ordered the new case for it but i wanted to feedback of you more experienced guys. Thank you.
September 28, 201510 yr Does the noise diminish if you pull the clutch in with the engine running?Its possible the gearbox bearings have been damaged by the watery oil if it's been run like this for some time .If it goes quieter with the clutch in the problem is in the motor not the box.Could you post a video so we can hear it?
September 28, 201510 yr Author I cant post a vid im afraid as weve got it in bits now. The noise was more noticible when we pulled the lanyard kill switch and as the bike was dying out could hear the what sounded like groaning in the gearbox area. I know if theres water in with the mix then the bearings etc wont be proper lubricated.
September 28, 201510 yr Don't take a chance. Strip the gearbox, 2007 Beta is easy engine to strip, and check and replace bearings. Far cheaper to do this than have a bearing go completely and trash the whole box or burst the cases. Magnesium case corrosion is a problem on these Betas. Use OAT antifreeze mixed at 50% and change it every six months. Mix with distilled water if you live in a hard water area. You can repair a lightly corroded case by cleaning the corrosion off thoroughly and putting on a coat of JB weld. Edit Simply Bearings good price and quick delivery for bearings and seals. Edited September 28, 201510 yr by dadof2
September 28, 201510 yr Author Is there a manual on stripping these engines down. Is it all accessible from the clutch side or would head and bore need to come of too?
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