chewy Posted March 9, 2009 Report Share Posted March 9, 2009 I.m probably a bit late in this conversation....... how do you know it's the mains? I have a similar quandry with my 08 200..to me, for all the world it sounds like piston slap at exhaust port with the screwdriver to the ear. Some folk who have had a listen say all beta's are quite noisy mechanically ,some say its definitly the mains , some say its primary drive noise. I think the noise has got louder since i changed gearbox oil to A.T.F. which certainly made clutch action better.One guy whose opinion I trust (him having been around even longer than me) reckons it's mains but that they could go on grumbling like that for a long time yet. I remain reluctant to strip it down without being sure it's neccesary so any comments or pointers wouldbe appreciated. Quote Link to comment Share on other sites More sharing options...
gaz Posted March 9, 2009 Author Report Share Posted March 9, 2009 I.m probably a bit late in this conversation....... how do you know it's the mains? I have a similar quandry with my 08 200..to me, for all the world it sounds like piston slap at exhaust port with the screwdriver to the ear. Some folk who have had a listen say all beta's are quite noisy mechanically ,some say its definitly the mains , some say its primary drive noise. I think the noise has got louder since i changed gearbox oil to A.T.F. which certainly made clutch action better.One guy whose opinion I trust (him having been around even longer than me) reckons it's mains but that they could go on grumbling like that for a long time yet. I remain reluctant to strip it down without being sure it's neccesary so any comments or pointers wouldbe appreciated. Without trying to imitate funny sounds using it letters, the best way to describe it like a scraping noise that "sped & slowed" with the engine. started off intermitant then eventually constant. Then a couple of other guys (like mentioned in one of the earlier replies) confirmed it by saying the very same had happened to him. Quote Link to comment Share on other sites More sharing options...
betabegood Posted March 9, 2009 Report Share Posted March 9, 2009 SKF was the make of bearings that came out of my bike. Which also sounds like a scraping noise, and it rumbles and you can feel it through the frame and pegs. I'm going to try and talk to lampkins to see if they will get me the code off one of their oe bearings to see what sort we should be using. Just had the crank re-aligned, the 2 halves were out of alignment. So it looks like someone has been there before. Quote Link to comment Share on other sites More sharing options...
chewy Posted March 9, 2009 Report Share Posted March 9, 2009 thanks for that guys It's been a long time I had motor with "shot" mains your comments about feeling it and grating roughness have been a big help I think I'll go on believing it's a bit of piston slap 'cause it isn't a harsh "serious" noise. PS i Quote Link to comment Share on other sites More sharing options...
betabegood Posted March 14, 2009 Report Share Posted March 14, 2009 (edited) OK, the two crank halves were way out, could be like you said chewy, the flywheel is massive Spoke to Lampkins last week who were very helpfull and the double shielded bearings are the correct ones. Apparently they have been using them for a few years now in Beta's. My bike is now back together Edited March 14, 2009 by BetaBeGood Quote Link to comment Share on other sites More sharing options...
ham2 Posted March 14, 2009 Report Share Posted March 14, 2009 As for the sound that dodgy main bearings make, I would describe it as a ''swishing'' noise, especially when the revs are falling. Imagine you have a very dry or loose bearing in your hand and you spin it with your fingers..that noise multiplied by a few thousand (revs) is the ''swishing''. Very bad mains can be detected by simply leaning the (running in neutral) bike over to extreme angles to hear the varying side loads on the bearing. Quote Link to comment Share on other sites More sharing options...
gaz Posted March 15, 2009 Author Report Share Posted March 15, 2009 OK,Spoke to Lampkins last week who were very helpfull and the double shielded bearings are the correct ones. Apparently they have been using them for a few years now in Beta's. My bike is now back together Iv just got my bearings out and they were open race, and as far as Im aware they were factory fitted. I was suprised that they were some japanese brand, which I would have thought to be durable. Anyway got some SKF's for Quote Link to comment Share on other sites More sharing options...
chewy Posted March 16, 2009 Report Share Posted March 16, 2009 Swishing it is.. Just got mine apart dead easy job..and boy are those bearing knackered!; for all those who are going to have to do this job it's worth remembering that all of the gearbox stays in the clutch side , the primary gear (taper fit on clutch side may ping off and smack you in the face if you are using levers/ heat and of course getting bearing out is much eaier with a little heat to expand the ally faster than the bearings, ofcourse an air wrench makes it so much easier to get the clutch centre nut undone ..and don e back up I imagine. I don't know about putting it together as I now have to wait for bits to arrive ( gasket set seals and bearings) I had thought about moaning at John Lampkin as my bike is only 17 mjonths old and I am not the sort to thrash a bike ( I wouldn't be at 58 years young) but there is evidence of condensation/wet although the piston and bore are spotless and unmarked (you would expect an engine thats has a "drink" to be evenly affected by the dirt, or for it to have blown the head or barrel of or bent a con rod...water doesn't compress); I can't recall ever giving it a "drink" of water but then I can't imagine why a factory would assemble a motor with corroded bearing. It just seems bizzare that so many Betas are having this problem and it would be helpfull if there was any preventative medicine available ( thats opened the door for Beta bashers !). Its not really a difficult job I reckon its taken me longer to write this than t did to get the engine apart it's just that it shouldn't be neccessary. Quote Link to comment Share on other sites More sharing options...
gaz Posted March 17, 2009 Author Report Share Posted March 17, 2009 The biggest trouble i found chewy was splitting the casing. I used a nylon drift I made up at work and had to use alot of patience as the locating dowls (spelling?) were holding on quite tight. The bearings were easy enough to fit. It just took abit more patience putting the casing back together. Although I didnt bother with a new gasket kit, I just got a new crankcase gasket and new crank seals. I personally didnt think the seals looked bad bought thought that while im this far I might as well just use belt and braces! But like you mentioned, the mains bearings does seem to be a common issue on beta's. I'm not really sure how this can be overcome as a mod, I just take the system of not letting it take a swim and run the engine up after washing it. Quote Link to comment Share on other sites More sharing options...
hrc1 Posted March 17, 2009 Report Share Posted March 17, 2009 Mains on Betas - were never a problem, until recently. I wonder why. I had 5 Rev-3s with no probs. Sherco went through a period of running mains - are they cured now? Quote Link to comment Share on other sites More sharing options...
chewy Posted March 17, 2009 Report Share Posted March 17, 2009 Thanks for that Gaz every bit of info is usefull (eg the guys at BVM say you can only buy full gasket set I only need centre gasket). considering what a substantial bearing it is there has got to be something peculiar to Betas which is causing this (Not bragging but have a doctorate in mech eng. so do have some idea of whats what). One (wild) idea could be that Betas seem to be awash with fuel half the time.... ie is it diluting the lubrication film?. I have always followed that method of running motor up after washing at least untill the fan kicks in. another observation wast hat there was an awfull lot of crud behind the flywheel cover, ...as it doubles as sprocket guard it may be that crud is really being forced in when chain is carrying mud etc and packing it in there..I dont imagine that would happen so frequently in Italy, couple that with pushing it on in with washing process may be contributary factor . However that crud would have to get through the lip seal which would be ripped to shreds ..mine wasn't. Incidentally my bearings were plain unshielded unsealed yet earlier in this forum John Lampkin is quoted as saying shielded bearings are standard. could it be a crankshaft balance issue?...Beta have just changed that part of the motor I understand. Whatever it is mains are a fundamental part of any bike. I would be a worried man if I was "running" a fleet of them through SSDT... I understand there is a fuel issues as well now that they using extruded section for fuel tank on the Evo's. I expect after all is said and done the problem is going to be either crappy bearings as original equipment or dirt either on assembly or as we all seem to be discussing. Hope BVM send me some quality bearings and seals and I will be sure to put together in clinical conditions and then I can expect never to have to go there again. One thing for sure is these forums are it seems the only way to get an overview of issues such asd this. Quote Link to comment Share on other sites More sharing options...
betabegood Posted March 17, 2009 Report Share Posted March 17, 2009 I put the shielded type bearings back in mine so I hope they will last a while. My bike is quite old compared to yours as it was bought late 03 by first owner. Also I used some threebond on the centre of the cases with a new gasket. The old gasket had gone hard and brittle in places increasing the chances of crankcase air leaks. There was also plenty of sand and dirt in the flywheel side, when I get chance i'm going to seal round the grommet where the electric wiring comes through with some clear silicone possibly the flywheel cover too as that should have a gasket really. I was suprised when I looked on the parts list thought mine was just missing. Run the bike for a good 3 hrs solid on sunday and all appears to be ok. There is a bit of clutch chatter which seems to get worse as it warms up. Had to modify the float height to stop fuel overflowing from the carb but I think that's also normal. As for fuel oil mix effect on the bearings i'm using 1.5% and it runs good on that so far Quote Link to comment Share on other sites More sharing options...
chewy Posted March 17, 2009 Report Share Posted March 17, 2009 top man betabegood (no relation to johnny?) hope all goes well can't wait to get mine back together. I have seen people drilling drain hole so that crud can get out quickly it could almost do with a "scoop" to catch that which is being whirred around by the flywheel . I ready to try anything but like you I guesse I'll just try to keep crud out with a silicon "gasket all round. It would be better if there were more bolts 3 with a plastic moulding is a bit on the "light" side..there it is lets hope our experiences can benifit others. Quote Link to comment Share on other sites More sharing options...
gaz Posted March 18, 2009 Author Report Share Posted March 18, 2009 i was gonna try that chewy, a bit of silicon around the flywheel cover and cable gland to try and keep crud etc out Quote Link to comment Share on other sites More sharing options...
b40rt Posted March 18, 2009 Report Share Posted March 18, 2009 Use decent quality silicon, screwfix do a sanitary silicon for about Quote Link to comment Share on other sites More sharing options...
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