DTGordo Posted May 15, 2011 Share Posted May 15, 2011 Hi all, While I was out last week, the bike started making a bit of a racket with what sounded like a bearing playing up in the bottom end. I'm pretty sure it's at the back on the left, behind the drive sprocket. It will make the noise with the engine turning over in neutral. I've got the engine out and can get it to make the noise (sometimes) by turning the drive sprocket. I'm thinking I'm headed for getting the crankcase apart but would appreciate any words of advice before I start. Thanks in advance, Gordo Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 15, 2011 Moderator Share Posted May 15, 2011 Hi all, While I was out last week, the bike started making a bit of a racket with what sounded like a bearing playing up in the bottom end. I'm pretty sure it's at the back on the left, behind the drive sprocket. It will make the noise with the engine turning over in neutral. I've got the engine out and can get it to make the noise (sometimes) by turning the drive sprocket. I'm thinking I'm headed for getting the crankcase apart but would appreciate any words of advice before I start. Thanks in advance, Gordo morning gordo must say i'm a bit puzzled as to why it would make this noise "with the engine turning over in neutral" because the shaft you are questioning is stationary at that time? You need to isolate where its coming from I suppose. is it from the crank or is it from the transmission shafts...or the primary drive gearing? do the obvious like testing for play best you can. take off the primary drive crank gear and run the crank round by hand to check for noise etc. Spin the clutch basket checking for noise again If you really do have to split it you may have to put the primary drive gear back on and peg the con rod to enable the clutch boss to be undone, although it's better to have a proper clutch holding tool of course. (I know...unlikely for one of these old girls) Link to comment Share on other sites More sharing options...
DTGordo Posted May 15, 2011 Author Share Posted May 15, 2011 Yep thanks for that, I'll have a look tomorrow and see how far I get. I was thinking it's like a vibration in the bearing that hasn't got oil. You're right in that it's a bit wierd in that I can get it to make noise by turning the drive sprocket when in neutral and engine off but also that it is happens when the engine's running and in neutral and stationary. Good thing I'm on leave this week and can have some quality un-interupted tinkering time with the kids at school and the wife at work. Anyways, will post again when I know more.... Link to comment Share on other sites More sharing options...
DTGordo Posted May 17, 2011 Author Share Posted May 17, 2011 OK, Clutch basket is off. In neutral I can turn the main axle and the vibration and dodgy bearing feels like it's on the end of that inside the case. When it vibrates, it will start turning the drive axle a bit because of the vibration/friction. I can hold the drive shaft/sprocket, isolating it back to the main axle. There's a small hole on the side of the case where I can see inside a bit and the gears at the end of the shaft but not quite the offending bearing. I had a look on the parts diagram and can see a small bearing there which seems to be in the spot. Next step I'm thinking is to split the case to get at it.........? Link to comment Share on other sites More sharing options...
DTGordo Posted May 18, 2011 Author Share Posted May 18, 2011 Tracked down the vibration to the 4th gear cog being dry and not spinning freely on the drive axle. Cleaned up ok and with some oil spins nicely and doesn't appear to be damaged at all. Good time to check inside the crankcase as it had been sitting for a while with water in the oil before I got it. Bearings feel fine so will probably replace some seals if I can get them. Now to take a deep breath and fit everything back in...... Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 18, 2011 Moderator Share Posted May 18, 2011 I cant understand how it was dry unless the oil level was extremely low? Link to comment Share on other sites More sharing options...
DTGordo Posted May 19, 2011 Author Share Posted May 19, 2011 Yes, I'll need to put my hand up for the oil being low me thunks. Hadn't ridden it for a while etc etc. Schoolboy error. Bit of rusty looking grime around so I'm happy to get in there anyway. More soon... Link to comment Share on other sites More sharing options...
Moderator Cynic Posted May 19, 2011 Moderator Share Posted May 19, 2011 Being the voice of common sense here, while you have her down this far how about having at the output shaft bearing and seal by the sprocket. No mater how good you think it is it will have an amount of crud in it that has got past the seal and its the furthest from any lube so if 4th was dry then that bearing will have been too. Feel free to ignore the idea but for what? ten fifteen quid, its a cheap preventative measure, bearing (intended ) in mind its a total strip to get at it if it goes. Link to comment Share on other sites More sharing options...
DTGordo Posted May 20, 2011 Author Share Posted May 20, 2011 Thanks Cynic that's pretty much where I'm at with it too. I've been thinking about replacing all the external seals anyway as it would suck water into the case whenever I went anywhere near anything wet. I sent off a list to Mr bike shop yesterday and am just waiting to see the availability and prices..... Any other suggestions while it's all in little pieces? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted May 20, 2011 Moderator Share Posted May 20, 2011 ........Any other suggestions while it's all in little pieces? Check clutch plate thickness and piston ring wear (end gap) Link to comment Share on other sites More sharing options...
Moderator Cynic Posted May 20, 2011 Moderator Share Posted May 20, 2011 Thanks Cynic that's pretty much where I'm at with it too. I've been thinking about replacing all the external seals anyway as it would suck water into the case whenever I went anywhere near anything wet. I sent off a list to Mr bike shop yesterday and am just waiting to see the availability and prices..... Any other suggestions while it's all in little pieces? Don't ignore the genuine stuff, for my 175 the difference between genuine seals bearings and gaskets and patern ones was a whopping 20 quid. It was genuine all the way. All of 90quid all in. Link to comment Share on other sites More sharing options...
DTGordo Posted May 24, 2011 Author Share Posted May 24, 2011 I've got all the bits and pieces on order. I could get all the seals except the LH crank. Couple of questions: Mr shopman has Yamabond 3 which he was saying for the case. I'm not sure on that so any thoughts on this? And for the cover gaskets, does anyone use a sealant/bonding agent in addition to the gasket? I've never done this but saw this in a service manual. Otherwise hope to have it back together next week and clocking up he pushbike kms in the meantime. Thanks for the advice so far. Gordo Link to comment Share on other sites More sharing options...
Moderator Cynic Posted May 24, 2011 Moderator Share Posted May 24, 2011 I've got all the bits and pieces on order. I could get all the seals except the LH crank. Couple of questions: Mr shopman has Yamabond 3 which he was saying for the case. I'm not sure on that so any thoughts on this? And for the cover gaskets, does anyone use a sealant/bonding agent in addition to the gasket? I've never done this but saw this in a service manual. Otherwise hope to have it back together next week and clocking up he pushbike kms in the meantime. Thanks for the advice so far. Gordo To be perfectly honest i used red hylomar for the case to case seal and had no issues, as for the rest of the gaskets i did as i always have, light smear of HT grease. No such thing as RTS (the current silicone gasket sealent) when these were on the build run so why shell out for it. I have had no leaks on my DT. Link to comment Share on other sites More sharing options...
DTGordo Posted June 7, 2011 Author Share Posted June 7, 2011 Thanks for the feedback. It's all back together with no leftover bits. Had a short ride today and it's running nicely. Gordo Link to comment Share on other sites More sharing options...
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