Author Topic: Vibration-causes?  (Read 5109 times)

Offline BSA500

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Re: Vibration-causes?
« Reply #45 on: 13.12. 2012 09:53 »
Monobloc 376. I have checked the flange etc and not overtightened. Hopefully I am getting a dial gauge from Santa so I can use that to at least check the pressure plate. I suspect I may have overfilled the chaincase and got the plates quite wet as I had to wash the plates with petrol as they seemed to stick together and then used emery papaer to clean them up.It is just so cold at the moment I cannot be bothered to strip it all out again and check it over as I should. Also MOT in Jan and I need to tighten chains sort out a loose front brake plate. Roll on the week off at Christmas. BTW I had the vibration with the previous clutch but it needed replacing as the chainwheel and hub were well notched innit  *smiley4*
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Offline muskrat

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Re: Vibration-causes?
« Reply #46 on: 13.12. 2012 10:49 »
 First I would look at air leak. An old quick fix. Smear a good dollop of silastic around the flange, remove air filter, start and run till warm, give a few good revs and stop it by placing hand over the carb mouth. Leave overnight to set, clean off excess, don't use petrol or carb cleaner.
 Another place it can suck is around the slide if it or the body is worn. When closed the slide shouldn't move more than a few thou, more than 20 and it's on its way out.
 If all OK there I'd look at float height. These  http://www.amalcarb.co.uk/ProductDetail.aspx?Id=37397  are adjustable. Float height affects the whole range from 0 to full throttle.
Cheers
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Offline BSA500

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Re: Vibration-causes?
« Reply #47 on: 13.12. 2012 10:55 »
I don't use an air filter :!
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Offline muskrat

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Re: Vibration-causes?
« Reply #48 on: 13.12. 2012 11:06 »
Try one. That'll richen it up a bit.
Cheers
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Online bsa-bill

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Re: Vibration-causes?
« Reply #49 on: 13.12. 2012 11:18 »
Hi - been re - reading this thread, BSA500 your having far too much fun especially now it's so cold, I know what you mean I'm in NNE UK came in from the shed yesterday with feet I couldn't feel.
One thing bothers me a bit is your primary chain as I don't see you mention a new one and you have changed the chain wheel, probably you have renewed and checked the chain, but just in case you haven't, you should - renew it AND check the new one, my preferred method (preferred but not always stuck to) is put it on and adjust with the joiner at the top middle, check the lift, move the chain an of inch only and recheck, continue until the joiners is back at top middle, this will show up any tight spot and believe me new chains can have them.
As said you've probably covered this so none intended if you have

Quote
I don't use an air filter
not entirely needed in wet UK but might be an idea until you get the spitting back sorted (fire risk), might even help
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Offline BSA500

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Re: Vibration-causes?
« Reply #50 on: 13.12. 2012 11:25 »
I have a k&n in the shed I could throw on. The chain is new but I shall check for tight spots. This was replace along with the drive chain when I first started down the road of vibration detection with what I thought was the first problem of sleeve gear bushes. Its warmer in Kent today only -3 this morning happy days.
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Offline duTch

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Re: Vibration-causes?
« Reply #51 on: 14.12. 2012 09:54 »


Hey Andy, I can't suggest anything just now, but if any consolation, and at risk of sounding 'Off topic'- bike together, I started priming my oil situation(after rebuildish) the other day and detected a barely audible 'knock', which with more vigor became very audible, but narrowed it down to once per revolution at BDC, which doesn't mean sound is at bottom but that's the reference point.
 I'm fairly sure that as there's nothing else, it is the slightly larger-eye new Thunder Conrods only-just, by a bees-dick, contacting the oil scavenge bracket.
 Have it half stripped, and will finish tomorrow after more 'vocational disruption'- still means full guts out.

 I'm just saying this as to encourage lateral thinking, and no doubt it'll be the last thing you check.... *eek*
 cheers,and If I think of something will get on,
 duTch
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Offline Topdad

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Re: Vibration-causes?
« Reply #52 on: 14.12. 2012 10:33 »
bsa500, I've followed this thread and unfortunately my limited amount of knowledge has been passed by all the things already suggested and tried by yourself. You are an inspiration to us all and the speed that you strip and rebuild things is astonishing ,just don't let it get you down to much . My own two pennyworth now would be that it's something you've already looked at but which is being masked by one of the other newer problems, ( clutch, carb & timing etc ) keep at it and it will be worth it, by the way how many miles do you do a day ? very best of luck BobH 
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Offline BSA500

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Re: Vibration-causes?
« Reply #53 on: 14.12. 2012 11:32 »
Bob thanks for the encouragement. I do 26 miles a day getting a foot massage and rear. I still feel its around the drive side as most of the vibes seem to start there. I am not convinced by the balance issue it is just clutching at straws. I am sure it would benefit from a balance but the clutch/gearbox keeps nagging me. The easy option-when cash allows-is to build up the spare gearbox shell with new bearings and swop them over. This-if nothing else-can eliminate that side of things.
The clutch also bothers me because I replaced hub/chainwheel and friction plates and now it drags like a b*%$!^d. It crunches will not flick into neutral arrgggh. Its was working fine until I stripped it to check the crank one step forward 999 back  *sad2*
BTW muskrat checked the carb and the slide clicks about like a goodun ho hum could explain lean mix
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Offline BSA500

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Re: Vibration-causes?
« Reply #54 on: 14.12. 2012 20:47 »
I know off topic but an update to the clutch and carb issues.
Clutch- found i had cut the rod just a little short meaning I had to screw the adjuster right in and this was not the best leverage and had damaged the adjuster a little. So cut the rod hardened and put in a ball bearing. Seems much improved when flicking through the gearbox with the engine running.
Carb-slide well and truly shagged. For months I have been trying to track down a ticking/rattle which was getting worse sounded like the mag area. Yep it was the slide so knackered you can drive a team of fat horses past it.
Thats two steps forward *smile*
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Offline duTch

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Re: Vibration-causes?
« Reply #55 on: 15.12. 2012 23:12 »
 Hey Andy,
              Without going back through all the posts, I think someone suggested wheel balance..?
Does it rattle and shake at different revs in the 'workshop' too, or is it only when riding..?
Re the ball bearing, it may not be the case if the ends are hardened, but long ago I had something like that and and the ball either did or had potential to splay the ends of the rods and was suggested to me to use a 1/4" roller instead(better thrust area and less chance to go off-centre?)

  Good you got a couple of things sorted, I got my barrels off and upside down on a bench, and plenty clearance with scavenge pipe, so back to head scratching.
 cheers and good luck , duTch
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Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline trevinoz

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Re: Vibration-causes?
« Reply #56 on: 16.12. 2012 02:33 »
Dutch,
                It's not back lash in the timing gears causing the noise, is it?
Try it with the barrel off and no valve spring tension tending to push the cam back against direction of rotation.

Trev.
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Online KiwiGF

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Re: Vibration-causes?
« Reply #57 on: 16.12. 2012 06:52 »
Hi Dutch, or one of the 3 larger front primary chaincase bolts hitting the crankshaft?
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Offline duTch

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Re: Vibration-causes?
« Reply #58 on: 16.12. 2012 12:58 »

 Thanks guys, not intending to hijack Andys' gig here, but Kiwi no The plunger doesn't have those but in place(kind-of ), have two 'Hi-tech' stepped studs which carry the chain tensioner, but it's not that, was the first thing I thought of as had that issue way back.
 Trev, didn't actually think of gear-lash, but same gear train as before, same valves re-seated, same head-f*@# as yesterday. Not the scavenge pipe- heaps clearance.
Thought maybe something with the primary drive sprocket..- but seems ok apart from minor spline lash but have that doped up with Black grease (for splines).
 It is only there at ~BDC and seems bottom left side, but I know how sounds transmit- kindof!!
Throwing it back together, seems vocational joy won't interfere tomorrow, so may have a win?? It's all good practice anyway *conf*
  cheers
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Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline BSA500

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Re: Vibration-causes?
« Reply #59 on: 11.01. 2013 17:32 »
As I was riding home vibrating away I was pondering the gearbox main shaft being the issue, maybe. The only problem to my mind was how could the shaft suddenly get bent???. Then it came to me the bike was stolen in 2010 and recovered three days later after being ragged around the woods. Looks like I will have a use for the new dial gauge when I take the box down to do bearing replacement-watch this space.
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