'Clunking' feeling on rearsets

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enekoizagirre

enekoizagirre

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Jun 8, 2010
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Hi everybody,

I finished my '73 850 Roadster rebuild (complete, engine and gearbox included) a couple of months ago, and mainly thanks to this forum, the bike is running great (new electrics, Comnoz breather mod, Lansdowne damper kits, .....).

'Clunking' feeling on rearsets


There's just one little thing that's annoying me: I've installed Norvil rearsets and there's a strange clunking 'noise' I can feel through them sometimes, specially when I open gas hard. It's not constant, and not always, it's more critical when the engine is cold. I've checked belt and rear chain tension and everything is OK. The gearbox has been rebuilt and apparently works well (at least shifts perfect, both upward and downward). Could be a problem with the swingarm? Maybe this is just normal, I don't know, but I would appreciate your expert opinion.

Thank you very much

Eneko
 
Clunking or Clanking ? :lol: or rattling . :?

You could get a rattly buzz from stock ' pin ' linkages , on the gearshift . Heim Joints being Zero Slak , in the link rod , are superior . :)

Grasped securely , is there any slack / rock , in the pedals ? . Dry Lube - graphite or that wierd silver grese could eliminate .

I HOPE ITS NOT IGNITION PINKING / DETONATION . :shock: A crankey tuned up engine will do it on pump gas occasionally , or on some
pump gas ALL THE TIME at a certain R.P.M. / throttle setting / opening . ( bottom of the slides / around 2-500 . 3.000 ) as the wallys
brought up the throttle to hard . And is wrecking the rings .

Correct thingo is to milk the throttle a way , and if its Ign. Adv. related - fit heavier Adv Springs , a BSA Auto Adv unit , or NOT use
that throttle setting at those RPMs . Or Ride Quicker , so it goes straight through it and lifts the front instead . :D
 
Forks topping? I realize it's sort of a stretch but, hell, ya never know. The other more logical thought would be ISO's, with the out rubbers shot and you get a hit from the inners.
 
Primary cover hitting "Z" plates which receive the foot pegs? Check for witness marks between the inner primary cover and the LH "Z" plate.
 
Dances with Shrapnel said:
Primary cover hitting "Z" plates which receive the foot pegs? Check for witness marks between the inner primary cover and the LH "Z" plate.
Click to expand...
Yes, also perhap due to iso's.
 
Dances with Shrapnel said:
Primary cover hitting "Z" plates which receive the foot pegs? Check for witness marks between the inner primary cover and the LH "Z" plate.
Click to expand...


+1
 
Thanks for your answers

Matt Spencer said:
Clunking or Clanking ? :lol: or rattling . :?

You could get a rattly buzz from stock ' pin ' linkages , on the gearshift . Heim Joints being Zero Slak , in the link rod , are superior . :)

Grasped securely , is there any slack / rock , in the pedals ? . Dry Lube - graphite or that wierd silver grese could eliminate.
Click to expand...

I have no linkages, the gearshift pedal is a reversed one, so I don't think this is the problem. And I don't think it's something related to detonation as it's not always at the same rpm.

Forks are not topping, they work great, and the feeling is clearly on the rearsets.

I'll check hitting marks betwen the primary and the z plates.

Thanks everybody.

Eneko
 
Nice looking bike. I get a clunking on slow overrun, like going down a hill slowly. One other thought to add, maybe the centre stand is knocking. you could try lashing it fully closed to see if it stops the clunks.
cheers Richard
 
Loose cradle bolts? Kink in mis guided O-ring type chain snatching into tooth valley? ioslastic hop up front causing head stead to clank? Rear drum paddles twisting in the slots?
 
Is the clonk on both sides at the same time. or just one side?

enekoizagirre said:
Hi everybody,

I finished my '73 850 Roadster rebuild (complete, engine and gearbox included) a couple of months ago, and mainly thanks to this forum, the bike is running great (new electrics, Comnoz breather mod, Lansdowne damper kits, .....).

'Clunking' feeling on rearsets


There's just one little thing that's annoying me: I've installed Norvil rearsets and there's a strange clunking 'noise' I can feel through them sometimes, specially when I open gas hard. It's not constant, and not always, it's more critical when the engine is cold. I've checked belt and rear chain tension and everything is OK. The gearbox has been rebuilt and apparently works well (at least shifts perfect, both upward and downward). Could be a problem with the swingarm? Maybe this is just normal, I don't know, but I would appreciate your expert opinion.

Thank you very much

Eneko
Click to expand...
 
enekoizagirre said:
I've installed Norvil rearsets and there's a strange clunking 'noise' I can feel through them sometimes, specially when I open gas hard. It's not constant, and not always, it's more critical when the engine is cold. I've checked belt and rear chain tension and everything is OK. The gearbox has been rebuilt and apparently works well (at least shifts perfect, both upward and downward).
Click to expand...

Further to my note about checking witness marks between the "Z" plate and primary cover, since this seems to be temperature related you should check the trans mount bolts and all engine to cradle bolts for tightness (as mentioned earlier in this thread). The engine and trans have a significantly greater thermal coefficient of expansion than the steel through bolts so "colder = looser". Maybe there's one or more marginally loose ones. You can check for witness marks but may as well just go over the bolts with wrenches and then you know.
 
Hi everybody,

John, the feeling is on both rearsets.

I didn't get the time to go to the garage yet, I hope tomorrow morning I'll be able to check all the ideas you propose...

Piero, fa un suono come clank-clank-clank... :D

Thank you all!

Eneko
 
... looks so easy once you know what it's all about...

I had lost number 34 in the next diagram (and part of my pride, I have to say...)

http://www.nortonmotors.de/ANIL/Norton% ... &Plate=013

but I didn' notice untill I lost the bolt also (number 32)...

I've replaced both of them and the bike is running great, no more noises, feelings, paranoia... :roll:

Thanks everybody for your advice!!

Eneko
 
[

Hows the Lansdowne Damper,Better than the Originals?
quote="enekoizagirre"]Hi everybody,

I finished my '73 850 Roadster rebuild (complete, engine and gearbox included) a couple of months ago, and mainly thanks to this forum, the bike is running great (new electrics, Comnoz breather mod, Lansdowne damper kits, .....).

'Clunking' feeling on rearsets


There's just one little thing that's annoying me: I've installed Norvil rearsets and there's a strange clunking 'noise' I can feel through them sometimes, specially when I open gas hard. It's not constant, and not always, it's more critical when the engine is cold. I've checked belt and rear chain tension and everything is OK. The gearbox has been rebuilt and apparently works well (at least shifts perfect, both upward and downward). Could be a problem with the swingarm? Maybe this is just normal, I don't know, but I would appreciate your expert opinion.

Thank you very much

Eneko[/quote]
 
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