start up clanking

(RIP) Kaister

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Ever since i've had it - 1100 -18k mls - its 'clanked ' whenever its just started. ( 9 times out of 10 )
Being reasonably technically minded i 'think' its the camchain or tensioner.
Does everyones do this ? Is it an oil pressure'd tensioner or has my tensioner had it ?

- or is is something completely different ?

Phil
 
Both my Oilheads have "Rattled on start up if that's what you mean........but goes as soon as the Oil gets to where it's going:p

They all do that Sir is what a dealer will tell you.

CC

:cool:
 
nope - its definitely more of a 'clank' than a rattle ,or a dink , or a whirr, or a whine , or a tinkle , or a clatter.

Phil
 
Ahhhh....

Is it when you just set off on the road/track?

If so it could be the ABS setting/self checking/mutilating itself.......if you have ABS that is.......if not.........you got me :confused:

CC

:cool:
 
nope - its not the ABS - thats more of a klack-klack- everyone knows that !

its a half engine speed clank - honest

does about 4 of them , then stops - exactly like a hydraulic camchain tensioner building up to pressure

Phil
 
Alternator belt a bit loose? Who knows but it's an easy one to check!...I just ride em.
 
Moto,

I took mine for new tyres today, the guy started the bike to move it into the workshop and said "cor, that's quite a clanking, innit!" I'd never thought anything of it but now I'm concerned.

Does your's still "clank" or has it fallen to pieces/exploded into shrapnel/become posessed by a ghost?

Is it autumn where you are now?

Cheers,

simon
 
Yep, mine usually gives a sharp 'clack' when first started. I assume it's the cam-chain tensioner giving the chain a good clout.
 
Originally posted by motomartin its a half engine speed clank
Phil, are you a musician? If not, you have a good ear, because you are correct. Here is an explanation of the origin of that noise:discussion on LCCT
Here is a DIY pictorial explanation:LCCT replacement or in pdf.
Most people do a replacement of the left cam chain tensioner to correct a clanking at idle, but it also helps a lot with the startup noises.

Carlos
 
Okay, I've looked at the tensioner replacement explamanation and it looks very do-able, but...what's the worst that could happen if i ignored it and hoped it would go away?
Fingers in ears and lalalalalala whenever I started the bike kinda thing?

I've got to say that it's a beautiful description, and very well photographed too.

Ta

Simon
 
Does your's still "clank" or has it fallen to pieces/exploded into shrapnel/become posessed by a ghost?

Blimey - this is a while back....

I sold that bike when i moved from the UK - looking back, i think it was 'possibly' the cam chain tensioner.
However, it never got worse and was better after a semi-synth oil change.

However, i've now got almost exactly the same bike here in Aus. - and this 'clanks' very occasionally too.

I've also seen the thread on advrider about the tensioner change, but haven't seen this new one yet ( above ).


Autumn is starting here - cloud and rain this week - cooling down to 20-ish deg C
Spring and Autumn seem to be the best for biking here - much more manageable temps.

cheers guys :thumb

relevant text copied here - applicable to ALL oilhead motors


The SYMPTOM: with the engine warmed up, between idle and 2000 RPM it sounded like it had spun a rod bearing. With a mechanic's stethoscope, I found that the noises were loudest 1) at the fastener that holds the top of the fixed left cam chain rail, and 2) at the left cam chain tensioner.

The SOLUTION: BMW enhanced left cam chain tensioner, part 11 31 2 325 563.

The PROBABLE CAUSE: open up the left valve cover and turn the engine manually. As the crank rotates, it also turns the camshaft by means of the cam chain. However, when the intake valves begin to close, their springs push on the cams hard enough for the camshaft to suddenly “pop” and lead the crank. When this happens, the tension in the chain reverses: the section under the tensioner becomes taught and the lower half of the chain sags. This load reversal also causes the tensioner to fully compress. In other words, the tension in the chain varies enough in one revolution to cause chain flutter and the corresponding bottoming out of the tensioner plunger. In its “normal” installed position, the whole tensioner assembly is about 71.5 mm long. In this position, the plunger has about 10 mm of play.

The DIAGNOSIS: to ascertain that the cause of the noise was chain flutter, I reduced the amount of plunger travel by inserting a steel rod inside the tensioner spring (try this at your own risk!). I found that a 56 mm rod reduced the play in the tensioner from 10 mm to only 3 mm. The result is dramatic: all you hear when the engine is running is a light ticking, similar to a loud injector.

The REASONS THE NEW tensioner WORKS: the enhanced tensioner is a two-piston design. The spring is invisible and it is hidden inside the larger piston (plunger). The operation of the device is not obvious, but there are several clear reasons why it would apply more force to the chain rail:
-spring force is about twice that of the standard design
-there is no oil drain slit on the plunger’s wall, as there is on the standard one
-oil cavity volume is minuscule compared to standard, and it does not empty when the engine shuts off. Oh yeah, startup clanking noises are nearly gone too!!
-plunger diameter is slightly larger, so more force at equal oil pressure
-once installed, plunger travel is about 5 mm, as opposed to the 10 mm in the standard one.

THE INSTALLATION: piece of cake. Losen the three clamp rings, slide the intake of the left TB out of the way, and slide the TB out of the intake boot. The tensioner is the bolt behind the TB. Substitute the tensioner, put together, and you're done in 10 minutes!

The APPLICABILITY: as far as I can tell, the part number is valid for all oilheads, even the 1100. I used it on an R1150R. I would not use the part if you do not have a problem with the chain noise. The tensioner clearly puts more force than the standard one, and there could be more wear on the chain guide. I wish we could get some technical information from BMW. Unfortunately, they are the most secretive automotive company I know.
 
Slimie said:
...what's the worst that could happen if i ignored it and hoped it would go away?
Simon,
The noise won't go away. However, I have not seen any evidence that the noises do any harm to the engine I find it really surprising that I haven't heard of any chain rails breaking. In fact, it is the enhanced tensioner that could accelerate wear, since it puts more pressure on the chain. Therefore, replace the tensioner with the enhanced one only if you have a noise problem. I did it, and I am delighted with the results.
Also to be considered: the new tensioner is more expensive than it looks: list price is more than $200!

Carlos
 
Thanks for all the information, I didn't worry till it was mentioned at the weekend, I'll try the semi-synth next change and see it that helps, if not the tensioner change looks straightforward.

Moto, enjoy the riding, I've been dreaming of 20ish deg C!

Thanks again

Simon
 


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