Clutch

stuart jenkins

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So yesterday my clutch plate decided to lunch itself on the M25... all ended well and was home within a few hours!
It was one of the only things I didn’t replace after an engine refresh over Christmas, I now realise I should have. One of the things I did do was put in a new Siebenrock asymmetric cam, with this, and previous mods, the engine does feel a lot more torquey, and I’m wondering if it is now a bit much for the standard r80 clutch? Does anyone know if the oil resistant clutch plate that Motobins/Motorworks sells are anymore robust?
Cheers
Stuart
 

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I wouldn't use the Oil resistant

I have built a great many engines ove rthe years but still prefer the standard set up so far

I have pulled the fancy clutches out of most of them and replaced them with a new standard one

Most common complaints

"It's a very heavy pull"
"It's very grabby"
"It's hard to get a nice biting point!"
"It's either on or off!!!"

You'r plate was how many years old? Looks like metal fatigue

Or you possibly have an issue with cable or the release mechanism

OR you are simply just hard on the clutch letting it out with a bang instead of "easing" ??
 
I’d agree with what has been said above.
What other mods have been done to the motor?
I’ve found that 1000cc high comp pistons,fancy cams etc can be a bit much for the standard clutch.
They will slip under full load.
 
mikeyboy said:
I’ve found that 1000cc high comp pistons,fancy cams etc can be a bit much for the standard clutch.
They will slip under full load.
Click to expand...

I have to disagree there Mike

I have about 3 customers 2 with 1070 Seibenrocks and one 800 - 1000 Seibenrock Conversion which all came in to have the HD seibenrock ones pulled out

A complete new clutch assembly (properly adjusted) has held up well in each case for over 5000 miles and in one 22000 miles now

(All ridden "briskly" by an Ex racer and Ex Polis Escort rider and a long distance ADV rider )
 
My red scrambler,prob pushing 65/70 hp clutch let’s go at max power.
Talk to RM.at 70 bhp the standard clutch won’t cut it,
End of,sorry jay.
 

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What happened when the clutch disintegrated on M25, did it jam and lock back wheel or the opposite with no connection at all between gearbox and crankshaft?
 
mikeyboy said:
My red scrambler,prob pushing 65/70 hp clutch let’s go at max power.
Talk to RM.at 70 bhp the standard clutch won’t cut it,
End of,sorry jay.
Click to expand...

We will have to Agree to Disagree

I know what I have seen and I had reservations about going standard with the first 1070 but fitted all new bar the flywheel as such and they still cope and don't let go at full poke

Forgot I had Richie Moore built engine fitted to an R100R which went standard too, to add to the list

A K10016V is not much different dimension wise and copes with 100 BHP plus when chipped and free flow Air filter and Remus

I will give you this!

If you are slipping it lots to drive it on You WILL cook it! End off!

There is not enough ventilation in there to dissipate the heat in that instance, Once heated they are never right after!! :rob

AND looking at the Original Post the two pressure plate components look blued to blazes

"Wondering" if that centre boss was stuck on input shaft and there was a lot of flexing causing fatigue in the web and then the breakage

Certainly shows its better to do a complete job rather than Assume the next bit down the line will be okay
 
Hi There,
Clutch wasn't slipping before this happened, had around 1000 miles on the engine since putting the cam in. Engine specs are Siebenrock 1000, gas flowed, twin spark, and the cam. I didn't replace the two pressure plates when the fiction plate and spring were replaced about 50,000miles ago, and there is definately wear on them, and uneven in places. Think I'll replace the whole lot with oem parts, and if it does slip, think about an upgrade latter.
Luckily when it happened I just lost drive, nothing locked up or jammed, and the M25 wasn't to busy, so could coast to the hard shoulder. There are a few marks inside the clutch housing but not to deep, so luckily I haven't got a holed the crank case or sump area!
Cheers
Stuart
 
stuart jenkins said:
Think I'll replace the whole lot with oem parts, and if it does slip, think about an upgrade latter
Click to expand...

Good call and likely cheaper than Snake Oil fancy stuff, that is not needed :green gri

Just make sure you leave the slack in the cable/clutch arm arrangement :rob

If they are tight (because you hunger for that immediate response etc etc etc Blah blah) even a mm just a mm of activation will make them slip :rob

While you are in there check the oil pump cover for leaks etc and your Crank seal !

there's a 59 x 3 mm O ring on the crank boss and just use a Double lip 100 x 80 x 10 Oil seal on the crank and not those stupid BMW ones!

makes sense while you are in there

Plenty of Info out there on them But feel free to ask a question or message if you want
 
stuart jenkins said:
Clutch wasn't slipping before this happened, had around 1000 miles on the engine since putting the cam in. Engine specs are Siebenrock 1000, gas flowed, twin spark, and the cam.
Click to expand...

Did you change to the Seimens Ignition kit for the more variable advance curve ?? Definitely a worthy add on for your motor

That must a Really Lovely Torquey set up

Health to ride :thumb
 
DrFarkoff,
Yes, replaced crank seal and oil pump o-ring when I had it apart at Christmas, so no leaks there :thumb
Went with bending in the bean can 'tabs' to change the advance curve and timed it accordingly, happy with that for the time being until funds allow otherwise!
Happy riding
Stuart
 
Just an update, new clutch assembly all fitted, and the bike is running sweet...

...Next bit of fettling is to upgrade the forks!
 

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stuart jenkins said:
Just an update, new clutch assembly all fitted, and the bike is running sweet...

...Next bit of fettling is to upgrade the forks!
Click to expand...

So what are the forks you are upgrading with, and where did you get them , cost, etc...

Or am i recalling (from another thread) that you are an engineering genius who has done most of this yourself?
 
michaelmy said:
So what are the forks you are upgrading with, and where did you get them , cost, etc...

Or am i recalling (from another thread) that you are an engineering genius who has done most of this yourself?
Click to expand...

Hi Michael,
The forks are W/P Extremes 50mm, off a KTM lc4 620 I think 1997. Ive restricted the travel to 200mm (originally 290mm) to make the more in line with the G/S length. Mods I did to the frame and swingarm last year gives me 25mm more hight at the rear, i want to keep the geometry as close to the standard G/S as possible as I like the way it handles. Triple clamps are off a Hyosung GT650, as they have the right amount of offset (and only cost me £35), I would love a pair of custom made triples but they're £££! Bottom steering bearing is same as Airhead, top is 25 I/d so have got a 52/25/16.5 to fit. I had to make sleaves to take the fork tubes because they are 51mm top and 54mm bottom on the triples (forks are 50mm).
I'm going to get them all together then think about springs and if they need to be re-valved for the heavier airhead. I may experiment with cutting the springs down to increase spring rate first, and then think about if I need to have some springs made, as with most things at the moment budget is small (as in sweet F A) so progress is slow and all avenues are considered before out laying £!
Hope this helps.
Cheers
Stuart
 
Good choice on forks - I had those on my 640 Adv and they were superb.


Sent from my iPhone using Tapatalk Pro
 
Nin said:
Good choice on forks - I had those on my 640 Adv and they were superb.


Sent from my iPhone using Tapatalk Pro
Click to expand...

:thumb Didn't want to go the upside down fork route, these supposed to be some of the best of the bunch for conventional forks.
 
Yep. The biggest diameter fork made apparently.


Sent from my iPhone using Tapatalk Pro
 
Thank you - Stuart ! Good luck with all of that !

stuart jenkins said:
Hi Michael,
The forks are W/P Extremes 50mm, off a KTM lc4 620 I think 1997. Ive restricted the travel to 200mm (originally 290mm) to make the more in line with the G/S length. Mods I did to the frame and swingarm last year gives me 25mm more hight at the rear, i want to keep the geometry as close to the standard G/S as possible as I like the way it handles. Triple clamps are off a Hyosung GT650, as they have the right amount of offset (and only cost me £35), I would love a pair of custom made triples but they're £££! Bottom steering bearing is same as Airhead, top is 25 I/d so have got a 52/25/16.5 to fit. I had to make sleaves to take the fork tubes because they are 51mm top and 54mm bottom on the triples (forks are 50mm).
I'm going to get them all together then think about springs and if they need to be re-valved for the heavier airhead. I may experiment with cutting the springs down to increase spring rate first, and then think about if I need to have some springs made, as with most things at the moment budget is small (as in sweet F A) so progress is slow and all avenues are considered before out laying £!
Hope this helps.
Cheers
Stuart
Click to expand...
 
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