981 Clutch oil seals and tank colour and JETS

[Husabergpete]

Hi Gents,

Had the 1973 380 going with new Vape Ignition. Brilliant.

New issue is oil leak behind the dry clutch.

Question - what are the sizes and or id numbers for the seal (and type maybe)  and oring/s   ?  Possible 50 x 65 x 8 mm but not sure if single or double lip, or spring etc if it matters.

Question - size of the Oring on the kick starter shaft ?

Question - I want to paint a steel tank in the original '73 Blue colour. Any idea what the colour code is or close to it?

Many thanks once again

Pete

[tony27]

I use a viton seal for the clutch, deals with heat better than the normal nitrile seals. Can't remember the size at the moment but know like all the seals & o-rings they are available from most bearing or seal suppliers
I feel that where the leak generally comes from is not the seal but the o-ring on the back of the clutch hub, the step that the o-ring sits on is larger than the o-ring thickness so all the sealing work has to happen on the outside diameter. I modified my sidepiper clutch by having the step ground down to 1.9mm & a new thicker washer made to keep the stack height the same, basic idea was to sandwich the o-ring, so far it's worked perfectly
I have a look in my parts book on Wednesday for the sizes if you want

[Husabergpete]

Thanks Tony. You are a champion.

Much appreciated.

I am in touch with my local bearing supplier and will change it to Viton etc.

Might look at that mod as well.

Kind regards

Pete

[tony27]

Clutch seal is 50x65x8  The seal I have sitting here has 2 lips, 1 at each side

O-ring for clutch hub is 26x2
O-ring for primary gear that seals the clutch basket is 35x4
O-ring for kickstart shaft that sits inside the cover is 20x2

Hope that helps

[Husabergpete]

Thanks so much Tony. Got a couple of them yesterday and the rest on order.

Had another win yesterday. Got hold of an original 1974 parts book. Will do electronic copy soon for who ever needs it. Super helpfull book

Cheers

Pete

[tony27]

Yeah I have the 74 parts book as well, the 73 manual from bear motorsports has the parts book in the back as well so it's well worth getting, also have their sidepiper manual

[Husabergpete]

Hi ya Tony,

Now the clutch seems fixed I got it hot and found the jetting was a little lean.

Not sure if you have a favoured mix of jets - looks like a newish 36mm Mikuni

I just took it apart again so I'll document what is in it.

Main  280

Nozzle Jet   159  Q 5

Needle  6F5

Clip was in the middle  - as of yesterday dropped the clip one down - richer and it went a lot better

Pilot - 25

Slide 2.5

Air Screw was at 1 and Half

Im going to do some searching now.

For future reference the Clutch Seals and Bearings are as follows

The 2 needle bearing inside the clutch are K 25 x 30 x 13  ( C3's )

Item 26 is an ORing 43 x 35 mm

Item 8 is an ORing  26mm ID and 2mm diameter/thick

The Kickstarter seal is an ORing  24 x 20mm

And the main seal that goes in the clutch cover is 50 x 65 x 8  double lip with a spring - I used the normal black one because the Viton was only single lip I could get and wouldn't have worked.

Cheers Pete

 

[tony27]

Jetting seems close to what I used when my bike was still piston port except I ran a 45 pilot jet, can strip down the carb & confirm tomorrow

[Husabergpete]

Hi Tony,   Just back from overseas and see your last post about checking the jetting in your bike.

I noted you were using a 45 Pilot. Mine improved a lot from the 25 pilot in it to the 37.5 (which I had at home).  Just about to order a bunch of extra pilots and a few mains from Hadrick now.

I also got hold of an original 1974 owners parts list from Adrian's dad. I have made a PDF copy and a paper copy. Let me know if you could use the PDF.

Kind regards

Pete

[Husabergpete]

JET SPECS TAKEN FROM SPREADSHEET PROVIDED IN THIS THREAD

CZ 125 MX -72   VM 32   200   35   Q6   5FJ9   -   3.0   
CZ 250 MX -66   VM 32   240   35   Q6   6FJ6   -   3.0   
CZ 250 MX -66   VM 34   230   35   Q8   6FJ6   -   3.0   
CZ 250 MX -71   VM 34   210   35   Q5   6DP5   -   
CZ 250 MX -72   VM 34   240   40   Q8   6FJ6   -   3.0   
CZ 250 MX   VM 34   210   35   Q5   6DP5   -   
CZ 250 MX   VM 36   260   35   Q5   6FJ6   -   1.5   
CZ 250-380 MX   VM 34   300   40   Q6   6FJ6   -   2.5   
CZ 250-380 MX   VM 34   310   45   P8   6DH3   -   
CZ 360 MX -67   VM 34   250   35   Q6   6DP5   -   
CZ 360 MX -67   VM 34   230   45   Q6   6F5   -   2.
CZ 360 MX -67   VM 34   240   40   Q8   6FJ6   -   2.5   
CZ 380 MX   TM 36   290   45   Q6   6FP17   -   
CZ 400 MX   VM 34   230   30   Q5   6DP5   -   
CZ 400 MX   VM 36   280   25   Q5   6FJ6   -   2.5
CZ 380 MX   VM 36   350   45   Q8   6FJ6   -   1.5   
CZ 380 MX   VM 34   320   45   P8   6DH3   -   
CZ 380 MX -66   VM 34   260   35   P0   6DH3   -   2.5   
CZ 380 MX -69   VM 34   320   45   P8   6DH3   -   2.5   O. Persson
CZ 380 MX -71   VM 34   230   30   Q5   6DP5   -   2.0   AMS Racing USA
CZ 380 MX -72    VM 36   290   45   Q5   6FJ6   -   2.0   R.L Dengler
CZ 380 MX -72    VM 36   270   45   Q6   6DH2      3.5   Pete Maly specs
CZ 380 MX Reed Valve   VM 36   430   45   Q8   6DH3   -   2.5   C.M.

[Husabergpete]

27..01.24 jetting changed which improved it a lot.

Original 25 pilot changed to the 37.5 and now a 45. Great improvement.

After that it was still prone to increased revs by itself just above quarter throttle.

So left the Q5 in and replaced the 6F5 needle with a 6FJ6 (both middle clip)  No more self over rev.

Ridden around street, hot, but will need to get a track day to maybe increase the Main from the 280. See how we go.

Cheers
Pete

[Husabergpete]

Improved again.

50 pilot and 300 main and then raised the needle one step by dropping the clip one grove down from the middle groove....

Cheers

Pete

[PeterC]

Great work making progress