Slipery clutch keep me away from my own record on the 1/8 mile

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yves norton seeley

yves norton seeley

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To day must be the day of the judgment, but a slipery clutch decide another way...
I was very curious to see if all the work on the engine would help me to break my best time on the 1/8 mile: 08.857 seconds I did at 2012
The slipery clutch keep me away to go around 07.000 seconds
I did 100kms to go to the Drag track and the engine was going as hell, but on public roads I never do a drag start, so I was very confident for today, but at my first run it was a disaster, it was like riding on oil... usualy a go full in 3 gear, from the 5 from my TTI gearbox, to day I use only two gears becouse of the clutch. Result: a very poor 09.245 seconds with a reaction time from 0.202 seconds.
I go back home with the Seeley w/o any clutch problem, but w/o drag starts on the traffic lights.
Now I have to find a solution for the clutch, next year I wish to do the 1/4 mile at Santa Pod in the UK.
If you have any advise for my clutch, feel free to give it to me, at the moment the clutch is 100% original Commando
Thanks
Yves
 
Before any run it would be a good idea to pull the plates out give them a good clean and the plates a bit of rough up with some sandpaper some fresh tranny F oil with between 5 to 7 fl oz and no more, other than that you should have no problems unless your adjustment is out.

Ashley
 
"at the moment the clutch is 100% original Commando"
I am assuming you have triplex chain and stock clutch basket.
Maybe think belt drive and drop a tooth for final sprocket on gearbox. Most belt drives up the ratio by one tooth of original Commando gearing.
Cheers,
Thomas
 
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The Norton clutch WILL slip when oil is present, as discussed here:

https://www.nortonownersclub.org/support/technical-support-commando/clutch

Perhaps the most impressive mod is the heinz-kegler norton servo clutch mod that can be applied to both the commando and Domi clutch I’ve seen it don on the Commando but I have lost the post or it has be removed. Here’s what it will look like on say a Domi with the clutch cage filed/machined down on the power/ take up side, scroll down to N0rt0nelectr@, Jul 31, 2018;

https://www.accessnorton.com/NortonCommando/electric-starter-for-matchless-single.24204/page-2

Found the commando clutch post;


https://www.accessnorton.com/Norton...ne-of-these-amc-gearbox-clutch-centers.10997/
 
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Looking for the positive! with the 850 no clutch slip! with the 920 clutch slip! Could be more mid range power :D

Wash the plates, check the set up, as has been said. Be very careful to use a minimum of ATF in the chaincase.

Changing to belt drive is a lot of money for little return, it would only provide benefit once or twice per year.

A 30mm belt will be needed to allow you to retain the alternator, your 920 will give that a hard time every other time you ride it!.

So an alternative is no oil at all in the chaincase! :eek: Instead just boil the chain in chain grease and pour some of the liquid grease into the clutch bearing (or fit a sealed bearing).

For a 1/8th mile drag strip you could trailer the bike to the event, or ride very carefully to keep everything lubed!

After the event you could remove and clean the chain, but to ride home you probably just need to put some oil in!

In the 1970s I ran a Commando clutch drum dry with a triplex chain for my circuit racing using Linklyfe as above, the clutch did not slip. I was using fibre plates, but I don't think that makes a lot of difference.

The main difference between what I was doing and what you are doing is that in those days we did push starts which were easier on the clutch! Though it had a close ratio 4 speed, so still had to cope with slipping the clutch at hairpins! I ran this set up for 4 race seasons.
 
Hi Yves , though I never tried them , they could may be solve the problem
https://www.rgmnorton.co.uk/buy/bronze-clutch-conversion-with-5-hi-torque-bronze-plates_855.htm
, but if you have the lathe , you can do as Ludwig did it , simply turn out the inside diameter off , from the steel clutch plates .......though I see RGM only supplied one modified steel clutch plate ? or if you have any spare bronze one , you could try to imitate RGM ones ........! cheap ( I am!).
 
ashman said:
Before any run it would be a good idea to pull the plates out give them a good clean and the plates a bit of rough up with some sandpaper some fresh tranny F oil with between 5 to 7 fl oz and no more, other than that you should have no problems unless your adjustment is out.

Ashley
Click to expand...
Hi Ashley,
Yes I know, I am culty, in the last two weeks I was concentrate on the Keihin FCR carbs setting, with very good results, but I don't pay any attention to the clutch, the years before I strip the clutch and give a good clean.
This year I pay only attention to the adjustement...
I use 7 fl oz Harley Davidson primary transmission oil
What is tranny F oil?
Thanks
Yves
 
CanukNortonNut said:
"at the moment the clutch is 100% original Commando"
I am assuming you have triplex chain and stock clutch basket.
Maybe think belt drive and drop a tooth for final sprocket on gearbox. Most belt drives up the ratio by one tooth of original Commando gearing.
Cheers,
Thomas
Click to expand...
Hi Thomas,
In the pass I try different belt drive system, but no one give me full satisfaction, so I use the good old triplex chain.
The gearing I use is 23 x 36, maybe I should try a 23 x 38, but I wish to use 3 gears only becouse every gear change is a lost of time and I dont wish to go in 4 for the last 20 feets from the 1/8 mile
Thanks
Yves
 
Bernhard said:
The Norton clutch WILL slip when oil is present, as discussed here:

https://www.nortonownersclub.org/support/technical-support-commando/clutch

Perhaps the most impressive mod is the heinz-kegler norton servo clutch mod that can be applied to both the commando and Domi clutch I’ve seen it don on the Commando but I have lost the post or it has be removed. Here’s what it will look like on say a Domi with the clutch cage filed/machined down on the power/ take up side, scroll down to N0rt0nelectr@, Jul 31, 2018;

https://www.accessnorton.com/NortonCommando/electric-starter-for-matchless-single.24204/page-2

Found the commando clutch post;


https://www.accessnorton.com/Norton...ne-of-these-amc-gearbox-clutch-centers.10997/
Click to expand...
Very intresting
Thanks
Yves
 
yves norton seeley said:
If you have any advise for my clutch, feel free to give it to me, at the moment the clutch is 100% original Commando
Thanks
Yves
Click to expand...

Which clutch plates and how old (strong) is your diaphragm. You could take out your plates at the track and replace them with a set of dry fibre plates and wipe the oil from the steel plates. You would also need the correct pressure plate if you don't use the fibre plates now. If you want it even more grabby, you could sand blast a set of plain plates and change all plates at the track. Of course, run without oil for the drag runs.

We accidently tried this due to recovering a clutch. Needed to clean the steel plates so blasted them, put in new fibre plates, used a new diaphragm, and forgot to add oil. The clutch was very grabby and I suspect that the chain was not very happy is it was very clean as well.
 
Yves, you can also change out a steel plate or 2 for a thinner plate. This lowers the stack height of plates and gives a better grip between the plates, because the spring diaphram is near it's furthest extension point with a lower clutch plate stack height and is therefore exherting it's greatest pressure. The downside of doing this is that your clutch lever gets very hard to pull also. You could change plates for the drag race then change them back to ride home. With a wet primary case, it's a messy job to change plates. With a dry case (belt drive) it's an easy change...

good info here on dyno dave's site: http://atlanticgreen.com/ndnsclutch.htm
 
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SteveA said:
Looking for the positive! with the 850 no clutch slip! with the 920 clutch slip! Could be more mid range power :D

Wash the plates, check the set up, as has been said. Be very careful to use a minimum of ATF in the chaincase.

Changing to belt drive is a lot of money for little return, it would only provide benefit once or twice per year.

A 30mm belt will be needed to allow you to retain the alternator, your 920 will give that a hard time every other time you ride it!.

So an alternative is no oil at all in the chaincase! :eek: Instead just boil the chain in chain grease and pour some of the liquid grease into the clutch bearing (or fit a sealed bearing).

For a 1/8th mile drag strip you could trailer the bike to the event, or ride very carefully to keep everything lubed!

After the event you could remove and clean the chain, but to ride home you probably just need to put some oil in!

In the 1970s I ran a Commando clutch drum dry with a triplex chain for my circuit racing using Linklyfe as above, the clutch did not slip. I was using fibre plates, but I don't think that makes a lot of difference.

The main difference between what I was doing and what you are doing is that in those days we did push starts which were easier on the clutch! Though it had a close ratio 4 speed, so still had to cope with slipping the clutch at hairpins! I ran this set up for 4 race seasons.
Click to expand...
Hi Steve,
Yes the 920 and big valves conversion give me a lot of HP more and this must be one of the reasons of the slipery clutch. But I don't have 100 HP, maybe 75...
I remember when I was a Side car rider and using 620cc Konig engine, 120HP, with different gearboxes like Quaife or Shaftleitner, I was always using the Norton clutch with a morse primary chain, so the clutch was runing dry, and never a problem with the clutch, even in hillclimb where you start as in a drag race with two persons on board
Yes I can trail the bike to the event and run w/o oil
Thanks
Yves
 
Every vehicle I've experienced clutch slippage with slips most in top Gear.
Often there is no noticeable slippage in the first couple of years, maybe just a tad in 3rd and then noticeable slippage in fourth ( or 5 th with 5 speed)
So if it's slipping in the intermediate gears it must really be slipping in top.
Changing the stack height can increase or decrease the amount of spring pressure on the clutch.
You might need a bit more spring pressure.
The Atlantic Green site did have good info on this, not sure if it is still on there.
Also, there should be lots of info on the same subject right on this site.
Do a search using " Clutch Stack Height" as key words.
If you get it to stop slipping in top, it won't be slipping in the intermediate gears at all.

Glen
 
marinatlas said:
Hi Yves , though I never tried them , they could may be solve the problem
https://www.rgmnorton.co.uk/buy/bronze-clutch-conversion-with-5-hi-torque-bronze-plates_855.htm
, but if you have the lathe , you can do as Ludwig did it , simply turn out the inside diameter off , from the steel clutch plates .......though I see RGM only supplied one modified steel clutch plate ? or if you have any spare bronze one , you could try to imitate RGM ones ........! cheap ( I am!).
Click to expand...
Hi Marinatlas,
The RGM conversion looks very intresting, did someone try it yet? becouse as you know every special parts saler promess you a lot of HP more with is exhaust or camshaft and so on, when I look back on the stuff in my engine I must have 350 HP, and you know as good as me how difficult it is to find a singel HP more...
Thanks
Yves
 
One other thought, I wonder if the Kevlar fibre Barnett clutch plates, which are designed to run in oil, might offer more grip than the OEM plates.
I have them in my standard 850, obviously less torque output than your 920, but they hold with the diaphragm set up for very light presure, just one finger needed to pull the clutch lever.
Also, you might fit a DynoDave clutch pushrod seal if you don't already have one.
Without a pushrod seal in place, transmission gear oil can migrate down around the clutch pushrod and end up on the clutch plates. Even the run-in-oil type plates won't hold when contaminated with gear oil.

Glen
 
yves norton seeley said:
Hi Marinatlas,
The RGM conversion looks very intresting, did someone try it yet? becouse as you know every special parts saler promess you a lot of HP more with is exhaust or camshaft and so on, when I look back on the stuff in my engine I must have 350 HP, and you know as good as me how difficult it is to find a singel HP more...
Thanks
Yves
Click to expand...

Yves,
I’m on my third season with these plates. They seem to require less maintenance than either the bronze or fiber plates I have used. I can get then to slip a tiny bit if I shift at high rpm’s without backing off the gas. I’m sure that can be fixed with a little playing with. Seeing how I hardly ride my bike that hard it’s a non-issue for me. I believe Jim Comstock uses them with good results. Good luck with your bike.

Pete
 
worntorn said:
One other thought, I wonder if the Kevlar fibre Barnett clutch plates, which are designed to run in oil, might offer more grip than the OEM plates.
I have them in my standard 850, obviously less torque output than your 920, but they hold with the diaphragm set up for very light presure, just one finger needed to pull the clutch lever.
Also, you might fit a DynoDave clutch pushrod seal if you don't already have one.
Without a pushrod seal in place, transmission gear oil can migrate down around the clutch pushrod and end up on the clutch plates. Even the run-in-oil type plates won't hold when contaminated with gear oil.

Glen
Click to expand...
Hi Worntorn,
The question is: do I need a pushroad seal with a TTI gearbox?
Yves
 
Deets55 said:
Yves,
I’m on my third season with these plates. They seem to require less maintenance than either the bronze or fiber plates I have used. I can get then to slip a tiny bit if I shift at high rpm’s without backing off the gas. I’m sure that can be fixed with a little playing with. Seeing how I hardly ride my bike that hard it’s a non-issue for me. I believe Jim Comstock uses them with good results. Good luck with your bike.

Pete
Click to expand...
Thanks Pete
 
Sorry Yves, I forgot that you have the TTi.
I don't know the answer to that question.

Glen
 
yves norton seeley said:
Hi Worntorn,
The question is: do I need a pushroad seal with a TTI gearbox?
Yves
Click to expand...


I have a TTi with a dry belt drive, I haven't seen any oil through the pushrod tube yet! Just the light grease I put on the pushrod before inserting it!
 
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