Primary chain wear - P11

g80csp11 · Post by **g80csp11** » Wed Apr 06, 2011 12:03 am

I know that the P11 is not a touring bike , even though I use mine all the time and have travelled all over europe on it over the last few years. I does tend to eat primary chains, needing adjustment every 600 + miles

Single row chain on a 750 Atlas engine / AMC gerabox

Is this normal to other G15 / N15 / P11 models ?

Gerard Harrison · Post by **Gerard Harrison** » Wed Apr 06, 2011 6:38 am

The single row chain takes a beating,

even more-so if it runs dry in the primary case due to seepage,

There was a reason Norton moved to the multi-row chain approach with the Commando series and it wasn't aesthetics...

and even then,, the belt drive conversion to replace the multi-row chain was an appealing migration for many

I rebuilt/restored and put 12K miles in 2 seasons on a 1967 P11 before selling it, I loved the machine but it sure liked a lot of attention....

like a pretty girlfriend with a wandering eye...fun but at a cost

and the one thing about that bike that gave me wimmie-wammies was the continuous balancing act between the primary and final drive chains...

your 600 miles or so sounds about right as I recall doing a monthly review of the two chains' relationships to each other

Even with quality name-brand chains, excessive stretch seemed to be a fact of life

despite renewing of all bits including the clutch hub shock-rubbers and fanatical attention to proper chain tension

and I was not a Stop-Light racer on the bike popping wheelies or such... though I would get heavy on the throttle sometimes once underway

Suffice to say, you do NOT want a primary chain cutting loose

So in short, you suffer for your art

or look at a belt drive conversion

Edited by - Gerard Harrison on 06 Apr 2011 05:39:35 AMEdited by - Gerard Harrison on 06 Apr 2011 05:44:10 AM

Groily · Post by **Groily** » Wed Apr 06, 2011 7:52 am

Interested to read this, as one of the first things I did on my P was buy a new primary although it was reputedly quite new. In time and mileage terms it might have been . . . But! And I thought exactly what Gerard says - single row is not really up to the job on a motor that size, even if the oil deigns to stay in the case.
Glad to have been fore-warned and -armed, as my P is relatively new to me.
Maybe a belt drive would be a very good idea in this case, have to think about that.

g80csp11 · Post by **g80csp11** » Wed Apr 06, 2011 8:26 am

I usually put a new primary chain on every years , good to hear Gerard's comments
I did loose a chain through the side of the chaincase a few years ago . It sounds like it's normal for this application to suffer abnormal wear.

Gerard Harrison · Post by **Gerard Harrison** » Wed Apr 06, 2011 1:33 pm

I tend to think this arrangement was suitable (marginal?) for the Matchless singles models

but it was at its limits with an Atlas motor shoe-horned into the frame...

that being said I am in the final stages of doing up a G15CSR which has the same primary set-up

but with the ugly aspect of even more overall machine weight to haul around

whoopee

itma · Post by **itma** » Wed Apr 06, 2011 2:35 pm

By the time the P11 was on the market just about everything BSA/ Triumph even big Enfields was running duplex or triplex chain.

as gerard says good enough for a 500 single, but.....

Groily · Post by **Groily** » Wed Apr 06, 2011 5:33 pm

Dead right Ken - my Oilfield twin is excellent in that department. Even if it's notional 'close to 50 bhp' was a line drawn with a thick carpenter's pencil, there's still a lot of oomph and the duplex plus tensioner is miles better. (Shame about the clutch.)
Same with the plunger Beesas with the bolt-on boxes and duplex drive before they went into engineering reverse gear with the s/arm frame . . .
Nothing quite like having fixed centres. Still, gives us stuff to play with and whine about!

ranger · Post by **ranger** » Thu May 12, 2011 3:30 pm

Hello Peter
I don't do a huge mileage on my 67 P11 but after 5,500 miles, the pri chain is still good (dare I say that) and infrequently requires adjustment. Through the spring to Autumn months, I probably average around 100 miles a week at generally 55-60 mph tops. The eng sprocket/clutch wheel are exactly in line and I run it with 3/4 inch slack.

Cheers

Tim

Groily · Post by **Groily** » Thu May 12, 2011 6:41 pm

Funnily enough checked mine this very week, in light of the '600 miles between adjustments' thing, and glad to say, at 600 miles since replacement, it was quite fine. I also prefer a bit slack to a bit tight, with all chains. But I haven't hammered it as I'm makee-learnee with the thing. I really really like it. Looks different, sounds superb, goes well, weighs nothing. It's just great fun and I always always wanted one, so I don't care even if there are a few downsides I don't yet know about!

John Donne · Post by **John Donne** » Fri May 13, 2011 12:55 pm

The only trouble i had with the primary chain on my Ranger 750 was when i discovered that some of the rollers had broken up, and dropped into the bottom of the chaincase. The chain was replaced by a genuine Reynolds one back in 1995 and i have never had any more trouble. With all the P11 models there is a special way to adjust the rear chain. I always run all my P11's rear chains on the slack side, as this can pull the primary chain tight if the gearbox moves back due to all that torque from the Atlas motor. I have never really had any other problems with my other G15, or N15 models, even when they were being used for high miles. The Featherbed Dominators have a far harder time with their primary chains as they are much longer. The G15,P11 are much shorter as the chains do not stretch so badly. It could also be in the quality of the chains that are installed. I put a belt drive into my Featherbed Dominator cafe racer, so therefore i got ride of the chain stretch problem. This may be the way to go if a high miles is part of your world.