So this is what caused my breakdown

fourteener · Post by **fourteener** » Fri Jan 25, 2008 10:04 am

I was searching on Pelican about how much chain stretch is too much and if it's possible to change the chains without splitting the case. There's lots of posts by this owner who has had the exact same thing happen to him and proclaims the need to change the lay shaft sprockets/cam sprockets along with the new chains. He reckons the new chains made a good job of machining his sprocket teeth into a nice pointy profile like yours and his chain jumped in quite a small time period.

It might've been his sprockets were very worn anyway like the chains but would the new chains actually speed up the failure.....?
In the tradition of armchair-punditry someone reccomended to swap the chains with some used but 'slightly less streched/worn' items to prevent the pitch/tooth mismatch -whether there's any wisdom in that I can't answer.

Gary71 · Post by **Gary71** » Fri Jan 25, 2008 10:14 am

keep debating this please, I have a new set of chains sitting waiting at home for me to replace my stretched ones

58A - 71E · Post by **58A - 71E** » Fri Jan 25, 2008 11:15 am

fourteener wrote:He reckons the new chains made a good job of machining his sprocket teeth into a nice pointy profile like yours and his chain jumped in quite a small time period....It might've been his sprockets were very worn anyway like the chains but would the new chains actually speed up the failure.....?

Interesting one this - personally I changed the chains, cam sprockets and idler sprockets 1500 miles before (small time period as he says) because they were all as f**ked as each other. They were already well machined down and pointy due to incorrect fitting of the cam sprockets. What I didnt do was change the intergear/layshaft sprockets 'cos I was being a lazy git and didnt want to split the case

I probably should have realised that given the amount of wear on what I did replace it was safe to assume that the other sprockets were just as mullered - figure

Not sure if the new chain would accelerate the wear or not

I put it down to the fact that they were a ticking bomb, would have failed regardless and I should have known better

fourteener · Post by **fourteener** » Fri Jan 25, 2008 12:56 pm

Gary, I wonder if you can get a good view of the layshaft sprocket teeth through the sump plate to see if they are 'pointy'. I'm going to have a look..../wonders off

58A - 71E · Post by **58A - 71E** » Fri Jan 25, 2008 1:27 pm

Reckon you should be able to see them with just the timing chain covers off and a torch?

fourteener · Post by **fourteener** » Fri Jan 25, 2008 4:58 pm

Hadn't thought of the chain housings -good idea.
You can only see the teeth of one the duplex sprocket's through the sump plate. There's some decent profile left on mine despite looking pointy in this pic...

James -have you got a in focus picture of your sprocket for comparison?