Primary Chain slipping

[alexanderfoti]

Hi all

After a couple of test runs I am seeing a couple of issues with my primary drive

Mainly, that the drive chain is slipping when engine braking and occasionally jumping teeth when accelerating hard.

I am on the smallest number of links I can, and running a tensioner.

Do do you think there would be an issue with running a half link?

[Sphere]

I think you are trying to fix the wrong thing. If the chain is correctly tensioned, it should not slip. And it should not matter for a tensioner if your chain is half a link longer or shorter.

[alexanderfoti]

I thought as much, when decelerating the tensioner is pushed all the way down, so tomorrow I will try and locate some stronger springs. Many thanks.

[pietenpol2002]

A logical result of the chain being loaded in the opposite direction under deceleration. The spring gets depressed under reversed load, resulting in excessive slack on the top side allowing the chain to walk up over the teeth. I wonder if the amount of spring pressure required to overcome the chain tension under deceleration would be so great as to suggest that one simply go with a fixed, but adjustable tensioner.

I suppose the ideal tensioner would involve 2 opposing tensioner pulleys on a single pivoting arm that would allow them to float in the direction of taking up the slack. But then I'm always looking for any "solution" that tends toward greater complexity. It's my German heritage I fear.

[Sphere]

This low tech tensioner is present in my Enfield. Also it is a duplex chain which helps I'm sure.

[alexanderfoti]

A logical result of the chain being loaded in the opposite direction under deceleration. The spring gets depressed under reversed load, resulting in excessive slack on the top side allowing the chain to walk up over the teeth. I wonder if the amount of spring pressure required to overcome the chain tension under deceleration would be so great as to suggest that one simply go with a fixed, but adjustable tensioner.

I suppose the ideal tensioner would involve 2 opposing tensioner pulleys on a single pivoting arm that would allow them to float in the direction of taking up the slack. But then I'm always looking for any "solution" that tends toward greater complexity. It's my German heritage I fear.

I did think about having a tensioner on both sides, or a fixed tensioner, the only issue with a block of rubber from the fixed tensioner, is that the chain is not in an oil bath, so I worry that the chain will wear through the tensioner very quickly.

[pietenpol2002]

We're running a skate board wheel tensioner on the final drive with the DOHC CB750. And it's been holding up very nicely. It's a hard plastic and I doubled up on the bearings since there's space for them and I had a pack of them lying about.

[alexanderfoti]

We're running a skate board wheel tensioner on the final drive with the DOHC CB750. And it's been holding up very nicely. It's a hard plastic and I doubled up on the bearings since there's space for them and I had a pack of them lying about.

I am something similar, only with a nylon roller instead of a bearing+roller. Its doused in oil anyway, so seems to be holding up.

[alexanderfoti]

Right, I have now sorted my primary chain issues, Turns out the slipping on deceleration was from the chain which is now properly tensioned. The Jumping on acceleration was from the final drive chain! Stupid me for focusing on one thing.

On the last test ride, a weld gave way on the gearbox mount so that needs fixing first before I can tension out the rear chain and fix it all.

[alexanderfoti]

Turns out, I managed to get the engine a little bit closer to the box, and managed to take a link out, so now I dont need the tensioner! Happy days.