Manual Cam Chain Tensioners

[OB_Jay]

Manual Tensioners for the 'busa are again on the shelf.

I want to add a word of caution. We manufacture these tensioners as a racing part to eliminate the problem that I posted before about the automatic tensioners backing out when the throttle is closed.

Manual tensioners are not a maintenance free part like the stock automatic tensioners are supposed to be. Racers know to check the jam nut tightness when doing between race maintenance. Also the chain will require periodic adjusting.

I say these things because when the 'busa tensioner problem arose, we were swamped with orders for our race tensioner. We don't want street bike riders thinking they can install one of these and never have to touch it again. Cam chain adjustment now becomes another owner performed service.

Jay

P.S.
Cam sprockets are now done too.

Notice to the people who run this board...
If it is against forum protocol for me to mention product availability, etc. please post a note in this thread and let me know.
Regards.

 

[Frank Adams]

Thanks for the info Jay!

What do you recommend the maintenance to be with these tenioners?

And, what are you looking for when it's time to check them? (please give details)

 

[OB_Jay]

I guess the easiest way to describe it would be that when the crank is driving the cams, the chain load is in the front of the chain. When the crank is suddenly slowed down as in chopping the throttle, a certain amount of keneticv energy in the cams tries to drive the crank for a brief moment and that loads the back side of the chain trying to pull it straight. This causes some auto tensioners to "back out" slightly and then snap back in. For this brief moment there is slack in the chain and then it snaps tight. This is especially critical in very high compression drag motors where piston to valve clearances are run very close. With the valves momenterily out of time, these clearances change, and contact can take place.

On other models, it is just helping to kill the cam chain.

Jay

 

[DaveO]

Jay,

How do the tensioners back off when the throttle is closed??

Dave

 

[OB_Animal]

Question for the experts here:

Seeing the automatic type of tensioner on the Busa and understanding how it works, makes me think this can not happen like described above?

As it consists of a very finely threaded rod pushing against the slider and a light spring working against the rod as in constantly trying to screw it out in the direction of the slider, I can see absolutely no possibility of backing out here as the rod would not screw IN against the spring by just some pressure applied on it momentarily.

The only thing that can go wrong with these, as my understanding goes, is that the spring breaks (doesn't matter where really) and then no more spring pressure behind it and long-term vibration and pressure against it like described above will eventually lead to the darn thing backing out by screwing in/backwards.

I understood that this is what happened with the original Busa tensioner (spring breaking in a lot of cases, mainly at the end where the tab bends inwards) and this has also happened on a very few of the first Blackbirds!

[This message has been edited by Animal (edited 02 May 2000).]

 

[OB_Tak]

Jay, please answer Frank's question.

What do you recommend the maintenance to be with these tenioners? What are you looking for when it's time to check them? (please give details)

 

[OB_Jay]

Tak;

Not knowing how much the 'busa stretches the cam chain, I can only offer a suggestion.

The crew chiefs on race teams check all critical polts and nuts before each race, this would include the tensioner jam nut.

As for maintainence, I would suggest a chain adjustment with each valve adjustment.

Jay

 

[OB_Jay]

Frank;

We have not installed oner on a 'busa ourselves. However, Lee Shirts has done many. He could help you with adjustment, etc.

By the way. We are running spring bases at this time, and I have not received anything from your guy.

Jay

 

[Frank Adams]

Thanks for the info Jay.

I'll find out what the hang up is tomorrow?!

 

[Frank Adams]

Jay, could you give a brief describtion of what a person would have to do if they wanted to replace the stock tenioner with the one offered from APE?

And, how would you know if you had the tenioner too tight or too loose?

Thanks!