Timing chain tensioner replacement

[gzprock]

I recently replaced a leaking cylinder head gasket. When I reinstalled the head, I found a couple pieces of plastic down next to the chain. After riding the bike a couple hundred miles, there was a noticble knock. I pulled the valve cover off, and did not see anything wrong. Then I pulled out the chain tensioner out of the bottom of the right head, and found that it had been eaten away by the chain(see photo).

I was wondering if anyone has had to replace the plastic chain tensioners, if so how involved is it.

Do you need any special tools? Is there anything else that needs/should be replaced at the same time.

Any help would be greatly appreciated.

[bmwmick]

I believe Paul Glaves had to replace one on Voni's R1100RS at 300K miles. He had to split the cases to get at the rail but I forget if it was the right or left rail.

 

Mick

[Stan Walker]

I believe Paul Glaves had to replace one on Voni's R1100RS at 300K miles

 

As I recall the story.......

 

It was at about 1/2 the miles you mentioned, and the rail shattered while being ridden. The pieces of the rail were sucked up into the single oil pickup used on the 1100 oilhead engine blocking the oil flow. This starved the main bearings of good oil flow and they were destroyed along with the crankshaft journals. Basically a totaled engine.

 

Paul, being the great wrench that he, is rebuilt the lower end of the engine. As I recall the total for the parts exceeded the cost of a boneyard replacement. But he learned a lot and enjoys doing that type of thing.

 

Stan

[Stan Walker]

Do you need any special tools? Is there anything else that needs/should be replaced at the same time.

Any help would be greatly appreciated.

 

I would suggest highly that you get the shop manual and study it before attempting this. You won't know what else has been damaged until you split the engine case.

 

Out of curiosity, how many miles? How much of the damaged rail is still hanging there?

 

Stan

[gzprock]

The bike has about 37,500 miles on it. I don't recall seeing any lower rail in place when I put the head on. The 2 pieces I pulled out were only about 1 inch or so long. the upper rail was visible and in tact.

[Stan Walker]

The bike has about 37,500 miles on it.

 

Too few miles to be normal wear and tear. I've only heard of three failures of the cam chain guide rails. Pretty rare, unless your the one with the dead bike!

 

At one time I thought this might be the typical "end of life" failure for oilhead engines but that doesn't seem to be the case. Only one of the failures was at high mileage.

 

Good luck, no matter what you do, rebuild or replace, it's not a simple job.

 

Stan

[bmwmick]

I believe Paul Glaves had to replace one on Voni's R1100RS at 300K miles

 

As I recall the story.......

 

It was at about 1/2 the miles you mentioned, and the rail shattered while being ridden. The pieces of the rail were sucked up into the single oil pickup used on the 1100 oilhead engine blocking the oil flow. This starved the main bearings of good oil flow and they were destroyed along with the crankshaft journals. Basically a totaled engine.

 

 

Stan

 

Big Red, Voni's first R11RS is serial #0310167 and was among the earliest imported in May,1993. Big Red Too, her R11RSL is serial # 0311371.

 

Big Red got two warranted transmissions - one at about 50,000 and another after about another 50,000. It got the new clutch parts with the first transmission.

 

Other than the transmissions it really hasn't had significant issues except for a broken $7 cam chain guide. That was significant because it requires the engine to be removed and split to replace it. I think this was a fluke - very few cases of this one.

 

Big Red is now over 300K with valve work at 295K. The third transmission finally needed a new frontshaft due to spline wear at about that same 295K on the bike (195K on the transmission).

 

Big Red Too wore the original transmission output shaft bearing at about 177K but that is about the only remarkable issue with it at all.

 

So, I have no reason to fault the Beta models.

__________________

Paul Glaves

 

Stan, I think the TOTAL meltdown you are remembering was Darryl Richman's R1100RS over in Germany.

 

 

Mick

[Stan Walker]

My experience is you can expect to do a top-end overhaul at approximately 300,000 miles. We had the valves done on Voni's R1100RS at 295,000 miles. They would have gone longer but I had the heads and cam carriers off to deal with a worn cam follower. Original rings are still in the engine at 315,000 but I suspect it's due even though the compression is still OK.

 

I also expect that the bottom end is fine and needs nothing at 300,000 miles.

 

The above makes no mention of cam chains or cam chain rails. The only failing part mentioned was a worn CAM follower, which has nothing to do with the cam chain or rails other than be driven by them via the cam.

 

But you can email Paul for the nitty gritty of the chain rail failure.

 

Stan