Lost Weekend

[Selden]

Riding back from the Conyers Tech Day three weeks ago, I was a little disappointed that I couldn't notice any difference in the way the bike ran. Having learned the basics, I decided to, at my leisure, see if I could improve on my work three weeks ago. I took most of the weekend to get the rocker end clearances to .003 ± .0005, valve clearances spot on, and the throttle bodies as perfectly synced as possible. While in there, I replaced one of the vacuum lines, and cleaned the air control screws and the passages in which they reside (both fairly gross), something I had overlooked three weeks ago. This time, there is a noticeable difference. The engine sounds like a sewing machine, is noticeably smoother at all speeds, and backfires less on deceleration. It is worth the effort, but given the time it takes to get things "just right" it's no wonder that it's very unusual for a dealer to achieve this state of tune.

 

Next project is to replace the swing arm bearings with Rubber Chicken bronze bushings. At next fall's tech day, I'll probably go for replacing throttle, clutch, and fast idle cables, and the fuel filter. The bike should have about 80,000 miles on it then.

 

Tired, but pleased.

[Selden]

I forgot one thing: At the start of this maintenance orgy Saturday morning, when it was still quite cold (for Atlanta, about 25°), I wasn't patient enough removing the left side black plastic cover, and snapped off the front mounting post. Since I had just gone through a tooth implant, I decided to use the same basic approach to repair it. Drilled a small hole where the post broke off, and epoxied a small, self-tapping screw in there. Drilled the post, then screwed it on, and used a little bit of JB Weld to hold everything together, and make a smooth, tapered fillet around the joint. It's probably stronger than new.

[Unhofliche_Gesundheit]

re:and snapped off the front mounting post

 

i snapped mine off too - on my very first time taking it off (to do my valves and throttles, etc) cover seems to stay on ok without the post.

 

i was being relatively gentle - so i blamed the designer who made such an unforgiving assembly.

 

might try your trick - the broken piece is long gone but there is so much plastic in our lives now should be easy to find a replacement.

 

oh - and you are a genius! good tech transfer.

[AndyS]

Next project is to replace the swing arm bearings with Rubber Chicken bronze bushings. At next fall's tech day, I'll probably go for replacing throttle, clutch, and fast idle cables, and the fuel filter. The bike should have about 80,000 miles on it then.

 

Tired, but pleased.

 

Why? Are you experiencing play in the swing arm?

Have you checked the pivot at the FD?

 

Andy

[Selden]

Last summer I checked the rear with the brake locked. The swingarm pivot is definitely a little loose. Considering that BMW uses needle bearings in this application, and how incredibly little bearing area there is, it's not surprising that these don't last long. The Rubber Chicken replacements are sintered bronze, but due to BMW's engineering, have relatively little surface area, given the load on this area. My 1970 Suzuki T500 had swing arm bearings with approximately 4 times the surface area.

[AndyS]

it's not surprising that these don't last long. ... due to BMW's engineering,... relatively little surface area, given the load on this area.

My 1970 Suzuki T500 had swing arm bearings with approximately 4 times the surface area.

When you say you checked with the brakes locked, what did this prove?

This check generally locates the difference between knackered FD pivot bearing or a shot FD itself.

 

I can't really agree about the swingarm bearing,

What weight is your T500,

What mileage,

What is you average load carried on each bike?

Overall I'd say the swingarm bearings do OK as the bearings are a reasonable size and the twisting moment is well spaced.

However if you were talking about the FD bearing I'd agree.

 

Andy

[Huzband]

Sounds like YOU'LL be the teacher next year.

[sid]

I forgot one thing: At the start of this maintenance orgy Saturday morning, when it was still quite cold (for Atlanta, about 25°), I wasn't patient enough removing the left side black plastic cover, and snapped off the front mounting post. Since I had just gone through a tooth implant, I decided to use the same basic approach to repair it. Drilled a small hole where the post broke off, and epoxied a small, self-tapping screw in there. Drilled the post, then screwed it on, and used a little bit of JB Weld to hold everything together, and make a smooth, tapered fillet around the joint. It's probably stronger than new.

 

Any Pics of this one. I've been trying to figure out a repair, but don't see enough "meat" to mount anything.

 

Thanks,

Sid