Temporary gear shift failure

[Erick]

Looking for advice from all those who know about the RT's gear box.

 

The suspect bike: my 1996 R1100RT with 61,000km (almost 40,000 miles). I bought it Nov. 2003 from a dealer, who is doing all service and maintenance as well.

Regular dino oil, always at the dot. No excessive oil consumption (one quart every 7,000 miles).

 

The occasion:

Yesterday's ride to a baseball field, 65 miles of mostly slab at 75mph cruising speed in 5th gear.

When arriving at the field's village, after leaving the motorway, I could only shift down into fourth. Then, upon the next downshift around 40mph, it didn't go into third. I could tap the shifter down several times, but to no avail. Felt a bit 'spongey'.

I cruised for several hundred yards, and then finally it went into third. No strange sounds, or anything.

From then on, the engine could hardly be shifted into other gears. Only every 10th-20th attempt succeeded.

In second gear, I reached my destination.

 

After the game, the same thing. The engine fired up as usual, I could get it into first as usual, but after that, shifting into the next gears failed most of the time. No sounds, no clunk, just a soft feeling as if the bike was already in 5th gear and I wanted to shift up into a non-existent 6th gear.

 

I rode 50 miles of slab, and then parked the bike on its side stand at a gas station. Let it rest for 15 minutes like this. Then I tried again. And guess what? Everything went just fine! I could shift gears again as if nothing had happened. Arrived home safely.

 

Today, I took the bike for a spin after having it parked out front on the center stand. First I checked the oil level. Was OK. Then I rode a dike road, which requires plenty of shifting between second and fourth. No problem at all and everything seems fine again.

 

My questions:

- what could have caused the forementioned shifting problems?

- am I in trouble, despite the fact that things seem to have returned to normal?

- what to do if it happens again?

 

Thanks a bunch in advance!

[ShovelStrokeEd]

Erik,

I would take a long hard look at the shift linkage behind your left footpeg mounting plate. It could have been just a piece of debris somehow lodged in the mechanism, but more likely, the linkage has become worn or damaged and is in need of repair/replacement/adjustment.

 

Your dealer can do this for you or, you might just wish to tackle it yourself. Pay attention to parts, 5, 8 and 9 and also, wiggle you shifter in and out to make sure there is not too much slop in the bushings, part 4.

[Erick]

Hi Ed,

 

Thanks for your immediate reply. I just printed your message and the diagram, and went downstairs and out to have a look.

The easiest part was trying to move the shifter in and out. Well, it felt rock solid, so no slop in the bushings.

 

Then, without taking anything apart, I looked from under the bike, and actually located the parts you mentioned. These, too, looked in perfect shape.

 

So now I'm thinking...would it be a bad idea to try and clean the mechanism by spraying some WD-40 into and onto these parts? Or better leave it as is, and hope for the best?

[BucksTherapy]

Ed provided great advice. Inspect the linkage carefully,particularly for enough slack that it could bind. If there is little looseness or no binding in the shift linkage then I would take the bike for a run to warm it up thoroughly then immediately drain the transmission into a clean container. If there are parts starting to break down in the gear box then some of the chaff will remain suspended in the gear oil for a few minutes and you will see it upon inspection. If there is any loose material floating around in the transmission then these could bind gears and make shifing difficult.

 

I assume the clutch felt normal and the transmission felt like it was fully disengaged when the clutch was in use.

 

If the linkage is great, not anything substantial in the gear oil and the clutch appears to be working fine then you may be very lucky and just had something caught up in the linkage. This is highly unlikely and it is more likely that this will repeat and the source of the problem will become more obvious.

[ShovelStrokeEd]

Erik,

You can, of course, spray a light lube in there. I wouldn't use WD-40 in that application though. You want a dry lubricant that won't attract and hold sand and dust. Check with a quality parts distributer for a dry Moly lube (molebdinum disulfide) spelling may be wrong. A sporting goods store is also a good spot. Check the fishing or hunting supplies for things like DriSlide.

 

There is a possiblilty that this is an internal problem. The internal shift mechanism has a spring on the shifter shaft that is supposed to re-center the shaft after you complete a shift and release the lever. It sounds like that shaft may be sticking a bit or the spring is getting weak. If the shaft cannot return to center, it will not rachet the shifter drum into its new position nor will it be in a position to engage the gear in the opposite direction. This is a PITA as the transmission has to come apart.

 

You might wish to remove the stock linkage and inspect the area behind part 9 in the drawing, that is, between there and the case for build up. A small tooth brush shaped wire brush can help there.

[Erick]

Bob and Ed,

 

As soon as the weather gets a bit better (it's raining here again, and I don't have a garage) I will inspect the shift mechanism once more. I'll try to find a spot where I can position the bike at a little elevation, so I can crawl underneath it more comfortably. The wire brush is a good suggestion, too.

 

I'm not much of a mechanic at all, and even something simple like "draining the gear box oil" is not something I'd do leasurely. So, if I don't find anything that appears to be faulty in the "part 9 area", I guess I'll just take my chances and keep riding until something similar happens again, and then get the bike to the dealer.

 

Thanks again for your help and advice.