Hi there, does anyone have any advice or can point me in the right direction as to how I can lower the idle revs on my 1984 K100 rt thats done 26,000 miles?
I bought it as a non runner got it going and mot'd, but its always ran rough.I've replaced plugs leads air and fuel filters and reshimmed the valves as 4 exhaust and no4 inlet valves had next to no clearance. It ran alot better since but revs too high ( 1500- 1750) on tickover. We balanced the throttle bodies as explained on one of the threads on the forum, but cant get it no lower even if the TPS is moved. Also it threw its coolent out of the resevoir tank which its never done before as well. 
Any ideas please as I'm supposed to be going to the Alps at the end of May on it? Might be pushing me luck there I think

Mr Lee,
For the coolant problem, check if there is a split in the tube from the radiator to the bottle. 

What happens is that when the radiator is hot, the water flows freely into the coolant bottle, but on cooling, air is sucked back into the radiator via the split, leaving the bottle full, eventually overflowing.

Fortunately I discovered the split before I started to replace the seemingly failed head gasket!

Paul.

MrLee - 
                have you removed the TPS from the TB or have you only moved it?

 For my penny's worth it is better to remove it altogether(2 screws) and only then do a TB balance.

Others have had similar problems and found the TPS to have been incorrectly fitted causing a fast idle problem.

I had same issue on my RT with the pipe to the coolant bottle. But the sight tube plastic was also cracked so I replaced both tubes and no trouble since. Be careful about correctly routing the pipe to the expansion bottle and make sure you clip it in position. Mine has cable ties loose fitted to hold it in place, its possible to snag it when you are refitting the petrol tank. Also clean the radiator cap inside, but be gentle, there is a sealing ring in there. If you still have a problem swap the radiator cap.

Check the throttle can return freely at the injectors. You will see how it operates and then returns to a rest position at idle. On my LT one of the clips on the intakes was fouling the throttle and I struggled to get the tickover back down. One day I was able to push it back down to the idle position and saw what was happening, the clip was preventing the mechanism from returning to the idle position and leaving me at the same revs as you are seeing. I had to slacken the jubilee clips and move/rotate them clear of the throttle mechanism.

Also, have seen some comments on the 'choke' cable causing a similar problem. If you haven't done it the twist grip mechanism may need cleaning up.

Given the age and lack of miles make sure you replace the fuel pipes, with all the moving of the petrol tank they will have cracked. Use BMW pipe, its not expensive and make them slightly longer so you don't need to disconnect them to get at the radiator cap or the relay box. Angle the pipe clips so if you do have to remove the tank you can access them through the side slots in the left fairing panel to undo them without having to remove the fairing panel.

Also,

If going to the Alps you will be using braking a lot. I have had both LT and RT give me brake master cylinder leaks. Both I suspect were laid up for a while which can cause a few issues to seals etc etc.

On the RT I replaced pads and rear disc but also ended up doing both master cylinders. The rear fluid reservoir is very prone to age cracking and it too was replaced. All new fluids. Your miles are low but so were mine.

Do all new oils in transmission and final drive, if not already done.

Take a good look at the clutch cable, if you are replacing it use the BMW one but get the little sleeve for the lever as well, it does not come with the cable!.

What date are you going? Tackler, 88KE and myself are going to France on 30th May. Mostly west and south but Tackler is staying for a month and heading over to the Alps.

sidecar paul wrote:Mr Lee,
For the coolant problem, check if there is a split in the tube from the radiator to the bottle. 

What happens is that when the radiator is hot, the water flows freely into the coolant bottle, but on cooling, air is sucked back into the radiator via the split, leaving the bottle full, eventually overflowing.

Fortunately I discovered the split before I started to replace the seemingly failed head gasket!

Paul.

Thanks for that Paul,I will check once I can back to it

ungaas wrote:MrLee - 
                have you removed the TPS from the TB or have you only moved it?

 For my penny's worth it is better to remove it altogether(2 screws) and only then do a TB balance.

Others have had similar problems and found the TPS to have been incorrectly fitted causing a fast idle problem.

Hi Thanks for that, it sounds a good idea to get rid of that sensor

92KK 84WW Olaf wrote:Also,

If going to the Alps you will be using braking a lot. I have had both LT and RT give me brake master cylinder leaks. Both I suspect were laid up for a while which can cause a few issues to seals etc etc.

On the RT I replaced pads and rear disc but also ended up doing both master cylinders. The rear fluid reservoir is very prone to age cracking and it too was replaced. All new fluids. Your miles are low but so were mine.

Do all new oils in transmission and final drive, if not already done.

Take a good look at the clutch cable, if you are replacing it use the BMW one but get the little sleeve for the lever as well, it does not come with the cable!.

What date are you going? Tackler, 88KE and myself are going to France on 30th May. Mostly west and south but Tackler is staying for a month and heading over to the Alps.

Thanks for the advice on that. We're going to the Alps at the end of May leaving England on the 28 May, but although I have a couple of problems with my K100, I've also got my leg in plaster, so I've to get over that obsticle  first!!

The leg is an issue as in you will have to do serious physiotherapy on it to get it back to strength. Don't skimp on that because there is potential to do damage. If its left leg be particularly careful as you need it for side stand and getting on and off bike. A lot of steady physical activity will be better for you. Been there.

None of the tasks you have are particularly difficult or expensive but wriggling around with a leg in plaster is a challenge.

Keep us posted on your progress and don't be afraid to ask questions.

92KK 84WW Olaf wrote:The leg is an issue as in you will have to do serious physiotherapy on it to get it back to strength. Don't skimp on that because there is potential to do damage. If its left leg be particularly careful as you need it for side stand and getting on and off bike. A lot of steady physical activity will be better for you. Been there.

None of the tasks you have are particularly difficult or expensive but wriggling around with a leg in plaster is a challenge.

Keep us posted on your progress and don't be afraid to ask questions.

Thanks for that

If you push down on the idle adjustment screw do the revs drop, it is quite possible the throttle is staying a touch open and hanging on the cable. One other test is to let the throttle snap back ans listen for a very definitive clack as the idle adjustment hits the stop.