Hi, I have 87 k75 and just added 86 k100rt to the fleet , the mileage on the k100 is at least 93000 , got the bike home and had a hard time starting it , put in new gas cleaned wire connections, and it starts better , I did a compression test and got 123 on three of the cylinders and 90 on one. am I in trouble? The bike backfires a bit and makes some strange thunks., but I hope the thunks are the alt. drive rubbers , crazy frog- my wife and I were in Nova Scotia last week on the k75 and couldn't have had a better time,

Thanks
Brian

Hi Brian,
I would check the valve clearances as if one is a bit tight the valve may not be sealing tight. Check them and report back.
Regards,
K-BIKE

Hi, I just tried gauge and was able to fit .010 in that is on the tight side, but would that cause 90# compression

Thanks

Hey Yankeeone

First, why you didn't contact me before coming in NS? We could have met and I could have directed you to a couple of perfect rides that are not on the tourist flyers...

If the bike backfires, the first thing that I would check is the idle switch. This switch signals the EFI that you are shutting off the throttle and the EFI will shut off the injection until your engine runs at 2000rpm or under

When you start to give a little bit of throttle, you should hear the switch 'clicking' and when you release your throttle it should 'click' again.
Just try to set it up with the engine not running (otherwise you won't hear the switch).

Bert

Bert, I didnt even put the halifax connection with you, together till I got back home and on the site, we had seven days to tour and two were pretty heavy rain, but it was fun . One rainy afternoon we went over the old bridge into Halifax at rush hour, then parked the bike in the down town garage for two days while we looked around. Every where we went people were very helpful and we can't wait to go back and do some hikeing in Cape Breton . I'll check the idle for the backfire , but this after noon I put the mic.to the came lobes and they seem to be way small , like 3/16 short. any way I'll keep with it and if I really like the rt I'll find another one. with less miles.
Thanks
Brian

What ???

Hey, I live in Dartmouth, only 5 kms from the old bridge.
For your cam shafts, it cannot be 3/16difference. This is too much!
Sorry, You must be wrong.
Send your dimensions, and I will compare with some spare shafts that I have at home.
I know that they change the cam shafts at the end of 85 or the beginning of 86. The early cam shafts were more 'pointy" and the power was 90hp vs 80 in 1986.

Bert

Bert , I put the cover back on , but the spec. in the book say's the cam lobe should be 1.5374 ", so if you set tool to that #, and check your old cams, we will see if the book shows # for the 85 model. I looked in the trouble shooting guide and with the low compression, and back fire, the pessimist in me says burned valve. but I'll keep looking.
Thanks
Brian

I just measured my cam shafts, and all the cam lobes are 1.531"
I still cannot understand how you are getting such a difference. If this is the case, your valves open only 1/2 way. 3/16 is .187"
Do you see wear marks on the cams or on the shims?
Was it an engine running without oil?



Bert

Hi, I don't know if it ran without oil, but there is some galling on the down slope side of two of the lobes, I just bought the bike and heard it run but not for long and when I got it home I rode it, found the spedo not working. seller said it stopped yesterday, but you just have to wiggle the cable on the front wheel . I've been very lucky in life trusting people, but I think I got it this time. the cam lobes measure 149.66 or less. I think I am going to try and part it out to get some money back.
Brian

I really feel sorry for you and I hope that you didn't spend a lot of money on it.

This is honestly the first time that I hear a BMW rider screwing up another.
If the engine is really as bad as you say, you may want to contact the seller and ask him to get the bike back.
Here in Canada, if somebody sells you a vehicle with a bad problem without disclosing it, the law will be on your side and you can obtain a full refund. You may have to get a professional to estimate the extend of the damage but it will be reimbursed by the seller if you are right.
Do you have the original mileage on the bill of sale?


Good luck

Bert