The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: jp9094 on May 14, 2022, 09:51:40 PM

Title: Rough Idle after long run.
Post by: jp9094 on May 14, 2022, 09:51:40 PM
Hi All,

Took a little ride today. 47 miles (76 Km) each way with a 90 minute stop between rides. About 4 miles before the end of the trip went on reserve, and the bike started to idle roughly at the lights. Was fine when I got going again, but repeated at each stop. Admit it is about time for a service(fluids, plugs and valve adjust) and have not changed the air filter in 6000 miles.

Am I missing anything??

TIA
Title: Re: Rough Idle after long run.
Post by: dogshome on May 16, 2022, 11:48:30 AM
My first guess is junk or water in the tank that Freed itself into the carbs when switching to reserve.
Title: Re: Rough Idle after long run.
Post by: matthewjp14 on May 17, 2022, 11:52:20 AM
I'd have to agree with dogs, getting my r65 up and running I ran into similar issues except reserve would not drip at all. Sounds liek time for a petcock rebuild and filter kit, good thing they're not too expensive or difficult to get done. I think cleaning and fixing mine back to the bike took overall 30 minutes?

If you think it could be something else take the hose off with a cup to catch the gas underneath and check the flow of the petcock manually. sediment really likes to clog that lower filter.

and good luck!
Title: Re: Rough Idle after long run.
Post by: Bob_Roller on May 17, 2022, 12:47:09 PM
Sounds like you may have a restricted or clogged idle jet .
I'd remove the float bowls and check for ' debris ' .
The orifice for the idle jet is so small, it's hard to tell if it is clogged or not .
I would always find a fine sediment in the float bowls along with a drop or two of water whenever I removed them .
I installed a pleated paper fuel filter about 20 years ago and have not seen anything in the bowls since .
Also there is a rubber seal on the fuel cap, easy to miss unless you're looking for it, check for the condition, chances are it's never been replaced .

 https://www.denniskirk.com/visu-filter/high-flow-in-line-filter-1-4-in-8438-03-9909.p180205.prd/180205.sku

https://www.industrialspec.com/shop/media/catalog/product/pdf/8/4/8437-03-9909.pdf


Title: Re: Rough Idle after long run.
Post by: jp9094 on May 22, 2022, 09:14:56 PM
Just an update. The next day the problem seemed to have resolved itself. The 3 mile ride to the gas station was without problem and the problem has not re occurred.

Thanks to all who replied. I forgot to mention the last 35 miles of the original ride was in the rain, so have to think, as was pointed out, that some water made its way into the fuel system.

Many thanks again to all.
Title: Re: Rough Idle after long run.
Post by: dogshome on May 22, 2022, 10:53:41 PM
I'm now thinking plug leads.
Title: Re: Rough Idle after long run.
Post by: Bob_Roller on May 23, 2022, 01:58:05 PM
Do you have the original OEM black and gray ignition coil ?
It's a well known problematic part and usually has issues in wet conditions .
If you need replacement ignition wires or coils here are two US aftermarket suppliers . 


http://motoelekt.com/ignition.htm

https://www.euromotoelectrics.com/category-s/1904.htm

https://www.euromotoelectrics.com/category-s/1908.htm
Title: Re: Rough Idle after long run.
Post by: qwerty123 on May 25, 2022, 05:03:55 PM
I remember reading that rough idle after a long ride was a symptom of valves too tight / closed up.
Title: Re: Rough Idle after long run.
Post by: jp9094 on May 29, 2022, 10:21:18 PM
Thanks for the questions. I no longer have the original gray  coils. They were replaced 2 or 3 years ago. I agree, it is time I reset the valves. Thanks for the input.

TIA