Boxerworks.com

I bought myself one of those infra-red, non-contact thermometers. So now I've got something else to worry about. Of course I pointed it at the bike's heads ('86 R65) and I find that the left cylinder is consistently about 15ºC hotter than the right one. Depending on the ambient temperature the heads near the exhaust spigot are around L 115º, R 100º.

I've checked the valves, balanced the carbs, put in new plugs. The coil, leads and caps are fairly new. Same size mains, same needle position, fairly new needles and jets. The left plug has a little 'crusty' deposit that the right plug doesn't.




The bike is running really well and has been for some time so I don't want to get too paranoid. Any suggestions?

I would retire your new toy. I don't really think that 15c is worth worrying about

given that you say it's running well (spark is probably ok), you've replaced the needles/jets and balanced the carbs, it still from the look at the plugs that the right one is running rich, so I'd check the floats. Although I wouldn't normally worry about the 15 degrees, the difference in spark plug color says things aren't the same, left to right. Weigh the 2 floats. You might find the right one to be heavier, or maybe poorly adjusted.

This article may point out something that you didn't yet consider. http://w6rec.com/duane/bmw/Tuning.htm

I wouldn't be very concerned about the difference in temp, but, like you, I would be very curious. Sometimes I just have to know this stuff, even though it may never be useful, but then one never knows.

If you've read Duane's article by now you will note the oil vapor recirc going into the right side intake tube.
I've noticed it's NORMAL for the right side plug to look a bit sootier than the left no matter how good your tuning is.
OIL vapor does it.
If your carbs' floats are the same, you should stop worrying about this.
I'd question the accuracy of the instrument at these temperatures since what you temp gun sees is influenced by the color of whatever you're aiming at, too.

Thank you everyone for your reassuring replies. It cheers me up no end when a bunch of blokes who know what they're talking about all say 'Don't Panic'. (In fact I may write a travel guide with 'Don't Panic' written in big, friendly letters on the cover and...what?...oh).

I've never weighed the floats so I'll do that but mainly I think I'll just relax and put my new toy to better use.

Here kitty, kitty.

hzbloke wrote:Thank you everyone for your reassuring replies. It cheers me up no end when a bunch of blokes who know what they're talking about all say 'Don't Panic'. (In fact I may write a travel guide with 'Don't Panic' written in big, friendly letters on the cover and...what?...oh).

I've never weighed the floats so I'll do that but mainly I think I'll just relax and put my new toy to better use.

Here kitty, kitty.

Ah yes - keeping one's cat at a "just right" temperature is very important for efficient operation.



ps: Ray, some of the blokes here are sheilas. But 'bloke' may have become a 'non-gender-specific' term while I wasn't paying attention.

Hey Rob, Michael (Charlie's cat) has dropped his joint...

ME 109 wrote:Hey Rob, Michael (Charlie's cat) has dropped his joint...

"It's the paws that refreshes."