Cylinder head temperature

john998

Well Known and Active Forum User
VOC Member
Hello, Has anyone measured the head temperatures at working loads? and if so where was the probe fitted. I checked mine but only at tick over as my set up is not suitable to use on the road. John.
 

ET43

Well Known and Active Forum User
Non-VOC Member
Hi John, If you google CHT, then all sorts of information comes up. Usefull stuff from Volkswagen and Microlight sites, which suggest that the under spark plug temperature will be a tad over 300F. There are neat guages for single and twin cylinder applications. For my needs, I have to find a switch which can be programmed to turn on a fan at a given temperature, and to turn it off when the temp. drops. Cheers, ET43
 

john998

Well Known and Active Forum User
VOC Member
Hello, Is that at speed, it looks a little low as VW and micro light air cooled both quote up to 430F for short periods. John.
 

clevtrev

Well Known and Active Forum User
VOC Member
Hello, Is that at speed, it looks a little low as VW and micro light air cooled both quote up to 430F for short periods. John.

That was taken with gauges glued on to fin near plug. Reading immediately after stopping. 10 miles 100 miles 300 miles - No different. And I never ride slow.
If you really want to amuse yourself, get an infra red mobile gun, you will be amazed at the differing readings that you can find.
Good selection at bottom of page.
http://cpc.farnell.com/jsp/search/browse.jsp?N=1001725
 
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Tim Kirker

Well Known and Active Forum User
VOC Member
John

Talk to Stuart Jenkinson when you see him at the Annual. He has temperature sensors permanently fitted to both pots, with a dial on his dash board. He's been watching the needle for nearly 750,000 miles, so I guess he knows as much as there is to know about cylinder temperatures . . .

Tim
 

john998

Well Known and Active Forum User
VOC Member
Hello Tim, thanks for that, will look out for Stuart at the annual.
Further observations, dropping the needle in the Mikuni's just one notch caused a noticeable rise in head temp,
unable to quantify until I repeat the climb up Glen ogle. Also a following wind increases the head temp, presumably
because the air flow is reduced.
A local owner reported head temps around 200c, mine seem low especialy as my bike is hauling a Steib 500.
John.
 

john998

Well Known and Active Forum User
VOC Member
Hello, Just back from a repeat climb up Glen ogle, the head temp was 15c higher than last week.
Also it is going better, feeling sharper. Consumption is 50 to the gallon perhaps to good, will need to
keep an eye on the plugs. John.
 

harvey

Forum User
VOC Member
180C on both heads with t/couples under plugs, at 1/2 throttle measured at the twistgrip,, top gear, no wind, BTH at 34deg,set as per BTH instructions,no.4 slides, needles 1notch richer than central, ie raised from standard, 276 carbs, B7ES plugs, tailpipe has dark grey deposit. Plugs show a grey colour similar to cigarette ash colour on the insulators. Definitely not pure white,but not Tan or brown either! Is 180 too hot, and does grey mean weak mixture when using unleaded?
 
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