combat numbers
- Thread starter Lorenzo
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There was some dissaray in affairs at the time . Not keeping the mind on the job , and so on . Why ? Just look at some of those advertisements . 
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the reason I am asking is because I am raising some doubts about mine..[/quote]
If you are wondering if yours is a Combat engine there are a couple of things to look for.
On center of head in front there should be a "C" stamped.
May not be able to see it because of coils.
In order to raise compression they skimmed head so space between fins at junction of head to barrel looks tight.
If you are wondering if yours is a Combat engine there are a couple of things to look for.
On center of head in front there should be a "C" stamped.
May not be able to see it because of coils.
In order to raise compression they skimmed head so space between fins at junction of head to barrel looks tight.
rx7171 said:
If you are wondering if yours is a Combat engine there are a couple of things to look for.
On center of head in front there should be a "C" stamped.
May not be able to see it because of coils.
In order to raise compression they skimmed head so space between fins at junction of head to barrel looks tight.[/quote]
hmmm.. I am not sure if I did get it..
to be sure I am posting a picture of the head of my bike I wish may be helpful to anyone of you to help..
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Dunno if that ' C ' is not stamped up there in the centre batween the rocker covers somewhere ?
LOOKING - IN dead flat from the side, but At The ANGLE of the fins , fore & Aft . SO you CAN see
in between the top barrel fin / lowest head fin , you should be able to see the edge of the HEAD GASKET
if you keep it clean 
The Face of the head goes DOWN to the Gasket , so you see a fin , a lip .and the Gasket. . . . NOW . . .,
if that lip is not a lot or stuff all deeper than the gasket , its a combat , or at least , the heads planed a m.m. as per Combat
a standard Low Comp ? 9 : 1 C.R. head , that lip down from the fin , is more obvious . noticably thicker than the gasket ( 1 mm ) to a blind mans dog . :shock: AS the EDGE visable looking in between head / barrel fin is a flange the shape of the
gasket , in Plan . And the mateing face from the head , you see Above the Gasket , a few mm visable before the radius
into the fin , the lower fin ! . SHINE a TORCH ( Flashlight they tell me ! IN , and look ) Or use youre FLASH on the camera .
Weve got to see in there , the edge of the head gasket , Please .
:!: :idea:
LOOKING - IN dead flat from the side, but At The ANGLE of the fins , fore & Aft . SO you CAN see
in between the top barrel fin / lowest head fin , you should be able to see the edge of the HEAD GASKET
if you keep it clean
The Face of the head goes DOWN to the Gasket , so you see a fin , a lip .and the Gasket. . . . NOW . . .,
if that lip is not a lot or stuff all deeper than the gasket , its a combat , or at least , the heads planed a m.m. as per Combat
a standard Low Comp ? 9 : 1 C.R. head , that lip down from the fin , is more obvious . noticably thicker than the gasket ( 1 mm ) to a blind mans dog . :shock: AS the EDGE visable looking in between head / barrel fin is a flange the shape of the
gasket , in Plan . And the mateing face from the head , you see Above the Gasket , a few mm visable before the radius
into the fin , the lower fin ! . SHINE a TORCH ( Flashlight they tell me ! IN , and look ) Or use youre FLASH on the camera .
Weve got to see in there , the edge of the head gasket , Please .
:!: :idea:
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Lorenzo said:
It is unlikely that it was ever a Combat originally. A 220*** number would make it a 1973/750 MkV model possibly from around March 1973 production (is there a date stamp on the certification plate?). However, after nearly 40 years, any number of the original parts could have been changed.
Does the head have either RH5 or RH6 stamped on it?
Are the carbs 930/?? (30mm) or 932/?? (32mm)?
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Lorenzo said:
The RH number is usually stamped near the R/H exhaust valve inspection cover if it's there, however, as the carbs are 930 and I suspect the manfolds could also be the early tapered 30-28.5mm type then it could be a 28.5mm inlet port cylinder head?
http://atlanticgreen.com/nhth.htm
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What makes a Combat is the C head and 2S cam and 10: CR, so look for narrower fin gap at the barrel surface, measure the valve lift of cam and look for the low rear breather hose to ID if Combat crank case or not. A compression test might reveal the hoped for Combat PSI ~ 180-190+.
rvich
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Yep, take the tank and headsteady off. The C may not be easy to see as there is no promise that it was stamped deeply. Measuring the lift on the intake vavle will help determine what kind of cam you have. Its a pain in the arse but the lift on the Combat cam is much larger than standard. 0.375 vs 0.441 inches at the valve. In forty years time it is very possible that somebody might have assembled Combat parts into your engine. And visa versa.
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