later heads on earlier R80?

SeanW

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Are there any key differences between R80 heads from 79-on, like there are with the barrels?

Or can I bung a more recent (unleaded type) head straight on to a 79 R80?

(it's an 80/7 with steel liners)
 
Are you swapping them as a pair?

There were several valve sizes with the 79 heads being different to the later unleaded heads. In 1987 things change again with different valve sizes and different seat angles and I believe port shape and size. Have a look at www.realoem.com and check out the years/part numbers. You really need a pair of matching heads.

If you do fit later unleaded heads then you will need the support buttons for the rocker arm support blocks from your earlier heads. Part number 8 in the diagram

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ta Rob

Had a look and found there was a different part number for R80 heads from 11/79 - see below. Would this be the date that started coming with hardened valve seat inserts? If not, any idea what "SLS" signifies?

diag.PNG

My bike is Feb 79, though I can't say for sure it has the original heads. Valve seats are quite regressed though, and one of the exhaust pipe nut threads is very lacking in usable thread

But assuming they are pre-11/79, I'm still not sure if I need to make any other changes to fit the post-79 part. Though i can;t find any reference in the parts diags to other parts that come in pre/ post 79 versions. Valve sizes up to 87 seem to consistently to be 38/42 on R80 models

The heads I'm looking are on ebay and look like pre-87 and a pair.

http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=270982102706

Some numbers are visible in the pics, but they're not part numbers -no idea what they might signify if anything

Have asked the seller if he knows year/model of the bike they came off...
 
They went to unleaded heads after sept 85, though I have seen different dates quoted so it's anybodies guess but it is somewhere around this time. 87 will be the 30 deg valve seats. There are other differences with the heads.

Wouldn't it just be easier to get your heads converted? Richie Moore turned mine round in less than a week and that included his one piece valves and trick guides.
 
Wouldn't it just be easier to get your heads converted? Richie Moore turned mine round in less than a week and that included his one piece valves and trick guides.

Yes, that's certainly an option. though I'm guessing would be more expensive (though that's assuming I can actually find a pair of suitable used heads that will bolt straight on)?

The old ones are still servicable - was just thinking that while the bike is in bits it might be worth sorting the heads. but on the other hand, it;s not like it's difficult to pull em off at a later date

Btw, was trying to find a thread you posted a pic on of green airhead from atvrider which had its stock silencers mounted high level scrambler-style - don;t suppose you remember what thread it was?

My plan is not to hack the R80 about too much (if at all) but by swopping/adding a few key bolt-on parts (bars, headers, seat, fairing, panniers, wheels (maybe) etc) to make it into a "convertible" - that is I can convert it from a standard-ish hack commuter / tourer into a tasteful 70s scrambler style road bike in the space of an hour or two...

anyway, i thought that green bike looked like a good way of getting the scrambler look without buyign a whole new exhaust system...
 


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