Another New Guy

[Smokymb]

Hello all, just got my first airhead, a 1981 R65 that has supposedly been converted to R80 spec - whatever that means. Unfortunately I’m not currently collocated with the bike, so I can’t look for serial numbers on things to investigate. Been skulking around looking at postings and once I get my hands on the bike will try to ask semi intelligent questions. Tried to post picture, but file is too big and my brain is too small to figure out how to resize it. Maybe later.

[Smokymb]

Mighta figures out how to insert a picture of my new fun machine.

[Adrian]

Hi there & welcome to the tribe. Lots of great people & advice here [ch128521]

[Tony Smith]

Nice looking bike - twin ATE calipers on a non LS is a rare thing.

I'm looking forward to seeing a front 3/4 view to see if it has an R80 engine or not. BTW, if it does you will love it, the R80 engine runs the smoothest of all the boxers (some argue that the R75 has that "honour", but they are wrong (not that the R75 is not a damn fine engine - but the R60 is the smoother of the /5/6/7 varieties).

Anyway, if you do have an R80 engine, which by the way fits perfectly providing all the right hardware was imported with the engine the only thing you need to be aware of is a slight loss of cornering clearance - inconsequential in my view.


Lastly, welcome.

[Bob_Roller]

Twin ATE calipers were standard on the North American 1981 R65's .

[Tony Smith]

Twin ATE calipers were standard on the North American 1981 R65's .

Oh....

[Smokymb]

Looking forward to getting back to FL where the bike is sitting and waiting for me. Will report engine serial numbers, carb types, take photos, and report back to the group so we can figure out what I have and, most importantly, which parts to order when I start prepping it for a summer of riding. Thanks for your help.

[Smokymb]

As mentioned in my new guy post a few weeks ago, bought a 1981 R65 described as “upgraded by prior owner to R80 specs”. No other info available from the seller. I have been collecting clues; hope you guys can help me identify engine so I can order parts. I think it lived with a Harley, it leaks a bit of oil; definitely needs a few gaskets and a seal or two. Carb numbers match those listed for R65, jet sizes are unknown.Haven’t seen an R65 in person, but my cylinders stick out (more than 11 inches from engine case, see picture) a bit further than the R65 pictures I’ve seen. There is an “80” stamped at the base of each cylinder (attached picture). Engine number (attached picture) is not over the dipstick, but on a plate at left/lower/front corner. Gotta be an ‘83 or later R80 engine with R65 carbs, right? The number on the plate does not match anything I can find on the table in the Clymer manual, pg XII. I’d appreciate any help you can offer.

Oh, one more thing while I’m asking. I’m not especially weak, but have a hard time getting the bike on or off the center stand. The Yamaha scooter I have weighs within 10 lbs of the R65, and no problem popping it on or off the center stand. Seems I read somewhere that BMW addressed the issue, but don’t know what they did? Anybody else have same problem and found solution? Thanks again for listening.

[Smokymb]

Didn’t figure out how to put up more than one photo at a time, will add a couple more now. Slow learners are among us.

[davidpdx]

I had the same problem with my bike (center stand). Bought a used ride off center stand and it was one of the best upgrades I have made to the bike. You just have to make sure the center stand you buy is made for a R65.

[Smokymb]

@ davidpdx The name “ride off stand” is so wonderfully descriptive I thought I’d try mine out. I just scooted back on the seat and let the clutch out enuf to pull it off the stand! It worked! Is that the way it really works? If so, I already have a ride off stand and didn’t know it. Now if we could just “ride on”.

Thanks for our help.

[Tony Smith]

Ok I tried to find my imperial tape measure and failed.

Here are two photos for comparison, I'm not proud of the quality, but they are good enough to show the difference between an R65 barrel and an R80 one, although perhaps to be technically correct, the difference between an R65 barrel and a long stroke barrel.

[Tony Smith]

Ok, so the R65 barrel is about 170mm from the innermost fin to the top of the outermost fin, whereas the R80 barrel is about the same, give or take a smidgeon. BUT look at the difference in the base of the barrels, there is more than double the difference between the engine block and the first fin on the R80.

I also note that my wife's bike has "80" thoughtfully stamped on the barrel base.

Based on that I'd say that your engine is an R80 engine and not an R65 with replacement jugs.

My wife's bike has been an R65/80 since 1987, the only further change we ever considered was to out a higher ratio final drive on it, but as we got older we travelled slower so the revs ceased to be a concern.

If you ever ride a "genuine" R65 you will be staggered at both the difference in power and the general "willingness" of the machine. You can also rest assured that there is no downside - on long trips the wife and I get near identical mileage and given that neither of us seek to channel Mike Hailwood, the minute loss of cornering clearance is a non-issue.

I a looking forward to a further comparison when my R65 becomes an R86 in the near future.

[Smokymb]

Thanks, Tony, I came to the same draft conclusion .. R80 transplant. Found an engine serial number essay on Snowbum’s website, the number on my engine indicates it was completed the 28th week of 1984, definitely not OE on a 1981 bike. Makes some sense to me that you’d transplant a complete engine vs finding another 650cc block and kludge (love that word) on parts from yet another engine. Guess I’ll find out more when it comes time to replace head gaskets, etc. I’ll start by ordering 1984 or 1985 R80 engine parts.

While I’ve got you on the phone, do you still use the OE center stand? I have a hard time getting the bike off the stand, which I hear is a common complaint. I’ve found a Reynolds ride-off center stand (R361) for your 1984, but so far no luck on the model for a 1981 (Reynolds #R360). Found the Reynolds numbers on Snowbum’s site.

Thanks again for your help. Is there a subgroup for R65/80? I’ll join.

[Tony Smith]

T
Is there a subgroup for R65/80? I’ll join.

Yep, population here at present is you and my wife Sylvia.

To go back to your stand - providing the pivot holes have not been flogged out your stand is quite repairable, it involves welding metal to the "top and front" of the contact face on the stand. This is a regular job and I will be taking our stands off and welding them up later this week.

Some time back one of the other denizens here welded some stainless steel "wedges" onto the top of their stand in the hope of a more permanent fix, a search of the tech conference (where we really should move this) should find it.

Failing that, I'll take some photos when I do mine. Be warned I am not the greatest stick welder, in fact 40 years ago a friend described my efforts as beign the result of "the great steel pigeon with diarrhoea", sadly that sums up what my welds tend to look like but fortunately I own a good slag chipping hammer and an angle grinder.