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Discussion in 'Airheads' started by Rasputin Saint, Sep 23, 2013.
I beg to differ. Its only money.
You are correct in your statement about the cam, carbs and head, being a low risk strategy - If you can find the parts.
To be specific about the cam, most airheads above 600cc had the 308 cam including the 45 to 50hp R65's. The 27Hp had, believe it or not, a 256 cam. That is a very mild cam. For completeness since it's been mentioned, 35Hp R45's had a 308 and 27Hp R45's a 284. The cam numbers relate to the duration of the cam i.e. how long the valves are open although don't try to relate the 308 designation to published valve timings as it won't add up due to the published figures being quoted at a 2mm lift.
The R65 308 cam is not the same as 308's from other engines as the change in the angle of the push rods changes the cam timing if not duration. So you do need a 308 from an R65.
Yes , after some research I did it seems you are right. This doesnt mean I am wrong about my other thoughts though do you think?
So you think I should go for the
308 DEG. STANDARD CAMSHAFT TWINS 1979 ON
308 DEG CAMSHAFT. R45/65 1978 ON. (NOTE: THIS CAMSHAFT REQUIRES 1* 11511 INNER ROTOR)
as found in http://www.motobins.co.uk/bmw-parts.php?model=R Series 2 valve Twin
Are airheads had to come by in Greece? I would say your first stage of research would be to see how available bigger engines are & what cost they are.
By the time you start adding individual costs of pistons, valve work, even gaskets etc etc you may be in for a big surprise at the overall cost.
There have been quite few 65s purchased on this forum over the last few months & the main concern of most owners is to get more bang out of them.
bigger used engines start from 1000 euros and going up, plus that there is a big ? about the general condition of it and the real mileage.
This is the main reason that makes me thinking of upgrading this engine, after all up to 45 to 47 hp is very much enough for me.
As far as I know (and I own an '82 R65 with 180 000 + km on it which I rode myself), the early R45/R65 had a different engine (which was the basis for the post 81 other airheads...) And it is a perfect bike. Same set of barrel/pistons, same alternator, no failures. So highly reliable.
When they introduced the mono's, BMW madde a big mistake, by producing an R65 which was a small bore R80. If I'm not mistaken, everything else is the same in the R65 full power as to the R80. In France, these R65 where sold mainly to police forces. So they can be found cheap but very well worn out at junkyards. It is common, in France to put R80 barrels and piston to get a working bike out of a pile of R65 bikes....
We never saw in France the detuned version as the regulation did not ask for it.
So IMHO if you want to upgrade your bike, get a set of barrel/piston/head and carbs from an R80 and you're done. (maybe you can check in RealOem if the heads are actually different in the detuned version versus the R80)
To my mind you seem to be a bit too focussed on the potential problems of a used engine. Airhead engines are generally speaking reliable long mileage engines that if remotely looked after will last a lifetime or more of use- one of the big reasons a lot of us like them.
Doing all the work you want to squeeze a bit more or a lot more life out of your restricted R65 engine will be a lot or a hell of a lot of work/time/money- it really doesn't seem worth it to me.
I know it is not want you want to hear but If I was you I would spend my time looking for a very good used 80/100 engine that has a decent service history and is in good condition, and just do that swap and then a basic check and refresh of the engine.
Chances are most airhead engines, even if a bit worn out and abused, with routine maintenance will give good service beyond what miles and years most airhead owners end up owning them and riding them for.
I know the 85 -on R65's used the same frame as the R80 model but are you saying it's also an R80 engine with a reduced bore rather than the shorter stroke of the earlier R65 ? That would mean it had smaller than the stock R65 82mm bore.
I'm skeptical but prepared to learn.
When they planned the monoshock bikes, BMW had a will to go from 650 up to 1000 cc. And then then thought that keeping two different engines in the production line was too costly. So they used the 247 base (with some little improvements) to produce all cubic volume needed.
This is why the R65 has lost what was it's strength and attractivity : stamina, and smallness !
The R65 pre 85 is a wonderful machine, apt to compete with the 1000 even if less powerful, the last models are real dogs.
And you'd better buy an R80...
All the R65 share the same crank so they all have short stroke. This means that the housing are different on R65 and R80/100.
Some R65s used a 308 camshaft, but this is not the same camshaft used for R80/100.
Alibaba, I strongly disagree.
All pre 1985 R45 and R65 share the same crankshaft which gives a shorter stroke than the R75/80/90 and 100.
But after 1986 all airhead no matter which displacement, have the very same crankshaft. As they produced a full range from 650 to 1000 displacement, .... the crankshaft should be the same
You can check, if you want, with the part number for the crankshaft before and post 1986.
It is obvious if you actually look at the bikes. "old" R65 have a smaller engine than "new" R65....
As I doubt you had a lot of R65 made after 1985 in the US or Norway I understand you can be mistaken ;-) But given the number of such bikes one see in ex police junkyard in France, you've to be very cautious when buying parts for an 1982 R65 ... Otherwise, you have to try to make the junkyard owner give your money back... Guess how I know ?
P.S. : the "new" R65 is a real dog. The police complained about it in France, and, as the French customs officer where given the quite identical R80 but more powerful and a joy to ride, they complained more and more, and, finally they had new bikes more powerful ....
Are you sure you aren't referring to the detuned R65 mentioned earlier? I can't find ANY mention of late R65s have the same stroke as the R80 and R100 models in any specifications I have laying around. That's the first I've heard of this.
OK, just did a little simple research on the BMW Fiche. Went to 2 different sources. Max BMW as well as talked directly with Shane at Shail's Motorcycle who looked it up on his old Fiche as well as on his electronic one. Just to be certain.
From 1978 through to 1992, ALL R65 and R45 engines used the same crank and block, which is different from any other engine.
There were 2 different Camshafts used in 87-92. Prior to that, all the same.
01 11 21 1 336 439 CRANKSHAFT 78-85
06 11 31 1 335 181 CAMSHAFT - 308DEG 78-85
01 11 11 1 337 343 ENGINE HOUSING
01 11 21 1 336 439 CRANKSHAFT 85-87
06 11 31 1 335 181 CAMSHAFT - 308DEG 85-87
01 11 11 1 337 343 ENGINE HOUSING
01 11 21 1 336 439 CRANKSHAFT 87-92
06 11 31 1 335 181 CAMSHAFT - 308DEG 87-92
06 11 31 1 337 922 CAMSHAFT - 256DEG 87-92
01 11 11 1 337 343 ENGINE HOUSING
So, as the Crank and block are the same in all of the R65/45 engines, then differences for the low powered R65 must be with the 256DEG cam and other detuning parts.
I very much apriciate all of you guys taking time to answer. I belive I'm coming close to a final decision. Although an R80 engine would be a very nice solution, I think I will stick with its own R65 engine and work a little bit on it so it will get stronger. Dont forget its a 1990 model so all parts are interchangeble. According to Ulismotorrad mechanic to which I emailed the same question by changing the camsaft alone the engine gains about 10 hp. A pair of 32mm BING carbs can be purchased by a friend who is upgrading his R100 to the big bore kit and 40mm BING carbs, so things are on their way. Next step will be to find a pair of cylinderheads. I am not a speed freak after all even though the bike is a cafe racer I recently built ( didnt mention it before). Any more sugestions or talking about it will be taken under consideration though.
P.S. 1 any answers for message #24 ?
P.S. 2 how do I attach images?
I just checked and you're right for the R65 ! So now I wonder what kind of bike the French Police get. ! I can assure you that getting parts from these bikes and trying to fit them on a plain R65 is impossible !
You need the R45/R65 308 camshaft. If still in doubt check out one of the online parts fiches to compare part number for early and late R65's as Daveball did above.
You can't upload pictures to this site. You have to insert a link to another website or photo sharing location.
The French bikes have the same engine as the other R65's. All the parts should fit. I Have one my self and have no problem with changing parts from other R65 's
I'm completely confused