1979 or 1982 R65

[newteuton]

I'm hopeful of joining the ranks of boxer owners in Australia and have commenced the search for my very own R65.

I'm after some advice/ guidance from a practical perspective.  Is there any great advantage in going with the later model BM?  I understand the ignition was changed from points to elctronic and Nikasil bores became standard.... does this make any difference in a practical sense.  I am looking at machines with between 30 and 60 000km on them.  

I am unlikely to rack up big miles... just something to tool around on over the weekends really.

Any advice/ suggestions gratefully received

A

[steve hawkins]

The post 81 bikes are significantly lighter and we are talking 10s of lbs here and a little bit more powerful (50bhp as opposed to 45bhp).  

Much of the weight reduction was done in the drive train - much lighter flywheel, lighter starter motor (valeo), lighter airbox, nikasil bores etc.  The power was added by a combination of bigger valves(cant remember which ones) and redesigned airbox.

Not that the pre 81 bike is a bad bike, far from it, some prefer the heavier flywheel, especially if they tour rather than scratch.

However, if they were thin on the ground, I would take a good condition pre 81 over a rough post 81.  Although, conversly, if I had two identical condition ones, I would probably go for the post 81.

Mine is a 1979, with post 81 heads and no airbox....and a few lbs off the flywheel, so its neither one of the other...

Steve

[Semper Gumby]

Well Having ridden Not-So-Fast=Ed Bellair's 1986 R65 Mono and my own 1980 R65 I can safely say that I would go for the mono.  Better handling with the K75 front end.  The single rotor Brembo was stong enough to lock up the front wheel before the lever reached the handle bar.  The clutch action is smoother and lighter than mine and the tranny input spline is probably a longer lasting nickel plated on the mono.  The 85 and up monoshock bikes have the Long Wheel base frame which is supposed to be not as quick handling but Eds with stock sized BT45's 90/90 front and 120/90 rear was plenty quick in steering without being twitchy.  I had the bike up to 5700 rpms in top gear with no wobbles.  Also I like the two petcock tank that gives amost half a gallon more fuel than my 1980 single petcock tank.  The one thing I didn't like was the plethera of emissions control tubes eminating from infront of the airbox!  But I suspect that this is easily removed as is the pulse air injection system.  Oh and there was no 4500 rpm engine buzz.  It pulled smooth all the way to 6700 rpms!

One thing to be careful of is compression.  If compression is bad and it is not the valves (i.e. its the bores of the nikasil cyinders) then you will have shell out major bucks for new cylinders as they cannot be honed!!!

Now that is .02 worth!  Others will now chime in with additional info.

[newteuton]

Thanks Semper and Steve....appreciate the guidance... Semper, you've made it worse.... I wasn't even thinking Mono before your post (hadn't rejected it, just hadnt considered it).

What is the parts interchange like between the pre and post 81 models... am I likely to be needing to get a lot of R65 specific bits for the 1979? Will the post 81 flywheel fit the pre81 motor?

best regards

[steve hawkins]

The clutch/flywheel assemblies are interchangable, but not without modifying your gearbox input shaft.  Or get a later gearbox as well.

This was why I lightened my heavy flywheel.  However, it is still nowhere near as light as the post 81 - which effectively does not have a flywheel, but has a clutch assembly instead...if you get my drift.  I just reduced the flywheel effect a little bit.

However I am running brembos on my pre 81, and the post 81 heads on my pre81.  I am also running wire wheels off an R80ST.

I am still running a points ignition, but with a K100 twin output coil....confused?

There is a lot os interchangability between models, but you do need to be careful and do your homework.

Looking back, if I had done my homework a bit better, I personally should have opted for the post 81 bike....I am halfway there already!

I consider the late Mono R65s as a R80 with a smaller capacity engine.....a fine motorcycle there is no doubt, but they share only the engine with the twin shock R65 models....simplistically speaking.  At least they are closer to the equivelent aged R80, is what I am trying to say.

Cheers

Steve

[trolle]

I have no experience with the post '85 mono but as Steve points out, all the monos are alike, the only real difference is the size of the engine. If I were to swap my lovely '84 r65 for a mono, I would definitely go for an r80, which has a little more power than the r65 and a smoother engine.

If you opt for a post '81 r65 be aware that the valveseats might need changing, as BMW was a bit unlucky in choosing the proper alloy. The one they chose have difficulties transporting the heat away from the exhaust valves and with non-leaded fuel the problem is exacerbated to a degree, where the seats are worn away and the valves recede with a terrifying haste. The solution to this is a top job which will cost you between $500 and $750. See Sue's thread in the other forum.

The malady was remedied with the mono shock series of 1985.

Good luck and if you find an r65 in good condition you can look forward to a lot of joyful riding.

greetings from a sunny and relatively warm north - good riding conditions with dry roads.

trolle