850cc top end???

[awaffa2003]

Is it possible to put a R80 top end in a R65? I saw a pic of one on http://www.cafeboxer.com/WebScrapings/r65st.htm close to the bottom. How would you go about doing this?

[Bob_Roller]

There were a few higher displacement kits for the R65 from Luftmeister.

From the accounts of people that did the upgrade, it compromised the reliability of the R65.

Bottom end failures were the most common failure.

Seems like the R65 engine is best as it is, now if you want to install a larger displacement engine, that's been done before.

General consenus is if you own an R65 and want a faster bike, buy a faster bike.

You can make a cafe racer bike, like a few members here have, but I wouldn't mess with the engine too much.

[NC Steve]

2 words: "Hand Grenade."

On a mono with many shared parts with the larger bikes, maybe.
On a twin-shocker, don't do it!  [smiley=beehive.gif]  [smiley=flamethrowingsmiley.gif]  [smiley=steinigung.gif]

[Jon_P]

have to agree with the guys. if you want more cc go out and buy a bigger bore bike.

[Rob Valdez 79 R65]

From a discussion on Boxerworks:

[size=14]A twin shock R65 is narrower except for the handlebars because the engine is noticeably not as wide, lower because they have less suspension travel and a smaller front wheel, shorter because they have a shorter wheelbase and lighter because they are SMALLER.

You can put a bigger engine in one but with the lower ride height you will have some serious corner clearance issues. A friend of mine did it to one and that LITTLE bike looked like it grew wings! And yes, a 3.56:1 FD is a bit short for a bigger engine. A 3.36:1 in so many R80GS's that I have converted to R100's is PLENTY short![/size]

http://www.boxerworks.com/phorum/read.php?f=1&i=219680&t=219617

[nhmaf]

There is a fellow up this way who is selling an 84 R65 with a transplanted R80 engine in it - now as Rob points out, transplanting an
entire engine is much more do-able and wouldn't sacrifice reliability like trying to replace the cylinders would, but cornering clearance is
reduced.   As I was contemplating using this as the basis for a tug for a sidecar rig, that wouldn't be a problem.   But, this thing has been sitting
out on the lawn for 4 years, uncovered, and I think that it may not be worth the effort and $$ to try to revive it.    4 new england winters is probably at least as bad, or worse, than 4 summers in the desert.

[Joan]

[size=12]Sadly I'm with the naysayers. I LOVE the handling of our SWB bikes and have dreamed endlessly of giving the same bike a makeover with enough ponies to easily keep up with traffic on long 75-90mph days. A sleeper that sneaks past the whining squid rockets. More power climbing the Wasatch.

We all certainly have the means to do it since there are enough R75-100 motors around to pick apart and enough mechanical skilz to pull it off, but... personally, I have resisted.

MOSTLY it's because it's not an easy swap and for the money and effort, one could have a second, well running LWB with the bigger motor. Then there's the part of me that believes the extra torque would invite something more serious than the occasional but slight high speed headshake.

I have to say, however, our friend Ken's 78 R100S with it's well tuned suspension handles pretty close to as sweetly as our SWB R65's in the corners.

BUTT... do you what you want! And report back! [/size]

 [smiley=2cents.gif]
  

[thrang]

Like everyone else I'd say don't do it. If you want more go buy a bigger beemer, because the bullet proof crank on the R65 (well so long as you keep the oil clean and treat it with a little respect) doesn't take kindly to the extra horses as it tends to over stress the main bearings.

[steve hawkins]

I do not hold with the R65 'weak crank' folklore.  I have found 3 respected tuners in the UK who will quite happily upgrade an R65 to 800cc or above and do not agree with the above, and all of them were quite happy with a crank with some mileage on it - even mine with 100,000.  And I have also heard from other sources that most prefer a bottom end that is undisturbed - rather that one that has been rebuilt.    But you need to start with a post 81 engine in preference.

That is not to say that tuned R65 have never blown up, as they obviously have.

However, what stopped me was that it is very expensive and the power hike is just not there to justify it.

And for the price you would have to pay to get someone else to do it you can source an R100 engine, exhaust and final drive - and have more power to boot.

There are other ways to increase the power/weight ratio though, reduce the weight....where is my hacksaw?

This weekend I am going to lose 3 kgs of the front.....I am going to lose my second disc, caliper, pipe, etc.  I have purchase a single disc master cyclinder.  I would also like to lose my bosch starter and replace it with a Valeo - another few KGs lost.....  And I need to go on a diet

[MrRiden]

You could bump up the CC's but for what purpose? To go faster? It'll cost ya a lot more in time, money and frustration than buyin' a bigger bike. I'd say, get your R65 on the road and learn to be the best rider you can first. Take it from someone who beat much larger bikes on the twisties with a little 550cc. Club racing or track days will hone your skills. If that fails, more power will just get you in trouble faster. Like the T shirt says "Ride like a Knob and you'll die". Here's an old trick to create the illusion of speed [I do not condone smoking] When tearing up a twisting road with some friends I would get just far ahead 'nuff to throw down the side stand and park, rip a cigarette from the pack, tear it in half and light quickly. When my pals showed up there I was leaning back on the bike asking them "what took you so long? I'm almost done with my smoke". I'm not sure they ever caught on.
rich

[awaffa2003]

Oh wow...I thought it was just a matter of swapping heads and pistons. Then yea, I agree, if i want more power I should buy a bigger bike. But that's not likely anytime soon, I gotta walk before i can run.

BTW: my dad's friend came over my house today and was checking out my bike and the general response is "Oh you won't be able to ride over an hour on that thing..." is there any truth to this? Have I wasted precious time and money to just cruise around town and have uncomfortable rides for the rest of my streetfighting days? Tell me it isn't true!!! this is the best pic of my bike in case you haven't seen it.http://www.facebook.com/photo.php?pid=526600&l=6bdda&id=533986563

[fastcataz]

An hour huh? I was on my 84 last saturday for 13 hours, 520 miles. Half on the hiway, the other half in bike hell, i.e. pheenix, AZ. I had a great time. I hope to get another 500 miles in tomorrow...

[awaffa2003]

yea normally it would be fine, i have clip ons. they gave me the thumbz down on comfort level on boxerworks too.

[Jon_P]

the only thing you might have to fight off is your hands going numb. you still have your stock seat & stock peg settings. depends if you are like me for those clip ons, i am 6'2" and alot of my height is from my waist to my shoulders so those clip ons weren't so bad to me. if you have alot of weight on your hands you will do what i call the sportbike superman. have one hand on the bars and laying on the other arm on your tank, though i would never recommend taking both hands off the bars!

i had the bars flipped up so they were a little higher and running almost flat or you can flip the clips around so the bars have a slight bend down which i am told feels better but was harder on my hands.

if you want to ride all day invest in your saddle. send it to sargents or others out there who revamp your saddle for the long hauls. if your butt is happy you can ride alot farther.

nice looking ride you have! it will make you happy because you made it ours and there is not another like it.

[Rob Valdez 79 R65]

Oh wow...I thought it was just a matter of swapping heads and pistons. Then yea, I agree, if i want more power I should buy a bigger bike. But that's not likely anytime soon, I gotta walk before i can run.

BTW: my dad's friend came over my house today and was checking out my bike and the general response is "Oh you won't be able to ride over an hour on that thing..." is there any truth to this? Have I wasted precious time and money to just cruise around town and have uncomfortable rides for the rest of my streetfighting days? Tell me it isn't true!!! this is the best pic of my bike in case you haven't seen it.http://www.facebook.com/photo.php?pid=526600&l=6bdda&id=533986563

He was probably referring to the extreme handlebars and the loud exhaust.

With stock (Euro) handlebars, a good stock seat and an 18 year-old butt, I could ride for several hours!