R100 engine on a R65???

[steve hawkins]

I will measure the same on my bikes - i.e. The height above the ground of my cylinder heads, in the upright position, with weight on wheels. I will use the centre nut as the point to measure to, for comparison.  I have a 1979 R65 and 1982 R100.  And I bet if you had an RS or RT fairing on they would sit lower.

Wirewrkr - I do not dispute the fact that the R100 has longer travel forks.  We are discussing where they sit at rest - the point from where they start moving up and down.

But we are comparing apples and oranges - as neither of my bikes forks are standard internally - they both have heavy duty fork springs in them. And both bikes have koni's.  I can't remember whether the front springs are progressively wound though, which might also make a difference in the ride height

There should be something like 20+bhp difference between the R100 and R65.  This varies between models.  I would be noticable - especially the torque.  But on the road the R65 seems to be able to hold its own, especially when not weighed down.

However none of these issues should be insurmountable and it certainly would not stop me from going ahead with this excercise.

[awaffa2003]

DO ITTTTT!! To make everything easier, depending on the year, swap transmissions too. only problem i ran into putting a r90 motor in my 65 was the ignition. going from a wire harness for electronic ignition and trying to make it work for points was tough. this all again depends on the year of the motors though. exhaust was no problem though as i wasnt using stock bmw mufflers to begin with, if you're swapping, you'll need his mufflers to modify because your headers are smaller.

as for the final drive...leave it if youre putzing around town, it turns into a completely different animal. touring or commuting or if you just that concerned about mpg, change it. i left my stock 32/9 on and the first test drive after everything was squared away scared the @&!% outta me! no clutching or anything, just a handful of throttle and i stood my 65 up in the air almost falling off the back! now i don't wheelie on purpose but it wasnt the last time that happened. if i'm ever inclined to ride with gusto, 1st to second is a wheelie and 2nd to third is a wheelie...just saying.

the most valuable piece of advice i ever got was to WRAP YOUR FRAME! go get some blue painter's tape and make a good 4 or 5 layers on your frame lowers to protect the paint. that motor is small but awkward to take out even with someone helping and i promise that it will hit and/or be rested on the frame at one point or another. be careful not to hit the neutral switch and bend or damage the tabs.

also, it's common to remove or slide back the swingarm in order to pull the trans, then pull the engine. not unnecessary. it was easier for me to unhook the driveshaft, pull the rear motor mount, then tilt the motor and trans up towards the backbone of the frame, THEN pull the trans.

if i think of anything else i'll post or if you have questions, feel free to ask. i did the job on my own so it's not impossible or even drawn out, it just requires alot of patience. good luck.

SUPPORT HYBRIDS!!

[steve hawkins]

So I went home last night and sat on my 1982 R100 in the garage near a wall so I could keep the bike dead upright.  My son measured the height from ground level to the left rocker cover centre nut.  
15.5 inches.

The we did the same with my R65.  16 inches!

Yes, you read it right, the R65 was higher up than the R100.  No one was more surpised than me, we had to repeat the excercise, just to make sure!  I thought they would be close, but I did not expect my R65 to have more ground clearance than the R100.  But as far as my bikes are concerned, that is the case.

The rear shocks on both bikes were set to the minimum preload.  I suspect that the type of springs fitted to the front forks has a lot to do with this result.  But I also suspect you will find with standard springs, both bikes might be more equal footing.

I also am aware that my R65 is a 1979, which means more weight.  Heavy Flywheel, heavy bosch starter, heavy iron liners, etc.  Putting a lighter R100 engine in the frame might make it sit even higher.

So like awaffa2003, get on with it!  Great bike by the way!

Rev. Light

[tvrla]

awaffa - did you notice any ground clearance issues? Scraped valve covers?

I also prefer the method of removing the rear engine bolt and tilting the engine rather than removing the final drive. Used that method just this last weekend performing a clutch replacement.

Steve - glad you re-checked your measurements - I wouldn't have believed it either. Guess I'll have to measure mine now!

[awaffa2003]

you scrape pegs before your scrape your heads i'm sure. if not the pegs, then your feet. honestly if you're THAT worried about it, weld some plates on the valve covers. ACTUALLY i lied, get your friends R100 and your 65 side by side in the garage and lay them down on the heads. take a few steps back and ask yourself, "am I really going to be laying myself over that far" the answer will probably be no and if it isn't, i suggest that you invest in some knee pucks and stop talking to Reg Pridmore...

[tvrla]

True enough! I usually scrape a peg, side or center stand, or my foot first. The worst case is a bumpy corner that bottoms the suspension and loose a lot of ground clearance; a good reason to stiffen the suspension when riding sporty.

[awaffa2003]

yeps. it's not as big of an issue as people make it out to be. don't let a few degrees of lean angle dissuade you.  

[nhmaf]

For any street riding, I tend to agree - I've dragged my pegs, feet, stand, and mufflers on various airheads taking corners on the streets, but never valve covers (though some bumpy corners made it seem like a close call)

[bruce_launceston]

Scraping things while cornering is a very subjective issue. It depends on how people ride, how they corner. I've followed riders that 'lean out' ie they push the bike down and keep their body more upright. Riders that 'countersteer' through every corner will also run out of clearance long before a rider who sets themselves up and 'leans in'.
Unless I have seen how they ride I don't put much weight on claims of 'I was cornering so fast I scraped my pegs'.
Leaning in will maximise ground clearance, the extreme example is motorcycle racers who of course don't have any choice if they want to corner as fast as they do.
Leaning in is also invaluable on wet or gravel roads.

I'm not casting aspersions on any posters here who have scraped bits of bikes, I have been caught out on bumpy corners under brakes, I'm just passing on theory learnt through many years of instructing motorcycle rider training classes.

Cheers

[steve hawkins]

I think what we need is a few more points of reference.  Other peoples bikes might show other results, and we need to get an average.

Anyone who has both an R65/45 and a R60/R75/R80/R90/R100, to measure the ground clearance, as I did, as a comparison.  All we need to know is the difference between the two, the bikes compared and any known modifications.  If we can get even a small group of comparisons, that would be great.

Either way, I think we can agree that it would be cheap thing to sort if you felt you had an issue. And local riding conditions have a great bearing on this.  Either by going for stiffer springs or even just a spacer in each fork leg to preload the ones you have.  I am actually considering putting some spacers in my R100 to raise her up a bit.

And I have also seriously considered putting an R65 yoke setup on my R100 - but it is a complicated job, with instrument and ignition mount changes, not to mention changing the disc carriers and axle, as the fork legs are further apart.  And I have to consider the rake and trail of the new setup - when using R100 stantions.

Personally, I would like to put this 'internet myth' to bed, once and for all, if we can.  There is no telling how many people have been put off doing what awaffa2003 has done by attaching too much importance to fork leg length and not the real ride height of the bike with a rider on it.  Its probably originally come from some armchair 'experts' at a certain other BMW site that I stopped visiting some years ago, due to some of the acrimonious arguments on there.  Though I am led to believe it has quietened down these days and I still do occasionally lurk there as a guest.  But they have always 'looked down thier noses' on the R65.

[steve hawkins]

And I totally agree with Bruce's comment about riding style as well.