The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Tony Smith on April 08, 2016, 07:56:16 PM
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I'm toying with the idea....
The last time I though about this was way back when "madam's" R65 was still a 1979 650cc in all its breathless glory. I could not find *anyone* who had a positive experience of capacity increases in an R65.
Right now I have a high ratio top gear to fit and a new rear drive spline/drive collar pair waiting for me to decide if I am going to fit them to the existing 32:9 final drive or try and buy a 32:10 to play with.
When I built the R65 I didn't have any real intention of keeping it, but the little bugger has sort of grown on me a bit.
When I still could (I can't benz zee knees like I once could) I loved riding madam's R65/80 because it quite frankly is a pocket rocket witht he R80 engine.
The bottom end of my R65 is strong and done few miles, I am tempted to fit the 20% over 5th gear and a 32:10 final drive and a 850cc kit to it.
From all reports the Seibenrock 1,000cc kit for R60/75/90 is quality gear so I guess that would also be the case for the 650~850cc kit as well. I also think that by gearing the thing up to dramatically drop revs through the gears and particularly in top gear I would remove the No.1 cause of failure (IMLHO) namely sustained high revs.
What do other people think of the idea? The R65 engine is somewhat lighter and a hell of a lot narrower than the R80 - believe me you do notice it profoundly swapping between a R65 and R65/80 (i can ride madam's bike with my seat on it) - far more than you would think that you would in fact.
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I cannot recall which of our members bought one with the kit installed already - maybe it is wirespokes(?) In any case, he seems to have quite good experience with it thus far.
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Tony
where do you get a 20% over 5th gear
I have only seen the 5%
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Tony
where do you get a 20% over 5th gear
I have only seen the 5%
In an addled, aged brain, that's where.....5% i meant 5%. My Bad.
Motobins sell them in both pre and post April 1984 varieties.
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In an addled, aged brain, that's where.....5% i meant 5%. My Bad.
1/20th is 5% - makes perfect sense !
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I was thinking of getting the kit also when I found a wee nick in my Nikasil barrel. I think it'd be great, esp if you fit higher gearing. Don't know of anyone who has actually used the upgrade kit though sorry.
After a couple of recommendations I decided to re use my barrel so the price of the upgrade kit suddenly became too much, but I think it'd be a fun thing to do.
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Finding an 81+ R80 cylinder and headset used and in good nick would probably get you most of the way there, too.
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Finding an 81+ R80 cylinder and headset used and in good nick would probably get you most of the way there, too.
Using R80 jugs was always the starting point - But they need to be "trimmed" to suit the short stroke of the R65. Measuring the amount to trim off and paying someone to do that work is non-trivial and would I suspect add up to a tidy sum very quickly.
At the moment the whole thing is a "flight of fancy" on my part, I'm really only interested in doing it if it is a bolt up job and if I am not buying myself a world of disappointment.
I have to say that my research in the early 80s turned up a few people who had by various means increased the capacity of the R65 engine, at that time none were deliriously happy with the results for reasons such as vibration and short life.
When in 1987 the original R65 engine in my wife's bike dropped a valve and punched a rod out of the block I could have obtained an r65 engine with damage to the opposite side nothing. At that time I again investigated "big bore" kits for the r65 and again could only turn up a few people who had done it. Also in keeping with my research of a few years prior the only peopel who professed happiness with their big-bore R65s strangely seemed to want to sell them to me rather than enjoy all that new found power.
Against all that my thinking is:-
The R65 bottom end is just as tough as any other Airhead - the only real difference being the cam followers and then they were only changed to keep the push-rod angles more or less the same as other airheads.
Seibenrock are a mature and well respected manufacturer who generally make well regarded products. The only negative I have seen regarding their R65 big-bore kit is that 2 independant tuning houses say that they have used entirely the wrong "squish" band for the pistons and that you need to modify the squish in either the heads or the pistons (one of the tuning houses showed detail of how they modify R80 pistons).
Now this may seem trivial to some people but the squish band in the combustion chamber is pretty much where trouble free performance lives and dies given the poor quality lead free fuels we must now use.
What I really want is someone who had fitted one to tell me dispassionately how it runs on 92 Octane (RON method) unleaded fuel and whether the whole experience is "pleasant" or not.
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Tony,
The BMW OEM set is available at a mere 1388 Euro the lot (2 jugs, 2 pistons with rings and wrist pin, gaskets ) and the Siebenrock 860 cc kit is at 950 Euro the lot.
For this price, BMW offers the shipping in Europe :D but you have to buy the pistons after having got the jugs because you can choose the piston size but not the jug size...
Except for the squish band on the pistons, I bet that longevity of the "upgrade" kit is up to you. Crankshaft and engine case can manage the extra power and I bet the conrod too. I would be more concerned by the double valve spring Siebenrock advocate. This may place a higher load on the camshaft, tappets, and actuator rods. Bear in mind that maximal torque is increased but at a lower RPM than the original figure...
I will be on the market for this kind of parts in a couple of years (minimum) or five years from now. So I _do_ hope you will have something to report then ;-)
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Tony,
I just fitted the upgrade from Siebenrock to my 79 r65. Did it a week ago today, I'm still running the new parts in but so far I have noticed a substantial increase in "oomph" on the lower end, the couple hundred CC really is noticeable. I live in San Francisco so the biggest thing I've noticed is I don't have to crank up the revs to get the bike started up a hill.
Installation was easy as apple pie. I'm overall very happy with how its running, been feeding it 92 octane. No pinging or anything strange. This combined with a spline lube, new valves, and a EME electric ignition- the bike feels brand new and is very responsive. I read all that about the squish band too, i wanted to try it without modifying anything, maybe at some point I'll buy another set of pistons and have them machined a bit and we will see. For now I'm quite happy.
Everything I needed came in the kit, new rings, new gaskets and push rod rubbers. I'll keep you updated if I run into anything strange.
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Good day Hammer65,
I know that bumping a year and some change old thread may not work but I was curious about how your kit has been working after some time. I just got back from a trip out to Montana and Colorado area and I wanted to look into a little more power. :) (of course you shouldn't have to take a trip to want MORE POWER :) ) Thank you and have a great day.
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it looks like hammer hasn't been around much
hopefully someone will chime in
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Well I actually did buy a kit 9 months ago. Like a lot of my projects it is becoming time extended as I found something else to divert me, namely fitting a K100RS fuel tank, seat and fairing to the poor thing.
More recently I have been playing with the oilhead and the R100 awaits attention so it is a case of "watch this space" for fitting the big bore kit.
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We will be here waiting ::)
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Hello all
My 7rock big bore kit is hung up in customs
It is coming from MotoBins
Should have it this week
Right now I am trying to get a good serviceable final drive off of eBay
The first one was junk (bad pinion gear see picture )
Looks like someone set the pinion to deep >:(
Lets hope the second one is better
I am going with the 37/11 although I suspect it would pull a 32/10 just fine
I may also fit a taller 5th gear eventually
We ride a lot of hills and didn't want to go to high
I am also trying to use the old style final drive because it has a oil catcher if the drive side seal starts leaking and NO Orings on the brake shaft ;D
I decided to go ahead and try it because the splines on my current final drive are nearing the end of there service life and it was going to need repairing anyway
Stay posted ;D
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Well I actually did buy a kit 9 months ago. Like a lot of my projects it is becoming time extended as I found something else to divert me, namely fitting a K100RS fuel tank, seat and fairing to the poor thing.
More recently I have been playing with the oilhead and the R100 awaits attention so it is a case of "watch this space" for fitting the big bore kit.
Any up date Tony
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Well yes, the kit is fitted, I've done about 1000km on it and I am just impressed to bits. The engine runs smoother than it ever used to, which mich have a lot to do with th emuch lighter and well balanced pistons.
What was interesting was running side by side tests againt the R65/80 that also lives here. Up to around 75mph the 860 is way quicker in acceleration. but at about 75mph and beyond the R80 engine nails it - I suspect due to better breathing.
I have not changed carb jets, in fact I have not even moved the needle clip position as I had time booked on a dyno and was going to double check mixtures then. However a friend wanted to put his bike in the "Northern Nationals" drags so I gave up my slot on the dyno and have rebooked for July. I may even cancel this as I am satisfied that it is not running lean, there are no flat spots so I suspect that fiddling will most likely only go backwards.
BUT. If I were doing this again, I would do it differently. The limiting factor on the 860 kit is that the piston crowns are re-shaped to suit the R65 heads. Knowing what I know now I would start with the 7-rock cylinders but use R100 heads and 7-rock R100 pistons. The only unique fabrication would be to have a set of 40mm headers made up with R65 width to them. I suspect an engine built that way would deliver significantly more HP out of the box then using the R65 heads.
In the interim however, I am very happy.
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Tony
What final drive ratios are you using in your 800 and 860 conversions
Do you think a 37/11 may be to conservative
My kit is still stuck in customs >:(
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Tony
What final drive ratios are you using in your 860 (
Did you change the rear drive on the R65 before you went 860? Would have liked a camparo of the two rear drives with that kit
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Both bikes still have standard R65 final drives at 32/9. I will be fitting a 32/10 to the 860 (think you Wilcom)
BUT, it was recently said to me that the dimensions of the "old" and "new" final drive housings is diffferent and that therefore a pre-81 and post 81 swingarm are different lengths. I've never head this before and my intiial thought was that it is rubbish. But, I did a quick measurement and there may in fact be a difference.
I'm not particularly stressed either way as I do have a second pre-81 swingarm I can use, but until I get time to accurately measure the old and new parts and convince myself that they are the same dimensions the (as yet unfinished anyway) R75 final drive stays wrapped in oiled rags.
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Sorry i should have mentioned - from a power availabe point of view I reckon that either the R65/80 or the R860 will happily pull a 32/10 and woudl probably pull any of the higher ratio final drives, at some cost to acceleration and flexibility.
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BUT, it was recently said to me that the dimensions of the "old" and "new" final drive housings is diffferent and that therefore a pre-81 and post 81 swingarm are different lengths. I've never head this before and my intiial thought was that it is rubbish. But, I did a quick measurement and there may in fact be a difference.
BMW list the wheel base as different for pre and post 81 which I have always assumed was down to the swinging arm length as they are different part numbers. Never measured them though or thought the final drive housing were different other than the obvious oil capacity, brake spindle lube and brake shoe differences.
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The smooth case final drives are supposed to be interchangeable with the ribbed FD as an assembly
I sure hope so because i just spent $300 USD on a good one off of eBay
Just waiting for the gaskets and seals to but it back together and install it
It will be nice not having to deal with the brake shaft leaking
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There is an inmate (Solo Lobo) on the Adventure Rider site (Old's Cool/Airheads) who has a thread of many pages on his efforts recommissioning a R65LS originally owned and refined by another inmate named John Jen. When Solo Lobo bought the bike, it already had a smooth case final drive with a 32/10 drive ratio. Check out his thread; MANY pages and lots of good information dealing with several sophisticated improvements. Good reading!
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Here is a comparison of the bore sizes
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Here is a comparison of the bore sizes
Prepare to be very pleasantly surprised.
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Here is a comparison of the bore sizes
Prepare to be very pleasantly surprised.
I have a feeling I will ;D
I test rode a Moto Guzzi V7 III
And was amazed with the torque it had
I come very close to buying it
But instead of spending $7000 on it I decides to upgrade the R65 instead
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The smooth case fit just fine
Of course I disassembled it cleaned it out and resealed it
It is off of a 1971 R60/5 37-11 ratio
The older cases have some nice features that were deleted from the newer style cases
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It is off of a 1971 R60/5 37-11 ratio
A couple of days ago I dragged out one each of my "old" and "new" final drives determined to set my mind at rest one way for the other.
It suddenly occurred to me that the only measurement I needed to make was from the forward gasket face to the axle centre.
They are, as you already know, absolutely identical. Myth busted!
Your R60 final drive is a nice find. It's 37/11 is a ratio of 3.36 which is a useful increase from standard R65 which was either 31/9 (3.44) or 32/9 (3.56).
The R75 ratio I am going to use - 32/10 (3.20) is a bigger step, but I expect the 860 to pull it effortlessly.
One day I will try the R100RS ratio 32/11 (2.91) I expect it will "notice" that, but if I ever go touring it would be the "bee's knees". The only spare 32/11 drive I have is for a disc brake rear end and it doesn't have the drillings or "furniture" to mount drum brake shoes. The one on my R100RS, being the old case, does have the drillings and could be converted to drum brakes, but I don't feel any immediate need to try it as the likelihood that I will want to maintain a 160kph cruising speed on a naked R65 is pretty small.
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Got it back together and rode it 100 miles
Power is excellent ;D
It will easily run 70mph
But it definitely has more vibration :-[
Not sure if I can live with it
I will sync the carbs and ride it
I forgot to check the piston balance
You would think they would have check that at the factory
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Mrclubike
Sorry to hear that you have a vibration problem, mine was alread pretty good as I'd balanced the old pistons, but the 860 set were pretty much perfect out of the box.
You must have been very unlucky to get a set that are sufficiently out of balance to cause noticeable vibration.
It is a PITA, but you know how to fix that.
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The vibration is still in the normal range between 60 and 70 MPH
But it is more harsh in that range
At 55mph it is very smooth and at 70 it is very smooth
The bike has never been real comfortable vibration wise in the 60 to 70 range but was tolerable if i put me feet up on the passenger pegs
I forgot to check the piston balance when I was putting it together and like you said they may be just fine anyway
I am wonder if my rods could be out more than they should
When I get back from my trip in June I will pull it down and check every thing
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Here is a thought.
Did BMW do any component balancing prior to assembly? To be quite honest I very much doubt that they did as they would have specified a weight range from the suppliers and left it at that. Certainly most BMW engines I've ever pulled down showed no signs of metal removal for balancing purposes (except those that had been apart before).
When I put my R65 engine back together I balanced the pistons and mass balanced the rods (they were out by a surprising amount). I didn't "end for end" balance as I don't think that is warranted on a low revving engine.
Anyway it has always been as smooth as silk. The 860 piston were so closely matched I didn't bother trying to do anything further with them and the engine remains smooth, including a significant way past redline (which was an accident).
I wonder if you have always had a bit of an imbalance in your rods which is now highlighted after fitting the much lighter pistons.
Anyway, I hope you get a result as any vibrations become very annoying after a while.
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It is coming back apart tomorrow :'(
I hope I find something out of balance or the 860 kit will go back into its box and I will reinstall the 650 barrels
The 37/11 final drive will stay on regardless
I know when I replaced one of my pistons I didn't balance them and It vibrated bad enough I had to pull it back down
I discovered they were off buy 7 grams
Let me tell you it isn't easy getting 7 grams out of one of those little pistons :o
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I know when I replaced one of my pistons I didn't balance them and It vibrated bad enough I had to pull it back down
I discovered they were off buy 7 grams
Let me tell you it isn't easy getting 7 grams out of one of those little pistons :o
So you took off 7 gr from the other piston to balance them ? Btw how much is the weight you got previously from each piston ?
I have weird non dome piston in right side which I believe is not original piston for R65LS. And I have bad vibration and pretty low compression. I’m in process to open the other left cylinder to compare.
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So
The pistons were less than a .5 gram different and the and the rods were less than a gram different in weight
The old jugs are going back on and the 7Rock 860 jugs are for sale :'(
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I know when I replaced one of my pistons I didn't balance them and It vibrated bad enough I had to pull it back down
I discovered they were off buy 7 grams
Let me tell you it isn't easy getting 7 grams out of one of those little pistons :o
So you took off 7 gr from the other piston to balance them ? Btw how much is the weight you got previously from each piston ?
I have weird non dome piston in right side which I believe is not original piston for R65LS. And I have bad vibration and pretty low compression. I’m in process to open the other left cylinder to compare.
The origanal pistons are about 340 grams
And the 7rock pistons are 420grams
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Thanks for your sharing.
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So
The pistons were less than a .5 gram different and the and the rods were less than a gram different in weight
The old jugs are going back on and the 7Rock 860 jugs are for sale :'(
Well, that’s a real shame.
If the pistons and rods are actually balanced, I’m wondering where the vibration is coming from. Crankshaft counterweight imbalance/mismatch?
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Are there any markings on the piston crown, to show orientation ??
I just looked at my factory manual and the piston pins are not centered on the piston, they are offset .
I don't know if would make a difference or not .
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Are there any markings on the piston crown, to show orientation ??
I just looked at my factory manual and the piston pins are not centered on the piston, they are offset .
I don't know if would make a difference or not .
Yes they have arrows pointing forward and they were installed correctly
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If the pistons and rods are actually balanced, I’m wondering where the vibration is coming from. Crankshaft counterweight imbalance/mismatch?
I know Mrclubbike to be a skilled and careful mechanic. If it was anyone else I'd be suggesting re-torqueing the engine mounts.