R65 Project

Discussion in 'Airheads' started by Nick Makwell, May 11, 2008.

  1. Nick Makwell

    Nick Makwell Bavarian Murder Weapon

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    I'm collecting parts for a project based on a 1984 R65 that I'm picking up shortly (its in ok condition, engine/drive and frame is straight, rest is missing or beat up)

    I want to do the following and yes, it will end up being a Frankenbeemer!

    1. change gearbox to slash 5 4-speed with kickstart (and remove electric start)
    2. install a monolever final drive/swingarm and go to one rear shock
    3. use a K75 or similar 3-spoke mag rear wheel
    4. change front end (which is bent) to a Suzuki SV650 or something similar, even a Suzuki GS500 with one disc

    Questions:
    can I do 1-4 without any BIG dramas?

    I think the gearbox is a straight bolt on, but converting to monolever im not sure. Furthermore, what particular swingarm/FD is the best (or actually fits) and can take the 3-spoke rear wheels AND the /5 transmission?

    Im slowly researching this one and have started to gather parts - yes, it will end up a cafe racer, and I know it will cost a bundle, but I dont care!

    I'd really appreciate any help on this one, even if you can just point me to some links etc

    Thanks!
    #1
  2. StephenB

    StephenB G(/)S ... what else!

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    1) Very likely a 1984 gearbox does not fit without changing the clutch assembly as well (to the later lighter flywheel design), you have to customize the gear shift lever as well as the shift linkages are different
    2) Doable, but needs modifications to the frame for the upper shock mount, there might be other limitations I am not aware of
    3) If you want mag wheels go with 1985 rear end from a 1985 Monolever R80RT or something, that is plug and play except for issues mentioned under 2). If the bolt pattern matches to a 3-lug monolver drive, it might just work
    4) Be aware of rake angle and height: again, a 1985 monolever front end can be used, dual discs and brakes are half decent with options to modify/upgrade

    You can go much wilder and install a 1988-on paralever drive with a K1/K1100 disc brake rear end and front K100 forks. I have not seen the K rear end mod in Northamerica (it is quite common in Europe), Lornce did the K100 front forks mod on his R100.

    I personally like this BMW-Ducati hybrid with K1 front forks, a K100 rear end and custom made swingarm (based on a monolever) with two exhaust cans under the seat:

    [​IMG]

    [​IMG]

    [​IMG]


    Almost everything can be done.
    #2
  3. Nick Makwell

    Nick Makwell Bavarian Murder Weapon

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    Thanks Stephen - ive got the front on picture of that bike, but not the rest!

    I would like to go similar route that bloke has done, with cast wheels instead of spoked, and with the monolever rear end.

    I think converting to a monoshock entails a K100 type monolever (and similar shock) with a new frame tab and reinforcement (if necessary) welded on to the rear.

    I think going to the K1100 front end is overkill - im looking to use Jap bike stuff, maybe from an SV650 or similar, or maybe just one disk.

    Another Question - does the K final drive bolt straight onto ANY monolever swingarm?

    thanks again Stephen :1drink
    #3
  4. StephenB

    StephenB G(/)S ... what else!

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    No personal experience. Just a atter of asking the early Bricks guys for dimensions, I suppose. Also ask for dimensions for the input gear, that might need replacing with a R input gear.

    Do yourself a favor and research the subject to death, it might otherwise be a costly experience ...
    #4
  5. Spicy McHaggis

    Spicy McHaggis Darth Peach's cracker...

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    I'm watching this one, since I just picked up two (one running, one parts/project) R65's. One is an '84, the other an '82.
    #5
  6. Alfons

    Alfons Been here awhile

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    Hi lads,

    greetings from Germany! I talked to the guy who accomplished this marvellous BMW-Ducati conversion, and he told me that the K final drive DOES NOT bolt onto the monolever swingarm. So this involves a lot of intricate work: you have to weld a flange onto the mono swingarm, adapt the driveshaft (length and so on), which requires expert knowledge.
    But there seems to be another way of making a three-spoke K-wheel fit on a mono final drive. The wheel and a brake disc canboth be fitted with the four bolts just like the mono wheel, what you need is an adapter for a brake caliper plus all the rest of the disk brake equipment.

    best wishes

    Alfons
    #6
  7. Uncle Ernie

    Uncle Ernie Long timer

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    Post /2 kick-start levers have an extremely short throw. I suspect you will be mighty sorry you got rid of E-start.
    #7
  8. AntonLargiader

    AntonLargiader Long timer

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    There will always be big dramas on stuff like this.

    The kick will work OK. You might get tired of it. You'll have to either go to the early flywheel and clutch or make some other conversions because the /5 tranny isn't 100% compatible with your clutch. But you can get the kicker in an '81-on 5-speed tranny also, which will just bolt on.

    You'll have to use an '85-on Airhead monolever and final drive. Then it's mostly a bolt-on. Otherwise you'll have to adapt the driveshaft and so forth. Remember you'll have to work out the rear brake, since all of the monolever Airheads were drum and the 3-spoke wheels are all for disk.
    #8
  9. Nick Makwell

    Nick Makwell Bavarian Murder Weapon

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    Thanks for the replies so far.

    Update - bike is bought, and will be shipped to me by the end of the week.

    I have already done some research, but will be spending a lot more time as I get into this more - I have my eye already on a pre-74 (1971 /5) tranny - apparently after '74 the kickstart lever wasnt that well built.

    I'm used to low compression kickstart bikes, and this project will be a Sunday morning/Friday night poser bike (I admit that!) so, I don't think I'll be too concerned about the kick!

    I thought that the best way was a post 85 R-airhead monolever swingarm and final drive, mated to a 3 spoke K bike should only require a bracket/space etc for the disk brake - so thanks for confirming that Anton - and YES I have been reading your site too!

    Hmm...changing the clutch/flywheel etc may be a drama - but I may have to replace the original clutch anyway on the donor bike, so maybe not?

    Thankyou Alfons for the info as well - the BMW-Ducati conversion is brilliant. I have a picture somewhere of a guy with similar swingarm and front end, but with no fairing. Ill post it later.

    Just bought a spare R65 triple tree - so I'll start researching what front end I can put on the bike (the original will be sold, its a single disk with a pitted fork).

    anyone know the fork diameter on the R65?
    #9
  10. RocketJ

    RocketJ Been here awhile

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    Of course, if you are real good with angle grinder you can cut .250 off the 4 speed input shaft..............:lol2
    #10
  11. Alfons

    Alfons Been here awhile

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    Hi it is Germany again here,

    R 65 forks are 36 mm just like the forks used in all the type 247 airheads. I would suggest considering K 100/K75 forks as these are made for bikes which are not as heavy as the K 1100s, so the forks springs might work well in a much lighter bike.
    If I were you I would keep an electric starter since they are more convenient than a kick starter, particularly since the kick starters of the later series are useless, and with a /5 gearbox you would be restricted to the heavy flywheel.
    Keep us informed

    Alfons
    #11
  12. Zebedee

    Zebedee Been here awhile

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    I hate to disagree, but having just acquired a very tired example of an R65, the info that I've found is that the R65 forks are not interchangeable.

    [edit: full article here]

    I'd love to be proved wrong. :thumb

    Regards

    John
    #12
  13. Alfons

    Alfons Been here awhile

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    Hi John,

    again it's Germany calling. You are right in so far that the forks are definitely not interchangeable since yokes (fork legs are about 7mm wider apart) and interiors are different from the the forks used on the /5 to /7. However, the diameter is the same.
    :freaky

    greetings

    Alfons
    #13
  14. Zebedee

    Zebedee Been here awhile

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    Well you live and learn ... :thumb
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  15. Nick Makwell

    Nick Makwell Bavarian Murder Weapon

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    link doesnt work?

    interesting - in my search for a different front end, i hadnt contemplated the K100/1100 front (see first photo above) but, am open to ideas...and I might be able to get my hands on a good example, complete.

    So - another question - :D - does that front end bolt on to an R65 frame, or need some mods?

    failing that, what other bikes have 36mm forks?

    Bike is being shipped this week........happy days. Wife has told me to hurry up and sell first bike, but she's interested in this project....
    #15
  16. Zebedee

    Zebedee Been here awhile

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    Oops ... Should be OK now :thumb
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  17. StephenB

    StephenB G(/)S ... what else!

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    All Airheads from 1969 to 1987 had 36mm fork tubes, but the legs evolved over the years to accomodate everything form drum over single ATE to dual ATE to single brembo to dual Brembo front brakes. Triple trees were the same for all except for the R45/R65 family which was always a bit different.

    There might be a lot more subtle differences between the R45/R65 and the "mainstream" Airheads /5/6/7 that I am not aware of, because I never had a R45/R65.
    #17
  18. Nick Makwell

    Nick Makwell Bavarian Murder Weapon

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    so has anyone had any experience in putting different front ends on Airheads - i have seen some dirtbike Airhead threads....might have a closer look.

    Parts for Jap bikes are a LOT cheaper than BMW equivalents.....

    I have a picture somewhere of an R100 with a GSXR1000 front end, but that may be overkill for a R65!!!! :D
    #18
  19. Zebedee

    Zebedee Been here awhile

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    Nick,

    Have a look here this guy is suggesting that BMW and Honda CR 500 head bearings are the same dia, (different length).

    I know nowt about other head bearings, but it would be nice to think that other Honda's used the same bearings, and therefore that you could swap the front end without too much grief.

    Any other info gratefully received ... :ear

    Cheers

    John
    #19
  20. Nick Makwell

    Nick Makwell Bavarian Murder Weapon

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    Thanks John - Ive had a good read and copied some photos...

    I wonder what the head bearings spec is for the Honda CR500 - might be a range of front ends that are similar that are able to be used....
    #20