Results 1 to 6 of 6

Thread: /2 to later engine/transmission conversion

  1. #1
    Registered User lmo1131's Avatar
    Join Date
    Jan 2010
    Location
    Pismo Beach, CA
    Posts
    3,928

    /2 to later engine/transmission conversion

    I'm just starting the information search for converting /2 to later drive train.

    Anyone have a source for an overview?

    Thanks.
    "It is what you discover, after you know it all, that counts." _ John Wooden
    Lew Morris
    1973 R75/5 - original owner
    1963 Dnepr

  2. #2
    '99 '03 '06 National Co-Rally Chair Friedle's Avatar
    Join Date
    Mar 2003
    Location
    Poughkeepsie, NY
    Posts
    1,530
    Engine swap is the easy part. The harder part comes next. Integrating the existing /2 controls and switches with the electrical system of the implanted motor. Gets to be even more fun if the new motor is dual plugged. Oh, and don't forget integrating 6 volt stuff with 12 volt stuff...or just making EVERYTHING 12 volt. Then comes the really fun part with the transmission, gearbox, shaft and final drive. There are adaptor plates to connect the modern trans output flange to the /2 tranny, clutch and drive shaft, but now you are trying to put twice the design horsepower thru the /2 clutch, tranny, drive shaft and final drive. Not gonna last too long. Especially if you plan on adding a chair to the mix.

    BTW, did I mention the fun of rewiring the WHOLE bike while fitting all the extra relays somewhere on the frame under the tank. Or an extra set of coils if dual plugged.

    Well, now that your converted /2 is MUCH faster, comes the question of how to stop the damn thing !

    Best advice is to locate a well done, sorted out conversion already built and tested by SOMEBODY ELSE if that is really want to do.

    I've been riding my 62 R 75/6 conversion for about 30 years hooked to a Steib S 500. It was very well built, not by me, and still confuses me when I pull off the gas tank or look inside the headlight shell. But God is it fun to ride.

    Friedle
    Ride fast safely

  3. #3
    Liaison 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    19,560
    Here's a Yahoo group that seems to be into this sort of thing:

    https://groups.yahoo.com/neo/groups/...nversions/info
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  4. #4

    Doesn't seem that difficult.

    This would be my shopping list. A know good /5 or /6 motor and transmission. A /5 headlight complete, /5 wiring harness, / 5 handle bar controls, A /6 or LWB drive shaft with coupling bell/ splines and some patience. To install the motor you only need to spreed the frame rails slightly to drop it in with the transmission attached. You use the /2 swing arm and final drive but use the LWB or /6 drive shaft, you have to machine several thousands off the outside of the rear coupling bell /splines to get it to fit inside the /2 swing arm.

    You would change your 6 volt bulbs to 12 volt and wire it just like a /5 or /6, you would have to be a little creative when you hide the relays and coils but it can be done quite nicely if you take your time.

    You might have to alter the lower cross brace on the front end down tubes depending on the year and model of the front end. If you need more stopping power you can always lace you front rim onto a /6 disc brake hub and have a couple caliper mounts welded onto the earles fork swing arm, you might have to use a handle bar mounted master cylinder and alter the wiring a little to make it work

  5. #5
    Liaison 20774's Avatar
    Join Date
    Sep 2005
    Location
    San Antonio, TX
    Posts
    19,560
    What about exhaust headers and mufflers? Do the later engine parts match up on the frame?
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  6. #6
    '99 '03 '06 National Co-Rally Chair Friedle's Avatar
    Join Date
    Mar 2003
    Location
    Poughkeepsie, NY
    Posts
    1,530
    I am running /5 head pipes and /2 Hoske mufflers. The Hoske mufflers mount as they would on a /2. Sound nice too.

    Friedle
    Ride fast safely

Similar Threads

  1. engine # on R90 74-76 & transmission #
    By 70816 in forum Airheads
    Replies: 1
    Last Post: 07-28-2015, 10:43 PM
  2. 1993 K75S Conversion Set Engine Spoiler
    By ghyber in forum Flying Brick K-bikes
    Replies: 33
    Last Post: 07-11-2012, 01:06 AM
  3. LT to RS Engine Conversion
    By justmike in forum Flying Brick K-bikes
    Replies: 3
    Last Post: 02-27-2009, 01:36 PM
  4. /2 engine conversion with r100
    By p1800cpe in forum Vintage
    Replies: 3
    Last Post: 05-07-2008, 02:10 PM
  5. vw engine conversion?
    By kenfyoozed in forum Campfire
    Replies: 3
    Last Post: 01-31-2004, 06:53 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •