1200 Power Planet into 79 GL1000 Frame


Information and questions on GL1200 Goldwings (1984-1987)
  • Sponsored Links
Post Reply
Dan1todd
Posts: 13
Joined: Sun Mar 18, 2018 7:05 pm
Location: Bakersfield, CA
Motorcycle: 1975 and 1979 Honda GL1000 Goldwing

1200 Power Planet into 79 GL1000 Frame

Post by Dan1todd » Sun Aug 05, 2018 10:48 am



I have a beautiful 1979 GL1000 that my brother-in-law wrecked. I have replaced many parts including the motor, but I am not winning. I found a 1200 power plant, transmission and shaft drive for a fair price and considering putting it into my bike, BUT not sure to frame can support the 1200.

Has anyone had experience with these 2 bikes? Was the platform/frame the same or was there modifications? What kind? How was the final product?

Dan

1979 GL1000
1979 GL1000




User avatar
ekvh
Posts: 321
Joined: Thu Apr 29, 2010 9:52 am
Location: Grand Forks, ND
Motorcycle: 1977 gl1000

Re: 1200 Power Planet into 79 GL1000 Frame

Post by ekvh » Sun Aug 05, 2018 1:19 pm

Several have done it, myself included. The 85-87 1200 will almost drop in. It varies from bike to bike likely due to jig differences at the factory. Mine needed a little love from a hammer where the stator is closest to the frame, but others haven’t had to do that. It is tight by the lower left rear motor mount (on mine)and starter and the front right belt cover is a squeeze to get in. The frame will handle it. The motor doesn’t way much more than a 1000 but has a lot of improvements for longevity. The forks are pretty wimpy even with a 1000 so I upgraded to 41mm forks.

One thing you must do if using the 1000 final drive is remove the rear cover and swap the output shaft from the 1000 into the 1200. The 1000/1100 output shafts have a groove for a circlip to hold the drive shaft in place. People have tried without this and had the shaft fall out in the front.

Depending on carb choice, air box will need modifications. The 1200 motor is 5mm wider on each side so carbs from earlier years have to be pulled out a notch in the runners, but if the runners are in decent shape they seal.

The 84 has rear ignition and a frame mod must be done to accommodate it or it can be removed, the hole plugged, and a different ignition source used. Some have used 1000 early cams and heads and its ignition system. Mine is a cobbled effort using a cb750 PowerArc off the front crank. ( I don’t recommend it.)

I’m ready to try the 1200 heads back on mine.

You will be able to smoke the rear tire, pick the front end up, and best of all, you will like it.

Dan1todd
Posts: 13
Joined: Sun Mar 18, 2018 7:05 pm
Location: Bakersfield, CA
Motorcycle: 1975 and 1979 Honda GL1000 Goldwing

Re: 1200 Power Planet into 79 GL1000 Frame

Post by Dan1todd » Sun Aug 05, 2018 1:24 pm

Buddy, this is great information. Me and my buddy, the mechanic, are seriously looking into this and you’ve given me great detail. I will endeavor to start this project next month. Because I have so much money already invested in this 79, it’s probably the best bet for me long-term to have a good writer like that.

Greatly appreciated, Dan

User avatar
ekvh
Posts: 321
Joined: Thu Apr 29, 2010 9:52 am
Location: Grand Forks, ND
Motorcycle: 1977 gl1000

Re: 1200 Power Planet into 79 GL1000 Frame

Post by ekvh » Sun Aug 05, 2018 6:12 pm

The other part I neglected to include, among others, but you may know, is the 79 has a 3.40 final drive. The 1200 has a 2.83 so to help it has an even lower first gear, but a taller fifth gear/overdrive. It screams pretty quick off the line. If you aren’t ready, it will pull the bars right out of your hands. The overdrive keeps the revs down a bit. If you can find a Lester 18” rear wheel, it will help highway mileage.

To use the 1200 ignition, you will need the “black box” controller for the 1200 along with igniters, I think. I think the “ecm” just helps the 1200 advance the timing at certain points in 4th and 5th gear using a vacuum pulse. Coils will have to be different.

Dan1todd
Posts: 13
Joined: Sun Mar 18, 2018 7:05 pm
Location: Bakersfield, CA
Motorcycle: 1975 and 1979 Honda GL1000 Goldwing

Re: 1200 Power Planet into 79 GL1000 Frame

Post by Dan1todd » Sun Aug 05, 2018 6:50 pm

Thank you again. I guess I would use the existing 1200 carborators unless you have another recommendation.

User avatar
ekvh
Posts: 321
Joined: Thu Apr 29, 2010 9:52 am
Location: Grand Forks, ND
Motorcycle: 1977 gl1000

Re: 1200 Power Planet into 79 GL1000 Frame

Post by ekvh » Sun Aug 05, 2018 10:27 pm

The 1200 carbs are probably best, easier and cheaper to rebuild unless a diaphragm gets torn.

Dan1todd
Posts: 13
Joined: Sun Mar 18, 2018 7:05 pm
Location: Bakersfield, CA
Motorcycle: 1975 and 1979 Honda GL1000 Goldwing

Re: 1200 Power Planet into 79 GL1000 Frame

Post by Dan1todd » Sun Aug 05, 2018 10:33 pm

Ok, great! Thanks for all your help!!!



Post Reply