!200 engine swap

Information and questions on GL1000 Goldwings (1975-1979)
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Posts: 7
Joined: Fri Jul 31, 2015 4:16 pm
Location: Saratoga, CA
Motorcycle: !976 Honda GL 1000

!200 engine swap

Post by guidowitz »

I have a nice 1976 that needs a new engine.

I was hoping to find a 1976 or 1977 replacement to keep things period correct but nothing is coming up on my radar over the past year here in northern California.

I did find a nice used 1200 for sale locally . Asking $300.

I was hoping to keep the rig period correct, but now realize I may have to venture into a custom project if I ever expect to ride it again.

For those that have done a 1000----->1200 conversion I would be grateful to hear the advantages and pitfalls related to this swap.

I'm feel I'm experienced enough to do most the wrenching necessary, although my time is limited.

I just don't know what I may be facing in terms of the customization required and hoping that some who have journeyed here can give me advice.

Joy and peace for the holidays and new year!


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Fred Camper
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Re: !200 engine swap

Post by Fred Camper »

I have not done it, but others have. There is a tach drive issue and something on the rear is too long for the frame so that part of the engine needs a swap.

Also the gear ratios in the transmission are different so you need to watch the final drive too.

It works out well but takes much more effort. Nice tutorials over at NGWClub.com that you may chose to review prior to the purchase.
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Re: !200 engine swap

Post by Shadowjack »

I'm right in the middle of doing this now--putting an '85 1200 into a '75 1000 frame. They fit, but it's not just a bolt-in.
An '84 1200 engine has the ignition system on the back of the engine, and it hits a crosstube under the fuel tank. You have to cut out about 4" of the tube (or maybe cut the diameter to about half; I didn't research this closely).
An '85-up engine clears the crosstube, but the rear cover is deeper to fit the larger alternator stator, so it hits the left frame tube. I dimpled mine about half its diameter.
The 1200 starter hits the engine mount tab on the left removable frame tube. A small bit of grinding will clear it.
1200s have electronic ignition. I just nabbed a module for the proper year (84 is different from the others) and will connect it with a new wiring subharness I'll have to make. I intend to mount it at the rear of the right shelter, where the 1000 carries the spare kickstart lever.
I have the 1200 coils as well. Had to make a couple of adapter straps so they bolt onto the 1000 brackets. The alternator stator will plug into the 1000 harness. The neutral switch is different, so the wiring will need to be adapted.
I'm using the 1200 carb set. Clearance is tight under the frame, but they do go in. Also the choke cable won't fit past the front engine mount shroud without cutting a hole in it. The 1200 aircleaner box will fit, but not without cutting on it a little, and I had to reshape the reinforcing strap at the top front engine mount to clear the airbox.
The 1200 has an electric fuel pump that runs off a relay triggered by the ignition module. Modern bikes use a bank sensor to cut the pump if it falls over. Either way needs to be worked out.
The 1000 uses a snapring to hold the driveshaft u-joint to the output shaft. The 1200 uses a spring in the rear end to push the driveshaft forward. The rear engine cover will need to be removed and a 1000 output shaft installed, with the snapring groove. It's a slide-in. Change the starter clutch parts while you're in there.
The overall final drive is essentially 10% lower on a 1000 than a 1200 by the time you factor in the tire sizes. The internal gear ratios don't vary all that much.
The 1200 uses a hydraulic clutch. Plenty of used and aftermarket master cylinders around. You need to get a braided line to reach from the slave to the bars.
The tach is an issue. as mentioned above. The 1200 tach is electronic so it doesn't have a mechanical cable to drive the 1000 clock. '84 Standards had regular round instruments, but the others all had them in a big module. The round tachs are like hens' teeth.
Anything I haven't listed here, I haven't addressed yet.
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Re: !200 engine swap

Post by DenverWinger »

I've heard of using 1100 or 1000 heads on a 1200 block, that would address the tach and fuel pump issue, and if the 1000 heads were used you could even stay with stock points ignition.

I don't know what other cans of worms the head swap might bring up, how about it, Gurus...
There are 10 types of people in the world, those that understand binary numbers, and those that don't. :lol:

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Re: !200 engine swap

Post by guidowitz »

Thanks for all the useful information here.

I would like to take the swap on as it is well within my mechanical aptitude. Time is my real enemy.

Looking forward to organizing the project soon!

Best for the new year!


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