What's involved in an 1200 engine swap into a 1000 frame?

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ericheath
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#16

Post by ericheath »

If you like the nature of a 1000 and the lower end torque of the 1200, then a swap of either 1000 or 1100 heads and cams is the best of both. The extra cc’s help, but the extra torque from the longer stroke helps too. The 1200 piston is only 1/2 mm larger than the 1100 but the stroke is 5mm longer.

The larger intake valve of the 1000 or 1100 helps and the cam profile and solid lifters permit the higher revs of the early years. Some people don’t think the extra 2mm of the valves help (36mm 1200 vs 38mm 1000/1100) but if you calculate the curtain areas of the two, ( circumference of the valve times the lift of the cam) the 1200’s valve and cam is fully open exposing 656mm^2 to the 1000’s valve and cam is 845mm^2. An 1100 cam would yield 801mm^2. To those numbers you can factor in a little longer duration as well. Another 2% potentially of duration. ( 235 duration for the 1000 vs either 225 or 230 duration for the 1200- there were two cam profiles used.) When they do their damage can be tweaked a bit too.

36 compared to 38?? Or 656 compare to 845?? A significant difference in the numbers. They may not flow as much at certain rpm, but I find the torque (stroke) helps the low end and the the lift and size help the top end.

If I had a stock 1200, I’m pretty sure I would put a set of early heads on it. I’m pretty sure a different set of carbs would help them too, like Randakk’s Weber mod. Although, when I first did mine and put 1200 carbs and intake runners on, it performed very well. That doesn’t seem to make sense because you have a mismatched port area with the 1200 intake elbow at around 1.25” meeting a large intake port of 1.44” or so. Robin, who knows a thing or three about current motors, has said he thinks the ports are too big, and my butt-dynamometer says he might be right on that. Apologies in advance if I am quoting him wrong.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#17

Post by Easter »

The Standard 1200 is getting scarce, don't rule out a later Interstate or even the Aspencade. My current thread ("All it needs is a battery and maybe a carb clean") started as an 85 Interstate and the only real issue is the wiring harness. Which can be worked around. 1100 Shelters can be adapted without much difficulty and then choose your accessories.
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#18

Post by CYBORG »

I HAVE a 1200 engine in a 1000 frame utilizing the stock 1000 rear drive unit, and a 1200 front forks and wheel. Stock engine. Very fast,...very compatible. Ask anyone who has rode with me. It also has a mono shock in the rear, which is vast improvement to the handling
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#19

Post by Rat »

CYBORG wrote:I HAVE a 1200 engine in a 1000 frame utilizing the stock 1000 rear drive unit, and a 1200 front forks and wheel. Stock engine. Very fast,...very compatible. Ask anyone who has rode with me. It also has a mono shock in the rear, which is vast improvement to the handling

Yup ....

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Re: What's involved in an 1200 engine swap into a 1000 frame?

#20

Post by ericheath »

I didn’t say it wasn’t.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#21

Post by CYBORG »

ericheath wrote:I didn’t say it wasn’t.
No reflection on what you said. Just an observation, and statement. Every change from the factory, (designed for overall performance), usually targets a specific factor. A smart man once said "everything effects everything".
I seldom tool around at speeds below 30 or over 100, so I design for my normal which is around 50 to 75. That's my sweet spot. Others may have a different idea of "normal riding". They, of course, would design a different "sweet spot".
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#22

Post by MegaDan »

Cyborg, just out of curiosity, how far out do you rev your 1200 engine? With the internet being so full of "facts" it is hard to find the actual facts. Will the 1200 engines still rev out to 8500rpm like the 1000?
1975 GL1000 - Delkevic exhaust with stainless studs, Corbin Touring seat, Race Tech Gold Valve cartridge emulators, Progressive 11-1100 springs, Progressive 412HD rear shocks, Shinko 230 tires, Fork Brace, Trucklite 27270c headlight, X-Arc Signals (run, brake, turn), Hydraulic Clutch conversion, EBC Clutch discs, HD springs, and Barnett Steels + Plate B eliminated. BikeMaster DLFP-50N18L Lithium battery, Rick's Motorsports CBR600F4 Mosfet Regulator/Rectifier upgrade.
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#23

Post by CYBORG »

I rarely rev over 6k. The sweet spot is between 3500 and 4500. I have an 86 engine. for the overdrive. 75mph is right at 4200. No need to downshift to pass,. And I can pull away at idle. (1200rpm). I think it is safe to say the 1200 was never designed to rev as high as the 1000. At least in my experience. I don't put a lot of faith in the internet. More in my personal experience.
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#24

Post by x01660 »

Ok, so this consideration is important; I LOVE revs. I rev my 1000 out to 9k all the time.

So a combo of 1200 block with early 1000 heads and cams is the way to go?

Also, does anyone have any experience with Webb or any custom ground cams?
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#25

Post by MegaDan »

In theory the 1200 motor could rev just as high as the 1000. They have the same stroke. So the piston speed and acceleration is no different. It is more a question of needing to rev that high.
1975 GL1000 - Delkevic exhaust with stainless studs, Corbin Touring seat, Race Tech Gold Valve cartridge emulators, Progressive 11-1100 springs, Progressive 412HD rear shocks, Shinko 230 tires, Fork Brace, Trucklite 27270c headlight, X-Arc Signals (run, brake, turn), Hydraulic Clutch conversion, EBC Clutch discs, HD springs, and Barnett Steels + Plate B eliminated. BikeMaster DLFP-50N18L Lithium battery, Rick's Motorsports CBR600F4 Mosfet Regulator/Rectifier upgrade.
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#26

Post by ericheath »

They do not have the same stroke. The 1200 has 66mm compared to the 1000/1100’s which have 61mm stroke.

I rev my 1200 with 1000 heads cams carbs to 9k anytime I want. If you ride with Fish’s philosophy— “wind it out until it quits pulling, then shift”—- you’ll hit 9k a lot. If I don’t look, I’m doing 9k. It probably pulls just as good in the next gear if you shift a little sooner, but it’s a heck of a kick when you hit second.

When I shaved the heads a little under 0.030” and used a thinner head gasket of 0.030”, I had piston and heads hitting on the outer edges— probably at the higher rpm. The 1000 chambers probably should be enlarged a little deeper. That’s beyond my skill set and wallet.
DEA960C6-C9AD-4B20-90DA-676D84B646B6.jpeg
DEA960C6-C9AD-4B20-90DA-676D84B646B6.jpeg (202.17 KiB) Viewed 427 times
There seem to be quite a few who’ve done the swap with no issues at stock thickness.


I’m not an engineer, Cyborg is. Honda has a whole bunch of engineers. Somewhere here I read that the lower rpm of the 1200 was due to the hydraulic valve train. Others have opined that the 1200 block is beefier and probably can handle the higher rpm. Is it better? I can’t say. It’s just an option. I can say- it’s fun.

A 1200 in fifth gear with a 1000 final drive is almost the same final gear ratios as a 1200 in fourth gear with a 1200 final drive. It has to be sportier. I could be wrong, but I don’t think the weights of the bikes will be much different if both have a 1200 and the same front ends.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#27

Post by MegaDan »

Thanks for correcting me on the stroke. I thought they were the same, but I guess that would account for the difference in width.

My curiosity stems from the potential of needing a new engine. The heads on my 75 are perfect, so it may be worth looking into.
1975 GL1000 - Delkevic exhaust with stainless studs, Corbin Touring seat, Race Tech Gold Valve cartridge emulators, Progressive 11-1100 springs, Progressive 412HD rear shocks, Shinko 230 tires, Fork Brace, Trucklite 27270c headlight, X-Arc Signals (run, brake, turn), Hydraulic Clutch conversion, EBC Clutch discs, HD springs, and Barnett Steels + Plate B eliminated. BikeMaster DLFP-50N18L Lithium battery, Rick's Motorsports CBR600F4 Mosfet Regulator/Rectifier upgrade.
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#28

Post by ericheath »

An 1100 is an easier swap with a boost in power as well, but not the stroke. Just remember putting the 1000 heads on a 1200 will require pistons to be notched for the larger valves.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#29

Post by x01660 »

ericheath wrote:An 1100 is an easier swap with a boost in power as well, but not the stroke. Just remember putting the 1000 heads on a 1200 will require pistons to be notched for the larger valves.
Sorry to revive an old thread, but its relevant:

viewtopic.php?f=30&t=64280&start=30#p728798

I need a motor.

That said, I found a rolling frame 1100 nearby for $250. its an 81 GL1100

How hard would it be to fit the 1100 in the 1000 frame? Any notching needed?

https://ventura.craigslist.org/mcy/d/19 ... 72658.html
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Re: What's involved in an 1200 engine swap into a 1000 frame?

#30

Post by wingrider »

You will still run into a little trouble with the electronics poking out the back of the 1100.
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