Gl1100 engine gl1000 frame

[Wingersparty]

Hi guys,
Help me out please. I am thinking of putting gl1100 engine in my 1000 frame. I know theres a good topic in this forum about this subject but i cant find it.
Please help me out

[CYBORG]

Should fit right in.

[Shadowjack]

I don't have an 1100 to look at, but do they have a bulge on the rear for the ignition, like an 84 1200 engine? If so, it may not clear the frame.

[Wingersparty]

As i have heard this is not plug n play mod.

[Sidecar Bob]

Having done the opposite (1000 engine in an 1100) I don't think I'd like the result. They changed the final drive ratio between the 1000 and 1100 and the transmission gearing was altered to suit.
Combining a 1000 transmission with an 1100 final drive produced significantly higher overall gearing such that 1st on my bike was higher than 2 on a stock bike of either type. This was great on 2 wheels because it loped along just over idle at 80 Km/h with improved fuel economy too.
Combining an 1100 transmission with a 1000 final drive would have the opposite result with 5th gear lower than the stock 4th so the engine would be running faster all the time and burning more fuel.

[ericheath]

Guys that have done it like the quicker take-off from the gearing. You will need to modify the frame of the 1000 or modify the ignition on the 1100.

If you can weld, the frame mod is fairly easy. I have seen pics at Saunders where people have cut half of the cross brace tube for the ignition to fit, others who have replace the tube with a slightly bent tube to allow ignition to fit.

Others have put 1000 cams in and used the 1000 ignition as on the 1000 bikes. This way is a bolt on procedure, but then you need to make a plate to cover the hole after you remove the 1100 ignition. Or swap the 1000 rear cover onto the 1100. And you’ll of course need to rewire for the 1000 ignition and probably need new coils.

Check the “Similar Posts” at the bottom of this page.

[Sidecar Bob]

I guess it's a matter of taste bit for me the quicker takeoff wouldn't compensate for the engine running so fast on the highway.
If you want to see what that would be like try running through a tank of gas without shifting into 5th gear. Then try not shifting above 3rd because 5th with an 1100 transmission and a 1000 final drive would be somewhere between 3rd and 4th on a stock bike.

[ericheath]

There are a few of us with 1200’s in 1000 frames. You’re right, it’s a matter of taste. If a 1200 is happy running at higher rpm, an 1100 will be also. Higher rpm annoys some people, some don’t mind. On a Goldwing, not looking at the tach, and having ear buds in, I could not feel any difference at the extra 500 rpm, just more responsive to throttle. I think it’s the well-balanced nature due to its design. My mpg with the 1200 was the same as the 1000. I experimented with different wheel sizes and put a 1500 final drive on one. Mileage was not improved, and stayed virtually the same for me. If I really behaved and drove modestly, I might get 40 mpg, but most times it was 37 and if averaged I’ve a full summer or longer stretch, it was pretty close to 37. If I am in town and lots of rapid takeoffs, 32mpg, maybe even 30. Did I occasionally get 45 on a tankful? Yes, when there was a tailwind or long gradually declines. I read reports of people consistently getting 50mpg from various old Goldwings. I never could.

[Sidecar Bob]

I don't know about the 1200's transmission but with an 1100 trans + 1000 FD I would expect it to be more like 1000RPM higher than stock on the highway, maybe more.

[CYBORG]

Same on the 1200's

[ericheath]

From data several years ( lol, maybe decades) ago at the Saunders site, the gearing differences are all cited from the manuals. I believe a lot of people only look at the transmission gear ratios and don’t take into account all the gearing factors. ( This one has the lowest first gear and that one has the lowest top gear….) I multiplied all the reductions out and multiplied them for comparison using the gl1000 final drive. The results are surprisingly different with the 1100 transmission when including all gearing factors.

75-79 ratios: primary, secondary, fifth gear, final drive ratio
1.708 x 0.825 x 0.939 x 3.4 = 4.50

80-81 with 1000 final drive
1.708 x 0.973 x 0.909 x 3.4 = 5.13 (12% increase in rpm)

82 only with 1000 final drive
1.708 x 0.973 x 0.829 x 3.4 = 4.68 (4% increase)

83 only with 1000 final drive
1.708 x 0.897 x 0.829 x 3.4 = 4.31 (4% decrease!!)

84 was virtually identical to the 83 transmission.

85-87 with 1000 final drive
1.708 x 0.973 x 0.800 x 3.4 = 4.52- nearly the same as a gl1000

The secondary gearing is the overlooked factor in my opinion.

To these you also need to factor your tire circumference differences. Gl1000 and 80-81 gl1100 had a 17” rear tire, the 82-83 had a 16” rear tire and the gl1200’s had a 15” rear tire.

I can post the spread sheets of data if needed.

[Sidecar Bob]

I had a '79 engine in my '83 (with '82 final drive) for over 20 years. I loved it on 2 wheels but the gearing was too high for pulling a sidecar so I eventually changed to an '82 engine.
The difference felt like a lot more than 4%.

[ericheath]

You’re comparing apples to oranges, but I believe they’re still closer. The post was about 1100’s in a 1000 frame. You’re comparing a 1000 in a higher geared 1100 frame to an 1100. Tye 1100’s gearing spreads varied a great deal according to the data.

[Sidecar Bob]

When I put Mr.H together the stock 1000's RPM per speed in gear was still pretty fresh in my mind. I remember at the time noting that the RPM/speed in 1st gear was lower than the RPM for the same speed in 2nd gear on the stock bike.
If that is true the RPM/speed for stock bike should be lower than a 1100 engine with a 1000 final drive (the opposite setup to what I had) by about the same amount.

[ericheath]

So now you’re discussing first and second gears, which are different than original post about highway speeds.

Here’s the math on them in first gear, excluding tire size:

Note that the 75-82 had the same first gear ratio of 2.5:1 but were different overall due to changing secondary ratios, 0.825 to 0.973 to 0.897. Which final drive would not affect these for comparison purposes as long as the same final drive was used for each one.

75-79 gear ratios :1
Primary Secondary First gear Overall ratio
1.708 x 0.825 x 2.5 = 3.527

80-82
1.708 x 0.973 x 2.5 = 4.154

83
1.708 x 0.897 x 2.642 = 4.047

So your recollection is probably correct that the 82 was closer to 15% lower gearing in first gear than the 79.

Second gear was 1.708 for 75-79, and it was 1.667 for all the rest through 1987, but remember the secondary ratio changed in the 1100’s.