Are all final drives interchangeable?

[andmoon]

I want to drop cruising rpms on my 83 850G.
I see a few final drives from 1000 & 1100Gs on ebay.
Are these just a bolt it?

[Steve]

I think that they are bolt-ins, but they may not do what you want.

True, the 1000s and 1100s have lower RPM at a given road speed, but they also have different secondary drive ratios. I believe the final drives are all the same ratio, except the ones for the GK models. Someone had a chart on here before, so it could be found with a short search, but I seem to remember that the 850 uses a 3.09 final ratio and the GK uses a 2.90. At 70 mph, that would drop your engine speed about 400 rpm.

Personally, I will offer you the opinion to just learn to live with the higher engine speed. The smaller (than the 1000 and 1100) engine needs a few more revs to to the same work, and they do a WONDERFUL job of singing along at 5000 rpm at 70 mph all day long.

By the way, you want to have some fun? Just twist that throttle a little more, a little longer. Get the engine speed over 6000 rpm and be prepared to be surprised. The powerband on these engines is two-stage. Nice and mild-mannered under 6000 and a nice improvement over 6000.

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[Nessism]

The '83 - '84 GS1100G (all models) have the taller rear end. I have one from a GL in my 850. One other thing that can be done is install a 17" rear wheel if your bike has a 16".

[Steve]

One other thing that can be done is install a 17" rear wheel if your bike has a 16".

The G model should have a 17" wheel already, but you know how previous owners are.

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[Nessism]

The G model should have a 17" wheel already, but you know how previous owners are.

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Yea, G = 17", only some members here say G when they have a GL. Just being safe.

[BassCliff]

Hi,

Here is the chart that Mr. Nessism put together for us...



I found it on some guy's website in the "Engine Odds and Ends" section.


Thank you for your indulgence,

BassCliff

[andmoon]

Thanks all.


3.09 to 2.91 doesn't seem like it would be worth the trouble.

[1948man]

Would a 17" wheel fit in an '83 1100GL with no problems?

[Nessism]

Would a 17" wheel fit in an '83 1100GL with no problems?

Member Grandpa used 16 and 17" rear wheels interchangeably on his GK, which came with a 16 originally. Not positive about your GL but I think it would fit.

[emjay]

So, it would look like the way to get the best reduction possible for an 850 GL would be to replace the secondary and final drives with those from a GK and then swap the 16" wheel for a 17er, correct?

If you've got a G then you'd already have the bigger wheel.

[Dave8338]

So, it would look like the way to get the best reduction possible for an 850 GL would be to replace the secondary and final drives with those from a GK and then swap the 16" wheel for a 17er, correct?

If you've got a G then you'd already have the bigger wheel.

Correct and correct...

[Nessism]

I have a 2.9 rear end in my 850 and the bike requires more clutch slipping to get the bike moving off the line. Something to consider for those comtemplating this mod. Going even taller won't be without some downsides.

[emjay]

I have a 2.9 rear end in my 850 and the bike requires more clutch slipping to get the bike moving off the line. Something to consider for those comtemplating this mod. Going even taller won't be without some downsides.

Good point. I'm not planning it, but was just wondering.

[Steve]

Another thing to keep in mind is co$t. All of these mods might be worth trying, but only if you have all the parts around and are willing to put some time into it. I don't think it would be worth buying all the parts for what might be a very minimal return on the investment.

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