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FJ 1200 Gear ratio

Started by Meraco, June 07, 2024, 09:54:55 AM

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Meraco

Hello,

It is time for me to replace my chain and sprockets for the FJ. It currently has a 17/40 ratio. However I was thinking of reducing the top end RPM at highway speed.

I was curious if anyone has any experience or insight about my trying a 17/38 ratio.

Thanks


Pat Conlon

I recommend a 18/40 ratio. The larger chain wrap on the 18 tooth countershaft sprocket is beneficial to your chain.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

FJmonkey

I agree with Pat, 18T is easier on the chain.
The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Bones

Go 18/38. Relaxed long legged touring with still plenty of power for overtaking. 100kph @ 3500 rpm.
93 fj1200
79 suzuki gt250x7


Too young to be old but old enough to know better.

Millietant

I went with 18:40 for about 24,000 miles and loved it, but when I V replaced my chain and sprockets again, I decided to go a bit firmer and opted for 18:30. Now I've had that for a good few thousands of miles, I'd recommend that is the best option for your needs.

It's a bit e relaxed again at Highway speeds but still has more than of the overtaking power the FJ is legendary for  :good2:
Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.

Meraco

Quote from: Bones on June 07, 2024, 03:44:28 PMGo 18/38. Relaxed long legged touring with still plenty of power for overtaking. 100kph @ 3500 rpm.

Since the consensus is to have the front end at 18, and I am already committed to the 38 at the back. It looks like Ill be trying your suggested configuration.

Currently I am getting 90 kph @ 3500 with the 17/40. I like the idea of bumping up to 100kph at the same RPM.





Millietant

Quote from: Millietant on June 08, 2024, 02:49:37 PMI went with 18:40 for about 24,000 miles and loved it, but when I V ("V" should not be there) replaced my chain and sprockets again, I decided to go a bit firmer (should read "further") and opted for 18:30 (should read 18:38). Now I've had that for a good few thousands of miles, I'd recommend that is the best option for your needs.

It's a bit e (should read "more") relaxed again at Highway speeds but still has more than ("enough" was missing here) of the overtaking power the FJ is legendary for  :good2:

I shouldn't type on my phone, without my glasses.....when I read my comments on my computer later, I realise how rubbish they are...and it's too late to correct them.
 :dash2:
Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.

fj1289


Meraco

I now have the 18/38 installed. Took it for the first ride yesterday and the specs you guys gave was spot on.

Was doing 90/kmh @ 3,000 RPM.

And the lower gear torque doesn't seem all that affected. It's still punchy.

Now I need to clean the bike up.

Thanks everyone for the advice.

gumby302ho

I am running 18\39 because at the time RPM was out of the 38 tooth option, my 86 is showing
3100rpm at 100km\hr on the clocks.