'76 speedo and tach ratios
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'76 speedo and tach ratios
Pretty sure on the CB750's I've worked on the ratio was 4:1 but no idea if the same applies these 'wings. Shopping around for an aftermarket replacement as the speedo/tach on mine is shot...
Last edited by jimbonaut on Wed Feb 08, 2023 4:05 pm, edited 1 time in total.
- Lucien Harpress
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Re: '76 speedo ratio
I could be wrong, but I'm fairly certain the CB750 and the GL1000 both run a 2240:60 speedometer ratio (along with many other Japanese bikes of the time). If you're looking to replace with stock, or at least close to, 4 into 1 sells some VERY nice replacements.
The tachometer is a different story (that's where the 4:1 or the 7:1 makes more sense), but I'm even less sure about that one.
The tachometer is a different story (that's where the 4:1 or the 7:1 makes more sense), but I'm even less sure about that one.
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1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete
All advice I give is only valid until an expert corrects me.
1980 KZ1300- Bike's Haunted
1976 GL1000 (Yellow)- It Runs (Poorly) and Doesn't Leak (Mostly)
1974 Velosolex 3800- Better Than Walking
1972 CB750- Broke the Chain And Ate the Motor
1969 CT90- The Most Fun You Can Have on 90ccs.
1965 CA77 Dream- Needs a Full Teardown, but Complete
All advice I give is only valid until an expert corrects me.
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Re: '76 speedo ratio
Thanks for the pointer Lucien and you're right, those replacements do look very nice. Did you try removing your speedo/tach from the original housing and replace it with a new set? The OEM housing looks fairly secure and I don't want to break anything by whaling on it too hard. Are the units fairly easy to swap out?
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Re: '76 speedo ratio
Checked the 4into1 website again and seems they no longer sell the replacement tach? Or maybe it's just out of stock...
- Sidecar Bob
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Re: '76 speedo ratio
Speedometers are usually rated by the cable RPM at a specified speed and all of the Japanese bike makers use the same speedometer ratios:
2240 RPM = 60 MPH
2330 RPM = 100 Km/h
This means that you can use any speedometer intended for a Honda, Yamaha, Suzuki or Kawasaki.
Note that the gear ratio in the drive gear on the wheel varies depending on wheel size.
Tachometers are rated with simple ratios
Yamaha and Kawasaki used 1:5 tachs
Suzuki used 1:4
Honda used 1:7 for engines below 750cc and 1:4 for 750cc and larger. I am unsure which the 700cc "Harley tariff" versions of bikes that were 750cc in the rest of the world had and to add to the confusion Motofaction says that the CX family use 1:4 but other sources indicate that they need 1:7.
2240 RPM = 60 MPH
2330 RPM = 100 Km/h
This means that you can use any speedometer intended for a Honda, Yamaha, Suzuki or Kawasaki.
Note that the gear ratio in the drive gear on the wheel varies depending on wheel size.
Tachometers are rated with simple ratios
Yamaha and Kawasaki used 1:5 tachs
Suzuki used 1:4
Honda used 1:7 for engines below 750cc and 1:4 for 750cc and larger. I am unsure which the 700cc "Harley tariff" versions of bikes that were 750cc in the rest of the world had and to add to the confusion Motofaction says that the CX family use 1:4 but other sources indicate that they need 1:7.
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Re: '76 speedo and tach ratios
Any idea if this tach would work? It's listed as fitting a CB750 but no mention of a Goldwing. Sure looks the same...
https://www.cb750supply.com/products/99 ... cho-speedo
https://www.cb750supply.com/products/99 ... cho-speedo
- pidjones
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Re: '76 speedo and tach ratios
Should. I used a GL1000 tach on a CB750F.
"Love 'em all.... let God sort 'em out!"
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
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Re: '76 speedo and tach ratios
Thanks pid, good to know - wonder if the housing/mounting holes etc are the same on the CB's and GL's?
- pidjones
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Re: '76 speedo and tach ratios
Don't remember that. I do remember that the bezels are different. Here are '79 CB750F and GL1000 tachs.
"Love 'em all.... let God sort 'em out!"
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
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