Higher ratio diff R65

[cringe]

1981 R65 runs nice upto 4500 rpm(65 mph ?) then vibes set in, have 37/11 diff in garage hoping that lifts speed at 4500rpm to70+mph before vibes set in. Can I fit other spedo drive to compensate for difference in diff ratio,or remark original spedo face......Chris

 

[(RIP) Proff]

1981 R65 runs nice upto 4500 rpm(65 mph ?) then vibes set in, have 37/11 diff in garage hoping that lifts speed at 4500rpm to70+mph before vibes set in. Can I fit other spedo drive to compensate for difference in diff ratio,or remark original spedo face......Chris

Before worrying about remarking dial etc,, do the conversion and use a sat nav to see if and how far out you are, then either mark the surround or live with it, you may even find that the speedo will now read correctly as I usually find airhead speedos up to 10% optimistic..


I'v not known many "vibey" 65's.. try the engine bolts and wheel balance first...

 

[cringe]

higher ratio diff R65

Proff..... wheels balanced and engine bolts tight,cruises nice up to 4500rpm but vibes set in until 5000rpm.Read somewhere that by altering torque on engine bolts helps but a kit was available using rubber washers between frame/engine. Happy to cruise 70/75mph.Carbs also synchronized.

 

[Steptoe]

Proff..... wheels balanced and engine bolts tight,cruises nice up to 4500rpm but vibes set in until 5000rpm..

Perfectly normal for an R65. Ride below 4500rpm or above 5K rpm.

On mine ( pre 81 heavy flywheel model) 4500 rpm is bang on 70 mph.

.

 

[(RIP) Proff]

Perfectly normal for an R65. Ride below 4500rpm or above 5K rpm.

On mine ( pre 81 heavy flywheel model) 4500 rpm is bang on 70 mph.

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AHHHH Many thanks o' great one
It must be my size that dampens out the vibes when I ride them

 

[cringe]

higher ratio diff R65

Checked speed at 4500rpm (start of engine vibes) spedo read 70 but sat nav 62. could do with fitting a higher ratio diff to bring speed up to 70 for touring,but which diff ratio? Have a 37/11 but nearly same as R65. Also as my bike is 1981 onwards with ribbed diff,will earlier non ribbed diff fit? Thanks for past advice......Chris