Just wondering what gearbox oil people are using these days.

I would like to try synth equivilant 10W/30 or /40 as i use in my gas gas - can anybody comment please?

I will stay with ATF in the clutch though.

Also i have just rebuilt my M199 forks (just two new o-rings and made up new piston seals)what a difference. the forks are now the best i have ever had on a Taco but feel a bit firm for my light weight.

I have always gone by the what is the norm (180cc - SAE 20/25) can anybody comment on a lighter oil or more airspace before a go to the effort of changing it.

thanks

Hi in the 199 gearbox the recommended oil is EP90 -

usually available from car factors or lawnmower shops.

Using 10w40 proper motorcycle gearbox oil is ok - 500ml

don't use car 10w40!

In the forks the std oil is 15wt fork oil , you could also

try more oil in each fork , but don't go over 200ml in each leg.

If they are still too soft then install new springs.

Hi - For my Bultaco I always use 600ml Castrol ep 90 in the gearbox. Older manuals recommend sae 140 but its hard to get and probably ep90 has superceeded it anyway.

For the forks I use 180ml Castrol synthetic sae 10. Other people I have come across use atf and some heavier oils - depends how you like your forks to feel I guess. If they are not fitted already, a set of top nuts with valves are a good modification over standard.

Tim

Edited July 21, 200917 yr by bultaco49

Thanks for your input.

I will go to a lower grade oil @ 180cc first.

I have the top nuts with valves fitted - i thought this was only to let built up air out - is this correct, or is there another purpose please?

Hi bogwheel , the fork caps with air valve are ONLY to let air OUT

NEVER pump them up- you will blow the seals!!

STD fork oil for a sherpa is 15wt , but you need to try different

weight to suit your liking.