Fork oil

[MalcW]

Hi

My 1960 twin should have 20 sae oil in the forks. They seem rather under damped, so I suspect they are somewhat low. My local Halfords only sells 15 sae fork oil - would that be worth a go? Could I put classic 20/50 in?

Thanks,

Malc

[Dave T_LAPSED]

I've just put 5w30 in my forks. When I shook a bottle with 20 in comparison to the 5w30 it was "thinner" so I tried the multigrade. It does firm them up quite a bit and the ride is a bit less bouncy now. 20w50 would be really hard, I tried it once in a ducati and the forks were just about solid! You could try it anyway and report your findings!

[bitza]

Sae 30 is fine.

[Rob Harknett]

Plenty of 20 SAE fork oil available. Did you put in the correct amount? I usually drain my forks via the two drain screws. Give the forks a few pumps. bit messy. Then put in the correct amount. What ever may be left in the forks has not seemed to make any difference. So its always correct amount + what ever is left. I follow instructions in the book. Been working OK for me since I first had a bike 63 years ago.

[bob121]

I've just put sae 30 fork oil in my m31. Massive improvement overall. Although a little firmer than I'd like at low speed. But only slightly.

[oldandsmelly]

Hi Malc

I bought SAE 20 fork oil from one of the large dealers selling shiny new Triumphs. Someone told me that I should use 'proper' fork oil as it has special additives in; whether this is true or not, I'm not sure.

As my forks were being completely rebuilt, I added the recommended amount for a clean system i.e. 185mls or six and a half fluid ounces in old money. The manual suggests adding less (170mls) when just changing the oil as you can't get all the oil out. I'm not convinced the amount of oil needs to be so precise, but I did what it said.

My forks are now a treat and absorb the bumps without bouncing up and down like a water bed.

[MalcW]

Hi Malc

I bought SAE 20 fork oil from one of the large dealers selling shiny new Triumphs. Someone told me that I should use 'proper' fork oil as it has special additives in; whether this is true or not, I'm not sure.

As my forks were being completely rebuilt, I added the recommended amount for a clean system i.e. 185mls or six and a half fluid ounces in old money. The manual suggests adding less (170mls) when just changing the oil as you can't get all the oil out. I'm not convinced the amount of oil needs to be so precise, but I did what it said.

My forks are now a treat and absorb the bumps without bouncing up and down like a water bed.

Hi Bruce

I've just put in some 5W/30 fork oil, as did Dave T, mentioned a bit further up this thread. I haven't ridden it yet, but a Bounce Test suggests that they are better damped than before, but still moving freely. The amount added was a bit 'approximate' shall we say. It was all a bit of an anticlimax really; I dug out the appropriate allen key, put it into the first top bolt, and heaved, all the while thinking what my strategy was going to be to free it off, and it just came undone, no drama. Same on the other side. One tip to maybe help others: if you remove the drain screw but leave the top bolt in place, some oil will come out, but when you pump the forks to remove the rest you can easily squirt it across half the garage. Removing the top nut first keeps things under better control. The RH drain screw was a pain to remove, and required an impact driver to get it moving. It turned out not to have a fibre washer, but a scrap of thick gasket paper and a hole punch sorted that out.

Cheers,

Malc

[Rob Harknett]

I think some people panic those screws will fall out. They do not seem to screw in very far, so they tighten as much as possible. Always use the fibre washer. If it gives any peace of mind, in 63 years, I have never had a screw fall out. Back in the 1950's we used to get little 1/3 pint bottles of Orange juice from the milk man. One of those bottles full was used as the measure to top up with. You never got all the oil out, like wise, all in from the bottle. Amounts must have differed a bit but hardly noticeable. Yes do undo the top nuts so most of the oil will drain before pumping. Perhaps bandage the holes to stop oil spurting far away.