NC30 fork oil weight

[The Stranger:Me]

I have an NC30 manual here. It lists the "Recommended fork oil" as "Fork fluid", well that is a big help.

Does anyone know what the specified oil grade is for an NC30 please?

[montsta56]

According to Grey bike forum 405cc of Sae 5 fork oil. Is ment to be the go.

[arj127]

changed the oil in my forks. You will need to use a light fork oil or you may blow the seals. I used Motul Fork oil very light 2.5W (which is recommended in the manual). Cycletreads have it on there shelves. Made a huge difference to my bike.

[more_fasterer]

changed the oil in my forks. You will need to use a light fork oil or you may blow the seals. I used Motul Fork oil very light 2.5W (which is recommended in the manual). Cycletreads have it on there shelves. Made a huge difference to my bike.

hmmmm... I used 10W oil in the old-style (preload only) forks and that made it more controlled than the 5W it was before. Worked for 5,000km without any leaks before the forks were swapped out for the later type. Are the NC30's fork seals really that susceptible to blowing?

[rookie]

hmmmm... I used 10W oil in the old-style (preload only) forks and that made it more controlled than the 5W it was before. Worked for 5,000km without any leaks before the forks were swapped out for the later type. Are the NC30's fork seals really that susceptible to blowing?

Its always best to stick to genuine parts and factory recommendations.
I found out the hard way...when reading my service manual it said that standard spec was 5W fork oil set at 85mm+/-2mm. Also in my manual it states a set of recommended settings for a 60kg rider.

Now....i thought i would be clever and use a thicker fork oil since i weighed (at the time) 83kg. So i picked up some seals(non-genuine items) and some 10W oil....however.... the shop didnt have 10W but had 15W...and at the time i didnt know that the scale of viscosity was relatively linear.

Ok to shorten the story - the bike cornered like shit on any road that wasnt perfectly smooth(for obvious reasons) and the fork seals blew on the third ride after replacement. I replaced the seals with genuine items(which were cheaper...go figure!!) and 5W oil and with a bit of tuning the bike was handling mint again.

[The Stranger:Me]

Its always best to stick to genuine parts and factory recommendations.
I found out the hard way...when reading my service manual it said that standard spec was 5W fork oil set at 85mm+/-2mm. Also in my manual it states a set of recommended settings for a 60kg rider.

Now....i thought i would be clever and use a thicker fork oil since i weighed (at the time) 83kg. So i picked up some seals(non-genuine items) and some 10W oil....however.... the shop didnt have 10W but had 15W...and at the time i didnt know that the scale of viscosity was relatively linear.

Ok to shorten the story - the bike cornered like shit on any road that wasnt perfectly smooth(for obvious reasons) and the fork seals blew on the third ride after replacement. I replaced the seals with genuine items(which were cheaper...go figure!!) and 5W oil and with a bit of tuning the bike was handling mint again.

There were so many different recommendations for oil weight that were all at odds and the different models of NC30 have different oil height specs.
This one was a K model J-spec bike as near as I could figure it.
I went for 7 weight oil and 90mm. I think 10 weight would have been the go, but it feels quite reasonable as is. Will need to see how it performs when pushed and adjust if necessary.
The seals looked quite good, they are the first fork seals I have seen that are effectively double sealed, most of the ones I have seen have a single lip and a single spring, these one had 2. May increase stiction, but so far so good.

[TygerTung]

Do NC30 forks blow if you look at them sideways? I usually run about 20 weight in most of my bikes, one of them has 30 weight in it. I don't really like soft spongey forks eh.

[more_fasterer]

Apparently... although they look like they're very similar if not identical to most other small Honda's and it's not like it's a common problem, is it?

hmmmm... I used 10W oil in the old-style (preload only) forks and that made it more controlled than the 5W it was before. Worked for 5,000km without any leaks before the forks were swapped out for the later type. Are the NC30's fork seals really that susceptible to blowing?

I've now done 3,000km on the new (later style) forks. These had been revalved & resprung before I got them; I put 10W in these too and haven't had any trouble.