fork oil weight is 15w too heavy ?

[ChrisC]

It's probably an old chestnut of a question....I'm changing my fork oil and mentioned to the guy in the motorcycle shop that the forks where to "spongy" he recommended i upgrade the oil to 15 weight at 448ml per leg .I've done this and the front suspension now feels too"solid"with some movement.I don't want it to blow the fork seals.....any help would be appricated

[goody]

You might find this interesting
http://www.ablett.jp/bikes/vtr/vtr_sus.htm
I used 7.5 oil can't remember the air gap (which is how you should measure how much oil to put in)
Seems fine now, good enough for me anyway gives a nice compliant ride.

[ChrisC]

Thanks for the info.....I'm in the process of draining the forks......rather be out playing in the traffic that will teach me to buy something without checking it out with people who know what there talking about...
thanks again cheers ChrisC

[Stratman]

I have used 15wt for several years

[tony.mon]

Try having a look at this guy's site- plenty of good fork info.

http://www.vtwo.demon.co.uk/firestorm/firestorm.htm

But goes against what Roger suggests.

I had three goes at mine, and was at the point of blending up some 12.75 weight when I thought:
"I'll just ride it, then".

[ChrisC]

hey thanks Stratman, can you remember how much oil you used per fork leg?. I'm thinking that being heavier oil perhaps i need to increase the air gap by lessening the amount of fork oil, I've tried 448 ml and the forks only travelled about an inch and a half max when fitted on the bike.

Cheers ChrisC

[ChrisC]

Thanks for the reply Toni. mon .....As per normal lots of good info
Cheers ChrisC

[sirch345]

ChrisC,
I agree with Goody, you need to be measuring the air gap and not concentrating so much on how much oil you need. When measuring the air gap the springs and spacers need to be removed and forks fully compressed. Measure from the top of the fork stanchion (tube/leg) down to the oil.

Going by what you say about very little movement I'd say you have to much oil for sure.

Chris.

[ChrisC]

I sure you fellas out there have got it right, I'll start again .....making a narrow brass tube with measure on it to draw off the oil. But can't start work on the bike till Wednesday , Thanks Chris for the advice

ChrisC.

[AMCQ46]

I second the comments on doing the oil based on air gap, not quantity....only way to do it.

I use a big medical syringe [wifes a nurse, so the uniform, rubber gloves and big syringes are perks of the job!!!!!], and cut a length of screen wash tube to the desired length for the Air gap.

Also at the risk of embarrassing myself, I have to admit that 20 yrs ago, I didnt realise that the springs had to be removed when doing the air gap, and did the fork oil on my old Suzuki 750 before a weeks playing in the lake district. ............ the forks were nearly solid, and I didnt road test before setting off for the week, so I had to ride it like that.

So 1) read the manual, 2) use air gap, 3) keep an eye on teh quantity, as it is a good cross check that you did #1) properly

[ChrisC]

Hey AMCQ46, Thanks for the reply, A weeks trip around the lakes with solid forks......I guess thats how you met you missus, her being a nurse and all
Cheers mate.........Ride safe
ChrisC

[ChrisC]

Hey Fellas, Forks sorted....don't know why i pratted around measuring fork oil,
measuring the air gap was much easier,
regards to all...ChrisC

[sirch345]

Glad too hear you've got it sorted

Did you stick with the 15w oil in the end

Chris.

[ChrisC]

Hi Chris, Yes I went with the 15 weight ,Thought it might help the suspension cope with the extra weight(way too many chip butties lately) Got to say the measured amount of oil that I put in at first, was'nt that much different from the amount that went in the second time.It must be more critical than I had realised, But it does feel a damn sight better now "happy days".But if i feel any adverse effects with the heavier oil out on the road i'll put it on the forum, Also I had a new tyre put on whilst the wheel was off, So I'm going to have to be a bit careful until it is scrubbed in .Thanks again for your time and the trouble you go to for me and others on this forum.
regards ChrisC

[sirch345]

ChrisC,

Nice too hear we could help

Paul (Stratman) uses 15w oil so you're not on your own. Also I know he wouldn't use it if he was not happy with it.

Take it steady and see how things go I would suggest, ideal you have a new front tyre to scrub in at this moment in time I'd say.

Cheers,

Chris.