Front fork quantity increase

[Chris Canning]

With the delightfull weather we are having in the Uk,it's time to get on with all the bike jobs(I've got a lot) have had the front end of the Tiger drained fork oil out,hung the legs upside down for 2 days!! looked at the quantity on my 01 955(720cc),it was 15wt that was already in,so changed it for the same but went 750cc instead.

Way to bad to ride it and find out,but when I rolled it off the work bench(comes off the ramp at 100mph :roll: ) grabbed the brakes and the way the forks dipped felt like it had possibilities,just an idea for you tinkerers this winter.

[iansoady]

Too cold for me in the garage!

[Chris Canning]

Ian

When we knocked the house down and started again,the priority was a door straight out of the living room into the garage,big radiator and fitted carpet,it's been paying off these last couple of weeks  :D

[NKL]

I reduced the air gap in my xtz750 forks to stop the dive under braking and it worked a treat, didn't affect the suspension for normal riding, only under brakes.

[2004Tiger]

I also increased to 15 wt and 150 cc extra oil in each side. Much less dive and still very comfortable at speed. I read that the air volume above the oil is a compressible cushion so less air gives a stiffer cushion. Is this how it works?

[Chris Canning]

150cc  :shock: ,are you sure jeeze I thought an extra 30 was pushing it,must close to the top of the fork leg.

Your theory is something like,but your not going to get a great deal of feel over anything less than a pot hole!!

[2004Tiger]

No, can't see the oil level looking in the top. I wrote that from memory, now I decided to go back and refresh my memory.

http://tigertriple.com/forum/viewtopic. ... highlight=

I now have to correct myself and say I added an additional 100 cc each side, and I think my estimate of the resulting viscosity is wrong. Anyway, I like the result.

[NKL]

Technically the best and most accurate way of measuring fork oil is to measure the air gap at full compression, but I can't remember what I reduced my super tenere to.

[jwray76]

any problems with blown seals when reducing the air gap? I believe this would be the biggest issue since the smaller air gap will create a bigger pressure differential across the seal.

[2004Tiger]

Seal strength did not occur to me when I increased the oil volume, but I've had no problems. My Tiger is a road bike with light loads, off road riding would impact the seal more severely?

[Chris Canning]

No, can't see the oil level looking in the top. I wrote that from memory, now I decided to go back and refresh my memory.

http://tigertriple.com/forum/viewtopic. ... highlight=

I now have to correct myself and say I added an additional 100 cc each side, and I think my estimate of the resulting viscosity is wrong. Anyway, I like the result.

You looking into the leg when it's in situ,I'm talking when the leg is off the bike and fully compressed as is when you measure for the oil level,you can most certainley see it then.

[2004Tiger]

No, can't see the oil level looking in the top. I wrote that from memory, now I decided to go back and refresh my memory.

http://tigertriple.com/forum/viewtopic. ... highlight=

I now have to correct myself and say I added an additional 100 cc each side, and I think my estimate of the resulting viscosity is wrong. Anyway, I like the result.

You looking into the leg when it's in situ,I'm talking when the leg is off the bike and fully compressed as is when you measure for the oil level,you can most certainley see it then.

Now I understand what you are talking about, and you are probably right. I have not had the fork tubes off the bike. Do you see a problem here? As I said, brake dive is much reduced and it works great on the road. If Hinkley could not fit a better fork, at least they could have tuned the one they gave us like my modification, which I'm sure most riders would prefer.
Mind you, I do not claim equal performance to the good mechanical goodies available for our forks (none of which I have ridden), just a nice improvement over stock.

[JTT]

I wouldn't worry too much about seals.  What you want to be cautious about is hydro locking the fork.  As someone already mentioned, the air left is intended as a cushion of sorts to take up the volume displaced by the slider moving down into the lower fork.  Less air space means the pressure ramps up faster (more progressive), more air means less progressive.  This is why the brake dive seems to be reduced as the initial part of the travel is minimally effected, however as  you get deeper into the travel the air acts as a progressive spring making it stiffer, faster.  If you don't have enough air volume, you run out of space and come up solid...not nice.  

Make yourself a dipstick and measure the oil level with the fork fully compressed.  Make sure to leave yourself some air space at fully compressed.

[blacktiger]

looked at the quantity on my 01 955(720cc),it was 15wt that was already in,so changed it for the same but went 750cc instead.

I'm working that out (roughly) at a 25mm increase in oil level.
cc / (Py x fork I.D.) = height
30cc / (Py x 3.6cm) = 2.65cm

I've always been wary of going that much so I'd be interested to hear the results.

[KuzzinKenny]

I'm working that out (roughly) at a 25mm increase in oil level.
cc / (Py x fork I.D.) = height
30cc / (Py x 3.6cm) = 2.65cm

WTF  :?  :icon_scratch i should have paid more attention at skool  :shock:

 :roll:

KK