YZ250h - fork damping modifications and suspension rebuild services.

[Reinald]

Hi All,
1. I've never posted on this site before - and I have searched for threads that may answer this one but to no avail.
Took my owned from new 250h for a blast in the bush the other day and after she had been sitting for a few months after Classic Dirt both fork seals blew.  The thing is for my speed and the type of riding I do the front end works so much better in this condition [until the level drops of course].  I would like to drill out the damper rods to achieve a similar reduction in compression/rebound damping and would like some advice on what diameter to try?  I usually run 10wt with no air and have tried 5wt.

2. I have also purchased another shockie and had that rebuilt [no appreciable improvement in action] but it blew and now I have put the original back on still going strong after 30 years !!!!! Anybody know a good suspension service fro older shocks?
Thanks and great to see some of the H's on this forum restored to their former glory.

[cloggy]

 I have a set of 38s and a set of 36s: run maico springs in the 38 and have cut loads of coils off the 36s to get the rate up. If your springs are right in the first place then cartridge emulators are a good way to go. My 38s use race tech and my 36s use YSS ones. Both really good. How effective they are depends on how bad the stock rods are in standard form. They feel much plusher and if your forks spike they get rid of that.
 There is a possibility that reducing the amount of oil may improve your fork. Sounds like it may have been air pressure that was making them harsh, but I'm no expert.

[Reinald]

Thanks Cloggy,
That has made me think.
Re - emulators are they legal for evo? [probably not gunna stop me as I recreation ride mostly but the price might].
Not air as I religiously bleed air every ride/moto.
I was going to start with increasing damper hole diameter by 50% and try 5wt as a starting point but being lazy was hoping somebody may have tested these mods previously.  Sure I could just get  IT but I've owned the old girl from new and couldn't sell her on this site....recently so might as well keep it.

[tony27]

As far as I know pre75 bikes can run emulators as they are unseen

[Ando]

Hi Mark, Iv'e just worked out who you are! Mate I'm in the starting process of sorting out both my 250 & 465H's front & rear ends as we speak! I waiting on prices for 43mm fork kits from a couple of sources, I will let you know what I come up with.

Cheers
Brad Anderson

[Reinald]

Thanks everyone.
My local bike mechanic suggests 5wt oil, chamfering the damping holes in the rod and a reduction in fluid height. Standard is 150mm from top of tube, compressed no springs, vertical from the manual. So maybe 140??? Any suggestions??? Any body had luck with chamfering???

Things are tight so valves maybe a way off.  But if i do bugger up the damping hole mods don't these need to be way big for the emulators to work?

Went through my records and found I was using 5wt oil in the mid 90s in trail rides around the Bunya mountains but still very hard front end for this type of riding [except for the ten or so minutes I could actually get her onto the main jet ].   When I was racing motocross on a sand track at Hervey Bay I used 10wt and they were perfect for that track so I am convinced Ill need some changes to go Vinduro riding. So I am still interested in modifying the damping holes.There is three at the top in progressively smaller diameters.
So I was wondering about all three widened by say 0.5mm radius each?

Standard is 150mm from top of tube, compressed no springs, vertical from the manual. So maybe 140??? Any suggestions???
Thanks in anticipation of any further advice.

[Reinald]

I've settled for chamfering damping holes with a dremel [mechanics advice and my old riding buddy said your a tool if you drill them bigger - in not so many words], Gone for 5wt and 160mm from the top [10wt 150mm standard]. Rebuilt with all balls racing dust seals. Showroom floor suspension test [bounce em up and down and go Hmmmmmm] looking positive. A bit more compliant ....test tomorrow.

Was running 21mm out of triple clamps gone for 26mm to steepen her for an Vinduro coming up.

[Reinald]

test ride went real good -  alot more compliant early in the stroke.