Reba Race losing negative air pressure

bails87

As above, my 2008 Reba Races are losing pressure from the negative chamber. I think it's since I removed the AT spacer to up the travel to 115mm.

For example, on Sunday afternoon I set the pressure to 110psi in +ve and -ve. Did a 9 mile ride. I left the bike, and then did 12 miles last night. As I was giving the bike a quick clean afterwards I noticed it was harder than normal to 'pump' the forks through their travel. So got the shock pump out and the +ve was still ~110psi but the -ve was ~70psi.

Could I have damaged a seal or something when I was removing the spacer? I've had the bike since Feb 09 and have done 1500 miles on it. I've done the basic service (remove lowers, clean, replace fluid) every 500 miles so more regularly than every 50 hours.

Is it time for a proper service and seal replacement?

TIA

nicklouse

what does the pump read if you immediately reconnect it after setting the pressure?

MarkLG

The air volume in the -ve chamber is pretty small - when you hook up your shock pump the pressure can drop 20psi as air is transferd into the pump and guage. If you set the pressure, remove the pump and then refit the pump to get a reading you'll see an instant drop in pressure.
Also If there's a bit of drag in the forks and they don't quite reach full extension you'll get a different reading.

bails87

Pressure drops from 110psi to 100psi if i disconnect and reconnect immediately.

From setting them at 110psi last night, they were at 70psi again the first time I connected pump just a few minutes ago.

Put them at 110psi 3 or 4 times, and each time, when reconnected straight away, it went to 100psi. So I don't think it's down to losing air when reconnecting the pump.

nicklouse

yep time for some fettling.
after checking that the valve core is not leaking.

bannedbiker

I have the same problem on my 09 Reba SL's, doesnt happen quite as fast, maybe over a week. I've also upped the travel to 120mm.
You guys reckon they deserve a trip to TFtuned then?

Almightydutch

They are well shagged Bails, :shock: i'll have em off you at bargain basement price

stumpyjon

bannedbiker wrote:

You guys reckon they deserve a trip to TFtuned then?

Either a seal or the valve has gone. TFTuned are really good but it's not a massive job to do this yourself. The service pack comes with replacement valve cores along with all seals and washer for around £ 25.

bannedbiker

Cool, I'm pretty happy doing stuff like that, might have a look next weekend.

The Spiderman

Check the valve core,and seals,and make sure they are not dry.I`d also reccomending letting all the air out,neg 1st then +.Refill doing + first,then - and start with the pressures even in each chamber.

The order and having not too big a difference say no more than 10 psi,seems to be quite critical as otherwise you can get a slight imbalance and the forks being sucked down in their travel.

Had a similar problem imeediately after removing a spacer and having gone through the above procedure, they have been fine ever since.

bails87

Cheers guys, I'll go through everything above, and see what works.