Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 851 / 888 > more stupid questions

[keith888]

Sorry guys but I've got a couple more questions for you;

(1) Do I gap the NGK DCPR9EVX plugs to the same as the manual recommends for Champion plugs (0.5-0.6mm)? I thought I'd better check as cars usually run tighter gaps for NGKs

(2) Do I really need to strip the fork legs out completely to change the fork oil as per the manual ie invert them to drain the oil? Is it not possible to drain them via the damper bolt at the base of the legs?

Thanks,

Keith

[Rob B]

The US guys where talking about this recently, fork strips, and said yes, down to the bone for a thorough clear out

[Rob B]

Quoted from last months posts:

"On cartridge forks, it is really important that you disassemble the forks and get everything perfectly clean. When the slider bushings wear, the debris from them becomes suspended in the oil. The debris then gets caught in between the valving shims, and this causes the damping to be erratic. That is the main reason a newly serviced front end feels so good."

AND, from another poster:

"We do about 20 sets of forks per year and concur, the forks need to be
cleaned properly, if there are a lot of miles on the forks and the
oil/ fluid has not been changed I would replace the Teflon coated
bushings too, the suspended particulates become embedded into the soft
Teflon and cause excessive wear to the fork components. Personally, I
would change it first time at about 5K miles and then do it at the
recommended 12K interval. If the oil has not been maintained, the
valve stacks really need to be removed and cleaned. This would be a
good time for the Penske upgrade we do! In the Sowa forks 15W is far
to high a viscosity and will make the forks harsher than ever. ATF is
not that bad a thing in forks; it is around 10W, in dextron anyhow. I
use 5W either Ohlins or Motorex brand.

On a fork service, we immerse the components in a parts washer after a
total disassembly and use special brushes to clean out all the
internal tubes thoroughly. We have an arrangement with a good hard
coat anodizing shop to coat the outer tubes to keep down the
particulates and keep the oil cleaner."

[keith888]

Thanks Rob. Looks like another major job to add to the (ever expanding list). The bike has done 16,000 miles and the last few service sheets do not mention the forks so I suspect the oil has never been done from new.......

[Douglas851]

For sparkplugs, use Denso IX27 iridium, and gap them to 1.0 mm to improve throttle response.
Should last around 20,000 before replacement is needed.

Douglas

[paynep]

Originally posted by keith888
Thanks Rob. Looks like another major job to add to the (ever expanding list). The bike has done 16,000 miles and the last few service sheets do not mention the forks so I suspect the oil has never been done from new.......

If you're feeling up to it, why not just try an oil change yourself?
Its not hard and if the forks are basically sound I bet you won't notice the difference between £7 for some 7.5w oil and the correct oil level (note NOT quantity) and a couple of hundred quid for a "proper" job. ..... just a thought, having done the odd fork or two

[keith888]

I will strip and do them myself as I've done a few forks over the years(though admittedly not USDs). I was just hoping that I could get away with a simple oil change but sounds like I'm best to fully strip/clean and rebuild with fresh fork seals/oil.

Cheers,

Keith

[Shazaam!]

The 9 in DCPR9EVX means that they come pre-gapped by NGK to 0.9mm. The Denso iridium plugs are also factory-gapped to this value. Do not reset the gap to the smaller gap value specified for conventional plugs.

http://ducatisportingclub.com/xmb/vi...age=#pid129479

[loony888]

shazaam, i'm pretty sure the 9 in dcpr9evx is a heat range rating. note also that with ngk's the higher the number the colder the plug.

[Shazaam!]

Sorry, my mistake. The NGK coding is as follows

Example: NGK DCPR8EIX-9 iridium plug

D = 12 mm thread diameter
C* = Hex size 5/8 in. (16 mm) - standard Ducati OE plug wrench (non-C 18 mm hex)
P = Projected insulator type
R = Resistor type
8 = hotter
9 = cooler
E = 19 mm thread reach
A = special design
VX = platinum
IX = iridium
-9 = 0.9 mm gap

Also, you should only use resistor-type plugs in a Ducati 8xx bike. The main concern is with the computer found used on fuel injected bikes as the radiated EMI can interfere with the computer and corrupt signals which can affect engine performance and reliability. Theoretically, non-resistor plugs can provide more power, but the reality is that the ignition noise they produce can corrupt computer signals.

[Edited on 12-2-2005 by Shazaam!]