ST1100PP Police fork spec

Oh I've had fun... As already mentioned I bought a rusty ST1100PP 1993 Police Spec. Its got a lot of miles on, and one fork leg is pitted and the seal shot, so time for some work. I have cleaned both legs and Its good enough for new seals, so I bought from M+P the 1993 oil and dust seals. I also grabbed myself a couple of fork springs from a low mileage UK Police liveried bike in my local scrap yard. Belting I thought and took the forks apart. I NOW know that there is a difference between the Forks of Police and civilian version's. I NOW know that the bike in the scrap yard is a civilian bike converted by Sonic to look like a Police bike but they didn't change the forks.
My bike has springs 47.5cm and are 34.1cm wide, the other a 41.5cm and 35mm wide, and wont fit down the chromed pipes . Unlucky I know.
So here is the question using a micrometer both versions of the chrome pipes are the same diameter on the out, but are different on the in.
Are there specific seals for the PP ? or can I use the Civilian 1993 ones ?

Update - Answered my own question, having just checked all the parts fiches for the non ABS1990-2003(P) all the same fork seals part number :- 51490-MN8-305.

Next does anyone know if the air gap / fork oil level measure is the same on both versions - Right 190mm and left 187mm ?

Tommo said:

My bike has springs 47.5cm and are 34.1cm wide, the other a 41.5cm and 35mm wide

Click to expand...

non ABS, (IIRC all years): length ~41,7cm, diameter: 35mm (just measured the two sets I've in my stash here...)
ABS-I/TCS fork springs: length 47,42cm, diameter as above... (ST1100 w/shop manual)
Police spec fork springs: length 47,42cm, diameter as above... (ST1100P w/shop manual)
(seems they used the firmer ABS-I springs in them P-spec...)

Fork oil levels: R 177, L 174
Fork oil capacity: R 372,0 +/- 2,5ccm, L 418.0 +/- 2,5ccm (bot also from P-spec manual/addendum)

You could enter your ST's VIN at CMSNL to see if its a genuine P-spec, or indeed retrofitted.

There also other items to ID a P-spec by:
- enforced VRR with aluminum heatsink
- headlight adjuster knob sits above RHS valve cover (I'd really like to see a pic of that bracket once...)
- genuine voltmeter in LHS panel (oposite of clock)
- calibrated speedo (possible some kind of calibration gear on the cable, right below the instrument)
- both crash bars have a plate welded on top, featuring mounting points for siren speaker and others
- coil of rear shock in black paint
- RHS switchgear as well as those in the LHS inner fairing
- a striking additional wiring harness and a bunch of relays

ST1100Y – Thanks for the information.






I've been back to the fork legs and re checked. I haven't measured the right leg springs as they are still compressed in the damper cartridge, but the parts fiche says both sides are the same.






The left Police fork spring measures 475 mm x 34.2 mm, and the left Civilian Fork spring is 416 mm x 35 mm. Also the internal diameter of the pipes is different as well, I tried to use the newer springs in the Police pipes and they don't fit. Its possible to screw / force them in but they don' t run free like they should. https://www.st-owners.com/forums/album.php?albumid=4334






I have loaded some pics on my gallery https://www.st-owners.com/forums/album.php?albumid=4335 of the Forks, and also have take pics of the headlight adjuster of my police spec bike, should you want a gander. I tried to load them on this page but it threw me out.







The project stumbles on !!


UPDATE: Could be a mute topic this. Had more than a little glitch with a bolt https://www.st-owners.com/forums/showthread.php?135107-How-important-is-the-10mm-engine-mount-adjusting-collar&p=1711067&highlight=#post1711067