RZ250 Front Fork Springs free length

[exup]

Hi all,

Anyone know the factory spring free lengths for RZ's?
I'm overhauling my 86 RZ250 and went out and ordered from YSS suspension AU the springs and PD Valve kit. It seems on their site all the models from 83-96 suit the same spring and PD valve for Rd/RZ 83-96

Anyway I measured the old spring that came out and its free length is 417mm and OD is 28mm
The new spring is measured at 490mm and 26mm OD (OD = outer dia of the spring spiral)

So that's quite a bit different. My old Haynes manual for the 350 models says all except '83 are 429mm which is very close to my original springs.

The original spacer is 100mm long + spring = 517 which is longer than the new spring.

• Im not sure if I discard the original spacer which would not make the same length overall
  The old spring in the bike was wrong
  YSS have stuffed up my order

any advice here would help.

Looking at the part numbers for the bike the spring part numbers are the same except for the leading 3 digits
The piston, little rebound spring and oil lock parts are all the exact same numbers for all models.

• 88 model = 1UA-23141-00
  86 model = 1UA-23141-00
  85 model = 51L-23141-00
  84 model = 31K-23141-00

[mboddy]

The 23141 in the part numbers says that the part is a fork spring. The trailing 00 is the revision number.
The leading three characters are the model number.
31K is the original RZ350.
51L is a later RZ250.
1UA was the RZ350 with the rectangular headlight and full fairing.

The PD valve sits under the spring and so you have to cut the spacers to fit with original spring and spacer.

[JonW]

The forks are all different, some subtly but some very different. Ie the early RZ is more like the LC and the 86 is a very short spring as youve discovered.

You can fit them with shorter spacers as youve suggested but its annoying that 30+ years on manufacturers just say 'all the same' as they are not.

What you may well have noticed is that springs always get shorter over time as there is weight sat on them. Yamaha are the VW of the bike world with soft springs for suspension, but it seems all their springs are weak (think clutches) and they go baggy very quickly. What starts out soft just gets worse over time and almost every spring in an old yam is too short/weak for its job.

Hot tip with part numbers: if the model number is different then the part is different. if the revision is different then you might well be able to fit it as its probably just plated/painted a different colour.

[exup]

I ended up checking my other RZs from 82 and they all have the same spring so I am a bit confused as to why YSS list these as suitable for any age of RZ. In the end I just used the new longer ones and see what they are like, they certainly have more Newtons of force required over a given length.

Whats an example of a Revision parts number in the catalgoue how could I tell its revised? Ive posted a pic of typical part catalogue as an example.

[JonW]

revision = original ends in 00 and revisions start and 01 and go upwards

82... er, thats and LC. 83-on for YPVS models.

[exup]

Ah yes you're correct. In my others are 83 84 85 models.

And cheers for tip about last 2 digits