RL250 Fork Springs

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cwc
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RL250 Fork Springs

Post by cwc »

I have a long neglected 1975 RL 250 that I'm trying to make into a "user".

When I took the forks apart to fix a stiction problem and replace the leaking fork seals I discovered that there were no fork springs.

I've got a few fork springs in my stash that fit in physically, but I don't know what spring rate and length are standard.

If someone has this information it would be very helpful to me.

Or if some has an actual spring and could tell me the spring ID or OD, wire diameter, number of coils and length, I could calculate the rate.

I would also like to get a service manual.
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Re: RL250 Fork Springs

Post by pop »

I would not not worry about the fork springs, instead drill a hole on the fork caps and stick a schrader valve in there[ from an MX bike] Iv used the valve and stem from a bicycle tube and araldite with no failure or leakage, but only use a hand pump to adjust the spring rate and use a good air pressure gauge,
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Re: RL250 Fork Springs

Post by FM350 »

If you have 35mm forks get hold of springs intended for something like Bultaco MX bike, which seem to work reasonably well on most trials with 35mm forks fitted.
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Re: RL250 Fork Springs

Post by David Lahey »

for an RL250 you should be looking for a rate around 0.35 kg/mm
length I don't know but I expect you would need 50 to 60mm preload with 0.35 kg/mm rate springs
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Re: RL250 Fork Springs

Post by Greg Harding »

Hi Everyone,

cwc, Just rode the Queensland Titles on my 1974 RL 250 loan bike, the original springs in the front forks were way too soft. The springs in the bike are out of a Yamaha XT 200, can't remember exactly but about 1/2 mm bigger in wire diameter and 30mm longer than srandard. These work well for my 85kg slightly used body! Hope this helps?
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Re: RL250 Fork Springs

Post by FM350 »

OE springs in some 70s bike were very soft, as forks were fitted with air caps. This never seemed to work that well, and blown fork seals meant forks that bottomed very easily.
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Re: RL250 Fork Springs

Post by BOGWHEEL »

Air valve in the cap is for letting built up air out
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Re: RL250 Fork Springs

Post by pop »

BOGWHEEL wrote:Air valve in the cap is for letting built up air out

not so much in the mid 70s.
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Re: RL250 Fork Springs

Post by cwc »

Thanks to all for the good info.

I'll try the springs that I have, but think they will be too stiff, so will be on the lookout for something a little closer to the correct value.

I'm a little slow to respond because I was busy getting my street bike in order after somebody backed into it with their car doing about US$1000+ damage. :(
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Re: RL250 Fork Springs

Post by FM350 »

The XT springs will be much too hard.............springs intended for Bultaco are very easily available here in the UK, and i would be surprised if they didnt work fine on your RL, if you can find some in Aus.
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