KX250 A5 shock length changes?

[bishboy]

I believe the factory shock length on a KX250 A5 is 16.5". 

My question is, what are the consequences of putting on a set of 17.5" fox shocks, apart from the arse end sticking up in the air.  I'm assuming measurements of both factory and the fox shocks are eye to eye.  Is there a way to adjust/rebuild/modify the fox's to make them the right length?

[motomaniac]

yer you can put a spacer in them to shorten the overall length.

[JohnnyO]

If you run the 17.5" shocks the arse will be so high it'll handle like a pig and probably throw chains because it will be so loose when the shocks are at full extension.

[Trent Farlow]

You can run the 17.5 inch shocks with no problems, however you must fit longer forks to restore the geometery. If you can find a set of 1980/81 KX250 forks they slot straight in with no mods (same front wheel, axle etc) and have an extra inch and a half of travel. You can also use KX420 forks, but the spring rate in them is a bit stiffer, depends on your weight.  Alternatively you can always upgrade to a 43mm front end off a completely different bike.  I noticed that my A5 corners better with the original forks and shocks than the longer ones, slightly lower to the ground. However when I have the 43mm forks and 17.5 Fox shox on, the ride is better through the rough stuff.  Hope that helps.

[JohnnyO]

Why would you want to raise the height of the bike by nearly 2 inches with the longer shocks anyway? it's already a tall bike. The 17.5" shocks only have about half inch more travel than the 16.5" shocks so you are gaining bugger all...
My A5 has 16.5" Airshox on it and it works well. I'd put a spacer in the shocks like motomaniac said and make them the correct length.
I do agree that 43mm forks would be a good addition and plan on putting a YZ465 front end on mine to keep it Evo legal..

[JohnnyO]

bishboy , the aim of long travel bikes is what the words say " long (max ) travel " . spacing down your long shocks would make them equal to travel of  400 mm CTC shocks . If you you really like those 445 mm units so much , then cut 10 mm of the tube  and 15 mm of the shaft , that will give you max stroke and the correct length of 420. i spotted some new  Alu shocks at the nationals  on a CR 250 79, that amused us  very much . Because that manufacturer does not have long bodies and long shafts , they simply used 360 mm long shocks and fitted  80 mm extensions ....    Not the solution top riders prefer, than you would be better of with the OEM shocks , I would say  .

You are right in what you say Wasp but it gets expensive to cut down the bodies and the shafts and have them re threaded.. it would be cheaper in the long run to buy the correct length shocks or use a shaft spacer for the cheap easy way out, which seems to be what most people are looking for...

[bishboy]

I just saw a pair of Fox's for sale for what I thought was a reasonable price, but it seems it'll be more hassle than its worth 

Walter, I'll have to talk to you about a pair of shocks once I get around to that stage in the rebuild.  Performance difference (for a racer) between the C362T and TRC shocks enough to justfiy the price difference?

Johnny, do you use the YZ triple clamps as well?

[JohnnyO]

Johnny, do you use the YZ triple clamps as well?

Yes you have to use the YZ clamps, you couldn't bore the KX ones to 43mm safely.

[bishboy]

Is the geometry of the KX changed by the YZ triples & forks? 

Benefit is that you get the TLS brakes, I had been thinking how to graft the YZ hub onto the KX, didn't even cross my mind to change the whole front end

[oldfart]

John, is that the front end Trent was selling.....  as it  looked to be in good nick

[JohnnyO]

John, is that the front end Trent was selling.....  as it  looked to be in good nick

No i think that front end Trent had was '83/'84? I have another one sitting around in the garage.

[JohnnyO]

Is the geometry of the KX changed by the YZ triples & forks? 

Benefit is that you get the TLS brakes, I had been thinking how to graft the YZ hub onto the KX, didn't even cross my mind to change the whole front end

The YZ front forks are actually 10mm shorter than the KX forks from axle to the fork cap so it will lower the front by 10mm but i run harder springs so the ride height should be about right.

[holeshot buddy]

dont lengthen rear shocks stick to standard length
i run ohlins on mine they handle perfect
also have the yz front end and brake
all makes for a good combination

[JohnnyO]

dont lengthen rear shocks stick to standard length
i run ohlins on mine they handle perfect
also have the yz front end and brake
all makes for a good combination

After riding yours i'd have to say the suspension is really good!

[motomaniac]

The Fox air shox use the same body for multiple lenght shocks , I think from memory from 16.5 - 17.5 the body is the same , so you can just add spacer .Thor lawson sells spacers if you cant make your own.