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KTM 65sx pitbike build need suspension help..

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ok, so i picked up a 03 ktm 65 sx.. i am going to build it into a pitbike that can handle jumping and my weight..

I'm shooting for a setup that will handle small doubles and rollers, but i also want it not to be to stiff so my nephew can also ride it.

I'm 170lbs. and my nephew is probably 90lbs'ish.....

I'm thinking of going with the .46kg/mm front springs with 15wt oil and leaving the valving alone. I do know the front end was revalved for a slightly heavier rider than stock setup of 70lb. rider.. Only concerns are the weight of oil, with 10wt the rebound may be to fast?? any input on this would be great.. i'm not worried about compression adjustments, as i can adjust oil level for that..

now for the rear shock... stock is 4.0kg spring with 2.5wt oil..

somehow i need to find a spring close to 44x223mm in a 5.5-6.0kg

also maybe going up to 5wt oil will help with slowing down rebound and comp.???

i'm also going to try to setup the rest of the bike to be a happymedium setup somewhere between my needs and my nephews needs.. slightly higher bars, longer shifter maybe??

thanks in advance!

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You'll be hard pressed to find a .46kg fork spring that'll fit that little fork.

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and with a 90lb rider it wont move.

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You'll be hard pressed to find a .46kg fork spring that'll fit that little fork.

they are available..

race tech spring calculator for 140lbs. is .320 for front and 5.70kg for rear.. now i'm 175lbs, but my nephew is 100lbs. so i'm going in the middle at 140lbs setup..

if i do springs only, will the rear shock be ok with the stock 2.5wt oil? or should i go to a 5wt? rear shock does have comp/rebound adjustments

for front its USD 35mm marzocchi's with no adjustments, so if i go to .320 springs (which was stock, but forks were redone and i'm sure theres lighter springs in it now) would the 10wt oil be good.. i can play with oil level to get a perfect compression setup, but for rebound would it be better to run 15wt oil?

i have found both .320 and 5.70 springs at cannon race craft..

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You can use the springs for the marzocchi shivers...its the same fork basicly..usually they use 7Wt oil in that fork...maybe ask on Planetminis.com ....there are looooooots of guys with experience to tune that fork ... paxracing..NCC ,trailpimp33 ,etc. for example:thumbsup:

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You can use the springs for the marzocchi shivers...its the same fork basicly..usually they use 7Wt oil in that fork...maybe ask on Planetminis.com ....there are looooooots of guys with experience to tune that fork ... paxracing..NCC ,trailpimp33 ,etc. for example:thumbsup:

yup, i have the same thread on planetminis also... i just know theres more suspension guru's on this forum....

i found the springs, and i also now found that the stock fork oil is 7.5wt not 10wt.. so that means running 10wt. should match the heavier spring setup nicely..????

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... i just know theres more suspension guru's on this forum....

unfortunately they do not care about pitbikes...sad!:)

I would advice a revalve in some suspensionshop...only the oil chance wouldn^t cut it I am afraid:thumbsup:

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the reason no one wants to answer is this, the 2 extremes you want it to do are too extreme, we know the one setup will be a massive compromise, so we feel its not a question we can answer well, it would be better to set it for the young un to be safe, and the adult put up with how soft it is...

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Ditto on what mog is saying, we just set up a friends bike, now this little guy is only 70lbs but youre not going to be able to compromise between the two of you, theres very little valving in those forks. let the boy have the 65 and set it up properly and get a bigger bike for yourself, thats a small bike even for a pitbike and you'll end up busting it and yourself or worse still the younger rider, sorry if thats not what you want to hear, just my 2 cents.

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i'm going to set it up for closer to his weight than mine.. i can handle the soft setup.. i have several big bikes, and a mildly modded klx110... but i guess you just gotta ride one of these 65sx's to realize why an adult would wanna pitbike it..... they rip, and have 10X better suspension than a KLX110..

thanks for the help???

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i have rode one, i was amazed how fast it was.

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