need help setting up my bike

[$heepy]

ok i have got my bike pulled to pieces, and i want to make both the front and the rear shocks stiffer.

from my understanding fork oil is just hydraulic oil if im right, and i can get my hands on plenty of this for free or next to nothing, and seeming as im a tight arse atm because of getting a car i need to know whether this will work or destroy my forks.

and also another question for the forks, spacers in the forks. how does this work? (do you just stack washers in? and if so do they just go ontop of the spring or do they go between for some reason?) what will the effect of doing this do aswell as replacing the oil?


now to the rear. my bike has a 43cm shock so im finding it hard to find springs and such for it. im wondering if just tightening the spring and slowing the rebound to its slowest will work for stiffening it up and not making it to badder pogo stick. and yes again i dont have any money to go to wreckers and pay for parts. i want to get my bike set up well for winter again and dad wants my bike back together and not taking up the space in his shed again so a quick response will be much appreciated.

thanks in advance all you tech gurus

 

[davedonzella]

I recently stiffened up my forks, I took out the china oil and put 15w fork oil in. But I still wanted it a bit stiffer so I added about 50mm work of spacing above the spring. I made the spacers out of some stainless pipe now they're perfect.
Make sure the spacers have really nice round smooth edges though.

Hope this helps

 

[numroe]

$heepy,

The viscosity of the fork "oil" can make a big diff. Especially in USD forks with adjustable dampening where 5 or 7.5wt works best. Old style conventional forks from China usually like some heavier fluid like 20wt. Cheap fork oil from Shell works great, and i doesn't cost much.

To stiffen up your fork compression you can use more oil to harden up the bottom of the stroke, since more fluid = less air, and only the air compresses, so with more oil (and healthy fork seals) you get a stiffer "air spring" for FREE. But if you want to raise the static front ride height you need stiffer springs if you want a nice fork action, or else go the cheap path and make up some spacers.

Shock: Most shocks come with 1000 lb/in springs. I use an 800 and I weigh 73kg. With the rear axle full aft and doing 2 or maybe 3m vertical jump flat landings, I never feel the rear bottom out harshly. But my shock is reasonable at slowing down the compression stroke. What is supposed to happen is you get a spring which suits your weight and riding terrain. Then you get a shock inside that spring which works ok. Lastly you adjust the spring pre-load to fine tune the height of the rear vs front of the bike. This spring preload adjustment changes your steering rake and trail and effects how your bike can corner, depending on how you ride it. If you use the pre-load to compensate for the springs stiffness being too soft or the shock being a dud (just like using spacers on forks), then it will feel stiffer initially, but on large hits the rear end will still feel like the same old harsh bottoming out POS.

 

[$heepy]

well to find springs for my bike i think will be real hard. i have searched ebay and absoloutly nothing, remembering this is a 250 china. so the spacers on the front will work??? and i was thinking of mabye going and getting 10w fork oil

 

[numroe]

Rear spring specs include the unloaded length, the internal diameter, and the spring rate. You'll need to work out your spring rate. Either it's written on it, or the seller can tell you, or you have a wild guess, or get it measured by a local bike or car suspension shop. Then you can phone call around to a few Aus suspension shops (eg. see ads in the back of ADB mag) and try to buy one. It might cost you around $100, or perhaps a lot less if you get lucky with a used spring.

 

[thump*140]

Sheepy, for starters i would try 7.5w oil in the forks. if you havent already dumped the original oil, take the top caps off the forks, and with the bike on a stand, jack up the front wheel until the forks are fully compressed... then measure from the top of the forks, how far down the oil is, inside the fork leg... this will give you your fork oil height... eg usually 130mm from the top of the forkleg to where the oil starts on most USD forks... drain the forks, and refill with 7.5w forkoil up to perhaps 115mm from the top of the forkleg... this will in effect give you a stiffer action, still retain all your travel, as well as give you better bottoming resistance... this is usually the best place to start with forks, as well as the spacer option you have mentioned...
as for the shock, these are a little more difficult to tune in the backyard once you have tinkered with spring preload and clicker settings...
I know it's a bit of a trek from the hills, but there is a shop on bridge rd, i think near pooraka or para hills called HOEY SUSPENSION...(ph 82623600) and they are usually happy to have a tinker with China suspension, for a pretty reasonable price... I had the suspension on a KTM 250SX-f copy revalved by them, and for the $180 it cost me to have the front and rear done, the bike now handles as close to a jap mxer as you could expect a 2-grand china to behave...
well worth the money and the drive down... plus it saves you doing all the dirty work yourself, and pulling apart bits you may not be able to put back together, which bike shops WILL NOT TOUCH disassembled....
Hope that helps mate

 

[$heepy]

ok i have run into alot of trouble. i decided to take my forks apart my self. bad idea i think.

so i took one apart. took the end cap off, pulled the springs out, and the rod that the springs sit around has like a dipstick running through the middle so i took that out and drained the oil. approx 200ml of oil came out so i replaced that with 250ml of 10w fork oil, put the 'dipstick' thing back in. and now the forks are flat as a tack. compared to what they were with just the old oil in them and pushing it down and having them spring back up.

now im just meaning with out the forks put back together. im just meaning using the rod that the spring goes around and pushing it down into the lower fork.

i have tried putting air in the valve underneath the fork but after putting some pressure in the valve started leaking air. so what do i do? ad more oil?

 

[thump*140]

maybe try reassembling the fork, springs and everything, and start pumping them up and down, try and get the oil to circulate... the dipstick thing is your damper rod... when you turn the clickers on top of your forks, that will also turn... i think with your particular forks they alter the depth of the "dipstick" in the damping valve stack... basically makes it harder or softer with your compression or rebound, depending on what leg you have pulled apart...
there should be a bit of pressure on the rod in the downward stroke when you have the forkcaps off, but not too much that it's difficult to replace the fork caps... pumping air in the bottom wont have a great deal of effect... at least the valve should be there to bleed air OUT of the forks, not so much pumping air into them...