have an 02 dt125r, nothing wrong with it accept the front fork oil is probably still the same stuff from new so thought i would have front and back suspension serviced, is it possible that i could have seen on this or another website that its quite common to put 10 weight oil in the front forks and have an airgap off 100m/m so as to stiffen the front slightly, not bothered about going offroad as its just something to potter around on during the summer. Also can the rear shock be serviced or is it a waste of time ?

Dont think shock absorbers get 'seviced' as such..more a case of an expensive rebuild! I wouldnt bother, your time and money would be better spent making sure all the pivots are free and greased

rear is all good, stripped and cleaned all the linkage then regreased and rebuilt it all but cant believe that 12 year old fork oil is still capable of doing its job so thought a quick strip/clean and fresh oil must improve it no matter how good or bad it is at the present time thats why i asked about oil weight quantity and airgap

Well you can change it if you want to of course but it really isn't needed, unlike most oils the front fork oil only really lubricates the works and takes the pressure during compression unless you have a leak or let water in to contaminate it. 10 weight oil is usually the recommended oil for most bikes but if you want to stiffen the front up you can use up to 30 weight tho that can blow the valves if you really hammer it. All the forks have an air gap it's how you set them up so all you need to know is what air gap you should have and fill it till it's on the right mark.

This is just an example so you will have to look your bike up and use the correct level from the manual.

This is also just an example but shows a normal type set up for most road bikes.

absolutely agree with you but have spent many hours over the last two weeks trying unsuccessfully to find airgap measurement, even tried local dealer but they weren't sure so thought i would try here before i go down the "just give it to a suspension company" and pay a load of money unnecessarily

Thicker oil makes the front stiffer and fork oil should be changed every once in a while. Remember that fork springs start to sag too and a common way of dealing with that, and stiffen them, is to pack the tops with large washers - or sometimes 2p coins.

To measure the air gap - empty the fork. Fill with the correct amount of oil. Get a stick and slide this in the fork, mark where the stick where it touches the top of the fork. Pull the stick out and measure the stick from the top mark to where the oil is on the stick. That is your air gap for future reference.

Hi Tooslow I think what you will find is that the air gap is varriable depending on rider weight,it is on my wr .Why not just measure what's in there now for a air gap and use that for a refrence.You can always suck some out or add more if you don't like the way it works.

yep know all about thick oil, thin oil, shim stacking, preload(there probably is none), rebound rates(there probably is none) but what i dont know is :- HOW MUCH OIL IS IN EACH FORK LEG, IS IT 10 WEIGHT OIL AS STANDARD, WHAT IS THE AIRGAP ON THE FORKS and no i cant empty mine and measure it as how do i know that it had the correct amount in there in the first place and how do i know i have got all the oil out ?

no need to shout look in the f-ing manual ! It'll tell how much oil should be in there

no just looked through mu yamaha manual as doesnt say how much oil goes in each leg and sorry dont know what your on about with this shouting thing

no just looked through mu yamaha manual as doesnt say how much oil goes in each leg and sorry dont know what your on about with this shouting thing

what I meant with 'this shouting thing' is the use of capital letters, widely recognised as portraying a bit of a temper, if you dont get the answers you are looking for in the time duration you self impose then it's no use resorting to shouting...just soldier on patiently, anyway not every question is answered...what do you thing we are the oracle?

just looked in my manual (Haynes) and the info is in there so how come it's not in yours?

sorry dont really understand all this internet techno jargon, was just making the letters bold so as to highlight them. The manual i have is the one that came with the bike, its not a Haynes manual its a Yamaha one about 150m/m by 75m/m, a white cover with red/orange writing on the cover with the Yamaha tuning fork in the background and the manual comes in three languages English, French and German

well you've just had a free lesson in internet forum etiquette, arent you glad you came here

, god knows what you are describing, it's so small it must be an owner manual?

Haynes says for model 3RN1 onwards...495cc per leg, SAE 10W fork oil

just had a phone call and was told after being stripped and cleaned, 500ml each leg using 10 weight oil but to make it just a touch firmer mix 250ml 10w with 250ml 5w and that should do the trick without overloading the seals, does that sound about right for what you have in your haynes manual ?

yes its the owners manual, also just found 1L castrol 15w fork oil on the internet 9:95 so will be collecting that in the morning

Yip , Haynes manual has it in mine ,[ DT MX MODELS] under forks , 195cc ,

just had a phone call and was told after being stripped and cleaned, 500ml each leg using 10 weight oil but to make it just a touch firmer mix 250ml 10w with 250ml 5w and that should do the trick without overloading the seals, does that sound about right for what you have in your haynes manual ?

you got this wrong, 5W is thinner than 10W, so mixing 50% 10W and 50% 5W would give you 7.5W...thinner than the 10W you started with !

yes its the owners manual, also just found 1L castrol 15w fork oil on the internet 9:95 so will be collecting that in the morning

I would put a bit less than the specified amount in because you arent starting from a bone-dry fork assembly

yes the forks will be dry as there going to be stripped and the internals cleaned and dried out before everything is put back together so they should be ok with 500ml of oil and the bike not going to be used off road so should be ok, thanks for the mention on the oil as well and it reminded me to never trust "my mate" again

yes the forks will be dry as there going to be stripped and the internals cleaned and dried out before everything is put back together so they should be ok with 500ml of oil and the bike not going to be used off road so should be ok, thanks for the mention on the oil as well and it reminded me to never trust "my mate" again

so if you want thicker oil than 10W you could go the whole hog and use 15W or a less severe change 50% of 10W and 50% 15W and you'll have 12.5W

going to go with 15w as i've ordered it now and as i said its not going offroad it'll only be used on the streets by a bloke who's at the age where he should know better