A forum for owners of Yamaha TTR250 trail and enduro bikes!

Ironhorsend · Member

Fork Oil Change??

yamalama · Veteran Member

Hi, I would also like to know if the fork oil can be changed without partially stripping the forks. Looking at the manual that I downloaded via this site I was surprised that periodic changing of the fork oil wasn't in the maintenance schedule, and the only place where adding fork oil gets mentioned is during the fork rebuild section. See page 6-43 & 6-44. Here it appears that you need to add the fork oil before doing something with a rod puller and rod holder. Is this absolutely necessary or can I just remove the cap, turn the fork upside down in an oil catch container and let it drain? On my xt600 I have just added a measured quantity of oil into each drained fork, not measured the oil level. The XT's forks don't have any of the adjusters that the ttr does. Do these adjusters mean that such a basic approach is no longer appropriate? PS: Why are the spaces between my paragraphs disappearing?

verticaltwin · Member

I'm also interested in this topic... as I don't think my forks have ever been serviced since new. New seals and fluid would be good, and thinking about 7w Bel-Ray since I don't want to firm them up too much. Strange to me that there are no fork oil drain screws, but I'm used to working on much older bikes.

Kyle

KentJ · Veteran Member

I know this post is old, but did you guys ever get it figured out? I'm going to attempt it this weekend as I'm sure my oil is in terrible shape.

Without any specific instructions on how to drain/change the oil, the best I can figure is to remove the top caps, remove the forks from the bike and drain out the top. The service manual lists "Drain Fork Oil" as step 4 under dissasembly, so it can't be that hard to get to (steps 1, 2 & 3 are remove cap bolts, remove collars, seats & springs).

Will post back with my results.

-Kent

Rger8 · Member

Mmmm, I am wondering if there is a quick and dirty way to do this. In my old KLR 650 I just removed the top fork caps, pulled out the springs and stuck a big tube with a syringe on the other end and sucked it out as best I could. I then measured out the new stuff and put it back in along with a couple of 1/2 PVC spacers to firm things up. I wonder if it will work on the TTR250???? Unless someone know if this wont work because on the internals I will have to give it a try.

Cheers!!! biggrin

TT-R250M · Super Guru

This is what I did to my previous OE TTR250...

Removed the 10mm air valve/bleeders, turned the forks upside down in a drain tray (one at a time) and compressed the forks repeatedly until all fluid was drained, taking note of how much fluid was drained. Now the messy part... I then used a valve saver bottle (any bottle with a small enough nozzle will work) to fill the forks while compressing and decompressing the forks.

The problem is that some may leak out while filling the forks so it is a ''guess-timate'' how much is in the forks once filled.

This method worked fine for me but I take no responsibility for any damage arising from using this method.

Jarrah

KentJ · Veteran Member

Well I dumped the old oil this weekend and replaced it with Bel-Ray 5W oil. The local Yamaha shop only carried Bel-Ray so that made the choice easy for me. They did also have the OEM oil, but at $48/litre I didn't even consider it...

I pulled the forks as per the service manual and once I had the top caps + springs out I just turned the forks over and dumped the oil into a container. The first oil to come out (from the top of the tubes) was actually not too dirty, but got progressively dirtier as the stuff from the bottom made it's way out. All of the dirt settled at the bottom of the forks and that was the stuff that was hardest to get out. I poured some kerosone into the tubes and flushed them out that way too and was able to free up a lot more grime. I left them upside-down on the workbench for a while to drain out completely.

I think if you change your oil regularily you could probably get away with suctioning the oil out, but given how much crap was stuck at the bottom of mine, I'm glad I was able to invert them and drain that way. This was my first oil change ever, so I'm sure it was dirtier than someone's who maintains them properly.

I measured the oil level before draining, and it was lower than the specified 130mm. I'm hoping that with new oil and the proper level I'll see an improvement in performance from my forks. As of lately, the forks have been increasingly harsh and unstable. The small, high-speed bumps (tennis ball sized rocks, roots, pot holes on dirt roads) are so bad that it's a challenge to control the front wheel sometimes, not to mention extrememly tiring on long rides. We covered nearly 500km of dirt road/double/single track last weekend and my hands were killing me. If I don't see an improvement, I'll be looking at installing some upgraded springs from Race Tech.

-Kent

yamalama · Veteran Member

Hi all,

I have now done this on two sets of TTR forks, and it is nowhere near as involved as it first appeared when reading the Yamaha manual.

I would advise against trying to drain the fork oil by removing the rebound valve at the bottom of the forks while they are still installed on the bike. You would most likely need an air (rattle) gun to undo them and would struggle to stop the fork internals from turning when trying to refit them, unless you use an air gun but then can you be sure you will tighten them enough / aren't about to overtighten them and strip the threads? Plus you are supposed to use threadloc on the threads when refitting them, and for this to work they need to be oil free. I expect fork oil wll keep trickling down for days!

Anyway, it isn't actually that much trouble to do it by the book. You don't need to remove the fork seals and you can easily improvise the special tools. To hold the spacer on top of the fork spring down Brian says an adjustable spanner will do. I used a bicycle cone spanner with a 13mm slot on one occasion and a bit of 2mm sheet steel about 70mm square with a 12mm slot from the middleof one side to the centre on the other. Dimensions are not critical so long as slot clears the 10mm wide rod bot catches on its (17mm?) nut. And for the tool that attaches to the top of the damper rod, a bit of stiff wire, thin enough to wrap one end around the damper rod, under the loc nut works well. You could even manage with string.

If you use Brians tip in the forks sticky of dropping the fork so that it is just held by the lower clamp and then loosening the top cap, so as to not need to disturb the handlebars, I suspect it won't take that much longer that the short cut methods being suggested in this thread, and you should get more of the dirtier oil out from the very bottom of the forks.

Lama

petenz · Super Guru

Ironhorsend wrote:
Hi Guys,
This may sound like a silly question, but does anyone on here do a fork oil change WITHOUT changing the seals? If so, do the forks need to be removed in order to drain the old oil or can I remove the rebound valve at the bottom of the forks while they are still installed on the bike?
I'd like to change the fluid as it's never been done, and I'd like to switch to 10W oil to firm up the front end just a little bit. Also looking at installing the RACETECH FAGV 02 Gold Valve's in the forks as well. If anyone has any experience with this modification, feel free to comment.
Of course the alternative is the YZ fork swap, but I'm wondering if the gold valves and oil would be adequate.
Feel free to offer your opinions/insight if you have done any of this yourselves.
Thanks much,

Darin

If you are going to put gold valve in.... You have to pull the forks apart & drill the holes in the damping rods

so they no longer work... that transfurs all the compression & rebound damping to the gold valves...

I had a set in my XT660R.... I made them... They worked... but I'm not sure if I had the springing correct

for the damping plate or compression damping valve... But were a lot better than the damping rods...

I now have CR250 USD forks in it.. That have been re-sprung & had the damping vavle stacks modded

from MX to Enduro valveing... MX valveing dosn't work on the trails... MX tracks don't have rocks/tree roots/

rutts / rivers etc... I'm about to do a USD fork mod to my TTR... 05 YZF front end...

.....................................................................................................................................................................

If you do put them in... When you sell the bike you have can't remove the gold valves... there will be no

damping... you are then selling a bike in a un-safe state to someone..

KentJ · Veteran Member

Just a follow up on my previous reply; I finally got out riding the last 2 weekends and the forks are performing much better! Given how easy it was to do (a little time consuming but not too complicated), I really wish I had done this a long time ago. The only parts needed was the new fork oil.

It will be a part of my regular maintenance schedule (yearly or 2 years?) on any bike I own. The fork action is much more controlled and big hits don't make the bike feel like it's being hit with a wrecking ball. No better than stock I'm sure, but much better than it used to be. :)

-Kent

TTRHead · Senior Member

Fork oil change

petenz · Super Guru

use a 5 weight oil or a oil with a cst rating no higher than 18...

.....

TTRfan · Super Guru

10w can make the forks a bit harsh for normal trail riding but works fine for an overweight porker like me! 5w absolutely OK unless you are very light in weight or want a plush ride.

Had lots of squeaky top rear shock bearings but not had any squeaky forks - new one to me confuse

Squeaks are normally caused by two dry surfaces rubbing so maybe when you refill your forks with oil it will disappear - hopefully wink

Brian

TTRHead · Senior Member

Saw this in Halfords but not really sure what 5w/30 ist?

-- Edited by TTRHead on Wednesday 16th of November 2016 11:08:16 AM

devon_rich · Senior Member

Mine squeaked with old oil in. Seals were fine so just did the oil

TTRHead · Senior Member

My squeak has gone I can just hear the springs compressing is that normal?

-- Edited by TTRHead on Wednesday 16th of November 2016 11:13:22 PM

petenz · Super Guru

TTRHead wrote:
Saw this in Halfords but not really sure what 5w/30 ist?

-- Edited by TTRHead on Wednesday 16th of November 2016 11:08:16 AM

5w30 is a SAE rating for lubecation...prob no better than putting ATF in the forks..

forks work with flow rates... or the CST " Centistroke rating"

Just stick with a known brand of real fork oil....

..