Author Topic: Fork oil change (Read 10703 times)

cugsy · « **on:** March 19, 2014, 02:23:16 PM »

Apologies for asking what might be a simple and straight forward question. I can't find an answer in the forum. And I've been away for a few months. No bike riding because of poxy arthritis. Summat and nowt as they say over here.
Anyway, I finally got out with the bike yesterday for a 50 mile bimble. One of the things that always surprised me was the bike wanting to understeer on big sweeping bends. I took it to the good bike shop I go to and we got to talking. The easiest thing to do was change the fork oil - tyres and pressures are fine. But the fork oil might be shite and need changing. OK, says I and took home a litre of 10W. First surprise - no drain plug for the forks. So I need to drip them out and pour the oil out. there is conflicting advice over the way to remove the top plug. Do I back off all of the preload and undo the top 19mm plug? If so, do I still have air to bleed from the top of the fork? The bike is supposed to be a 2002 model but big george has told me its probably a 1999...
Thanks in advance folks John

connie_rider · « **Reply #1 on:** March 19, 2014, 03:13:12 PM »

Loosen the pinch bolts on the upper tripple tree as they can squeeze the tube down a bit (and possibly) grip the top plug.
Then take the preload off the tube.
Lastly remove the Upper Plug.
(Should be no air pressure inside but the spring can shoot it across the room if your not paying attention.

NOTE: I prefer to use a socket and speed handle to remove the top plug.

(As you said) Unfortunately there is no drain screws, so you can suck out oil and flush, or remove the tubes and dump..

Ride safe, Ted

cugsy · « **Reply #2 on:** March 20, 2014, 03:51:34 AM »

Good enough for me Ted. ta

RFH87_Connie · « **Reply #3 on:** March 20, 2014, 05:41:12 AM »

Assuming you still have the progressive rate springs, while you're in there, cut off 5" of the close-wound coils at the end of the springs and replace it with SD40 PVC pipe and washers to make up the difference (to bring them back into spec). I think the washers can be about 1-1/8" outside diameter. You may consider trading your oil for 15w (unless you're lighter than most). You will get a much better ride and handling.

cugsy · « **Reply #4 on:** March 20, 2014, 07:21:19 AM »

As far as I know the bike is standard. I'm a tubby too..just a teeny bit over 200lbs...just ..sort of..I'll try a couple of options. 1- 10w first 2- 15w and then maybe chop the springs ..

Rick Hall · « **Reply #5 on:** March 20, 2014, 07:31:55 AM »

Just a little tidbit. Make sure there's a jack under the engine before you remove the fork caps.

Rick

RFH87_Connie · « **Reply #6 on:** March 20, 2014, 07:42:20 AM »

Quote from: Rick Hall on March 20, 2014, 07:31:55 AM

Just a little tidbit. Make sure there's a jack under the engine before you remove the fork caps.

Good point! You may want to also use a rachet-strap to keep the centerstand pulled forward by hooking it to the stand and the lower fairing frame (or something else reasonably sturdy). Doesn't have to be real tight, just enough so it can't be folded back up. You wouldn't want it to crash to the ground without the front wheel and forks on. I always do this when I change the front tire.

Jim __ · « **Reply #7 on:** March 20, 2014, 08:36:28 AM »

When you have everything apart, mark your fork cap/plug so you can tell where the threads begin when you have a wrench on it. Then mark the fork where the receiving threads begin. I used a paint pen. When you reassemble, line the marks up then turn the cap ever so slightly CCW. Push down hard till the cap and fork mate and then twist CW. Your threads should grab on the first twist of you wrist. This is especially helpful if you do cut your springs since you'll need greater force to compress during reassembly. BTW - I'm in the 160 lbs range, cut 3" off the springs, used 15W oil and I'm very pleased with the results.

cugsy · « **Reply #8 on:** March 20, 2014, 10:07:31 AM »

As usual, this isn't straight forward. By the way,thanks for the advice about safety fellas but I've been doing this for 35 years and still got 9 1/5 fingers..
Anyway, top plug out - no movement from the spring. Took out the top washer (preload spacer) and 8" long ali tube...duh! Wassat for? then a short 8" spring and another very thin (pointlessly thin) spacer. And thats it - apart from about 150ml of black shite posing as oil. Has someone already fiddled with this fork set-up? Anyone got a pic of the post 96 set up? John

Strawboss · « **Reply #9 on:** March 20, 2014, 11:32:26 AM »

In a pinch, or even whenever, you can count on the forum for all your answers, but the best advice is after you are finished with this job, go out and get a Kawasaki shop manual. Best thing I ever did, combined with a Clymers manual its a real help as the Kawasaki manual tends to lean towards a mechanics way of doing things as it assumes you know already how to get to a part or assembly to work on another part or assembly.

cugsy · « **Reply #10 on:** March 20, 2014, 11:57:03 AM »

The manual I have is in pdf form (from George I fink!) and it says Kawasaki heavy Industries at the bottom. I assume thats the big K themselves. The diagram of the forks doesn't tie in with what i found or what I expected. I can't cut 3 inches off what ain't there..

RFH87_Connie · « **Reply #11 on:** March 20, 2014, 01:32:43 PM »

Sounds like something odd was done to your fork springs. I think the spacer is correct, but not the short spring. Perhaps it was cut in half and the other piece is still in there? I think the spring should be in the neighborhood of 18"? I don't have the late model so I can't tell you for sure. I added a pic that shows the stock length from a late model. I'm pretty sure they are unaltered OEM progressive springs.

cugsy · « **Reply #12 on:** March 20, 2014, 01:58:18 PM »

Nope - nothing else in there because the forks are hanging upside down draining just like yours...sans fork brace though. Very odd. Should there be an 8-10" tube ? Funny what you find $:-\$

enim57 · « **Reply #13 on:** March 20, 2014, 04:55:33 PM »

Quote from: cugsy on March 20, 2014, 10:07:31 AM

Took out the top washer (preload spacer) and 8" long ali tube...duh! Wassat for? then a short 8" spring and another very thin (pointlessly thin) spacer. And thats it - apart from about 150ml of black shite posing as oil. Has someone already fiddled with this fork set-up? Anyone got a pic of the post 96 set up? John

Sounds very similar to my Racetech setup. The manual states standard spring length for A1 - A8 is 514mm with service limit of 504mm (page 12-9), after market springs are much shorter. I have Racetech springs and the aluminium spacer was cut to 175mm long to acheive desired preload. I have emulators so without them the spacer would be about 20mm(?) longer, that's nearly the 8" you speak of. Hope this helps.

Regards, Russell

PS Just noticed your bike is A13, manual states spring length 543.3mm with service limit of 533mm.

cugsy · « **Reply #14 on:** March 21, 2014, 03:24:15 AM »

Thanks Russ. I'll take a pic and show you later. About the ali tube, does it have manufacturer markings? I mean,you can't just bung a bit of pipe in there...can you?

cugsy · « **Reply #15 on:** March 21, 2014, 08:17:29 AM »

Took this quick pic of what was in both forks. Both spring and tube are 260mm. About 200ml of oil came out. According to the frame number mine is an A17 which ties in with the 2002 registration plate.
The book says something strange about oil quantity - 388ml (320 ml at change) EH?

Whats the consensus chaps? John

cugsy · « **Reply #16 on:** March 21, 2014, 08:18:23 AM »

oops....forgot the pic

Mettler1 · « **Reply #17 on:** March 21, 2014, 08:55:22 PM »

WOW! Never saw a spring that short and a spacer that long in a Concours ? That IS different.

cugsy · « **Reply #18 on:** March 22, 2014, 03:06:35 AM »

Somehow, that doesn't make me feel any better.

Oh well, it can't be any worse with new oil in them. I'll have a guess......

connie_rider · « **Reply #19 on:** March 22, 2014, 08:37:55 AM »

Cugsy, that spring is so short that I would be concerned with spring bind.
It looks like a stocker that has been "seriously" cut down.
I'm not familiar with the RaceTech Emulators.
Possibly they use an ultra short spring, but I don't think so.

Assuming that is a stock spring that has been cut down, the front end should be really stiff?
Makes me think the bike was set up for a really heavy rider.

I think at this point; I would take the forks apart for an inspection. (to see if the forks have been extensively modified)
I would get my biker friends (ie: Boomer/Hans/anyone) to send me a stock set
I would modify a stock set by removing the 5 1/2", or buy aftermarket springs.

When you reassemble, don't worry about the volume of oil.
dump oil in each fork leg (specified volumn plus more)
exercise the fork to get the air bubbles out
compress the upper tube (spring removed)
**suck the excess oil until it reaches a desired level
set the oil level to a measured level (I recommend 6 1/2")

** If you don't have a tool to suck the oil out, you can build a cheap tool, by using a Turkey baster and a section of hose.

Ride safe, Ted

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Author Topic: Fork oil change (Read 10703 times)

enim57