I am in the process of changing fork seals on my mc28 and have a couple of questions.

1) Do I need to undo the cap screw type bolt underneath the fork to be able to break the fork apart? If yes how, its so tight and allen keys arent that strong?

2) The forks are the KV3 - 671 model. Can anyone tell me which model they are off because they are not the original forks from this bike. I need to know for the oil level height.
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94 mc28 SE

yeah the bolt at the bottom of the fork (where the wheel pinch bolts are) holds the damper assembly so its gotta come out to part the fork slider from the stanchion tube. I used a good, tight fitting T-bar style allen key on mine. I guess it wouldn't hurt to spray some releasing oil on it and let it soak first and maybe put your allen key in the bolt then strike the end with a hammer to shock the bolt's threads. I find this all contributes to freeing siezed bolts off.
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After years of moaning about immigrants now i am one...

Impact driver with the allen key sockets . Do you know the King Tony brand ?

The heads got threaded . Managed to drill them out quite easily though thank goodness.

Now just need to sort out the oil level? Anyone got any ideas how to tell which forks i have?
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94 mc28 SE

Parts manual says mc28 se/sp.

Neal wrote:Impact driver with the allen key sockets . Do you know the King Tony brand ?

King Tony...Taiwan brand I believe.

Very good tools and not too expensive. I have quite a few King Tony bits and bobs

120 mm from the top

Resurrecting an old thread, to change the fork oil do I need to remove the spring and damper rod? Or can I just remove the fork cap and pour out the old oil then pour in the required amount? Bike is an MC18r2j with standard R suspention. Once I've done that, what would be a good place to set the preload adjusters to? They are adjusted pretty far in at the moment, I know the rear end benifits from as much preload as possible, the same for the front?
Thanks for your help.

If it were me, and I was spending the money for new fork oil, I'd also change the fork dust and oil seals and pull them all the way apart to clean everything.

Dana
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2016 Husqvarna 701SM
2021 Husqvarna FS450 supermoto
2014 Honda CRF250R supermoto
1995 NSR250r MC28

You don't need to remove the fork guts to drain the oil, just take the legs out of the triple clamps and leave them upside down in a container (with the caps off) for a fair while to let as much old oil as possible make its way out.

The rear seems to benefit from as much ride height as possible but i don't think maximum preload is necessarily the way to go. You want only a certain amount of static sag for best results with the preload - you'd need to read one of those setup guides where they get you to measure sag under just the bike's own weight and then with you on it to see how much preload you need. Same goes for the front end. The adjustment will depend on your weight and how the bike gets used: on the road or track for example.
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After years of moaning about immigrants now i am one...

The only problem with just draining the oil out is you're not getting all of it, and you're not getting the filth and contaminants that knackered the old oil in the first place. You're better pulling them apart, cleaning everything thoroughly and starting fresh.

Cool, thanks for the advice. Just what I needed to know. Going to have to get motivated to finally make the F3 shock link plates. Giving everything a good clean sounds the go.

MC18 is a damper rod not a cartridge fork so you can drain almost 100% of oil from it, however there will be lot's of black dirt still sitting at the bottom of the forks, even with forks completely dismantled it takes some effort to get it out.

I think 10w with 120mm will work for this (measuring oil or actually air gap from the top of the oil to the top of the fork tube, spring out fork collapsed)

what you will really benefit from is a RaceTech cartridge emulator, makes much difference and while you there I would replace the springs, bushings, seals... probably about $400 in parts by the time you are done but it will be like new. Just changing oil will not make any noticeable difference unless you make changed to the oil level.

Yeah, I should change the seals and bushes, I see david silver still lists the seal kit. Might have to wait until after christmas though, getting quite hard to find any garage time at the moment!

I've been keeping my eye out for some front fork options, been watching other peoples threads with interest and of course there is so much info on the site. Not that there is anything wrong with the R type forks for my riding style.

As a bit of a hijack, what options are you looking for? I have just changed out the rvf400 frontend out for a rebuilt 28 frontend that Maxton redid with the installation of one of their adjustable GP20 cartridge setups. So on the shelf I now have a stock RVF400 setup, 28SE internals (from the maxton installation), 28SP setup and a 21SE forks with tyga adjustable caps. All surplus to my needs so looking to start offloading them.

cheers