Been lurking for 10 years, finally have a question.

[maverick31210]

I've had an 04 250 since 2006. I have ridden on and off for years. I'll be upgrading soon but until then, I commute daily on my 250.

The bike sat for about 4 years until a few months ago. I brought it over from my parents' place and got to work on it.

Went through the carbs, adjusted the valves, plugs, oil, etc...all the basic stuff after the bike's been sitting. I threw in some thicker (15W) fork oil to combat that springyness that's plagued me since I got the bike. Most recently I put on some new tires, Sport Demons front and rear.

As soon as I got the new tires on there I noticed a slight loss in power. I'm thinking the clutch is wearing out and the grippier tires are making it more noticeable.

What clutch plates and springs are recommended?...Brand wise I mean.

The bike gets ridden pretty damn hard, for what it's worth.

[cuong-nutz]

Barnett, EBC, stock. Either one will be fine. I just choose what I find cheaper of the 3.

[maverick31210]

How long is a good average to get out of a clutch? I know this is hard to put on a number on but just a ballpark will help. Bike has 8K on it now and again, that's been hard riding shifting around red line almost all the time.

[Ghostt]

The clutch itself is pretty much bulletproof, Kawasaki used the same set-up on bigger bikes like the ZX1000, etc....

What type of oil did you use? Most modern oils contain additives that while work for car engines are not recommend for wet clutches. Due to the additives which are super slippery, not good for wet clutches which will cause slippage. Any 10w-40 to 20w50 rated JASO-MA/MA2 oil will do just fine, a personal favorite around here is Shell Rotella synthetic T6.

The other thing is the clutch springs themselves are weak from Kawasaki, due to the bike is made for the entry market, the EX500 suffers the same problem.

IMHO the springs themselves need to upgraded to a heavy spring, here's my write-up on the subject, I have done this to both my Ninjette and EX, and it's popular on the EX500.

From the EX500 forum,

What Are Clutch Springs?

Clutch springs determine the recoil of the clutch lever; how hard it is to pull the lever and, when the lever is released, how much force is holding the lever up against its stop. Weak clutch springs make it very easy to pull the lever, which is convenient for weak riders, but can result in some clutch slippage, as the engine is not fully engaged when the clutch is released. With stiffer clutch springs, the lever is harder to pull, but when the lever is released, the clutch is fully disengaged, and there will be no clutch slippage, so the engine is allowed to direct all of its power to the rear wheel. It is believed that, since many newbies and female riders are attracted to the EX-500, Kawasaki opted to use softer clutch spring that would allow easier disengagement of the engine.
Our beloved FOG strongly recommends replacing the stock clutch springs. He says that he was losing about 500 RPM at redline to clutch slippage on the race track. With the stiffer springs holding tighter, the engine was now able transmit more of its power to the rear wheel.

Upgrading to performance clutch springs by Ghostt

Choosing Clutch Springs

Barnett aftermarket clutch springs for a 1985-1989 ZX-600, Part # 501-50-05055. You can view them online at the Barnett catalog, here: http://www.barnettclutches.com/produ...&clutch_cc=600 They can be ordered through your local dealership, or at a number of online sources. Here is one such online catalog: http://www.exoticsportbike.com/6001.htm

Another option is the EBC CSK10 (see http://www.ebcbrakes.com/motorcycle_..._springs.shtml). This kit isn't quite as stiff as the Barnett, but is better than stock and usually a little cheaper. The kit does include six springs, while the ninja 250 only uses four.

Also here's some more information about fixing a slipping clutch,
http://faq.ninja250.org/wiki/How_do_...ping_clutch%3F

One a different note, the thicker fork oil doesn't effect spring rate, just dampening, you should cut the stock springs to better suit your weight. It increases the actual spring rate, it's easy and cheap enough to do.

[maverick31210]

Thanks for that.

Maybe I should just try new springs first. Like I said, I noticed this once I got the new tires on. I feel like the better grip of the rubber is making the clutch slip more evident.

Bike has Rotella in it so I know the oil isn't the issue. Tomorrow morning I'll pop the cap off and look at the plates. If they look fine, springs it is.

[rojoracing53]

I've got 80,000 miles on my bike currently with all the original motor parts and it still runs fantastic. Is it possible for someone less skilled with a clutch to kill it much sooner? Yes, but you'd have to be pretty bad with a clutch. I doubt you could feel the clutch slip only a little. I'd think it would just go like most bikes do. Even an experienced rider like myself by the time we notice something odd it's only 20 miles before it's totally gone and your limping it back home.

Remember a clutch can't sap power from the bike, it will only let it slip passed. Meaning you'll see on the tach and hear it the RMPs.

[rojoracing53]

Oh make sure you clutch lever has at least 1/16-1/8 gap of slop at the perch. Meaning you should be able to jangle it around when its not in use. If you don't have this slop in the cable it'll slip slightly until it quickly kills the plates entirely.

[maverick31210]

Originally Posted by rojoracing53

I've got 80,000 miles on my bike currently with all the original motor parts and it still runs fantastic. Is it possible for someone less skilled with a clutch to kill it much sooner? Yes, but you'd have to be pretty bad with a clutch. I doubt you could feel the clutch slip only a little. I'd think it would just go like most bikes do. Even an experienced rider like myself by the time we notice something odd it's only 20 miles before it's totally gone and your limping it back home.

Remember a clutch can't sap power from the bike, it will only let it slip passed. Meaning you'll see on the tach and hear it the RMPs.

Hmmm...then what could it be? Could it be all in my head?

I've been wanting to upgrade and am currently looking at 600 double R's, I just need to save up a little more scratch. I don't know if I'm just wanting more and noticing it more now? Bike only has 8K on it and from what I know about this bike owning it for 10 years, that's nothing.

[rojoracing53]

If you've ridden anything else that's more powerful between when you last rode the 250 and getting the new tires and riding it now then it'll feel slow. I'm not the type of person to have my perception screwed with easily but after only a quick ride on a 100+ HP bike I'll hop on my 250 and think that the motor is failing for at least 30 mins into my ride.

I normally carry a Mtb on my 250 which adds quite a bit of wind drag and weight. On the rare times I take the Mtb off it feels like I just gained 10HP and the bike is fun all over again.

[MrAtom]

Originally Posted by rojoracing53

I normally carry a Mtb on my 250 which adds quite a bit of wind drag and weight. On the rare times I take the Mtb off it feels like I just gained 10HP and the bike is fun all over again.

A mountainbike?

[cbinker]

adding new tires creates too many variables to assume its the clutch. not to mention that you are increasing grip and circumference which will change the feel of power delivery.

[spooph]

did you take the wheels on and off, or did the shop do it?

The axles might be over tightened, and THAT you can certainly feel. When I got my bike from the factory the axles were ridiculously over torqued. Torquing them correctly allowed more power to the ground.

When you replaced the oil, did you tighten down one side of the triple tree clamps, or did you tighten the front axle first and then snug up all of the triple clamp bolts at the same time to make sure the front end is straight?

The rear wheel could also be misaligned, causing it to bind and waste power.

With only 25hp, every little bit counts. I can scrub off 10mph on my top end if the wheels aren't aligned properly. On this note, you might also want to look at the brakes, and maybe bleed them to make sure they have good fluid and are releasing properly (only thought of this because it's been sitting for a long time).

Following the KISS principle, look at what you changed first instead of looking for gremlins somewhere else.

The clutch could be the problem, but I highly doubt it. Verify the drive line is silky smooth and then start looking at the clutch. Hope this helps.

[allanoue]

Originally Posted by MrAtom

A mountainbike?

https://www.ninjette.org/forums/showthread.php?t=157087

[adouglas]

TEN YEARS????

[maverick31210]

I actually went through all of that.

I always make sure to not over tighten the axles. I snug 'em up and let the cotters do their job.

The forks are bent so I know the front end isn't the straightest thing in the world. It's a little off but nothing crazy, it was the same way before.

I readjusted the clutch this morning and fiddled with the idle adjustment and that seemed to help.

Part of me really thinks this is all in my head LOL.

[maverick31210]

Originally Posted by adouglas

TEN YEARS????

LOL...no kidding right?

Over the years I think I've lurked just about every Kawi and Ninja forum out there.

[adouglas]

You win the Internet for today.

[dcj13]

Welcome, Laurence! You already know everything about the forum and your fellow members.

[maverick31210]

Originally Posted by dcj13

Welcome, Laurence! You already know everything about the forum and your fellow members.

Thanks bud, much appreciated!

Hopefully I can share some knowledge with new members as well, I generally do all my work on my own cars/bikes.

[APEmike]

Originally Posted by rojoracing53

I've got 80,000 miles on my bike currently with all the original motor parts and it still runs fantastic. Is it possible for someone less skilled with a clutch to kill it much sooner? Yes, but you'd have to be pretty bad with a clutch. I doubt you could feel the clutch slip only a little. I'd think it would just go like most bikes do. Even an experienced rider like myself by the time we notice something odd it's only 20 miles before it's totally gone and your limping it back home.

Remember a clutch can't sap power from the bike, it will only let it slip passed. Meaning you'll see on the tach and hear it the RMPs.

Most of my customers replace their clutches once or twice a week...

Then again a 10" car tire, a slider style clutch, and a bottle of nitrous per pass will do that.

Really it just depends on your riding. Highway? City? Clutched shifting? Lots of low speed 1st gear stuff using the clutch to regulate speed? MSF bikes get clutches often. Usually 5 -10 in their short life times, and not THAT many miles. We just had a Hayabusa engine roll in here with 186K miles on it and the only cover that had ever been removed was the valve cover for the occasional adjustment. Everything else was original! All highway miles. The only reason it was in to us was because he was looking for more power. It still had perfect leakdown numbers and the clutch was near original thickness....


Anywho... I can vouch for Barnett! Excellent street clutch! Much more smooth engaging than EBC.

Like others are saying though, a slipping clutch wont cause it to feel like its a little boggy, or tired.

Tire size and weight can make a big difference. Fuel formulation, oil, carbs not cleaned in a hermetically sealed, dust free, environmentally controlled Clean Room...

Plus, it hasn't been ridden in how long? Maybe it just feels slow to you because you aren't used to the bike any more.

[maverick31210]

Thanks for the info!

I mean, the bike is ridden hard but I wouldn't call it abused. Like I said, it seemed to be alright this morning after some adjustments. What I'll do is keep is simple as someone else suggested.

I'll order a set of springs and toss them in when I change oil the next time in about 2K miles. See how it likes that. Even it's not the case, I wouldn't mind having a firmer clutch pull.

[Ghostt]

Originally Posted by maverick31210

Thanks for the info!

I mean, the bike is ridden hard but I wouldn't call it abused. Like I said, it seemed to be alright this morning after some adjustments. What I'll do is keep is simple as someone else suggested.

I'll order a set of springs and toss them in when I change oil the next time in about 2K miles. See how it likes that. Even it's not the case, I wouldn't mind having a firmer clutch pull.

FYI: If you remove the clutch cover, while on the kickstand, not the center stand, you lose hardly any oil, so no need to wait. Either use a new gasket, or RVT.

You can inspect the clutch itself, and change out the springs, hopefully you ordered the Barnett aftermarket clutch springs for a 1985-1989 ZX-600, Part # 501-50-05055. Firmer springs themselves will mean a harder pull, but not ridiculous. The springs will make a difference with keeping the clutch fully engaged, and firmness, you'll feel the difference.

The picture below shows the difference between OEM(yellow stripe) and HD springs(red stripe) in length, and wire gauge thickness.

Don't forget to follow-up.

[maverick31210]

Originally Posted by Ghostt

FYI: If you remove the clutch cover, while on the kickstand, not the center stand, you lose hardly any oil, so no need to wait. Either use a new gasket, or RVT.

You can inspect the clutch itself, and change out the springs, hopefully you ordered the Barnett aftermarket clutch springs for a 1985-1989 ZX-600, Part # 501-50-05055.

Don't forget to follow-up.

Haven't ordered yet but I will, appreciate the part #.

If I can get away with using gasket maker then there's nothing holding me back. Will update once I get it done.

[Ghostt]

Originally Posted by maverick31210

Haven't ordered yet but I will, appreciate the part #.

If I can get away with using gasket maker then there's nothing holding me back. Will update once I get it done.

IMHO i put the upgraded right up there with doing the suspension.

Also don't forget to lube the clutch cable, and as long as your at it do the throttle cables too.

I personally use this kind, it's a lot easier than the spray lubes, and no need for the lube tool.



http://www.amazon.com/Bike-Dri-Slide.../dp/B001F2Y25G

[maverick31210]

Originally Posted by Ghostt

IMHO i put the upgraded right up there with doing the suspension.

Also don't forget to lube the clutch cable, and as long as your at it do the throttle cables too.

I personally use this kind, it's a lot easier than the spray lubes, and no need for the lube tool.



http://www.amazon.com/Bike-Dri-Slide.../dp/B001F2Y25G

Interesting that you say that...right up there with suspension?

I've known suspension was a must do since I've had the bike but just recently got around to it. Not sure if I mentioned it before but I put in a newgen shock for the rear and heavier fork oil. Rear shock blew on me on the way home one day. Found a newgen one on Ebay for $40 shipped. If I wanted to wait I would have picked up a ZX6 one but I needed it ASAP and I'm actually real happy with the newgen one so far.

You're saying clutch springs should be right up there to do?

Since we're shooting the **** about it...what do you recommend for fork oil? As far as I've read, the factory oil is 10W. I put in 15W. It's definitely better but still a little springy. I'm thinking I should add more but I'm concerned about the seals. I've read that 20W is too much but I don't really think it will be. Thoughts?

[csmith12]

I would shim (preload) the forks or replace the springs before running 20w, but that is just my opinion. I haven't had any issue with my clutch springs on my '10 or '92.

[Ghostt]

Originally Posted by maverick31210

Interesting that you say that...right up there with suspension?

I've known suspension was a must do since I've had the bike but just recently got around to it. Not sure if I mentioned it before but I put in a newgen shock for the rear and heavier fork oil. Rear shock blew on me on the way home one day. Found a newgen one on Ebay for $40 shipped. If I wanted to wait I would have picked up a ZX6 one but I needed it ASAP and I'm actually real happy with the newgen one so far.

You're saying clutch springs should be right up there to do?

Since we're shooting the **** about it...what do you recommend for fork oil? As far as I've read, the factory oil is 10W. I put in 15W. It's definitely better but still a little springy. I'm thinking I should add more but I'm concerned about the seals. I've read that 20W is too much but I don't really think it will be. Thoughts?

I would cut and space out the OEM springs, or look for a set from a NewGen, depending on your weight, they might be closer, as the PreGen fork springs are very weak.

@InvisiBill is better at explaining suspension than myself, hopefully he'll show up

@csmith12 I'm not saying the OEM clutch springs are inadequate, just on the weak side, I would see for yourself, and make your own judgements, it's a cheap upgrade, and if you don't like them I will or someone else will buy them off you. If your in a habit of being a spirited rider, then the upgraded springs will be appreciated.

Just like the suspension, yes it adequate for some, but.....


Here is an excellent write-up on the Ninjette suspension by @InvisiBill

I've done quite a bit of research and played around with a few different options on my 500, but definitely listen to the guys here who actually have real-world experience on these bikes.

Getting the spring right for your weight will allow the bike to bounce the proper amount. That allows the damping to have the best control over that movement. If your spring is too soft, it will bounce around too much and your damping system will have to work harder to try to constrain that extra movement. If the spring is too stiff, it won't compress enough to absorb bumps, and the wheel will skip. http://www.ex-500.com/wiki/index.php...ension_Preload is a long read, but it has tons of info, and I think it does a good job explaining everything with examples.

According to RT's calculator, the rear spring is ideal for someone who weighs 220lb (100kg). People here have said that may not be exactly right, but the spring is definitely quite stiff compared to the other little Ninjas (it's 73% stiffer than the 500 spring). I'm assuming you're lighter than that, so going to a softer spring should make the rear work better for you. The PreGen's spring is good for about 140lb on a NewGen, but the shock is a little shorter so it would lower the rear and make the handling a bit slower (plus it lacks any preload adjustment). If you can find a decent one cheap on eBay, it might be worth tossing one in just to try it out though (they're usually ~$20 here).

The stock shocks are simple, non-adjustable, non-rebuildable, lowest-bidder units. Aftermarket shocks give you more adjustment options for tweaking the damping system (usually separate for compression and rebound) and are built with higher quality, replaceable parts (so when something wears out on it, you just replace that one part instead of buying a whole new shock). £395 is US$615 which seems somewhat expensive to me. A new Penske is about $800 here, and used ones can be half that. The nice thing about buying a new shock is that they generally include a spring and calibration to match your weight. It should be basically a perfect drop-in upgrade.

If you can do a bit of mod work, the GSX-R shock swap is a pretty cheap way to get a decent shock, and there are a variety of spring rates used on the various models (there's a chart of different rates/weights toward the end of the thread). It's not made specifically for the Ninja's suspension, and requires a bit of work to make it fit, but they're usually on eBay for about 1/10 the cost of that Brook shock. The SV650 shock doesn't have all the adjustments (it's comparable to our stock shock) but should require less work to install, as another cheap DIY option that's probably more suited to your weight.


NewGen Fork Spring Rate Chart
Again, the NewGen has the stiffest fork springs of the little Ninjas. It's still a tad low, but should be acceptable if you're smaller. If you're a fatty like me, it's still quite a ways off, but it is possible for it to match up fairly well to the weight of a smaller adult (unlike the PreGen and 500, which have essentially useless fork springs).

The stock front and rear are pretty mismatched, so if you're smaller and go with a lighter rear spring, you're actually reducing that mismatch and making it less-bad than stock. On the PreGen and 500, replacing a soft rear spring with something appropriate can exacerbate the problems of the super-soft fork springs (because you're increasing the mismatch).

__________________________________________________

*** Ghostt, I'm not your mom and I'm not paying for your parts, so do whatever you want with your own bike. ***




|

[maverick31210]

@Ghostt

So if I read that right, it's saying that the Newgen shock is good for 140lbs?

That can't be right can it?

[alex.s]

pretty sure this site hasn't been around for 10 years.

[Ghostt]

Originally Posted by maverick31210

@Ghostt

So if I read that right, it's saying that the Newgen shock is good for 140lbs?

That can't be right can it?

NewGen rear shock is adequate for about 200lbs, the fork springs are lighter, and be trimmed down, and new spacers cut, to adjust there rate.

IIRC the NewGen is about .65 kg/mm vs PreGen .44kg/mm

Use this link to figure out how much it should be,
http://www.sonicsprings.com/catalog/...pring_rate.php

Then is a simple matter of math, cutting the springs down, making new spacers, set the sag, and your set, new spring rate = (original spring length / modified spring length) * original spring rate

In my case I had a spare set of EX springs, which is .585kg/mm. I needed them to about .80kg/mm, the length was 21.5" so I cut off 6"

21.5 / 15.5 x .585 = .81kg/mm is the new rate, after that it's a simple matter of cutting a new spacer and setting the sag, my spaces are 6.5" which also set my sag where it needs to be. I used 15wt synthetic fork oil.

Setting sag is important!!! Both front and rear.

http://www.ex-500.com/wiki/index.php...ension_Mod_.29

If your in the mood, you can install a set of Ricor INTIMINATORs to complete the forks.

http://store.ricorshocks.com/kawasaki_s/49.htm

Some members here have used them, and have reported great results.

[InvisiBill]

The info that Ghostt posted above is for the NewGen. Since you have the NewGen shock, it sort of applies, but I'm not sure exactly how different their suspension geometries are. Depending on how close the PreGen is to the NewGen and 500 (as well as your weight), that might be a bit stiff.

PreGen Fork Spring Rate Chart
The stock fork springs on the PreGen (and 500) are useless for adults. With such a soft spring, it will compress way too easily. Changing the fork oil increases the resistance, which fights that extra movement. Getting the right spring rate will result in the suspension moving the proper amount to begin with, then the damping system only has to control that appropriate movement.

It sounds weird, but if the springs are way too soft for you, getting stiffer springs (to match your weight) will actually give you a smoother ride. They'll be able to properly support your weight and give the springs room to absorb bumps.