Clutch notes
#1
04-28-2014, 06:01 PM
Clutch notes
I recently burned out the clutch on my 2007 KLX351. I did a little digging around trying to figure out what to do next, here's the current fruit of my labor.
Here's some basics that always help: People tend to minimize these points, but they may be the most valuable parts here. An hour spent cleaning your work area before you begin will pay huge dividends. Work slowly and deliberately, take pictures and/or make notes. Ask a more experienced friend to help. Placing a clean sheet of paper or a cardboard box cut to lie flat under the bike and another on the bench will really pay off. Things clean up better and quicker and small parts are easier to find on the smooth surface. Cardboard or paper tend to dampen falls better than a hard floor so dropped parts stay put better and not roll under a distant cabinet. A clean pizza box with the ends turned up is great. Take a good look at a parts schematic before you open the bike so you have an idea of what to expect. Learn the names of the parts as you remove them.
Get extra lighting. Get a beverage and or water. Don't start if you don't have enough time to come to a comfortable stopping place. If you can replace bolts in the same hole they came out of to keep them organized. If you cannot put bolts back in the same hole keep them separate and labeled. When you come to a stop before you finish cover any open internals in the bike, preferably with the actual motorcycle part e.g. replace the clutch cover just to keep anything from falling in or out. Place internal parts in zip lock baggies if they cannot be put back in the bike. Keep sub assemblies as whole as possible while work is stopped. e.g. reassemble the clutch as it was removed while you wait for new parts to arrive. Get everything you need, loc-tite tools instructions torque spec etc. in place before you begin.
Removing the old Clutch
You do not need to remove the whole right side engine cover, just the clutch cover. Not removing the whole cover will save time, an extra gasket and the potential dropping of any little parts that might be behind that cover.
After this, have someone hold the brake down with the engine in a high gear while you remove the 22mm central bolt that holds the clutch in place. I suppose you could also buy the correct clutch basket holder too, but what's the fun in that?
That bolt is waaaay torqued down. You will need an air or electric impact gun or a long breaker bar. Do not attempt with something that can loosen that central bolt quickly. Working at it without a breaker bar or impact driver will only cause frustration or round off the bolt. It's regular thread, though you can be forgiven for thinking that it's reverse thread as it's so hard to get apart.
Unlike the DIY Videos on You Tube from Rocky Mountain ATV and Tranworld Motorcross that show smiling mechanics simply removing the spring bolts and happily removing the clutch ours doesn't work that way, you need to get that central bolt out and remove the whole basket.
***carry the basket to a clean, well lit location and look at it as you disassemble it.*** Note the position of the outer friction plate and observe the position of the judder spring and spring seat within the innermost and final fiction plate.
Clutch replacement options:
Stock KLX250s plates. Good: this is the stock clutch and Kawasaki intended. Perfectly good for a 250. Bad: It's expensive friction plates alone are over $11 each and you need seven and may also require the steels. It may be a little down of grip when paired with a 351 that's ridden hard and so could go fairly quickly.
Stock KX125 frictions. Good: This is a Kawasaki clutch and fits properly. It has a lot more friction area and should last longer, grip better and possibly allow better control with the right springs. You use the stock KLX250s steels. It's a little bit cheaper than the stock KLX250s parts. Bad: this is a workaround found by someone on the forum, so you really don't have a lot of support or backup.
EBC Dirtrider DRC212 clutch kit: Good: this clutch is a knock of the Kawasaki replacement parts. EBC is a real company with service techs and support. It should work fine, similar to a stock clutch. It's the cheapest clutch here and comes with springs too. Since it's basically a stock clutch you can use the judder spring as Kawasaki intended. The Bad: it should have around the same grip power as a stock clutch. So, no improvement. You will read forum posts advising people not to use the EBC springs. I called EBC and they acknowledge that a bad batch of springs was released with these clutches some years ago, so not knowing when your was produced you can't really know if the springs will be OK over the long run.
Barnett Clutch: The Good: I have no idea about these clutches, but Barnett has a good reputation. Barnett springs seem to be the spring of choice for creating enough clutch pressure to use the stock plates or the EBC plates for a long lasting not slipping clutch. The Bad: These kits are expensive. At around $125 they're more that twice the price of an EBC clutch.
I am going with an EBC clutch and Barnett springs purchased separately.
The Judder Spring
The judder plate and spring are basically two large washers, one slightly coned that sit inside the first friction plate. The wide or flared side faces the clutch pack. The narrow side faces away from the clutch plates.
It's purpose is to make the clutch less snatchy at small openings. It's easy to drop this assembly as you take the clutch pack apart so be careful.
Many racing clutches delete the judder spring as racers want a lot of friction area and the placement of the judder spring somewhat limits the amount of friction area on the first friction plate, since the judder spring sits inside the first friction plate.
You CAN use the judder spring inside the first friction plate on the stick KLX and the EBC clutch.
If you use the KX125 friction plates you will need to use a KXL250 friction as the first plate to continue to use the judder spring. Should you choose to use all KX plates you will need to delete the judder spring. Since Barnett says their KLX250s clutch is compatible with the KX125 I would also have to use replace the inner friction plate with a stock KLX plate if you want to use the judder spring, further driving up the price of the clutch.
You bike will still run fine without the judder spring either way, but it may be more snatchy.
I guess the rest of what I have to say is the usual stuff, place the friction plates in a zip lock baggie of oil overnight before assembly. If you use hondabond or grease on the clutch cover plate gasket you can probably reuse it again.
I am very open to corrections or additional information here. I've not done a clutch except in a Moto Guzzi with a friend so I am new to this. These were questions I didn't readily see answers for and researched. So, i thought, why make someone else do that again. I've received a lot of help here, hope this pays back some.
Here's some basics that always help: People tend to minimize these points, but they may be the most valuable parts here. An hour spent cleaning your work area before you begin will pay huge dividends. Work slowly and deliberately, take pictures and/or make notes. Ask a more experienced friend to help. Placing a clean sheet of paper or a cardboard box cut to lie flat under the bike and another on the bench will really pay off. Things clean up better and quicker and small parts are easier to find on the smooth surface. Cardboard or paper tend to dampen falls better than a hard floor so dropped parts stay put better and not roll under a distant cabinet. A clean pizza box with the ends turned up is great. Take a good look at a parts schematic before you open the bike so you have an idea of what to expect. Learn the names of the parts as you remove them.
Get extra lighting. Get a beverage and or water. Don't start if you don't have enough time to come to a comfortable stopping place. If you can replace bolts in the same hole they came out of to keep them organized. If you cannot put bolts back in the same hole keep them separate and labeled. When you come to a stop before you finish cover any open internals in the bike, preferably with the actual motorcycle part e.g. replace the clutch cover just to keep anything from falling in or out. Place internal parts in zip lock baggies if they cannot be put back in the bike. Keep sub assemblies as whole as possible while work is stopped. e.g. reassemble the clutch as it was removed while you wait for new parts to arrive. Get everything you need, loc-tite tools instructions torque spec etc. in place before you begin.
Removing the old Clutch
You do not need to remove the whole right side engine cover, just the clutch cover. Not removing the whole cover will save time, an extra gasket and the potential dropping of any little parts that might be behind that cover.
After this, have someone hold the brake down with the engine in a high gear while you remove the 22mm central bolt that holds the clutch in place. I suppose you could also buy the correct clutch basket holder too, but what's the fun in that?
That bolt is waaaay torqued down. You will need an air or electric impact gun or a long breaker bar. Do not attempt with something that can loosen that central bolt quickly. Working at it without a breaker bar or impact driver will only cause frustration or round off the bolt. It's regular thread, though you can be forgiven for thinking that it's reverse thread as it's so hard to get apart.
Unlike the DIY Videos on You Tube from Rocky Mountain ATV and Tranworld Motorcross that show smiling mechanics simply removing the spring bolts and happily removing the clutch ours doesn't work that way, you need to get that central bolt out and remove the whole basket.
***carry the basket to a clean, well lit location and look at it as you disassemble it.*** Note the position of the outer friction plate and observe the position of the judder spring and spring seat within the innermost and final fiction plate.
Clutch replacement options:
Stock KLX250s plates. Good: this is the stock clutch and Kawasaki intended. Perfectly good for a 250. Bad: It's expensive friction plates alone are over $11 each and you need seven and may also require the steels. It may be a little down of grip when paired with a 351 that's ridden hard and so could go fairly quickly.
Stock KX125 frictions. Good: This is a Kawasaki clutch and fits properly. It has a lot more friction area and should last longer, grip better and possibly allow better control with the right springs. You use the stock KLX250s steels. It's a little bit cheaper than the stock KLX250s parts. Bad: this is a workaround found by someone on the forum, so you really don't have a lot of support or backup.
EBC Dirtrider DRC212 clutch kit: Good: this clutch is a knock of the Kawasaki replacement parts. EBC is a real company with service techs and support. It should work fine, similar to a stock clutch. It's the cheapest clutch here and comes with springs too. Since it's basically a stock clutch you can use the judder spring as Kawasaki intended. The Bad: it should have around the same grip power as a stock clutch. So, no improvement. You will read forum posts advising people not to use the EBC springs. I called EBC and they acknowledge that a bad batch of springs was released with these clutches some years ago, so not knowing when your was produced you can't really know if the springs will be OK over the long run.
Barnett Clutch: The Good: I have no idea about these clutches, but Barnett has a good reputation. Barnett springs seem to be the spring of choice for creating enough clutch pressure to use the stock plates or the EBC plates for a long lasting not slipping clutch. The Bad: These kits are expensive. At around $125 they're more that twice the price of an EBC clutch.
I am going with an EBC clutch and Barnett springs purchased separately.
The Judder Spring
The judder plate and spring are basically two large washers, one slightly coned that sit inside the first friction plate. The wide or flared side faces the clutch pack. The narrow side faces away from the clutch plates.
It's purpose is to make the clutch less snatchy at small openings. It's easy to drop this assembly as you take the clutch pack apart so be careful.
Many racing clutches delete the judder spring as racers want a lot of friction area and the placement of the judder spring somewhat limits the amount of friction area on the first friction plate, since the judder spring sits inside the first friction plate.
You CAN use the judder spring inside the first friction plate on the stick KLX and the EBC clutch.
If you use the KX125 friction plates you will need to use a KXL250 friction as the first plate to continue to use the judder spring. Should you choose to use all KX plates you will need to delete the judder spring. Since Barnett says their KLX250s clutch is compatible with the KX125 I would also have to use replace the inner friction plate with a stock KLX plate if you want to use the judder spring, further driving up the price of the clutch.
You bike will still run fine without the judder spring either way, but it may be more snatchy.
I guess the rest of what I have to say is the usual stuff, place the friction plates in a zip lock baggie of oil overnight before assembly. If you use hondabond or grease on the clutch cover plate gasket you can probably reuse it again.
I am very open to corrections or additional information here. I've not done a clutch except in a Moto Guzzi with a friend so I am new to this. These were questions I didn't readily see answers for and researched. So, i thought, why make someone else do that again. I've received a lot of help here, hope this pays back some.
Last edited by taxonomy; 04-30-2014 at 05:20 PM.
#2
04-29-2014, 01:16 PM
Nice job, tax; well done.
My PERSONAL preference is to always cut my own gaskets and use a very light bead of Permatex on both sides.... (I'm sure many of you may object; that's OK.)
My PERSONAL preference is to always cut my own gaskets and use a very light bead of Permatex on both sides.... (I'm sure many of you may object; that's OK.)
#6
04-30-2014, 03:00 PM
Agree^, and I use a fiber-based, thicker material than the cheap-o "onion skin" paper ones from Kawi. Yeah, it's overkill....just a personal quirk of mine. (I definitely do the same for water pump gaskets.)
#7
04-30-2014, 03:15 PM
I've never tried making my own yet, but after having to wait five to 10 days to get one from Kawi, and just for emergencies and other reasons, I think it's about time for me to try this. I've seen some good tutorials, but it was a while ago.
#9
04-30-2014, 05:34 PM
Correct; I don't make my own head gaskets, or valve cover gaskets, etc. Only the "flat surface" type; like water pump, clutch or side cover, thermostat, etc. (excluding head gaskets.) Keep a few sheets of gasket material and a regular 'ol paper punch handy.
Last edited by jeffzx9; 04-30-2014 at 05:36 PM.