Clutch problems

[ThumpMe]

All 'real' dirtbike clutches due this.

You are over thinking this.

The WR clutches all drag a little bit.

You can put in new plates, and shim the springs, and it will work great....unless you actually use the clutch for modulationg power....then eventually, even without damaging the discs, it wil drag again.

It's just not the most sophisticated clutch actuation design.

 

 

 I disagree. I have been riding dirt bikes since Hector was Pup and this '03 was just plain awful. As I mentioned my '99 works like a charm, This one was so bad when I first started in on it, it was causing me to crash and more than once made me soil my Fruit of the Looms when it would not quit pulling when I pulled in the clutch. Luckily her brakes are stronger than the continued pull when clutch was in...but not by much!

 

 If I was not riding so much tight stuff I probably would not have such issues with it but I quit most of the desert riding and now spend a LOT more time up in the hills in the woods.

 

 I have owned probably 50 bikes over the years. Everything from dirt to street and even a few D Sports. I was about convinced it was bikes like this one that cause people to quit them forever! But as I mentioned I am not much of a quitter.

 

 I am hard on dirt bike clutches but have NEVER burned a clutch out or had to replace one on a bike....yet anyway! THAT may change with this '03! HA!

 

I have put over 70K on a several street scooters and their clutches were still going strong when I sold them. I have a a'92 Seca with 72 K on the clock right now and its STOCK clutch is still GREAT.

 

My '99 WR 400 has just about 17K on it and I have just plain horse whipped that poor bike. The first 15K on it were ALL tight, fairly knarly to REAL knarly single track and if ANY clutch was going to fail it should have been that one but it is still working fine as well.

 

 The '03's were a first production year and I know some of them had some real issues. Unfortunately I have one, but it is IS getting better!

[aust014]

Hey guys well today I went over to a local motorcycle mechanic, I had the guy check my cable adjustment to see if I did it right.. Well I told them my symptoms and right away he said what you guys said; warped plates. But that was just his opinion on it with no inspection.

So I think ill order a plate kit, ill check out the one Steve got anyone else know of any other good plate kits that don't cost a lot? Also at the moment I have some Honda synthetic 10w-40 motorcycle oil in the bike..   But should I change oil to what you guys recommend, or just keep using the same oil? Should I soak the plates in that oil (the oil I use in the bike)?

[ThumpMe]

 If not familiar with all the clutch issues these blue bikes can and seem to  have that is a pretty normal response.

 

Before you go and buy a set of plates though pull it apart and check yours out. It is a real simple, straightforward and easy check and will tell you for sure if you really need them. No sense dumoing a bunch of $$ into it if not really needed.

 

 All you really need is a real nice flat surface and a set of feeler gages to see if they are indeed warped.Lots of folks use a ppiece of glass, but a nice mill table or even a good drill press table is flat enough to work.

 

 Definateley soak new plates in oil before installation.

 

 That oil should be fine...especially now that the hottest part of Summer is behind us.

 

 That oil question does bring up another issue with these clutches. They originally state in the manual for my bike to use 20W-40 in it. BUT Yamaha quit making that oil and so they told me to use 20W-50 which they still do make.Probably just did not want to loose the sale? I am going to go back to 10W-40 for the winter and just to try it and see if that loosens the clutch drag up any more. 

[Deputy Steel]

 If not familiar with all the clutch issues these blue bikes can and seem to  have that is a pretty normal response.

 

Before you go and buy a set of plates though pull it apart and check yours out. It is a real simple, straightforward and easy check and will tell you for sure if you really need them. No sense dumoing a bunch of $$ into it if not really needed.

 

 All you really need is a real nice flat surface and a set of feeler gages to see if they are indeed warped.Lots of folks use a ppiece of glass, but a nice mill table or even a good drill press table is flat enough to work.

 

 Definateley soak new plates in oil before installation.

 

 That oil should be fine...especially now that the hottest part of Summer is behind us.

 

 That oil question does bring up another issue with these clutches. They originally state in the manual for my bike to use 20W-40 in it. BUT Yamaha quit making that oil and so they told me to use 20W-50 which they still do make.Probably just did not want to loose the sale? I am going to go back to 10W-40 for the winter and just to try it and see if that loosens the clutch drag up any more. 

Ok will try to get around to inspecting the plates, thanks for the help!

[Deputy Steel]

Ok will try to get around to inspecting the plates, thanks for the help!

Sorry was accidentally signed into my brothers account... 

[ThumpMe]

I got out yesterday and put about 40 miles on it. It is noticeably easier to find neutral and the drag is down to where it would be acceptable although it does still pull slightly when dropped in gear. I want it better though as the REAL issue I have with it is how hard it is to start or re-start while in gear. This drag on it through the clutch slows down the turn over of the motor enough to where it just cannot quite light off easily after a stall or when trying to start it while in gear. Having to stop and go back to neutral to start it every time to me is just NOT acceptable.

 

 IF I do put it into neutral it fires right up immediately. Of course I did spend more than a few work sessions getting the carb dialed in so it should light right up. If in gear though it takes 3-5 trys to get her to start up almost every time.

 

 I re-thought that washer trick and realize it will not get me the results I would REALLY like, and that is a little more throw at the lever which would get me more  slack in the clutch once pulled in. This added slack in the clutch when dis-engaged would allow the oil to slip though the clutch plates quicker/easier allowing less drag. Well at least THAT is what I am thinking now but not sure yet how to accomplish this. 

 

 It could be accomplished by a longer lever arm at the point where the clutch lever/cable connects (PIA having to build a lever!) or possibly by making a different perch for the lever that would allow it to pull in a little more before the lever comes in contact with the bar/grip. That also could be areal PIA.

 

I think I will first try a lighter weight oil and see what that does.

 

 Will update, again, once I decide where I am headed with this..

[FORMA MOTO]

You can change the lever to a longer throw type (Honda has the longest), but then the pull is harder....so you install WR250 springs to comensate.....

 

ARC makes optional perch/lever combos with different lever ratios.....I run the Honda leverage ratio with (3) WR250 springs, and no washers.

 

http://arclevers.com/index.php?route=product/product&path=20&product_id=69

 

 

A Li Ion battery will turn it faster, allowing it to start in gear.....but you should be warned...if the clutch drags, and you start it in gear a lot, you will put a lot of load on the starter clutch, and wear it out prematurely.

 

What happens if you take almost all the slack out of the cable, at the perch.....does it still drag badly when hot?

[aust014]

My bike won't even try to start in gear, has to be in neutral. I think that's a Yamaha thing though..

[ThumpMe]

You can change the lever to a longer throw type (Honda has the longest), but then the pull is harder....so you install WR250 springs to comensate.....

 

ARC makes optional perch/lever combos with different lever ratios.....I run the Honda leverage ratio with (3) WR250 springs, and no washers.

 

http://arclevers.com/index.php?route=product/product&path=20&product_id=69

 

 

A Li Ion battery will turn it faster, allowing it to start in gear.....but you should be warned...if the clutch drags, and you start it in gear a lot, you will put a lot of load on the starter clutch, and wear it out prematurely.

 

What happens if you take almost all the slack out of the cable, at the perch.....does it still drag badly when hot?

 

 THAT is EXACTLY what I have been looking for! Thanks for the link Kah Ran Nee! I am thinking this might be the ONLY way to cure it but sure did not want to build a new one ( I could do it!) but THAT would probably take me at least a month! I have actually been trying to figure out a way to off set the lever further out on the bar some so I could get more pull/length of travel in the lever just to see if that actually would help.

 

 When I first got this bike (probably in '04) it made this gawd awful grinding sound and would actually stall the motor when starting it sometimes. One time on a BIG long clearing ride (we cleared about a five mile section of woods that had not been cleared in 4-5 years so LOTS of downed trees and re-starts all day long) it drained the battery down to where it was a kick start only. Turned out it had eaten the starter clutch and that was the grinding noise. I took the starter clutch all  apart and there is a spring inside it much like the one you see inside an oil seal, but  a lot longer. That was stretched, had been pinched,  and squashed in areas and the weird shaped sort of  three sided rollers that make the starter clutch function in one direction only had about half of them all chipped, broken, and some were ground up pretty well. Luckily all the bigger "chunks" were trapped inside the starter clutch due to its design. 

 

 I had to replace the starter clutch and then modified the starter gear and case to a 2004 model year to prevent this happening again. Was a pricey upgrade but worth it if it would cure the problems.

 

 I never did ride the 450 all that much though due to this ongoing starting issue from the dragging clutch and would usually leave it in the garage and take my 400 although by the end of the day I was beat from all the kick starting, even though the 400 is a one kick start most times. Well, till near the end of the day when I was most beat! This explains the real low mileage on the 450 as well. It only had 300 miles on it when I picked it up from PO. 

 

 Just last Fall I finally retired the 400 to DS rides ONLY (or occasionally running around town as they are both street legal) and the 450 has been outfitted with a chainsaw rack and pressed intro FULL TIME dirt service. (We have so many trees coming down due to all the past forest fires you do not go anywhere without at least one rider carrying a saw!)  So this Spring is when I really started to attack this issue and try to get to the bottom of the hard starting due to the drag. I think a lot of these other people who complain about hard starting issues are also brought on by the clutch drag but quite a few of them are looking in other areas for a fix....like carb/jetting, or hot start issues, when in fact they are brought on by a little clutch drag slowing the motor turn over speed down just a little to far for a quick start.

 

 I have the cable adjusted to where there is almost no play right now and have even tightened it up past that point trying it out and the drag is STILL/ALWAYS there. 

 

 I am going to take out all the parts in the whole push rod assembly and measure/compare them to the ones that came with the other clutch parts that came with the clutch I picked up off ebay and see if there might be some wear or difference that could account for the problem, but at this point sort of doubt I will find the solution there. 

 

 I may drill even MORE holes in one of those clutch bosses as this did make a huge improvement in being able to find neutral as well as cut the starting drag down noticeably, but not enough to where it will start easily while in gear, so maybe that is the route to take? 

 

 At any rate this adjustable perch is exactly what I think this scooter needs to make it (and me!) much happier so THANKS again! 

 

 I will update as to what I find.........

[ThumpMe]

 

 Well I think I FINALLY cured it!
 
 First I took it apart again and went through everything carefully and did quite a bit of measuring and checking of parts, here is what I found.
 
 First of all I do not see where the washer trick can do anything to help with drag. It will allow your springs to not coil bind if you have some improperly machined parts, but only if the improperly machined parts are either the clutch boss or pressure plate. Reason why is the compressed length of both the YZ and WR springs once tightened down in the clutch assembly is 1.130. The WR springs coil bind at a compressed length of .850 and the YZ at a length of one inch. You just cannot compress the springs of either while in the clutch assembly enough to bind. Unless you have a bad part.
 
 I measured the throw of my clutch pressure plate and it is  .083 so neither WR nor YZ spring can be compressed enough to coil bind. The YZ springs come closest but still have almost .050 travel/compression left in them when you run out of travel in the clutch pack from the lever.
 
 I was thinking I could go to that high dollar new clutch perch/lever and possibly get a little more travel but the clutch actuation rod is almost coming into contact with the starter motor now when the clutch is pulled in, so more travel would just cause the actuation rod to hit the starter motor and would not give me any more travel. Scratch that idea.
 
 All the parts that are in the clutch actuation and the new ones I received with the new ebay clutch are identical in every measurement so no worn parts found in my motor.
 
 I looked back through my notes at all I have done and the three times I made an actual  noticeable difference was when I enlarged the six holes that allow the oil out of the clutch boss and onto the plates on the original boss. Then when I added six more stock sized holes (.113)  in the oil grooves next to the six that were in the second boss I picked up off e-bay.  And the biggest difference came when I added the three holes under the outermost 3-4  clutch plates in line with three of the six stock holes/oil grooves. This last modification was real noticeable I think because the stock clutch did not even have any boss outlet holes anywhere near the first three plates in the clutch pack so I do not think much oil was ever getting out to them. 
 
 The stock clutch bosses on these 450's only have six holes and they are not really positioned to get a good even flow of oil to all the plates. This makes me  pretty sure the cause of the problem is in good even oil delivery to ALL the plates.
 
 So what I did was take the boss I had out of the bike already, which had been modified so the six stock holes were enlarged .015. I added THREE holes in line with three of the six stock holes located in the oil grooves on the inside of boss but out near the outside edge of the boss, out where not much oil is ever getting to the outer plates. I only made them .101 in diameter.  I then added TWELVE more holes (all .101 in diameter) in between the existing stock holes.
 
 Since I had enlarged those six stock holes I went a little smaller on all these other holes as I was not sure exactly how much oil I had in the boss to redistribute. It flows in constantly though so should be a pretty decent flow.
 
 The location of the twelve newest holes is like this:
 
 There are 30 ribs running around the outside of the clutch boss that engage with clutch plates. The stock holes come though every fifth rib. I added one hole to each of the two ribs centered between each of the ribs with stock holes. So if you look at the end and number the ribs, the stock holes are located in ribs number 1,6,11,16,21, and 26. I drilled new holes in 3,4,  8,9, 13,14, 18,19,  23,24,  28,and 29. These holes are all .101 in diameter.
 
 I just sort of randomly spaced each hole in or out on the clutch boss to try and get a pretty even flow of oil to all the plates.
 
 Put it back together and although I only started it up so far in the garage...WHAT A DIFFERENCE!  
 
 I can put it in gear while running  and EASILY  back up with ONE FOOT! Neutral just falls right into place. It re-starts with NO forward pull and I just barley hit the button while in gear with clutch in and it is running!
 
 I also noticed that it is still real hard to push when the motor is off and in gear with clutch pulled in but this is just cause the oil in the clutch is not getting spun out but I never push it anywhere other than out to the truck to load it so this does not matter to me at all.

 

 I have seen posts on where this same sort of modification was done on the 250's and folks said it cured their issues....just wish I would have started there instead of all the other things I tried, but either way I got there! 

 

 I am stoked and one Happy Camper!
 

 

[aust014]

 

 Well I think I FINALLY cured it!

 

 First I took it apart again and went through everything carefully and did quite a bit of measuring and checking of parts, here is what I found.

 

 First of all I do not see where the washer trick can do anything to help with drag. It will allow your springs to not coil bind if you have some improperly machined parts, but only if the improperly machined parts are either the clutch boss or pressure plate. Reason why is the compressed length of both the YZ and WR springs once tightened down in the clutch assembly is 1.130. The WR springs coil bind at a compressed length of .850 and the YZ at a length of one inch. You just cannot compress the springs of either while in the clutch assembly enough to bind. Unless you have a bad part.

 

 I measured the throw of my clutch pressure plate and it is  .083 so neither WR nor YZ spring can be compressed enough to coil bind. The YZ springs come closest but still have almost .050 travel/compression left in them when you run out of travel in the clutch pack from the lever.

 

 I was thinking I could go to that high dollar new clutch perch/lever and possibly get a little more travel but the clutch actuation rod is almost coming into contact with the starter motor now when the clutch is pulled in, so more travel would just cause the actuation rod to hit the starter motor and would not give me any more travel. Scratch that idea.

 

 All the parts that are in the clutch actuation and the new ones I received with the new ebay clutch are identical in every measurement so no worn parts found in my motor.

 

 I looked back through my notes at all I have done and the three times I made an actual  noticeable difference was when I enlarged the six holes that allow the oil out of the clutch boss and onto the plates on the original boss. Then when I added six more stock sized holes (.113)  in the oil grooves next to the six that were in the second boss I picked up off e-bay.  And the biggest difference came when I added the three holes under the outermost 3-4  clutch plates in line with three of the six stock holes/oil grooves. This last modification was real noticeable I think because the stock clutch did not even have any boss outlet holes anywhere near the first three plates in the clutch pack so I do not think much oil was ever getting out to them. 

 

 The stock clutch bosses on these 450's only have six holes and they are not really positioned to get a good even flow of oil to all the plates. This makes me  pretty sure the cause of the problem is in good even oil delivery to ALL the plates.

 

 So what I did was take the boss I had out of the bike already, which had been modified so the six stock holes were enlarged .015. I added THREE holes in line with three of the six stock holes located in the oil grooves on the inside of boss but out near the outside edge of the boss, out where not much oil is ever getting to the outer plates. I only made them .101 in diameter.  I then added TWELVE more holes (all .101 in diameter) in between the existing stock holes.

 

 Since I had enlarged those six stock holes I went a little smaller on all these other holes as I was not sure exactly how much oil I had in the boss to redistribute. It flows in constantly though so should be a pretty decent flow.

 

 The location of the twelve newest holes is like this:

 

 There are 30 ribs running around the outside of the clutch boss that engage with clutch plates. The stock holes come though every fifth rib. I added one hole to each of the two ribs centered between each of the ribs with stock holes. So if you look at the end and number the ribs, the stock holes are located in ribs number 1,6,11,16,21, and 26. I drilled new holes in 3,4,  8,9, 13,14, 18,19,  23,24,  28,and 29. These holes are all .101 in diameter.

 

 I just sort of randomly spaced each hole in or out on the clutch boss to try and get a pretty even flow of oil to all the plates.

 

 Put it back together and although I only started it up so far in the garage...WHAT A DIFFERENCE!  

 

 I can put it in gear while running  and EASILY  back up with ONE FOOT! Neutral just falls right into place. It re-starts with NO forward pull and I just barley hit the button while in gear with clutch in and it is running!

 

 I also noticed that it is still real hard to push when the motor is off and in gear with clutch pulled in but this is just cause the oil in the clutch is not getting spun out but I never push it anywhere other than out to the truck to load it so this does not matter to me at all.

 

 I have seen posts on where this same sort of modification was done on the 250's and folks said it cured their issues....just wish I would have started there instead of all the other things I tried, but either way I got there! 

 

 I am stoked and one Happy Camper!

 

 

Well good job getting that fixed! I'm planning on Friday or maybe Saturday to take the plates out and inspect them. So could I just enlarge the six holes with a grinder? If so do I need to be exact in measurements like 0.015? Or could I just kinda guess..  

[SteveThe Snakes]

Well good job getting that fixed! I'm planning on Friday or maybe Saturday to take the plates out and inspect them. So could I just enlarge the six holes with a grinder? If so do I need to be exact in measurements like 0.015? Or could I just kinda guess..

I wouldn't.

[ThumpMe]

 No they need to be drilled. I did mine on a mill but a drill press with a vise mounted to it would work just as well. They are not real critical in location but do need to be centered in the ribs that run around the outside of the clutch boss in order to keep the ribs strong, and NOT break out on the side of one of the ribs.

 

 If you were REAL GOOD with a drill motor and off hand drilling, you could probably add the new ones without damaging anything,  but it is not worth the risk as one of those clutch boss' cost right at a hundred dollars. Even a little bench top drill press with a small vise would be good enough to do the work as clamping the boss in it up on it's side really makes it simple and easy to do.

 

 The six existing holes could be enlarged by just using a larger drill bit and a hand drill as a drill bit will always follow the existing hole.

 

 Caution needs to be taken as the drill breaks through though, as if allowed to pull much past the break through point there are some features inside the boss that could get dinged or cause you to break the drill bit.

 

 Enlarging those six existing holes as I stated helped some, but the real  improvements came when I added the three more holes out near the outside area in the clutch boss where no oil holes were installed from the factory, and the best  gains came by adding the twelve smaller holes in the areas between the existing holes.

 

 The existing holes in my boss were .113 in diameter which is a number 33 drill bit, I opened those up using a #30 drill (.128).

 

 All the other holes I added (15 all together) were with a  #38 (.101) drill bit. It probably took about an hour to add them by setting the boss up on edge using a vise.

 

 Numbered drill bits are pretty common and can be bought from most any tool or hardware store, or even Sears and probably even Lowes as well as Home Depot's.

[aust014]

 No they need to be drilled. I did mine on a mill but a drill press with a vise mounted to it would work just as well. They are not real critical in location but do need to be centered in the ribs that run around the outside of the clutch boss in order to keep the ribs strong, and NOT break out on the side of one of the ribs.

 

 If you were REAL GOOD with a drill motor and off hand drilling, you could probably add the new ones without damaging anything,  but it is not worth the risk as one of those clutch boss' cost right at a hundred dollars. Even a little bench top drill press with a small vise would be good enough to do the work as clamping the boss in it up on it's side really makes it simple and easy to do.

 

 The six existing holes could be enlarged by just using a larger drill bit and a hand drill as a drill bit will always follow the existing hole.

 

 Caution needs to be taken as the drill breaks through though, as if allowed to pull much past the break through point there are some features inside the boss that could get dinged or cause you to break the drill bit.

 

 Enlarging those six existing holes as I stated helped some, but the real  improvements came when I added the three more holes out near the outside area in the clutch boss where no oil holes were installed from the factory, and the best  gains came by adding the twelve smaller holes in the areas between the existing holes.

 

 The existing holes in my boss were .113 in diameter which is a number 33 drill bit, I opened those up using a #30 drill (.128).

 

 All the other holes I added (15 all together) were with a  #38 (.101) drill bit. It probably took about an hour to add them by setting the boss up on edge using a vise.

 

 Numbered drill bits are pretty common and can be bought from most any tool or hardware store, or even Sears and probably even Lowes as well as Home Depot's.

Ok so I won't be doing that unless I have access to a mill or proper measuring equipment 

[ehoward381]

I just did this with a pistol drill I put extra holes in the ribs that were in the middle of the ones that had holes so they were spaced evenly this made the most effect along with the small washers under the spring bolts giving the clutch more throw also slackened cable of and put a ball bearing between thrust bearing and rod ended up with my yz 400 clutch being as light pull as a 125 and no more dragging also extended the arm by around 5 mm

[FORMA MOTO]

So you are saying the plates are sticking together because there is not enough oil flow, even though everytime you pull in the clutch, all the plates are bathed in oil?

 

...and you've proven this by starting it in gear in your garage?

 

If that were the case, holding the clutch in for a while, getting plenty of oil on everything, then putting it in gear, it should not drag......but it does.

The metals do not hold anything but a microsopic film of oil. Adding more won't stick.

 

The washers have nothing to do with coil binding.

It's about allowing the plates to be engaged with with less force, so they don't grip each other as tightly, and can move more freely, sooner, when you pull the clutch in.

Edited August 28, 2014 by Kah Ran Nee

[SteveThe Snakes]

Also be very cautious about asking oil to move where it's not suppose to be. As in starving another part of the motor.

Somehow I don't think drilling the holes has anything to do with clutch drag.

Put in new plates and be done.

[Dexter42]

Drilling holes on a basket is not gonna starve nothing of oil. Look at most aftermarket baskets, they all come with slots on the fins. I don't get the washer thing on springs, Spend the $10-$15 on new HD springs if they're out of spec. Most drag problems are in the plates and fibers them-self or the outer basket and inner basket grooved up. The clutch only moves about 1/8"=.125" if that. Has a very small throw, with this said 1 warped plate or even the smallest steps/groves on the baskets will not let the plates disengage/ move freely back and forth. Make sure all the surfaces that the plates ride on are smooth. Use a fine file to rough them smooth them finish off with some 220 grit paper. Baskets will be good as new.

Edited August 29, 2014 by Dexter42

[FORMA MOTO]

Yamaha clutches disengage about .110, and that is the problem

So every little bit helps.

 

I think the best thing would be to change the actuator cam profile on the throwout rod. That would change everything. 

 

You first....

[aust014]

Yamaha clutches disengage about .110, and that is the problem

So every little bit helps.

 

I think the best thing would be to change the actuator cam profile on the throwout rod. That would change everything. 

 

You first....

Sorry this is off topic, do you have the white backgrounds flu team graphics? If so do you have any more pictures of the bike with them?