KTM Forums banner

Inner clutch hub spring post broken - fixing the fix

7K views 21 replies 3 participants last post by  ktmfreaky 
#1 · (Edited)
Hi Everyone,

Assembling the engine and finding parts that need to be addressed. The latest is the inner clutch hub spring post. Looks like it was broken off before and fixed with a countersunk flathead from from the other side, the common fix. Right now the screw is seems pretty tight to the post but there is play in between. Doesnt look like it was properly countersunk since the hole isnt uniform, so suspect the constant pull created additional some play?

My plan is to take it off and replace/tighten the screw, but it's pretty tight on there. No other screw on the adjacent post and didnt notice any crazy off-balance feeling so that's good. I read people saying to do the other side for balance. Some said not a huge deal since its not spinning as fast. I guess I could say it wasnt a huge deal since I didnt noticed anything crazy, but at the same time, I never felt it without the fix so who knows!

Beta runs 4 springs on their clutch. Has anyone taken out 2 springs on a KTM and ran with 4? I heard some people tried that to reduce the clutch pull. Figure maybe it would be a good time to try 4 springs.

Worried about getting the screw out without messing up the post. Hope they didnt use Red loc-tite!

I read maybe a TIG welder can fix this? Any feedback on welding?

This part is no longer made. I actually found a post on the forum via google search, and the person ran into the same situation for 2000-2001 KTM 250 EXC.
101083
101084



EDIT!
Well since I have a fully disassembled 2008 KTM 250xcw, I decided to compare the two parts. Glad I did! Stock 2000 KTM 250 EXC entire clutch system is interchangeable with the 2008 KTM 250 XC-W system. The gearing is 1 tooth different for the primary gear; 2000 uses 25T and 2008 uses a 26T. BOTH use 72T outer clutch hub. I continue to use my 25T because that's the my only spacing options.

This does not show up with the cross-reference tactic I use with https://www.ktmonlineparts.com.au/
You could say this is a tried and true interchangeable part between the years!



I
101086
 
See less See more
3
#2 · (Edited)
Yep. It becomes a little of a pain when you can not get OEM bits anymore. Check some of the ones who supply after market clutches. We have a Hinson clutch basket in our two bikes and we are very happy with them!! They also supply the inner clutch hub. But not sure if they have one for your bike?? This is not Hinson but DBT testing them (but perhaps go searching or contact Hinson directly?) Hinson Billetproof Clutch Hard Parts - Dirt Bike Test

EDIT: Here Hinson:Hinson Clutch Components | High Performance Racing Products
 
#3 ·
All good information for study. I have destroyed enough clutches in my racing career to have a few opinions here. The screw repair shown is a temporary fix and very risky. I wouldn't have it. You could cement that screw with loctite every day and find the screw loosened up within hours of service. Not a reliable repair and high risk of damage. Probably safer to run 4 of 6 springs and give them more pre load with a shim under the springs or simply calculate total spring compression of 6 and find 4 springs with more compression (thicker wire) and substitute for your stock springs. You can find industrial supplier to source any spring needed. Be sure to use correct spring material for high temperature service.
 
  • Like
Reactions: ktmfreaky
#4 ·
Yup, I contacted Hinson and they dont make parts for mine, or the 250 xc-w.

Yup yup, will not be running 6 springs in this. I have a new inner clutch hub coming since I am running the 2008 clutch!

I started entertaining the idea of a new 2021 300 XC-W TPI because finding an inner clutch hub used was going to be slow, but now I dont have to. Give TPI a few more years to get even better.
 
#5 · (Edited)
Well guys, crazy stuff.... bought the inner clutch hub. Same part# as the 2 above. But look at my bad one, where the thrust washer sits. The step up is taller than the 2008 one. The one i ordered matches the 2008 one, even though both are the same part #

Rockymountainatvmc.com sent me a cracked and damaged hub and wanted me to fill out a form and wait till Monday for the warranty department... gave them a little mouthful as to their recent quality control issues ive had and making me do a warranty on a "new" part... I asked for a manager. He came back and said we will ship you a new one and send you a label..

Anyway, I had to get a thicker thrust washer machined. Gave the machinist the 2 hubs and original washer and said make a washer for this one to the same height as this old one. Done. Installed and inner clutch hub rotates inside the basket without clearance issues. Someone on amazon bought the same part and ran into the same issue, sooooo....

Rode the bike and now the clutch is NOTICEABLE loud. After some research, people said this is normal? I never had this noise with the old hub. Could it be the thicker washer causing this? Thi5king of getting the basket too. The basket is also different.
101405


Thought it was knocking with brand new OEM crank assembly, vertex piston. I did verify the squish. Got a .038mm gauge under it. Ring gaps in spec too. Bike runs GREAT, but then noise ITmakes it concerning since I never had it.

 
#6 ·
If you get a rattle and compressing clutch lever silences it your basket is rattling. Common issue. If you really have a bad one you can get aftermarket basket. Be sure to purchase basket with new cushions. The cheapie ones dont include cushions.
 
  • Like
Reactions: ktmfreaky
#7 ·
Ahh good to know. Was thinking of getting new basket to go with the new hub.

No issue. The basket didnt look "notchie" but couldnt tell what the cushions looked like. Yo guys ever punch out the rivets, replqce cushions and rivet back up?
 
#8 ·
Yes. Very simple operation. Some of the KTMs have hollow end rivets which allows drill to pick up center easily. Others require careful measuring to center punch rivet before drilling. You would drill only to surface and stop drilling. Once rivet head is drilled you can carefully drill out only enough rivet material to remove drive plate to prevent enlarging or distorting plates bore. The new basket should be supplied with screws to fasten basket to drive plate.
 
#9 · (Edited)
Ohhh nice, I like the fastener way. I dont do much rivet work, only a my wheel well which I guess was pretty strong and tight, when I think about it. I drilled and filled. Was worried about off balance situations but I guess those rivets are a tight fit?.Dont think my rivet gun goes that big thought.

OEM basket cost $500!

I just watched the video again and the noise is loud!

Also, a mistake I MIGHT have made was using the 25x2 oring on the crank and not the 25x1.5. I dont see that causing this noise. There was no bind or resistance during the install. I couldnt find the 25x2 o ring for the countershaft, and still had the 25x1.5, so....
 
#10 ·
Basket rattle is more of an annoyance than a hazard. Once clutch is released and bike is moving it centers the basket as it loads the drive pins and holds the whole mess tight. It does generate a bit more metal shavings in transmission due to metal on metal contact but regular trans oil change solves that. The cable operated clutches will get a bit stiff when the basket is loose. You won't notice the difference with loose basket until you replace it and your bike suddenly feels like a new machine.
 
#11 · (Edited)
I tried prying around the 72t gear and basket to see if there is movement but there was none at all. There is notching but doesnt seem as bad as ive seen on Google images

I did order a new Wiseco basket, bearing, dampers, springs and plates on it's way, but hard to beleive it's the basket/dampers since I've never had this issue before tear down. Doesnt look bad, does it? Feel like tryingmy old hub with the 4 screws to see if there is a difference

Although right when I heard the bad conrod, i was riding with studs and, sbow around 8 inches. Did it cause excessive wear?🤔

I also pulled the top end and eveything looked good, no damage

101432
 
#12 ·
I tried prying around the 72t gear and basket to see if there is movement but there was none at all. There is notching but doesnt seem as bad as ive seen on Google images

I did order a new Wiseco basket, bearing, dampers, springs and plates on it's way, but hard to beleive it's the basket/dampers since I've never had this issue before tear down. Doesnt look bad, does it? Feel like tryingmy old hub with the 4 screws to see if there is a difference

Although right when I heard the bad conrod, i was riding with studs and, sbow around 8 inches. Did it cause excessive wear?🤔

I also pulled the top end and eveything looked good, no damage

View attachment 101432
Looks like the basket fingers have been filed to reduce the effect of the wear in them (deep ridges will limit the plates movement and reduces the ability of the plates to produce the gap needed when pulling the clutch). If that is the case it is not a major and works well. But as result of the wear the fiber plates will have more free play causing more noise when you pull the clutch. But as you have a complete setup arriving that should sort the issue. Good Luck!!
 
#13 ·
HI Axzon, The noise is only coming when I am moving in gear. I dont hear it when idling and revving the engine. The sound goes away when I pull the clutch in. I have not tried filing down the basket. but possible the PO did,. Ive ran this clutch basket for at least 500 hours. and the plates 400hr.

Might try my friends 2008 clutch basket and hub to see if i hear a different. grrrrr
 
#14 ·
So you are saying that only when you sit still with the bike and you have the bike in gear (as in waiting for the start gate to drop) there is no noise, but as soon as you let go of the clutch the noise is there? If the answer is "YES" then I think there are no issues with the drive from the crank.
How is the shaft the clutch hub fits on? If you grab it with the clutch and the clutch hub off, is it as you would expect; no up-and-down movement (bearings in gearbox all good)?
 
#15 · (Edited)
Edit
Hmm, just checked for play again with basket on and tight. Have some up/down play. No play with the transmission bearing though, thats what i checked initially. So it's the needle bearing. Do people order new sleeves with the bearing? I have a new bearing on delivery now but not the sleeve.

During part rummaging, the bearing slipped out and i had no idea which way it went in the case.
Turn audio up



That is a YES. The shaft is good . Just as you mentioned, I grabbed the shaft with the clutch off and did not have any up/down movement.

Yup, all bearings good in the gearbox. All were rotating smoothly and replaced when I did the bottom end 400hrs ago.

I even started checking the flywheel nut but as I was taking it apart, i realized, if it was that, I would hear it at idle/revving. Checked anyway, as well has trying to move it up/down for play. All is good. Crank bears are brand new from Pro X. I installed and always checked for binding/resistance with the crank. There was none of that.

I also added red RTV to the exhaust to cylinder connection. I normally do that but decided not to this time. Thought it might be some funky exhaust sound under load but still hear it after the RTV.
 
#16 ·

here is what a rattling basket looks like. Screwdriver tip in photo points to shiny witness marks where drive plate rubs basket. This one had a healthy rattle when warmed up and sounded like a handful of marbles in a tin bucket. I have seen them much worse than this. Some discs had 1/8" shiny spot on them. Your basket pictured is slightly grooved but the billet basket and new cushions should make your clutch slicker than weasel $hit once you get it together. The needle bearing in basket is a tight running fit to its inner race. Be sure to coat it with moly assembly lube. Most of them need coaxing to install. Dont beat it. I use the feed on my drill press to push it into bearing carefully. Careful use of a vise or press would suffice but I would apply pressure carefully, thus I use weak pressure of drill press to feel if it is binding.
 
  • Like
Reactions: ktmfreaky
#17 ·
Regarding fitting the bearing: I tend to warm up the outer shell (in this case the clutch hub) in my oven. Then cool down the inside fitting (normally an axel or similar) in the freezer, but yours being the shaft from the gearbox that is not an option. Perhaps a cold bearing will help a fraction?
 
#18 ·
Mines definitely not tight. Dont recall having issues installing, but I also never replaced the collar. I Did replace the bearing during the 400hr rebuild rebuild. Will order new collar too!

Found a way to chill the shaft during crank bearings. I used and a moldable ice pack and wrapped it.
 
#19 · (Edited)
Until i try a new collar and bearing, im inclined to keep looking for possibilities. Just hard to believe this noise was never heard ever.

I bought new tm design chain slider and roller replacement. Was just looking and it's a pretty tight fit. I read of possible chain slap as a common sound. Chain and sprockets are less than 20hrs and i adjusted the slack prior to riding but with that clearance, even the slightest slack will hit it!

How does the clearance look? Possible slap sound? Maybe i should try the oem roller again.
101480
101481
101482

This is my collar.
 
#20 ·
Collar doesn't look too bad. Polish it a bit or replace. Once the bearing is in basket hub the bearing crushes the collar a bit and tightens the collar to the extent it is hard or impossible to turn by hand. Every one I have worked on was tight this way. It would seem too tight but it has to run tight in bore to keep clutch action positive.
 
  • Like
Reactions: ktmfreaky
#21 ·
I sent an email to TM Designworks and they immediately answered. Love it! Talked to the very knowledgeable Rep. Verified that because mine the 250 exc is an enduro model, the material used is harder and does produce more noise, (on top of the added noise for the regular material), as well as riding style and the noise it produces from 'on the pipe' to just puttin' around. We talked about drivetrain and things and was a pleasure talking to him. Based off this, I have to try the old roller and slider so I can rule it out!

Will keep you guys posted
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top