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The TTR250 FAQ web pages -> TTR250 -> Repair and maintenance "stickies" -> Sprag clutch questions and answers thread
Post Info TOPIC: Sprag clutch questions and answers thread
lee


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Sprag clutch questions and answers thread
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(See http://www.ttr250.com/Sprag_replacement/TTR_sprag_replacement.htm )

Well I eventually got around to fitting the new sprag I picked up from Brian.

I printed off the demo you did and followed it step by step and it went very well. The only issue was the lack of torque wrench, how crucial do you think the torque settings are?

I don't want to run the engine to operating temp only to find something is overstressed.

But like I said apart from that the bike starts well and shuts down nicely.

The old sprag was free but heavily worn 'teeth' and only about 5 retaining tabs remained and luckily everything else appears to be in tip top condition.

Brian, A really big thank you, I would not attempt a job like that previously but you're demo piece and showing me what to look for as regards to wear etc. gave me the confidence to give it a go.

And I'm stoked, thank you my friend.



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sammyttr


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How long does the sprag clutch last before it goes bang and takes engine with it, my ttr has 6,300 miles roughly

If i buy a kick start kit and undid the connections for the starter would that prolong the life of it.

how reliably is a ttr for everyday use and whats typical mpg

 



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sammyttr


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Sprag clutch
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thanks, as engine is still pretty new i hope it be alright for a few years before any thing starts going.

 

just wondering is there ment to be a cover for the battery as mine has the metal clip at the top and then the battery is just sitting there is there a strap or cover.



-- Edited by sammyttr on Wednesday 4th of July 2012 01:50:08 PM

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TTRfan


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The life of the sprag clutch depends very much on how the TTR has been used.

If used for commuting then it is only used a couple of times at the beginning and end of each day BUT if used for green laning then it is likely to be used 30 to 40 times on a ride.

You will know when it starts to wear if you have mechanical sympathy as the bang on switch off will make you wince.

Disconnecting the starter takes away one of the main advantages of the TTR in my opinion. I love that magic button wink

Brian



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truslack


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Hi Sammy,

Seeing this post reminded me of your PM on the other forum, sorry I forgot to reply. Seen one go at 20,000km, mine has just started at about 32,000km.

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sammyttr


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Dont worry worry about, I am just abit of a worryer and just wondering thats all, As its only got over roughly 10.000 km I think it should be all right for a while, I can see me being an absolute hooligan on this bike when I get my test done and get a fmf exhaust on.

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barra8


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Sprag clutch questions and answers thread
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Hey Lee,

            You will need to replace it asap as if you don't you will do damage to the other starter components.

Provided nothing else is wrong then all you will need to replace is the sprag clutch and gasket.

Check wear on all starter components and replace anything that is too badly worn.

Parts from 1999-2006 will fit fine for the sprag clutch

Jarrah.





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burton500


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Sprag clutch 1993 model
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Hi

I've had my 1993 TTR for  about 6 months and it's a great little bike.  Recently there has been a clatter when the engine stops, which after reading some of the posts here, the sprag clutch is probably on the way out. 

Couple of questions:

How soon do you need to replace it when it starts making a noise, and will carnage ensue if you don't?

I saw in one of the posts that the part no's needed are "Sprag clutch Part # 4GY-15590-00-00 and generator cover gasket Part # 4GY-15451-00-00" - can anyone confirm if these are the part no's for the 1993 bike as I'm uncertain if the parts changed with the newer models?

Lastly, availabilty - where is the best place to get one?

Many thanks

Lee

 



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barra8


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Sprag clutch questions and answers thread
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For Lee........... http://www.ttr250.com/Sprag_replacement/TTR_sprag_replacement.htm Might help for a visual when doing the job.

 



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TTRfan


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Riders are an excellent outfit to deal with and fairly local to me.

I can't beat the Boats.net price but have a couple of genuine new Yamaha sprags on the shelf a lot cheaper than from a UK Yam dealer wink 

See here

Brian



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sammyttr


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sprag clutch bang
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what sound does the sprag clutch make if turning off engine, mine makes a noise every now and again has anybody got a video of the noise

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domski1


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They all seem to make a small clunk when stopped most of the time, if the sprag needs replacing the clunk is very loud and will make you cringe! ( sounds like it coming through the engine casing! I changed one the other day and should have shot a quick video of the old one in action!

Adam.

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sammyttr


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mine makes a quiet one clunk so alright does it less so when turned off with kill switch bad habit I know, just making sure that's first bike I've had with electric start.

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domski1


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Sounds like its ok then, even with a brand new sprag you still get a clunk now and again. I also have a Yamaha wr250x with 1000 miles on the clock and that also clunks when turned off.

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sammyttr


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checking sprag clutch
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Just wondering what to check for on the sprag clutch, all the teeth are fine none missing and the splines look good am i correct in saying this is the one behind the Yamaha logo



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domski1


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The sprag clutch is behind the flywheel. They are very hard to check for wear as there is not much to see between a new one and one that is banging and indeed of replacement. If its not making an awefull clunk that sounds like it will break the engine casing and all the teeth are ok on the large idle gear ( behind the small casing with the yam logo) and the splines are ok on the starter then it may well be ok.

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Allweatherbiker


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I guess it's time for a sprag clutch
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Hi just to confirm that it is the sprag before I shell out big money.

It sounds like a cement mixer when I turn it over but once running it sounds sweet.

When kickstarting it clunks & sometimes turns the starter motor.

When turning the engine off it goes knock but not every time.

 

Thanks

Elt



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domski1


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Take the little cover off the left side of the engine ( the one with Yamaha on in and check the condition of the splines on the starter motor and the large idle gear. If you are getting nasty noises when starting as well as switching it off you may well need a few more parts and deep pockets!

Adam.

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Allweatherbiker


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LOL I dare not look just yet

Will look when I have a bit more coin...I will rest the bike up before it all goes bang



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Lin


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STARTER SPRAG CLUTCH
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With regular oil changes, can anyone give an estimation of the life of the sprag clutch (in miles or kilometers)? 



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domski1


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I changed the sprag clutch on my 2005 ttr at 9000 miles and to be honest it didn't seem in bad condition, it will depend also on if you do a lot of short runs etc. I would make a rough guess and say around 12000 miles to be on the safe side??

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TTRfan


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If you were using a TTR to commute then the sprag is only really getting two uses a day but, if you are trail riding it in a group, my experience is that you are stopping and starting the engine a lot of times - maybe 50 plus on a run? Probably a darn sight more. This would drastically reduce the mileage that the sprag would last.

I would go along with Adam's thinking - probably 10,000 plus miles of trail riding. I would hazard a guess at 30-35,000 miles of mostly commuting - probably more?

Brian



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noeyedear


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Just to put my pennies worth. My 2005 blue with 10k on the clock, is on its second replacement. I only use it for trail riding and change the oil ever 500 miles with quality oil. But I might just be unlucky.

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Wobbles


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Saving sprag clutch by kick staring?
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Does kick starting rather than using the button save on sprag clutch wear?

 



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Cubber


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Yes, but it wears out your leg/shin muscle and if used to excess makes you walk lop-sided. biggrinbiggrinbiggrin

Martyn



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What Martyn says is true lol, but the most damage is done when you stop the engine, rather than start. The gears, brushes and one-way sprag clutch get worn using them but it is when you kill the engine that it wears the one-way sprag the most. This is from the clunk that you hear when the engine is stopped.

Of course it will help a little but may just wear your leg out and make you walk lopsided with not a lot of benefit. wink

Do not worry about it, they last years and only people with older bikes should be worried as there will be more wear and tear (obviously).

Jarrah



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uteman


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Calling all Sprag Clutch experts
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Firstly: Yes I have kicked my own butt!

I never even started the engine on this rough 2009 bike before I stripped it down.

Engine back in after new piston, crank bearings etc.

Runs really nicely but has a metallic clunk on start up and again on shutdown.

It appears to come from L/H side of the engine and as I never dismatntled the sprag clutch I am thinking that may have been my mistake.

Does this sound symptomatic of a sparg clutch issue?

Rememeber, I will do the butt kicking! (Ouch!)



-- Edited by uteman on Friday 14th of June 2013 05:49:05 AM

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Wobbles


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RE: Saving sprag clutch by kick staring?
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Ok thanks

Will use the button then

Peter

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Sprag clutch questions and answers thread
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Hey Uteman,

If it only does it when starting or stopping, YES, it seems highly likely that it is your one-way sprag clutch (99.9%).

If you need to see a pictorial of this  repair CLICK HERE. 

Enjoy!

Jarrah

 



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uteman


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RE: Calling all Sprag Clutch experts
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A well detailed procedure.

I take it from the final comment in the procedure that there will always be a "Clunk"

Is the clunk or bang on starting something that remains after replacement and/or is this common with a failing sprag on these bikes?.



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uteman wrote:

A well detailed procedure.

I take it from the final comment in the procedure that there will always be a "Clunk"

Is the clunk or bang on starting something that remains after replacement and/or is this common with a failing sprag on these bikes?.

 Yes all credit to Brian. thumbsup.gif

It always makes a little noise when stopping but not when starting and it should not be loud.

Can you take a vid?

This is how it should sound...

Jarrah



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uteman


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I do not think that you even want to hear mine.

I will replace the sprag before any further embaressment.

It sounds ever so sweet between starting and stopping.



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TTRfan


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uteman wrote:

I do not think that you even want to hear mine.

Oh yes we do! It would be really good to have an audio clip of what a worn sprag sounds like - please please please wink

Brian 



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Andy_C


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yes would be a great idea to make a recording of a worn sprag as a tutorial to other owners,even make it a sticky?

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66T


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They sound absolutely terrible at the end of their life. When they're really shagged, the starter clutch jams and you have to use the kickstarter to free it. Then, finally, it jams solid and you have to remove the idler gear if you want to keep riding. Kickstart only, of course.
Which shouldn't really matter, except you know you should be able to just push the button...



-- Edited by 66T on Saturday 15th of June 2013 07:37:48 AM

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66T wrote:

They sound absolutely terrible at the end of their life. When they're really shagged, the starter clutch jams and you have to use the kicksyarter to free it. Then, finally, it jams solid and you have to remove the idler gear if you want to keep riding. Kickstart only, of course.
Which shouldn't really matter, except you know you should be able to just push the button...

 I would not let my sprag go that long as it can shatter into pieces and cease the engine.

 



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uteman


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Andy_C wrote:

yes would be a great idea to make a recording of a worn sprag as a tutorial to other owners,even make it a sticky?

 I took a video and the clunk can be heard. Now I cannot get it to load onto the forum for your listening pleasure! This was the first time that my wife and I had used the IPad for a video. Can anyone help with getting it onto the forum?



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TDVT


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Sprag clutch questions and answers thread
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So mine is kind of clunky too & I don't have the option of using the kick starter (US) so I suppose I better deal with it sooner than later.

Being lazy & haven't looked at the videos yet.  So to be sure, we ARE talking about Yamaha part #10 here (they call it the "STARTER ONE-WAY ASSEMBLY), yes?

TTR starter clutch.jpg

 



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uteman wrote:
Andy_C wrote:

yes would be a great idea to make a recording of a worn sprag as a tutorial to other owners,even make it a sticky?

 I took a video and the clunk can be heard. Now I cannot get it to load onto the forum for your listening pleasure! This was the first time that my wife and I had used the IPad for a video. Can anyone help with getting it onto the forum?

 Upload it to YouTube or similar, click the URL at the top of the tab/page then just copy (right mouse click) the URL and paste (right mouse click) to this thread. Or you can click the YouTube icon (after you click reply) and paste the link into the pop-up. It will then show as a video, not a link to YouTube.

 



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Nickj_UK


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RE: Saving sprag clutch by kick staring?
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Just a thought on this... At tick over stop the motor and it spins down quite quickly, a little throttle blip when hitting the kill switch and the motor spins down a little more slowly.
Kill from tick over = occasionally a little clonk
kill from a blip = no clonk, silent stop :)

My XR280 was kick only, it's partly a knack and having the carb set properly

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Cubber


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RE: Calling all Sprag Clutch experts
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Yup - that's what we call a "sprag" clutch

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Cubber


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RE: Saving sprag clutch by kick staring?
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Another way, but harsher, is to put the bike in second or third gear, put both brakes on and drop the clutch quickly at tick over. wink 

Martyn



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uteman


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RE: Calling all Sprag Clutch experts
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Andy_C: i do not have a YouTube sign and as I already have more passwords for different things than I can ever hope to remember it will not happen so I apologize but no video.

The unfortunate thing is that when I took the video the sprag simply would not clunk and slip on starting and only clunked once on stopping. I guess this is a bit like going to the dentist and the tooth does not ache!

I could email the video if someone else wanted to post.

I will be overseas for a week starting Tuesday 18th 8am Melbourne time

 



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KentJ


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So this guy here, is his sprag clutch toast? It sounds a lot like mine (not my video).

-Kent



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TT-R250M


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I wouldn't say toast, more like hot bread. Still more life in it yet.

I was trying to find the original link from the video but it is nowhere to be found. It's a shame as it had a lot of good info on this issue. hmm

If anyone remembers what they link headline topic was, please search it.

 



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fatboy686


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Hi KentJ,

Yes that was my video, the link to the topic is below. The consensus was that I shouldn't worry about it just yet. I still do though!

I checked the teeth on the starter motor gears and they looked fine. I'm trying to stop worrying about it now.

 

http://ttr250.activeboard.com/t52135442/yes-another-question-about-the-sprag-clutch-opinion-needed/



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TTRfan


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Sprag clutch issues - checklist
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Starter clutch.jpg

 

If you are going to the expense or replacing the starter clutch (#10 in the fiche pic above) there are a few things to check to make sure your investment pays off:

  1. Make sure that the boss on the large starter gear #7 (the sprag depends on this one to work properly) in good condition, not worn and with no pitting, scoring, ridges or other damage that might prevent the sprag doing its job.
  2. All the teeth on starter gears #7, #4 and #1 should be in perfect “sharp” condition with no rounding, burrs, roughness, wear or chips on the teeth. In particular, gear #1 has to be perfect.
  3. Check the bearings #2, #5 and #9 are all OK along with their housings and, in particular the housing in the starter gear cover for bearing shaft #3. There shouldn't be any movement that would allow the gears to misalign.
  4. Check the generator cover isn't cracked or damaged in some way that would allow movement of the gears and consequent meshing problems. A tell-tale sign of a cracked cover is an oil leak from around the starter gear cover area.

All the parts are available new here

Brian

 



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leigh


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Sprag clutch
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Hey peoples

 

Can the sprag also make a bad clunk on startup? Mine has started occasionally making a louder than normal clunk on shut off, but I'm starting to hear the same noise on startup very occasionally. Sounds like the sprag noise to me. Easiest way to make it happen is when I go to start the bike and it stalls and I hit the starter again. Get quite big clunk/clang when I do this for the stalling and starting. My bike has 20k on it.

Cheers

 



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BM Steve


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Hi Leigh

if you need one I have a perfectly good used one

I thought I needed one, got one from Brian then found out I didn't, Bugger confuse

They are about au $240 plus freight new !



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leigh


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I might take you up on that - although I'm not convinced I need one yet. I'm far from an expert.

In the last few months I've had the odd louder than normal clunk, not too bad, but I noticed it a handful of times. However in the last few weeks on trail rides out where you might start the bike 20-30 times I've noticed a decent clunk on startup sometimes. Louder than the normal clunk on shutdown. I only know of the sprag clutch symptoms from posts on here all the time.

What did yours end up being? Symptoms?

Cheers Leigh

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