A forum for owners of Yamaha TTR250 trail and enduro bikes!

I'm about to change the Sprag and reading the excellent "how to" on here.

Do you need a special tool to hold the flywheel to get the flywheel bolt off? Looks like you might, although I'll be using an impact wrench/gun - may not need to hold the flywheel?

Once that's off (I've bought the flywheel puller) is it literally just screw that in and keep going till the flywheel comes off?

Ta

-- Edited by leigh on Monday 11th of July 2016 05:55:51 AM

Great, thankyou Brian.

Easy.

Place a suitable sized Allen key into a flywheel balance hole and brace against the bikes frame.

Otherwise I am sure your system will work. 

 

I have an old plumbers spanner that has been ground to fit the flywheel "flats" which makes life a lot easier. These spanners are often in amongst the other old rusty tools at car boot sales and recycling centres.

LOL - the new plug you bought from me will turn up as soon as you have fitted the one from Steve 

At least that's how it works for me 

I'm thinking of fitting a kick starter to my TTR after the starter clutch failed the other day and leaving the electric start disconnected. Can anyone tell me if the failed sprag has to be removed first before the bike is used again. Had this happen on an old T3 Triumph Speedtriple some years back but still used the bike with no issues until it was fixed. The TTR has not run since it failed I might add just in case.

Hi Steve. Yes. It has been making a loud bang after switching off for some time and was a job I had marked up to do in the near future, knowing this would eventually happen. When the starter is engaged, it now spins freely without turning the engine over. And it has sounded rough when it was started up in the past. I'm pulling it this Sunday so will have more information as to what has actually happened when I get a look inside. This was a daily user and I'm missing it.

John.

I've only used my kick start a couple of times but have found it a bit awkward and turns the motor over a bit slow so cold starts and awkward hill starts are a pain 

Or maybe the electric leg has made me a bit soft 

You may be right Steve, but I found my starter gear would spin both ways without engaging on my project motor. Took the flywheel off and all the "teeth" fell out of the sprag! (Hence my order from the shop yesterday!)

On the kickstarter issue, I've never been able to start it from cold with the kicker. Been close a couple of times but had to resort to a push. When warm it's no problem (usually happens if I leave the ignition on with the lights on for too long) I don't see a problem leaving the sprag in place as long as it hasn't fallen apart, but removing it will lighten the flywheel (faster revving).

Kickstarter parts are harder to find than rocking horse s**t! (And probably more expensive than a new sprag clutch even if you do find them)

Ride safe,

Simon.

Sprag not spray. Phone auto spell fail.

On first glance it looks as though there is some wear or damage to the small idler gear in which case don't be tempted to re-use it.

What is the starter pinion looking like - is there matching wear or damage?

Brian

Hi Brian. I expected the starter pinion to be damaged as stated earlier by Steve but it appears to be undamaged with all the teeth showing little or no wear. I will be ordering a replacement small idler gear shortly.
As stated by Johnyboy, someone has been in their and not done the job properly.

Thanks Steve. Some parts arrived today. Waiting for the small idler gear then it's back in the workshop with endless tea.

Welcome to the forum! I hope you enjoy your TTR 

If you remove the starter gear then you should cause no problems.

Brian

I don't think this will be a complete fix.  The sprag clutch will still be in there with it's broken parts and still going round with the flywheel and will presumably still make the clunk of doom when the engine stops and still wreck the flywheel and other parts if it totally fails, although that might be less likely now it's not being driven by the starter.  Maybe a better option would be to remove the sprag?  Removing the pinion seems about the same as just not pressing the starter button to me, but a lot more difficult!

I'm not particularly clued up on the damage that's normally associated with this as despite having run mine for about 18 months wondering what the strange clunk was I still saved mine in time!  However, from other posts it does seem that you can get damage to the boss inside the sprag clutch.  What nobody will know is for sure how removing the pinion might affect things.  My best guess is that with no drive going into the sprag it will just stay in freewheel mode forever and give no problems, but there could be something we're not considering that could result in a seized on big gear spinning for ever more or lots of little bits of very hard metal floating around inside the casing so having got that far why not go a bit further and just remove the whole thing?  And having got that far why not just spend the money and restore one of the TTRs very best features!  It's ability to start on the very touch of the button when stuck in a hole or even after just stopping for a chat is something I would never give up - you're gone before they've even swung their kicker out!  The sprag itself is vastly over complex and has no place on a dirt bike but when it's working the overall starting capability of the TTR is almost unrivalled (apart perhaps from some really modern fuel injected bikes that I have no experience of that maybe start that well and continue to do so after being on their side!) and to me that's one of the main reasons why it's such a good trail bike.  Handy for my commute in town as well as I know I can filter to the front at the lights, engine off to save the planet, hit the button on amber and still be away just as the green comes on!

So I've changed my mind.  Don't take either part out except to replace the sprag.  You only live once, why spend it kicking when you could be riding?

 

I set it up with the bolts, as in the photo.

Added some arrows that followed the manual directions, for him to follow.

He said it came free quite quickly and easily.  A small amount of force was required.  He did it so quickly that I got the call to pick it up about half an hour later.  And didn't charge me!  I am a fairly regular source of small cash jobs, sometimes pay him a bit more than he asks for, especially when I've taken him something that I maybe, shoulda, coulda taken to him before that last step I did...

And there was no visible damage to the contact surface of the starter gear.  Win for me.

I'll edit it with some photos, a bit 'ron.

I appreciate that doesn't directly answer your specific question. 

I do think it's reasonable that he just followed the arrows. If he had been driving it on harder, it would not have released anywhere near as easily.  Until there was damage.  In fact, it feels like the clutch would pass the operation test now.  I've got a new one coming.