Starter clutch failure ?

[VTRdH]

I struggle with start up of my firestorm.
When engine is cold the startermotor turns but will not turn the engine( you hear slipping sound), when engine is on temperature after riding it starts. immediately, if you wait for aprox. 30 minutes the start gives the bad performance again.
Cold start is succesfull if you put it in first gear and move strongly so the engine rotates a bit.
Battery and regulator seem to be ok.Enough voltage power to start, no dip in lights when start, voltage on battery 12.9, charging voltage 14.4
I have two thoughts:
- starterclutch failure : However, if it would be damaged the problem should occur allways
- Oil issue: engine has 15w40 oil instead of 10w40, as this oil is thicker at cold engine temp could this be the problem?

Any suggestions are welcome

[VTRDark]

Have you checked the engine earth cable and check the cable under the rubber boot on the starter motor itself as these have a nasty habit of cording. Strange how it gets better as it warms but maybe if there is a bad or loose connection it's getting a better conductivity as things expand. The starter sprag clutch is also a common failute on these, which is behind the flywheel.

(:-})

[AMCQ46]

sounds like the reduction / idler gear could be slipping, or perhaps the sprag clutch. something that is being effected by thermal expansion so it is just working when the parts are hot

[VTRdH]

sounds like the reduction / idler gear could be slipping, or perhaps the sprag clutch. something that is being effected by thermal expansion so it is just working when the parts are hot

Just removed startermotor, all sprockets look normal no damage, however I tested the freerun and this is strange:
According to haynes manual the idle/reduction gear should be able to rotate freely anti clockwise, but it is running free clockwise (looking in the gap where starter is mounted and sprockets connect).
Anti clockwise it locks.
So would the starter clutch be the problem then?

[AMCQ46]

I think the CW or ACW is just a confusion on which side you look from. I would expect the reference would be looking onto the engine crankshaft from the alternator side, so that would be the opposite convention from your view looking in the hole that the starter fits in.

The 2 gears that make up the idler gear are friction fit onto a shaft, and this is what transmitts the torque from the big gear to the little gear, so it will be fine under no load, the question is if it will work under the torque required to get the engine over compression, so dont rule them out just because they spin ok in the free state.

I think the olny way will be to get them out and replace first the idler, then then if that dont work replace the sprag clutch.

Tony.mon is the best man to advise on how to do this and the exact symptoms for each, so wait for his answer before spending any $

[VTRdH]

sounds like the reduction / idler gear could be slipping, or perhaps the sprag clutch. something that is being effected by thermal expansion so it is just working when the parts are hot

It cannot have to do with the thickness of the engine oil that reduction/idle gear is slipping?
At the bikeshop the spoke about cleaning the engine with special additive as they think it could be some filth inside engine ?
Have no experience with it. I am not sure it's agood idea

[VTRDark]

This may be of help to you http://www.vtr1000.org/phpBB3/viewtopic ... rag+clutch



(:-})

[VTRdH]

This may be of help to you http://www.vtr1000.org/phpBB3/viewtopic ... rag+clutch



(:-})

Any idea why you have to remove the front CCT ? If i read this it looks the most reasonable cause, think the idle / reduction gear could be the problem then.
Thanks for support.. will be continued.

[VTRDark]

Any idea why you have to remove the front CCT

Sorry no as it's not a procedure I am familiar with. I expect Tony.mon will be along to give you some advice and guidance as he's the expert on these matters.

(:-})

[AMCQ46]

I think you need to slightly move the front tensioner blade to get the gear out, so you need to remove the CCT to get the tension off the cam chain.

[VTRdH]

I think you need to slightly move the front tensioner blade to get the gear out, so you need to remove the CCT to get the tension off the cam chain.

That seems logical to me, just have been to bikeshop with bike and after some discussion they also agreed on problem with reduction/idling gear, so here we go, not an extreme difficult job , will look on ebay as well for spare

Thanks for all support till so far

[tony.mon]

Yes, I can confirm what has been said.
The front CCT needs to be removed so that the bottom fixing bolt on the rearmost of the front cylinder's tensioner blades can be unbolted (you need a twelve-point socket) and then the idler/transfer gear can be just about slotted in without taking too much of the engine apart.

Awkward, but trust me; it can be done.

By the way, you remove the transfer gear's pivot pin (axle) by using a magnet; it just slips into place.

I've posted a "how-to" in the Workshop Knowledgebase- search for "starter motor problems".