Loud CLANG if the engine dies during slow idle

[Prairiehammer]

Recently (started this spring), I hear a very distressing "clang" when the engine dies from too slow idle. IE, when starting cold with the choke off and the engine cooled (at a gas stop, for instance) or when idling from a cold start and because the idle speed is too slow with the choke off. My "choke" has always been more like an on-off switch instead of the expected linear activation; so to avoid a racing engine while warming up, I reduce the amount of enrichment and try to maintain a semi-fast idle (1500 rpm) with the choke. I often fail that, and as I am suiting up, the engine may start racing or may just start idling too slow and die---with a clang!

It did an especially loud clang as it died while too slow idling this morning and then when I restarted, there was a definite "knock" emitting from the stator cover. I could feel the knock in the handlebars and placing my hand on the left engine guard I could feel a knock and simultaneously hear it.

Have I broken the starter sprag? Or one of the springs in the sprag unit that pushes the roller(s) back to the start (neutral) position?

[Snaggletooth]

Sounds like your starter engage is failing. The three rollers in the OEM engage only make contact with the boss on the 72 tooth ring gear that seats in the rotor when the motor is stopped. If the housing is cracked the rollers are not held in the proper alignment and may be boucing of the ring gear boss when the bike shuts down from a low idle. (maybe one or more springs damaged also)

 

The chattering or banging when starting supports that thought.

 

The first pics are of the OEM engage. First two showing damage and then the engage in the rotor, damaged but it does not show.

 

The last pics are the OEM and Danos upgrade side by side.

 

Then the details of Danos upgrade.

 

You have two options really. A New OEM for about $200.00 or Danos upgrade for under $300.00. (or what ever the price is these days)

 

I installed Dano when he first made them available. I think I was the first one to do it in the US. Won't ever have to do it again. Tuff Stuff.

Edited June 12, 2013 by Snaggletooth

[Prairiehammer]

You have two options really. A New OEM for about $200.00 or Danos upgrade for under $300.00. (or what ever the price is these days)

 

I figured you would speak up about this, Mike, since you were intimately familiar with the mod (and Dano?)

I suspected the worst. What is the long term prognosis? Will the starter catastrophically fail, leaving me stranded in New England in August?

Is Dano still able to get the parts he needs from Yamaha to do the mod?

[Snaggletooth]

In my experience with a couple of engage failures..... yeah it will get to the point where it will not catch at all. I put up with mine the first time until I was draining the battery and having to push start it.

 

I did a rebuild with a used engage body and installed new springs and rollers. That failed also after one season. Probably my fault on that one. Two things there. I did not replace the 72 tooth ring gear and I'm sure I did not get the alignment of the engage body into the rotor set as close as I should have. That can be critical to the rollers hitting the boss correctly.

 

Dano does all the hard part with his mod. He machines new mounting points. 6 instead of 3. He installs the engage into the reworked rotor with a plug that alingns the engage in the correct position. The upgrade engage is 19 (I think) elipital prawls instead of 3 roller bearings and ball point pen springs but instead a SS compession spring to set the prawls in place. He supplies a new 72 tooth ring gear that is different from the OEM issue gear.

 

Do I sound in flavor of Danos work? I suppose. I used my bike for work and that included sometimes 20 or more starts a day, 7 days a week for about 3 years.

 

Never a skip, bang or slip. It's dependable.

 

As far as what Dano has one hand, you'll need to PM or call him on that. I don't know what the current parts situatioin is. And there are no Yamaha parts involved in his upgrade as far as I know.

 

Now if you decide to do an upgrade, send me a PM. I have something here to help speed you along.

 

Mike

Edited June 12, 2013 by Snaggletooth

[Prairiehammer]

Just to be clear: the starter does not fail to engage. Nor does it spin freely, then suddenly noisily engage. The starter sounds perfectly normal. The clang (or BANG, depending on your semantics) occurs only at the seemingly last stroke of the stalling engine.

It sounds as if the engine is trying to run backwards for a split second.

This occasional noise started after I installed the Ignitech this Spring. I mentioned my concerns to Dingy at the MD. I wondered if there was too much initial advance programmed into the Ignitech. He adjusted the advance from 10° BTDC to 5° BTDC.

I hope that the perceived engine kickback or reversal didn't break something.