Need help - PLEASE

[TT Tim]

Hi Chaps,

My ST4s let me down a couple of weeks ago, by simply refusing to start after a short trip, didn't seem to matter what I did it wouldn't fire into life.

It's been sitting in the garage for a couple of weeks, I found time to look at it on the weekend.

I've changed the CPS, checked the belts haven't jumped, checked spark and fitted a new Odyssey PC680 battery.

The only thing I found was an injector didn't seem to be firing, intermittant?, I swapped over the leads and it worked fine, so have left it like that.

It now seems to start intermittently, when you crank it over it sounds like a bag of spanners, but when it catches it runs sweet as a nut.

It always used to start with a bit of fast idle, no problem, it now spins over, reluctantly, pops, either through the exhaust or intake and then starts.

Please, please any suggestions, I need to get it fixed.

Thanks

Tim

[latte committee]

Changing the CPS does not mean the air gap is correct.

Check the clearance and then get all your other settings back to spec.

Try baselining the TPS
Balancing the Throttle Bodies.
Air bleeds.
Throttle stops and idle setting.

[mw0dbb]

When the engine is cranking, does it sound metallic? I mean like metal scraping? If so could be the sprag clutch on the way out! I have changed mine twice now due to poor starting.

Sent from my Motorcycle iPhone app

[TT Tim]

Thanks for the replies.

Here's a Vid' of what it sounds like when cranking over:

Noisy st4s - YouTube

Normal?

Thanks

Tim

Originally Posted by mw0dbb

When the engine is cranking, does it sound metallic? I mean like metal scraping? If so could be the sprag clutch on the way out! I have changed mine twice now due to poor starting.

Sent from my Motorcycle iPhone app

[stryder]

Originally Posted by TT Tim

...it now spins over, reluctantly, pops, either through the exhaust or intake and then starts.

Please, please any suggestions, I need to get it fixed.

Thanks

Tim

Reluctantly? After watching that video I'd say that's a pretty accurate description. The engine is not turnig over normally. If it was the sprag wouldn't the starter spin freely? If it was the cps, the engine would turn over normally but wouldn't fire. If it was an EFI issue the engine would turn over nornmally without firirng. Your engine isn't turning over normally, *with a new battery.* I'm guessing you may have some bad connections somewhere, perhaps a bad ground, or your starter "brushes" are dirty. I'd check all electrical connections/connectors and the starter. Good luck.

[paulmm600]

quote

The only thing I found was an injector didn't seem to be firing, intermittant?, I swapped over the leads and it worked fine, so have left it like that.
quote

it might be dirty fuel, how about swapping leads back, fill the tank with fresh fuel and maybe some injector cleaner and then try roll starting it down a big hill.

[TT Tim]

Hi,

That crossed my mind to, I emptied the fuel tank, pulled the pump apart cleaned everything and put it all back together, it's clean as a whistle in there.

So, I'm right in thinking that it should be spinning over better than that?

Am I looking at Starter Motor then? We all know how susceptible these bike are to not starting when they're not spun over quick enough.

Tim

Originally Posted by paulmm600

quote

The only thing I found was an injector didn't seem to be firing, intermittant?, I swapped over the leads and it worked fine, so have left it like that.
quote

it might be dirty fuel, how about swapping leads back, fill the tank with fresh fuel and maybe some injector cleaner and then try roll starting it down a big hill.

[mw0dbb]

That's the sprag clutch, that is what happened with mine!! You can hear the starter motor just spinning! The string fell apart on the sprag the first time. Just take the cover and flywheel off.


Sent from my Motorcycle iPhone app

[Stick]

run your fingers along BOTH + and - cables immediately after cranking to feel for hot spots. The crimp connections, solenoid, all of the nutted connection points, those clips on the battery, etc. If anything is hot, it needs to be cleaner or tighter.

May be brushes in the starter.

I heard your starter sprag kick out a few times. You'll F that up if you continue trying as-is.

[Rev. Dr. Moses P. Lester]

that does sound like a starter idler gear with a sprag to me. intermittent metallic contact, with a whirring. the whirring to me sounds like the starter is spinning ok, and it's just not meshing consistently with the crankshaft because of the idler/sprag.