998s starting problems
 

My 998s fe. will not start from cold, I have replaced the battery(GS) and plugs for NGK ones.The voltage on the new battery is 12.5v and when running it is 13.6v. All the engine will do is turn over and over, with the occasional backfire. It sometimes seems as if it wants to catch but doesn't. If I jump start it from an aux battery it will catch and start. Although when left idling the engine speed will drop from 1k rpm to 500rpm where the engine will stall. When ridden or from hot it will start on its own battery. This is becoming a pain as I can keep riding around with jumpleads!
Please help!!

Has the bike been laid up for a while? My 998 is a B to start from cold after being left, I suspect the fuel has detriorated, very similar symtoms to yours.

Basically no fresh fuel has gone into the tank since last November and wouldn't start on its own battery despite it being well charged up.

From cold has to be jumped off, once warm starts OK.

Ray

It hasn't been used for a while, it had half a tank in it, I topped it up with new fuel. I will drain tank and see what happens...any other ideas while i've got my spanners out?

An idle speed that low suggests that it might only be running on one pot.

Touch the exhaust headers to see if they are both hot.

[Edited on 16-2-2006 by rockhopper]

Put new fuel in and it started on the button, although bike has run this afternoon, will try and start it in the morning to see if all is ok.
Cheers!!

Could be the battery,...is it the sealed gel type?
Your voltmeter may say there is 12.5v at the terminals but it still may not have enough oomph to start the bike.

I found that if I gave it too much choke it would not start first time. Also if it does fail to start, I always switch off and back on again. I usually turn the choke 1/4 to 1/5 of the way round. Then turn it up more once it has started.

Was it running ok before the new plugs?

Reason is, the hex on the specified NGK's is too low and using a conventional plug socket, you won't be able to tighten the plug up fully. Even a cheap box spanner is too thick walled.
The profile of the plug cavity at the bottom pushes the socket off the plug....
Wish they'd try and fit them before spec'ing them

Started today and all seems well. Looks as if it was the fuel.
I have turned down a plug socket, so it fits down into the engine when fitting NGK's. It wasn't starting before the new plugs were fitted.
Thanks for the help!:)

My 998 is a little hard to start if its been standing for a long time but once started its goes like stink!