Wont start and when does misfires when taken over 3.5K revs

[225]

After having her back from the garage for all of two days....
Having fun where the chim turns over, plenty of life in the battery but does not fire. When it eventually sputters into life it misfires after 3.5K revs but idles OK.
Its not the heat as I have let it get cold now and still the same, the green flag guy said I have fuel pressue and a spark to the dizzy.

Any ideas?

Cheers

[deano400]

225 said:

After having her back from the garage for all of two days....
Having fun where the chim turns over, plenty of life in the battery but does not fire. When it eventually sputters into life it misfires after 3.5K revs but idles OK.
Its not the heat as I have let it get cold now and still the same, the green flag guy said I have fuel pressue and a spark to the dizzy.

Any ideas?

Cheers

What did the garage do to her.

[225]

Had a new alternator fitted and various little body work things.
I cleaned the stepper motor but hasn't solved it. Theres plenty of juice in the battery as it turns over rapidly and constantly just doesn't fire into life.

[deano400]

225 said:

Had a new alternator fitted and various little body work things.
I cleaned the stepper motor but hasn't solved it. Theres plenty of juice in the battery as it turns over rapidly and constantly just doesn't fire into life.

Instinct tells me timing.

[225]

Hmmm bit odd as it started first time this morning and the garage have had it for a while and test drove it, oh well another day of shouting at green flag will begin tomorrow no doubt.

[chassis 33]

Could be the dizzy was knocked whenthe alternator got changed, so as previously mentioned timing. Also did the GF man say there is fuel pressure after testing with a gauge or just by checking to see there was fuel pissing out when the pressure guague valve was opened?

I had a very very flat spot on the racer at 3.5k that was due to the fuel presure regulator failing, it was fine at idle, but under load and at revs it backed right off to around 15psi (instead of 32 to 36 that is should normally be).

Regards
Iain

[225]

He just check the valve and saw fuel spurting out.

[chassis 33]

Get a fuel pressure gauge on it, or a cheap tyre gauge (the petrol can attach the seals in them) and see what pressure you get at idle and also when you rev it in neutral.

If it drops significantly out of the early to mid 30's then either the pressure regulator has failed or the fuel pump is dying.

Regards
Iain

[225]

It transpires it was the ignition coil.