Tuned up

[gsx600]

Just had a home tune done on the 400 ala 450 (Should I just call it a 450 now ?)
And managed to get the timing to 8deg, the co to 3.2 but having great problems with the unburnt fuel (should be about 500ppm) but can not get below 1000 ppm

The only way they could get below 1000ppm was to change the timing to 20btdc - not recomended !!

Anyone else had this issue ? The guys think maybe because of the bigger valves not helping.

Now runs great throughout the rev range, idles, and even starts properly - all for £45 - saves me messing every weekend.

[2 sheds]

It's a balancing act, you may need to raise the co in order to bring down the hydrocarbons, the big wedge cams are pretty hot and in some cases need to idle at 1200+ rpm in order to get anywhere near the emmision requirements.
Tim

[gsx600]

Cheers Tim

Would that also be the same for the Chimera 4.5BV as this is where the engine came from. Not sure what cam is in there as standard and could not find any markings without taking whole lot out which I didn't want to do !

[2 sheds]

Yes the 4.5BV is basically a SEAC engine, probably a kent/TVR 234 cam, what's the idle speed ?
Tim

[gsx600]

Got it idling at a lumpy 900 at present

[2 sheds]

900 would be fine for a standard 400 but too low for the cam of the 4.5BV if you increase idle rpm you will reduce the hydrocarbons, i would raise it 100 at a time until you get a good balance.
the only problem is that the ECU (i assume hotwire) won't like idling much above 1000, without modification
Tim

[gsx600]

Cheers I will try increasing idle. System is still flapper type !!

[2 sheds]

In that case no problem, i recon 1100 would sort it out, assume you're aware about adjusting the potentiometer if you need to adjust the throttle stop, although you might be able to use the bye-pass screw.
Tim

>> Edited by 2 sheds on Tuesday 5th October 17:34

[gsx600]

Which pot do you mean, the throttle one ?

Although seem to be able to adust to about 1500 on the allen key, now slightly smoother idle at 1100 but need to get levels rechecked as my machine only has CO on it - Halfrauds special

[2 sheds]

Yes i was talking about the position sensor attached to the throttle spindle, but sounds like you won't need to touch it at this stage, you should be able to tell if you have reduced the hydrocarbons as your eyes won't water as much
Tim