ATTN: TravTC

[Ben Wight]

Sorry, just read your message.

I would have to say that the air/fuel ratio will probably not have to be altered by putting the 1600 carby on your 1800. This is because of the theory of the carby supplying a specific a/f mixture throughout a given range of airflow (airflow increases with rpm). The 1800 will have slightly more airflow as the 1600 at the same rpm, but the carb will think that your engine is a 1600 just revving a bit higher, if you get what I mean.

The only area that you might come a cropper is really high rpm with the 1800, as the carb was not supposed to meter fuel for that amount of air when installed on the 1600. It may cope fine, it may lean out a little bit at say 6500 rpm with the 1800.

I really dont know, but I would guess that it will be fine as it is.

To actually change the mixture, you have to change the jet sizes as defined by the gregory's manual. A bigger main jet will meter more fuel for the same amount of air, thus a richer a/f mixture. A bigger air corrector jet will meter more air for the same airflow, thus a leaner a/f mixture.

The air corrector jets have a more profound affect at higer airflows though (higher rpm) so tuning them alone may overcome a high rpm mixture problem, whereas the main jet changes have a blanketting effect, over the entire rpm range, except idle off course.

Have fun.

Ben Wight

[TravTC]

Thanks buddy

I never have the guts the max it past 5500 anyway so i guess its not that big a deal. (with a set of genie's and a 2.25 with just a resonator it really sounds painful when i max it out).

Cheers again for your help mate

TravTC