Main jet confusion ???

[woodentopp]

Hi,

I have an LC2 with standard carbs, pipes from TSA, a standard airbox with the siphons removed and barrels from a N2/L2.

I am trying to jet the carbs correctly and have fitted 270 main jets. Yesterday I managed to do a plug chop on a long straight slightly uphill road (Not easy to find in rural Norway ) and got the results below!

I am now 3 jet sizes over the standard for an LC2 (240) and still too lean!! has anyone had any experience of this? I double checked the old jets from before I renovated the carbs and they are made of white plastic with 300 stampted on the top, is this right?

Any help or advice gratefully accepted (confused of Norway )

[rdstars]

You mentioned you done a plug chop but the plugs shown are not chopped. Need to start with a brand plug, then hold it flat out, hit the kill switch, come to a halt, take the plug out ( put a spare in ) go home and chop of the thread. You will see a smoke ring around the bottom of the porcelain and this will determain if your lean or rich.

[midlifecrisisrd]

as rdstars says you need fresh plugs for a chop

if you are running standard filter and airbox ( snorkels out ) with a standard motor and just pipes from tsa then 2 or 3 sizes up should be fine

standard is 240 so 270 should not be far off. have seen the plastic jets before and they seem a bit crap.

300's would be more like running pod filters.

went one size up for pipes and standard motor before and two for pipes and a mild tune and both ran fine.

steve

[woodentopp]

Has anyone a definitive method for a plug chop. The ones I've seen say just to check the colour on the top of the insulator and not to cut the threads away!

Don't know what I'm doing wrong but I have jetted to 270, checked for leaks, checked the carbs (bowl height etc) checked the PV etc and the bike won't pull top in 4th to 6th gear!

[rdstars]

Google 2T plug chop and that should come up trumps but here is how I do it ( lots of different advice out there )

Warm the bike up first out side of the house, take it for a short ride pulling through the gears just to make sure it is warm, Got a good bypass on my door step with a pull in so do just that pull in, take out one plug and put a new one in ( owch it's hot mind ) when it's clear start it up and trash it through the gears ( some people count to 30 second ) I just thrash it till I hit around 5th ( so still about 30 seconds ) All at the same time hit the kill switch, pull clutch in ( dont want to lock up now ) and keep the throttle open. Come to a halt ( either roll or use your breaks ) ALSO make sure there is knowone up your arse or your will get rear ended ( owch )

When your stopped take the new plug out, put the old one in ride home. ( Hot mind, carefull where you put your new plug )

When you get home, hacksaw all around the bottom of the thread of the plug and it will come off, all you will have left is the porcelain, on the bottom of the porcelain as if by magic you will have a smoke ring, depending on how many mm and colour etc will tell you if your rich/weak. Post up photos of the plug and people can give you advice. ( I hate jetting ) ( That was how I do mine, right or wrong chopping the plug is still the same )

Not you bike but with a Stock F2, PJ carbs etc and a set of nice pipes like TSA the mixture will come close to bang on as they run rich from stock ( still need checking and maybe a size up )
Also if I remember right Ian's bike TSA pipes and a full Mick Abbey tune was about 300MJ, your not ported I guess so not going to be near that.

Another thing but harder to explain esp because its a tinny 2T is listen to the note of the motor, when your high in the RPM does it sound tinny or more deep, tinny is weak deep bogging sound is rich,,,,,,,,,,,,,,,,But this is harder to do as all 2T are tinny sounding.

[rdstars]

Here you go, better description than mine and also I chop all of the thread off, find it easyer:

www.dfn.com/agservices/plugchop.html

[woodentopp]

Cheers, will try again