Hi all

i've just fitted a jardine slip-on and also at the same time changed the main jet from 130 to 150.
Started the bike up no problem and it sounded great.
So i donned my helmet and shades  8) and took it for a spin.....all went well for about 2 miles, noticed improvement mid range...but then it gave out half a dozen or so massive farts and died on me. :'(
After about 5 mins i got it started and managed to splutter home.
After retrieving my helmet, which i had right footed down the street, tried to start it again but no joy...battery getting flat now    
Took plug out and it was black and sooted.
"Maybe too much of an increase from 130 to 150" i thought , so i changed the plug and put the 130 main jet back in....pressed the button and away she went.
SO i decided to don my cool shades and now scratched helmet and try it again...this time i only managed to get to the end of the street before it died...pushed her home and sulked.
After getting over my tantrum, with the aid of a couple of bottles, decided to try again...

.........STATE OF PLAY AT THE MOMENT.......
130 main jet back in
jardine slip-on still fitted
it starts first press and idles but as soon as i blip the throttle it stops..and eventually after keep trying battery low
Going to leave battery on low charge overnight and try again tomorrow.
thought some of you might have some ideas to help.

could i have damaged something changing the jet?

could the jump from a 130 to 150 be too big without doing something else?

it wouldn't be the muffler would it?

please help....i now it may also not even be connected to the mods but it ran fine before i made them.

thanks
gaz

Were you at wide open throttle? If not, you may also want to consider upping your pilot jet.  However, backfires usually indicate a rich condition...

check out these jetting sites, too:

http://www.factorypro.com/tech/carbtune,CV,lower_rpm_engines.html

http://jimrace.com/faq/CVK40.html

http://www.mikuni.com/c-tuning_guide.html

Good luck,

KS

if your plug is charred and wet, you got too much fuel going into your bike that happened to me when i first put the amal on. Like i said in a previous post i hooked up the fuel lines before connecting the throttle cable so while connecting the throttle cable i was pooring gas in. Couldn't figure out what i had done wrong till i changed the plug. started right up after that . no problems since. just haven't had a chance to fine tune yet.

mornhm - FSO wrote on 12/31/69 at 16:00:08:


sorry,
didn't make it clear in "state of play at the moment" ending to my post
the 130 jet is back in...it ran fine before mods.

Hmmm, a stuck float could flood it easily.  Definitiely worth taking a peek at.

Just a thought, did you forget to install the small brass washer that goes between the main jet and carb? Luck with the carb.

Ed L. wrote on 12/31/69 at 16:00:08:


Good call.  There is definatly a washer.  Think I even remember reading in the Clymer manuel of the problems you describe.  But you said it works fine with the old jet.  Does the old jet have the washer still on it?

Just a thought, have You done the white spacer mod ?

Clive W