QuestionI have an 86 VT500C that I changed the exhaust on. I took the stock mufflers
out at the clamp and put straight pipes on instead. Since then I have had a bit
of lag when I punch the throttle. The stock jets in the carb are 112 and 120.
What should I do to correct this?
AnswerJames,
Since straight pipes mainly affect
high speed running I suggest trying
a #118 jet in the front carb and
#125 jet in the rear carb. This will richen
the air/fuel mixture at higher speeds.
The 1/4 to half throttle or so mixture
is affected by the slide needle position.
Some needles can be raised with a very thin
washer to richen this setting.
If the idle/pilot screws are not blocked
you can also try turning those out a bit.
After changing jets a "plug chop"
should be done to check the fuel mixture.
This is done with clean or new spark plugs.
Warm up the engine, do a high throttle run
in a safe place, keep the throttle above
3/4 throttle. Pull in the clutch and kill
the engine quickly. Check the spark plug
color to determine if the mixture is correct.
http://verrill.com/moto/sellingguide/sparkplugs/plugcolorchart.htm
Change the jets or carb settings as required.
