Why would my Zilla backfire when I kick start it.
Example, If it takes 5 kicks to start.. it will backfire on kick #2 and #4, then maybe start on 5, or 6.
Its out the pipe, not the carb.

Its got some mods. Ported, bored carb, shaved head, ect.. It seems to me like its doing it ever since the head was shaved and carb bored. (did both together)

What do you guys think?

-Matt

 

maybe your reeds i don't know

 

Mine did that ever since it was new till I learned how to start it right.

Cold motor start:

1
Turn on the fuel petcock, wait a minute for fuel bowl to fill

2
Turn ignition switch to the OFF position

3
Engage kick starter and slowly push down kick starter thru it entire stroke, just enough to turn over motor SLOWLY
Do this at least 5-6 times to prime motor.

4
Now turn ignition switch and choke on and give it one good solid kick, should start right up. If it doesn't start, repeat #2 & #3 to prime engine again.
Turn off choke (ASAP) as soon as you can keep it going with the throttle.


Warm motor start:

When the motor is already hot NO priming is needed. One kick with the throttle held 1/4 open should start a warm engine. If it doesn't start then try priming with a few slow kicks with the switch off.

This method has worked well for me and other Zilla buddies for years, the key is in priming the motor.
Let me know how it works for you.[img]i/expressions/face-icon-small-cool.gif[/img]

 

Hey Matt, Welcome to the world of high compression..

Not technically a 'backfire' since it's farting out the pipe... My best advice... roll the kick starter up to the top (So you get a full stroke), slightly crack the throttle (1/8 throttle or so) and kick once hard... Jack rabbit kicking on a big bore is a sure recipe for kick back (knee thrown back into the handle bars.... hurts like heck)

Most big bores do this...

 

Won't he hafta run high octane fuel then?

 

Mebbe! Depends on the squish velocity / angle along with the comp. ratio... Not just a function of compression.

High octane fuel still won't help with his complaint

 

Theres definatly a technique. But I have also heard that sometimes the keyway under the flywheel will wear and cause some backfiring when starting.