Super Jet Backfires....possible causes

[steve-uk]

hey keith yeah thats something else to put on the list to try, just not sure that this makes a difference with a carb that has a needle and seat, with a float carb yes, but all else failing it will be tried

 

[Magyar68]

My 62t is backfiring thru the exhaust Hoping its the Stator because everything else checks out ok. I will let you know if it solves my issue...

 

[Matt_E]

hey keith yeah thats something else to put on the list to try, just not sure that this makes a difference with a carb that has a needle and seat, with a float carb yes, but all else failing it will be tried

If fuel tank pressure gets big enough, it can easily push a low popoff n&s assembly open.

 

[steve-uk]

i was runnig 19 psi, now im at 25 psi and still have the issue, should hit the water in an hour or so, so maybe see if the better battery cures the issue

 

[raytherace]

does the kill switch is ok ?

 

[steve-uk]

kill switch is good

ran a decent battery tonight had maybe a couple backfires, ran great until the battery was getting low on juice

was night and day to how it was

 

[chriselmore_1]

Did you try a diff ignition?

 

[Superjetjim]

My money is still on timing... Stator moved/flywheel gap/brain..

Good luck with the testing!

 

[Big Kahuna]

Have you checked for water in gas? Did you swap brains?

Sent from my Kindle Fire using Tapatalk 2

 

[luker]

how is ur starter motor
ive had a similiar issue never had a problem with flame then a start up backfire started to come on the scene , the starter motor gets tired and uses more current than usual and scrambles the flame causing it not to pick up the correct 50degress , another thing we have done here is use a 12 v regulator before the brain to also help rectify this

 

[Marcgraham27]

That's a great tip..

 

[steve-uk]

this is a brand new brain, swapped it out recently, have checked timing etc buddy has a flame also we can swap it out for that one just to see

starter motor is approx 18months old (new oem)

gas tank has been drained suring all of this checking so fresh fuel in a dry tank

if you have details on the regulator id be interested to see the details

 

[steve-uk]

i have a brand new oem starter sat in its box maybe ill throw that on and see what happens

 

[Superjetjim]

i have a brand new oem starter sat in its box maybe ill throw that on and see what happens

Get it done, you have nothing to loose other than a bit of labour..

 

[steve-uk]

benefit of a pfp is the starter is alot easier to access!

 

[luker]

The starter may not be ur problem but sorted out myn , I ll try to get some details on the reg

 

[Superjetjim]

benefit of a pfp is the starter is alot easier to access!

Did it help any?

 

[yamanube]

Did you try a stock ignition?

 

[steve-uk]

havent gotten around to changing the starter yet, long weekend and family commitments

i wont be throwing stock ignition on there its too much of a pain to do when your running tl

im not sure what the difference between having this motor (team scream ss 865) and my previous motor (JM 718) would be that would mean its ignition?

i havent had a single back fire on the previous motor with this igntion

i also swapped out the brain for a brand new one to elliminate that, and have rechecked and reset the TDC/timing

is there somethng about a PV motor with billet cylinders or maybe the porting that can affect ignitions?

ive had many pms telling me that there are other guys with this issue and they are running various different types of ignition

ignition seems to be the easy thing to blame but from everything ive done so far i really dont think its that.

my feeling is it could be the starter, i ran this motor at wavedaze exact same set up and didnt have a single backfire there.

fingers crossed

 

[yamanube]

Its a tough pill to swallow when you spend a ton of money on a part and want to back their product but it seems that if you say "everything is good" but the only thing you haven't eliminated is the ignition, all signs point to....the billet cylinder has to be causing your backfires. Get rid of that and you should be good to go.
I thought I saw another thread with ATP and backfires in the same post. :shrug: