Super Jet Backfires....possible causes

steve-uk

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Barrie - ontario
Since changing the pop off from 19 to 25 its improved

previoulsy it was like a hand gun going off, last ride changed the pop off to 25 and ran a brand new battery only had a couple backfires

when it was at 19psi was running very rich so that was our thinking that there is alot of gas being left over

25 psi seems to be in teh right area, but now im jetted two lean

since changing the battery the backfires have almost gone, had maybe a handful and they were not enough to blow the pv boots off which is what was happening before, i would say its 95% better, now the carbs need to richened back up

but at the battery drained pretty quick, suggestion has been to change the stater as something is causing a draw, and it could be that

this draw is then maybe reducing the current on the battery causing the tl to reset as there isnt enough voltage there

or yeah maybe ill just swap out the billet cylinders and throw them in the garbage....
 
I was chasing a backfire on my dasa 970. With a hot sparking ignition you can get incorrect plug readings cuz the hot spark is burning up the fuel even though you can be running rich. It drove me nuts and finasly after 3 different ignitions, a few carb rebuilds and a full ski teardown i went from a 145 pilot to a 130 and its all good runs like a raped ape and no backfires. It was just running so rich that fuel was puddling somewhere and everywhere. I had so many backfires i bubbled my PFP waterbox, shattered all the teeth off my bendix and a woodruff key. But its all good now. Just a thought.
 
a bad starter will definately keep your battery drained. your ignition needs all the juice it can get. keep a battery tender on your battery.
 

steve-uk

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Location
Barrie - ontario
long time no update...

tried a number of things, list is to long to type.. not enough characters

my "ignition issue" was as simple as a start stop relay

it finally shiat the bed which gave it away

put a new one in this evening and went out for a rip, problem solved!

what seems to have been happening was the relay was causing a draw, which was draining the batter making the ignition run incorrectly and then in turn causing a back fire

now its running good i have to go back to carb tuning as it was running lean
 

steve-uk

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Location
Barrie - ontario
thanks man, yeah i was ready to give up hope

had just swapped out the battery for a HD battery, put in a brand new OEM starter, hit the start buttin and the starter spun and didnt stop.... had to pull the battery leads, pulle dthe ebox open and the evidence was there for all to see.. relay had given up completely and had exploded
 
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