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Backfire

Posted: Mon Jun 23, 2008 5:17 pm
Author: Taffus
Hi
took my Z650 out today as the GPz has fried its rectifier.
Haven't used for a few weeks, it was very hard to start this morning and will not idle, turned up the idle but it backfires a lot on closed throttle
Any ideas?

backfire

Posted: Mon Jun 23, 2008 6:14 pm
Author: Russ
Eyup dude
Whip your plugs out mate, if they're black its rich and if they're white its lean or ( and this can cause similar symptoms) the timings slipped.

Posted: Mon Jun 23, 2008 6:38 pm
Author: RALPHARAMA
.... another reason for back firing is a leaky zorst. Where the headers go into the collector on my 'arris it sucks in air and ignites the unburnt fuel in the zorst. Not a lot and I really can't be arsed to do anything to cure the occasional pop on overrun.

Have you got the dreaded NGKs in your bike? If so they prolly got a little damp from the not immediate start and and decided to play broken - another job for Denso Plug :D http://www.spark-plug.co.uk get 'em bought :lol:

Posted: Tue Jun 24, 2008 7:37 am
Author: Taffus
thanks for the replies, took the simple option and filled the tank from a known good petrol station, had to reset the idle to 1500.
Ran the bike this morning no pops or bangs and idle running at 2000!
I guess it was bad petrol (dregs?) as one of the stations I use is a Shell at Ripley just off the A3.
One of the other motorcyclist where I work has got the same probl;em on his revere and he uses this station too....

Posted: Tue Jun 24, 2008 8:42 am
Author: RALPHARAMA
Never a good plan to run old bikes on reserve for any period of time - ask Mikey :lol: :lol: