| [ Total Views: 669 | Total Replies: 14 | Thread Id: 43323 ] |
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 Dozza
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 posted on August 31st, 2005 at 04:53 PM |
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backfiring 1600???
Help!!!
I have tried all the obvious things....
Anyone got any ideas, I rebuilt the top end and cant find the fault.
Its fine at idle but when I increase the revs, she backfires and doesnt run smoothly.
I adjusted the tappets - twice! checked the points.... could it be the carb? I put new vacuum hoses..
Any ideas
Low Slow and Cruising
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 barls
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| posted on August 31st, 2005 at 04:55 PM |
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have you checked the exhaust for leaks cause that will cause backfiring when backing off.
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pete wood
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| posted on August 31st, 2005 at 06:08 PM |
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I think you have a timing issue. Are the plugs on in the right order? Have you checked the timing? In addition, is the vacuum hose connected to the
dizzy (standard dizzy, if it's a 009 don't worry)
BTW, is it off the throttle or on the throttle, under load or standing still?
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Anthiron
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| posted on August 31st, 2005 at 06:15 PM |
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is it running really lean? have u tried increasing the fuel mixture?
is it running to retarded? try advancing the timing a tiny bit.
could be a blocked jet in the carbie thats making the engine starve of fuel.
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Dozza
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| posted on August 31st, 2005 at 07:11 PM |
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Yeah I checked the exhaust.... no leaks.
It backfires on acceleration whilst standing and under load, also when slowing in third gear .... so I guess it back fires pretty much under all
conditions..... idles ok though!
I did the timing the old fashion method, static, and have tried adjusting it either way.... no difference...
Havent messed around with the carbie to much yet, I tried another carbie on it and it did the same so I thought it prob wasnt that...
Anyone got any steps to take from here???
Low Slow and Cruising
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lugnuts
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| posted on September 1st, 2005 at 02:29 AM |
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I reckon static timing sucks,buy a strobe,the timing might be perfect at idle but max advance is well u never know till u find out.:P |
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Old Dubber
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| posted on September 1st, 2005 at 05:56 PM |
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Just to get it perfectly clear.
It "backfires" from where?
Out the top of the carby ?
or out through exhaust?
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squizy
A.k.a.: Paul
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| posted on September 1st, 2005 at 08:54 PM |
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Are you running a standard carby and air filter? Is the air filter secured with no leaks?
How long has it been doing this for? Have you had a dodgy batch of fuel?
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Dozza
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| posted on September 1st, 2005 at 09:46 PM |
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backfires out the exhaust....
Dodgy batch of fuel??? I hope not! :P
Stabdard carbie, does it with the air filter on and off! makes no difference
just put the motor back
together again.....
Low Slow and Cruising
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76camper
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| posted on September 2nd, 2005 at 05:25 PM |
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cam gear not in correct place... take of ya dissy cap get it ready to fire cylinder 1, go take off the rocker cover for cylinder one and see if the
exhaust valve is open, spin it for how ever many degrees (some tell him when exhaust valve should open). If it seems outta wack then you are going to
have to pull it all apart and realign the cam gear, hopefully it isnt that... bitch to fix
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plough
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| posted on September 4th, 2005 at 08:56 AM |
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have you tryed the obivous... points in the dizzy????
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 Bizarre
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| posted on September 4th, 2005 at 10:49 AM |
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several times i have bought new points that have NO tension in the spring
Even though it may be new - check the obvious several times
Futue te ipsum!!!
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vwtrev1
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| posted on September 5th, 2005 at 01:42 PM |
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Backfiring 1600
I had this trouble for two years and tried everything/ plugs /points / timing/ vac leaks.
I fixed it by putting in smaller diameter air correction jet.
If the air correction jet is to large it will lean out the mixture making it back fire. Air correction jets work opposite to the main jet. Mine was
running 1.25 and I put in 1ml. A 127.5 or 130 main helps heaps also.
Trev//
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koolkarmakombi
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| posted on September 5th, 2005 at 01:47 PM |
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What sort of heads have you got?
A cracked head can let gas in/out and let it backfire.
air leak in any vacuum lines
dropping spark
exhaust leak
If its no obvious, slowly go back over everything
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