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post #1 of 8 (permalink) Old 04-30-2005, 12:48 AM Thread Starter
 
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Backfire on startup

I've had my 2001 for a little over a year now. About 3500 total miles. I bought from a reputable dealer and had no issues for about 6 months. It then started backfireing when I was cranking it to startup, ocasionally. for the last 6 months it's just gotten worse and worse. Now it backfires better than it starts.

Could it just be dirty plugs? Or is there a basic carb adjustment I can try?

A couple of months ago I got a slow coolant leek from the front cylinder bottom gasket, while engine is running. Since I noticed it I've driven a couple hundred miles and havn't yet needed to ad fluid, though I know I will have to have this delt with, but I'm wondering if it is a side effect of the backfireing.

Any ideas? And thanks
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post #2 of 8 (permalink) Old 04-30-2005, 07:59 AM
 
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Re: Backfire on startup

Portmuir,

I'd try a new set of spark plugs first. It's an easy (and cheap) thing to do to start isolating your problem, and it won't hurt to have a new set in there anyway.

CD in Anadarko, OK
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post #3 of 8 (permalink) Old 04-30-2005, 10:00 AM
 
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Re: Backfire on startup

Quote:
Originally Posted by Portmuir
I've had my 2001 for a little over a year now. About 3500 total miles. I bought from a reputable dealer and had no issues for about 6 months. It then started backfireing when I was cranking it to startup, ocasionally. for the last 6 months it's just gotten worse and worse. Now it backfires better than it starts.

Could it just be dirty plugs? Or is there a basic carb adjustment I can try?

A couple of months ago I got a slow coolant leek from the front cylinder bottom gasket, while engine is running. Since I noticed it I've driven a couple hundred miles and havn't yet needed to ad fluid, though I know I will have to have this delt with, but I'm wondering if it is a side effect of the backfireing.

Any ideas? And thanks
PM....my 01 used to do this occasionally...actually I it was my doing.
Don't work the throttle at all before initial cold starting...that's what the choke is for. I used to give it a slight twist just because....I don't now.
Check the adjustment on the throttle cables to be sure that the throttle plates are fully closing. If the cables are too tight, you may be getting unwanted additional fuel in there at startup.
Lastly...the battery. If it is not up to par, you will have starting issues. If you've got the stocker in there, I'd change it ASAP...to a MF AGM Yuasa/Westco.
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post #4 of 8 (permalink) Old 04-30-2005, 06:13 PM Thread Starter
 
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Smile Re: Backfire on startup

Thanks much, I just put in new plugs and battery and she started up clean and smooth. I have to admit, bearing in mind JM's admonishment to stay away from the throttle; I probably have been causing myself some of this trouble. Old kick start habits die hard.

As a side note, I observed something worth sharing during the plug change. I wuld recommend heartily that befor you pull the plug from the deep recess, you tip the bike to that side for a few seconds. It may just be an issue in the soggy Northwest, but that socket could hold alot of water that you would be dumping right into your cylander if you don't drain it off first.

Cheers all
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post #5 of 8 (permalink) Old 04-30-2005, 09:54 PM
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Re: Backfire on startup

Quote:
Originally Posted by Portmuir
I wuld recommend heartily that befor you pull the plug from the deep recess, you tip the bike to that side for a few seconds. It may just be an issue in the soggy Northwest, but that socket could hold alot of water that you would be dumping right into your cylander if you don't drain it off first.

Cheers all
Good tip...thanks

Steve "Fallguy" Fall
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post #6 of 8 (permalink) Old 05-01-2005, 10:45 PM
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Re: Backfire on startup

**As a side note, I observed something worth sharing during the plug change. I wuld recommend heartily that befor you pull the plug from the deep recess, you tip the bike to that side for a few seconds. It may just be an issue in the soggy Northwest, but that socket could hold alot of water that you would be dumping right into your cylander if you don't drain it off first.**


I read a tip that suggested blowing compressed air in before removing the plugs in case you've caught some sand or small rocks. Imagine letting something like that fall into the cylinder, ouch!!

'04 750A- and loving it!
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Using a Purlator One PL14610
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post #7 of 8 (permalink) Old 05-03-2005, 07:07 PM
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Re: Backfire on startup

Do you have a MF battery? These are also symtoms of a week battery. If you don't have a MF battery, make sure the water levels are correct in all cells and the battery is fully charged.

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post #8 of 8 (permalink) Old 05-04-2005, 05:31 PM
 
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Re: Backfire on startup

Loran's right - mine used to backfire like a cannon every time I started until I put the WestCo MF battery in. Too bad that's not the source of my "Loose Cannon" nickname...




Quote:
Originally Posted by Loran in Npvl IL
Do you have a MF battery? These are also symtoms of a week battery. If you don't have a MF battery, make sure the water levels are correct in all cells and the battery is fully charged.
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