Back Fire When Re-starting.....help! - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 11 (permalink) Old 03-25-2007, 11:10 AM Thread Starter
 
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Back Fire When Re-starting.....help!

I have a 86' that starts fine, runs great. However, after it is up to temp after running for a while, when you shut it off and try to re start it, she cranks and cranks, then lets out a hellava backfire that I have never heard as loud in my life. After a few min. of this she may or may not start.
Can anyone help a buddy out? I can not afford another right now she is all I got any help would be great!
THANX!!!!!!!!
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post #2 of 11 (permalink) Old 03-25-2007, 11:28 AM Thread Starter
 
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Other things I forgot is it starts fine when you first (cold) start it and again runs fine after it starts.
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post #3 of 11 (permalink) Old 03-25-2007, 11:47 AM
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First - get a maintenance free battery if ya haven't done so yet. It really does help with some starting issues and will save your charging system.

Backfiring is partially caused by the emissions crap kaw put on the bikes (part of it is you are probably flooding it in the morning). Do a search on marbling or coastering and that should help ya might have better luck searching for "reed valve". My bike backfired like a MF till I put some vacuum plugs on the reed valves (marbled first - that helped but the hoses were rotten - so I just put on vacuum plugs).

Curtis - Albany Oregon.
Currently receiving therapy from "Doc" - My 1985 VN700.

Daily rider in NorthWET Oregon.
Ammo Can Saddlebags
Shaved and Rejetted. Coastered. Degoated w/ Hardley pipes.

Bought Feb 2007 with 12K miles.
Hit the 24k mile July 2008

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post #4 of 11 (permalink) Old 03-25-2007, 04:29 PM Thread Starter
 
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bike starts fine in the morning or anytime it has sat for a long period of time and cooled off, it is when it's hot that it won't start proper. I don't touch the gas or the choke and it will still do it.
Thanks, keep um comin'
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post #5 of 11 (permalink) Old 03-25-2007, 04:45 PM
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That makes your bike like all of the others with its backfiring. First time mine did it, it scared the crap out of me. I did the MF battery and marbeled, both made unbelieveable differences, but I went a bit farther and instelled iridium plugs. I have yet to have the backfire occur, even in the middle of summer after an immediate restart of a warm engine. I won't miss to gun fire!

Ben-
SW Ohio

'02 VN750
Pipes drilled
Spline lubed
R/R relocated
AGM batteried
Iridium equipped
LED tail lighted
8000-ish miled
Soon to be MCCTed

Lovin Life.
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post #6 of 11 (permalink) Old 03-25-2007, 05:47 PM
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Ditto, everything above ^^^^^

Ron from Jersey
2005 VN750
HellFire windshield
Kaw extended backrest
Cobra exhaust
Re-located stator wires
Side bags
15,000 Miles July/2012
It's PAID OFF ! May 2009
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post #7 of 11 (permalink) Old 03-25-2007, 08:14 PM
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With the MF battery, they apparently do better with hot starts as well as cold starts - if you search the board, MF batteries solve a lot of the hot and cold starting issues.

Curtis - Albany Oregon.
Currently receiving therapy from "Doc" - My 1985 VN700.

Daily rider in NorthWET Oregon.
Ammo Can Saddlebags
Shaved and Rejetted. Coastered. Degoated w/ Hardley pipes.

Bought Feb 2007 with 12K miles.
Hit the 24k mile July 2008

http://photobucket.com/curtis97322
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post #8 of 11 (permalink) Old 03-25-2007, 10:16 PM Thread Starter
 
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Sounds great! due to my ignorance please explain what a "mf" battery is and what is marbeled?
It would be great, my new tank will be in tomorrow and I could try these items also.
THANX!!!!!
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post #9 of 11 (permalink) Old 03-25-2007, 10:41 PM
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MF = Maintenance free = Absorbed Glass Mat (AGM) battery.

Do a search (here) on battery and you'll find part numbers. Seems like there might even be a current thread with the same. Wesco and Yusa are the popular picks - the sears diehard AGM battery is made by one of the two (Wesco?) so is a popular choice.

Marbled - searching for that is a PITA here since some people have "marbled" in their signature - involves sticking a marble in the hose connected to the reed valve. Search (here) for "Reed Valve" for that information better stated.

Might be a good idea for you to check out the vulcan verses - there's a lot of good info there on some VN750 specific "what to do's".

Curtis - Albany Oregon.
Currently receiving therapy from "Doc" - My 1985 VN700.

Daily rider in NorthWET Oregon.
Ammo Can Saddlebags
Shaved and Rejetted. Coastered. Degoated w/ Hardley pipes.

Bought Feb 2007 with 12K miles.
Hit the 24k mile July 2008

http://photobucket.com/curtis97322
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post #10 of 11 (permalink) Old 03-27-2007, 12:21 PM
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Marbling is probably the easiest mod I've done yet. The hardest thing was finding marbles the normal size. You squeeze the clamp on the hose coming from your reed valve and remove the hose. Stick a marble in the hose, push it back far enough to be able to put the hose back on with the clamp, do it on both sides, rear cyl is on the back left top of engine, front cyl is on the front right kind of behind your air filter. I did mine in the parking lot where I work after I had aquired a couple of marbles from someone's desk top fish bowl. Now it rumbles when I decel, but it hasn't backfired once since I put in the marbles. Some have had to also adjust your idle mix screws out a little, but I never had to. My caps were already off the carbs so apparently the previous owner adjusted them to my liking.

Fergy
Kyle, TX VN750.com member #707 VROC#19556
2002 VN1500 Classic
Spline Lube Procedure, with photos, R/R Relocation and Coil Mod
Rusty Tank Cleaning!
Electrical Fault Finding Flowchart
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