Difficult starting when hot - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 13 (permalink) Old 09-03-2005, 05:18 PM Thread Starter
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Difficult starting when hot

I have a problem with my 1993 VN750 A9. It starts perfectly when cold but when the engine is really hot, say after a fuel stop, it can take a long time to start again. Battery & plugs are good & i've checked the throttle/choke cables & they are all adjusted correctly. If I wait 10-15 minutes it starts fine. Once running it goes perfectly. Any ideas? Also, I have aftermarket mufflers fitted, is there any way of reducing the backfiring I get on the over run? Had thought of backing out the pilot screws on carbs a little but am reluctant to do so until I have some advice on the matter. Have pulled the plugs after a good run & they seem normal in colour.
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post #2 of 13 (permalink) Old 09-04-2005, 09:05 AM
 
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Re: Difficult starting when hot

Quote:
Originally Posted by Ernie
I have a problem with my 1993 VN750 A9. It starts perfectly when cold but when the engine is really hot, say after a fuel stop, it can take a long time to start again. Battery & plugs are good & i've checked the throttle/choke cables & they are all adjusted correctly. If I wait 10-15 minutes it starts fine. Once running it goes perfectly. Any ideas? Also, I have aftermarket mufflers fitted, is there any way of reducing the backfiring I get on the over run? Had thought of backing out the pilot screws on carbs a little but am reluctant to do so until I have some advice on the matter. Have pulled the plugs after a good run & they seem normal in colour.
Ernie...you ARE cracking open the the throttle a bit when hot starting as per the OM, right???
I'll bet this is the #1 hot start problem. It plagued me for a month when a got my bike, then I read the OM....
If you are doing this, then check out the pickup coil gap, they are located under the left outer cover.
There is info on here I think, or over at the Y! group that could help with this.
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post #3 of 13 (permalink) Old 09-04-2005, 09:11 AM
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Re: Difficult starting when hot

this from the VN750 yahoo group might help

You might want to have your mechanic give this a try. I too have slight problem starting the bike when it is warm, but can usually get it going by choking half way, then rolling on throttle and backing off choke when it starts to catch.

But I found this a while back, somewhere, I don't recall where, and you might want to have your mechanic try this:
If I had more problems this summer I was going to give this a try, as well as relocating the RR, and new plugs, etc.

Sempai.


Possible solution to hard starting your VN7XX when hot.
================================================== =====

Problem: Once my bike was good and hot, I would pretty regularly have problems restarting it after shutting it off for refueling, etc.... Once the starter was engaged, the bike would continuously turn over but never fire. After some e-mail discussion with Gary Versteegh from the main VROC board, I adjusted my pick up coils as described below. This seems to have eliminated my hard starting problems. This procedure may or may not solve your hard starting problems. Also, please note that the pick up coils are not designed from factory to be adjustable. This procedure requires modification to the stock components.

If you have any question, feel free to send me an e-mail to [email protected]. I will be happy to answer any questions.

Adjustment of pick up coils.
Remove the 3 phillips head screws on the left side. This will allow you to remove the pick up coil cover. You will need to place something under the bike to catch the oil although oil loss will be minimal. A rag was enough for me. Once the screws are removed, the cover should either come right off or you may need to pull on it. Mine was on pretty good and I had to physically pull on it to get it loose. The three screws and the cover all have separate o-rings. Once the cover is off, you will see the two pick up coils mounted to the stator cover inside two holes. They are mounted at roughly the 9:00 and 11:00 o'clock positions. Behind the stator cover, there is a rotor. You may need to rotate the rotor using a socket wrench on the shaft bolt in the center to align the small "plate" on the rotor with one of the pick up coils so that you can measure the clearance. Once you have measured one, rotate the rotor again so that you can measure the other. Gary recommends .020 clearance. Mine were about .030 or more. To adjust the clearance, remove the two screws which secure the pick up coils to the stator cover. You will most likely need to slightly elongate or slot the holes in the "ears" of the pick up coil mounting brackets. Gary indicates that a chain saw file works well for this but I used a rotary tool with a small grinding wheel on it. You will also see that there are 3 small protrusions coming out of the stator cover that each of the mounting
"ears" of the pick up coils fit into for proper placement from the factory. You will most likely have to knock the one closest to the center off to be able to make the necessary adjustment. A sharp chisel works well for this although you may want to cover the holes in the stator cover with something to prevent the little piece from falling inside the engine. Once the protrusions are knocked off and the holes are elongated, it is time to put the pick up coils back on. Set them back in their holes and start the screws. Place your .020" feeler gauge between the coil and the rotor "plate" and tighten the screws. Once you are satisfied with the clearance, tighten down the screws and do the same with the other coil. Gary recommends that you use both an impact screw driver and lock tite on the screws. I don't have an impact driver but I did use lock tite. Once both are set, put everything back together and test it out. I don't have a digital camera or I would have taken and posted some pics but you can look through the pictures in the Clymer's manual to get an idea of what I am talking about. In my manual (I assume they are all pretty much the same) the pictures on pages 296 to 302 should give you an idea of what I am talking about.


ryanwilliamrunge wrote:

> Does anybody know of a good mechanic in the North Carolina/South
> Carolina area (preferably near Charlotte)? I am having the problem
> with my Vulcan 750 sometimes either backfiring or not starting at all
> when trying to start the bike with a warm engine (but other times it
> starts up fine it is very sporadic). It has been doing this ever
> since I bought the bike a year ago. I have taken the bike into the
> Kawasaki dealer, but they say that they can't fix the problem until
> they actually see the problem for themselves first hand, and, of
> course, every time they try to start it up with a warm engine, it
> starts just fine. I have given them copies of messages posted on
> this site from other people who have had the same problem, including
> messages that give suggested fixes to the problem, yet they won't
> seem to do any work on the bike until they actually see the problem
> with their own eyes. And the bike has been in the shop for over a
> month now. Since I am by no means capable of performing mechanic
> abilities myself, I'm hoping to find another mechanic that can fix
> this problem. Anybody know of one in the SC/NC area?
>
> Thanks

Dianna
Conway, AR
Patriot Guard Rider
2000 VN750 Sere (Serendipity)
1990 GL1500 (Ole Blue)
1986 VN750 EVie (project bike, heavy custom)
VROC # 11628 / 25000-H
ARVROC # 12 Coordinator and Crowd Control
OKVROC # 18 (H)
TNVROC # 45 (H)
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post #4 of 13 (permalink) Old 09-04-2005, 04:35 PM Thread Starter
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Thumbs up Re: Difficult starting when hot

Thanks for the advice guys. I always start the engine hot according to the owners manual. I am seriously thinking of trying the pickup coil idea though. Will let you know how I get on. It has been suggested to me that the IC ignitor may be at fault but I am not so convinced. Surely the unit should either not work at all or work perfectly? I am not an electronics expert so I can't be sure + the cost of a new unit prevents me from trying. I'm sure i'll solve the problem somehow.

Thanks again.
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post #5 of 13 (permalink) Old 09-05-2005, 04:08 PM Thread Starter
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Re: Difficult starting when hot

Hi all. Just an update on my starting problem. Don't know if this is a coincidence or not by I tried a little experiment earlier on. I have always used 95 octane unleaded in my VN but when I filled up earlier today I used the "super unleaded" 97 octane stuff. (expensive!) Did a 30 mile round trip to visit a friend with a couple of quick stops on the way & it restarted perfectly every time! Weird? Surely going up a little on the octane rating can't make that much difference? I know that unleaded can never be as good as the good ol' 4-star leaded we used to have before it was taken away. Also, I know you guys over in the US don't have as high an octane rated fuel on general sale anyway as far as I know. (correct me if i'm wrong) I rented a Chevy Tahoe for a couple of weeks when I was over there last year & I seem to remember using something in the region of 87 octane. What i'm basically saying is that the VN must be generally set up for lower octane unleaded seeing they are all built in the USA. (again, correct me if i'm wrong). Will keep my fingers crossed that I may have solved my problem. Also, my bike has just passed the 70,000 mile mark & still burns no oil - not bad eh? I've owned it from 3 months old with 2,000 miles on it.
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post #6 of 13 (permalink) Old 09-06-2005, 10:10 AM
 
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Re: Difficult starting when hot

Quote:
Originally Posted by Ernie
Also, my bike has just passed the 70,000 mile mark & still burns no oil - not bad eh? I've owned it from 3 months old with 2,000 miles on it.
Sweet!! Glad to hear this. I drive my bike a lot and I hope I can get the same results as you with the 'no oil burning'. it's only a month old with 2500 miles on her now.
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post #7 of 13 (permalink) Old 09-06-2005, 10:17 AM Thread Starter
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Re: Difficult starting when hot

Hey! I reckon anyone can achieve my mileage + more with a little tender loving care. I change the oil & filter every 3000 miles & never work the bike hard until it has warmed up. Think those are the most important things. I'm sure you'll have many years of trouble-free riding ahead of you.

Incidentally, I notice you are from PA. I have a friend who lives in Bedford County PA - a little place called Alum Bank. Are you far from there? I go over & visit him & his family every year. Love it over there, would love to move there someday. Have got the slightly irritating problem of not being able to get a work permit though. Maybe one day?

Take care for now & ride safe.

1991 BMW K1100LT

1980 Suzuki GS1000G
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post #8 of 13 (permalink) Old 09-06-2005, 06:26 PM
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Re: Difficult starting when hot

The owner's manual for the 2004 VN750 does say to use 87 octane gasoline. I've stuck to that and had no problems.

Wally Colly

2004 VN750 "Freedom"
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post #9 of 13 (permalink) Old 09-07-2005, 09:12 AM
 
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Re: Difficult starting when hot

Ernie: Yeah that is over towards Pittsburg. I live more towards Lancaster on it's east side. Maybe next time you are over this way we might be able to hook up one day? Yeah those work permits can sometimes be a pain to get.

Wall: So does the 2005 MOM

I'm coming up on my first 3000 oil change. Should need it at the beginning of next week.
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post #10 of 13 (permalink) Old 09-10-2005, 06:18 AM Thread Starter
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Thumbs up Re: Difficult starting when hot

Lazydog - yeah, would be a good idea to try & arrange to meet up sometime. Unfortunately I won't be able to come over until next year now but we'll try & arrange something nearer the time. I always rent a car when I come over so getting to you won't be a problem. At a guess, I reckon you are about a 120 mile drive from my friends house where I stay. It is my intention to visit Gettysburg when i'm over next so maybe I could combine that day with a visit to you. My friend from Alum Bank is off on something called the Dog Run today, up near Johnstown somewhere. Supposed to be around 600 bikes turning up. Wish I was over there to take part.
Anyway, take care for now & ride safe,
Ernie.

1991 BMW K1100LT

1980 Suzuki GS1000G
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