Trouble starting after sitting for a week - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 3 (permalink) Old 10-13-2018, 04:49 PM Thread Starter
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Trouble starting after sitting for a week

I had the same problem last weekend, but once I got The Beast started up for the first time, I was fine.

The symptom while trying to start is exactly the same as when I have a battery that needs to be replaced. It tries to start, and just never does. The engine is turning over, but not starting.

One problem I have, since I'm still a novice at motorcycle mechanics, is making the choice at the fork in the road between electrical and fuel, because they're definitely different paths. I haven't yet learned to tell the difference with this type of not being able to start.

Battery is the easiest to check. When I need a new battery, I can tell because the cranking voltage goes way down below the magic 9.6 number. But I'm above 10 when cranking. And besides, I bought one of those NOCO portable jump starters, and the bike acts exactly the same way when I use that, both last week and this week.

Last week I tinkered with it a bit -- checking ground connections, etc -- and then just happened across a post that talked about giving it some throttle before trying to start, so I did that and it started right up, to my surprise.

Obviously I tried that today, and nothing. I have an 86, so I have a Prime setting on my petcock. I saw where somebody suggested turning that one for a minute or so, so I did that, and nothing.

I'm pretty sure it will start eventually. And I'm pretty sure I'll be fine, once it does. I should probably also go back to my routine or riding a little every day or two, just to keep from having this problem, because it does seem like this only happens when it's been sitting for a week.

Any thoughts? I'd love to not do this every weekend.

1986 Vulcan 750
Purchased June 2018, as a first bike.
Put 1,300 miles on it so far.
Location: Murfreesboro, TN

AGM Battery, Iridium Plugs
SeaFoam does wonders, and I'm protected by Ride-On
Back tire: Dunlop Challenger.
Front tire: Dunlop Challenger, but about to replace it with a Kenda Cruiser.
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post #2 of 3 (permalink) Old 10-13-2018, 05:06 PM
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Carbs ever been cleaned? Just wondering if maybe the enricher circuits could be plugged up.

I guess a test would be a shot of gas or starting fluid into each carb.

My bike sat all summer and fired up quicker than ever. 10 miles down the road, carbs began plugging up.

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post #3 of 3 (permalink) Old 10-13-2018, 07:45 PM Thread Starter
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Quote:
Originally Posted by Spockster View Post
Carbs ever been cleaned? Just wondering if maybe the enricher circuits could be plugged up.

I guess a test would be a shot of gas or starting fluid into each carb.

My bike sat all summer and fired up quicker than ever. 10 miles down the road, carbs began plugging up.
Good question. No, I have never removed the carbs. I thought I was going to have to, that one time that I lost my Seaform virginity, raved about that, and then the bike wouldn't start the next day. Turned out that replacing the AGM battery solved that, because it wasn't getting enough cranking volts. So I didn't have to pull the carbs.

Right after I wrote started this thread, I went out and realized I had left the key on (hate it when I do that), and then I cranked it to make sure it still had enough battery. And it started right up. For no good reason. It just went from NOT starting, to starting.

But something weird happened, and the same thing happened after I stopped for about 20 minutes, at the halfway point of this afternoon's ride. The RPMs went up to 6-7k and stayed there for several seconds, eventually come down to a high idle. The only other time the RPMs went nuts like that was that time I mentioned before, when I was trying everything I could to start the bike (except changing the battery). I had tightened the idle screw all the way, so once I got a good battery in it, that idle screw caused it to go super high. Fortunately I remembered I had done that, so it only took me a second to start loosening that, which brought the idle to where it needed to be.

This time, though, that wasn't the culprit, and there was nothing I could do to fix the RPMs except to wait.

So... first of all... I'm wondering why that happened. Second... is it a clue to why it's difficult to start my bike after it's been sitting for about 6 days?

Back to carb cleaning: It really is a goal of mine to take some time (certainly as a winter project, if not before then) and pull out the carbs (probably doing an ear shave while I'm at it), and really familiarize myself with them. Taking them all apart, understanding what each piece is, and making sure everything is clean and in tip-top shape. But if course, while we're still in riding season, if I can avoid that fairly big piece of work, I'm happy to keep my bike running without it. As I said, once it starts, I've been real happy with how the bike has been running. Real happy.

1986 Vulcan 750
Purchased June 2018, as a first bike.
Put 1,300 miles on it so far.
Location: Murfreesboro, TN

AGM Battery, Iridium Plugs
SeaFoam does wonders, and I'm protected by Ride-On
Back tire: Dunlop Challenger.
Front tire: Dunlop Challenger, but about to replace it with a Kenda Cruiser.
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