Slow crank, no start 85 750. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 46 (permalink) Old 08-15-2018, 09:11 AM Thread Starter
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Slow crank, no start 85 750.

Like I said I have an 85 750 I just bought not running. He was riding on the highway and it sputtered for 5 seconds and died. Guy said carbs were cleaned 800 miles ago and I've got paperwork to prove it, but I have a slow crank and I cant get the bike to turn over. So far I've checked fuel, seems to be getting fuel as all the spark plugs are wet, it is getting spark on every cylinder. I've bypassed the starter relay trying to jump it and tried traditional jump starting from a literally brand new car battery still cranks turtle slow. However, it will crank at a fairly normal speed with the spark plugs out. I cant figure this out any help is appreciated where do I start
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post #2 of 46 (permalink) Old 08-15-2018, 12:02 PM
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sounds like starter motor brushes worn to me if ok with plugs out

Vn 750 A2 1986 rebuilt engine, crank shaft, half casing,shell bearings,con rods,rear cylinder head,oil pump,water pump ,(had ceased bearing rusted up),tie bar upgrade,clutch basket drilled,front cylinder cam chains,toc springs,stator,shaved, rectifier,agm battery,solenoid ,starter motor (used) re-spray ongoing.
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post #3 of 46 (permalink) Old 08-15-2018, 01:35 PM
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That couldn't have anything to do with the initial problem of dying on the highway could it?
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post #4 of 46 (permalink) Old 08-15-2018, 01:53 PM
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Don't rule out the possibility that there is more than one thing wrong with the bike. It seems unlikely that the slow starting is related to the 'dies on the highway' problem.
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post #5 of 46 (permalink) Old 08-15-2018, 02:49 PM
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Originally Posted by Iamizzy96 View Post
Like I said I have an 85 750 I just bought not running. He was riding on the highway and it sputtered for 5 seconds and died. Guy said carbs were cleaned 800 miles ago and I've got paperwork to prove it, but I have a slow crank and I cant get the bike to turn over. So far I've checked fuel, seems to be getting fuel as all the spark plugs are wet, it is getting spark on every cylinder. I've bypassed the starter relay trying to jump it and tried traditional jump starting from a literally brand new car battery still cranks turtle slow. However, it will crank at a fairly normal speed with the spark plugs out. I cant figure this out any help is appreciated where do I start
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That couldn't have anything to do with the initial problem of dying on the highway could it?
Did you make 2 accounts?

Anyway, could it be a compression issue? Maybe pull 1 spark plug at a time and crank after each one and see if the cranking is only easier after pulling a single plug.

Also, is the oil in half decent shape at least? If the oil is old it might have turned into sludge
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post #6 of 46 (permalink) Old 08-16-2018, 11:41 AM
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maybe a bad earth connection , that would affect performance and starting/turnover

Vn 750 A2 1986 rebuilt engine, crank shaft, half casing,shell bearings,con rods,rear cylinder head,oil pump,water pump ,(had ceased bearing rusted up),tie bar upgrade,clutch basket drilled,front cylinder cam chains,toc springs,stator,shaved, rectifier,agm battery,solenoid ,starter motor (used) re-spray ongoing.
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post #7 of 46 (permalink) Old 08-17-2018, 11:51 PM
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So, I've checked compression among all cylinders and theres no problems there. I've removed the starter and ordered a rebuild kit. Oil looked used but not awful it was still slightly transparent. It started a new issue when I crank it, it blows the main fuse.
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post #8 of 46 (permalink) Old 08-18-2018, 11:08 AM
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So, I've checked compression among all cylinders and theres no problems there. I've removed the starter and ordered a rebuild kit. Oil looked used but not awful it was still slightly transparent. It started a new issue when I crank it, it blows the main fuse.
Fuse problem may go away once the starter is fixed, probably just drawing too many amps, overheating the circuit.

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post #9 of 46 (permalink) Old 08-19-2018, 01:18 AM
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That's what I was thinking man, I appreciate your input and I will keep you all posted. This is my first bike and I am eager to get going before the weather turns here in Ohio. Have a good one ✌️
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post #10 of 46 (permalink) Old 08-21-2018, 05:17 AM
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So, the starter rebuild kit was a success but it did not fix my issue. Still a slow rather hesitant crank with no start. Definitely moving faster but still sounds like it's under heavy load in neutral. Where do I go next? I'm legitimately stumped.
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