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Discussion Starter #1
My bike is pretty new to me (it's a 2003, just got it used with 2250 miles on it), but I'm having difficulty getting it started quickly when the engine's hot.

When it's cold, even in warm temperature outside, I give it full choke or a little less and it starts right up. I've been through a number of tanks of Gas, so not a stale gas issue.

When it's hot, such as just after you kill the engine, I have a heck of a time getting it started. If you give it no choke, it will rarely catch. Sometimes, giving it a steady quarter throttle while turning it over works with the choke off, but other times I end up giving it a little choke. It all ends up annoying when you're sitting somewhere like the gas station.

When it's warm and has been sitting 30 minutes, it's more of a guessing game.

I'm the first to admit I don't know what's normal for this bike, so I'd appreciate any feedback. Think it's just me, or do I need to do some work to the bike (and if so, what?) ?
 

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Discussion Starter #4 (Edited)
The starter turns over plenty quick, and I have a receipt from a new battery this year. It just doesn't catch. Sometimes I'll get a backfire too.

Of course, I went out a few minutes ago after it setting for an hour and it went varroom... started right up.

Shut it down and gave it a minute, started again with a little throttle. Unfortunately, when I need it to start immediately, no dice.

I see some people are using Seafoam. I don't have any, but I just put in some Marvel Mystery Oil to see if it's a gum/varnish issue in carbs. I think not.
 

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The starter turns over plenty quick, and I have a receipt from a new battery this year.
Is it a maintenance free (MF) battery? If not I go with a good MF before you go for a stator rebuild. I had the same 'hot start' problem for years on my '93. The same problem you describe, found this forum and purchased a new MF battery no problems since.
 

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Sparky!!!
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ok time for my 2 cents worth...

I used to have similar issues... with a normal battery, useing the choke with a little gas no matter what temp the bike is at is normal... switched over to a MF battery, and have not had an issue since...in fact I don't even use the choke any more. also to go along with that, make sure your carbs are adjusted correctly with out the black knob adjusted all the way out... this will give you the best performance you can ask for.
 

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If your bike is cranking fast enough, and it should be pretty fast,Iridium plugs and setting the air gap on the ignitors made my 92 start like a new bike ,after I put a rebuilt starter I got from Crobins 365 on hereI also installed the iridium plugs but the cranking speed and the ignitor gap setting made all the difference .To see if it is a cranking issue ,ride it a while to get it good and warm and pull it over at the top of an incline and let it set about 5 minutes and then try to start it ,if it doesn't Let it roll down the incline and stick it in second gear and see if it fires right off,if it does you have a slow cranking issue and need to decide if it is the battery or the starter,I am thinking battery if you have a year old flooded wet cell battery.If not cared for IE:checking water monthly,and keeping a good float charger on it when sitting for extended periods, a year is about the life of them,Save yourself a lot of work and grief and get a Maintenance Free battery if you don't have one.After all the pushing and cranking I did on mine when it was warm I can sympathize with you.But now I don't worry it starts when I hit the button.The number one problem with mine was it just wasn't cranking fast enough,when all was said and done and current that should have been going to my coils was b eing sucked up trying to turn over the engine.:smiley_th
 

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1985 VN-700
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Vulcan hot starts. Boy its a popular issue. There is a good coil fix on here for that which makes a lot of sense. These bikes wont fire good if the voltage is less than 12 volts. So, from what I have read is all true. Good battery, good starter. Even though it cranks ok it could be pulling the battery down if less than perfect which robs starting volts to the coils. Same with plugs, fresh, correct gap. Im still stymied why the damn things start cold ok. I would think its harder to crank a cold engine than a warm one, so who knows. I actually wonder if these things get a little vapor lock. The motors are really stuck in there tight and the carbs are right between the jugs.
 

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Hot Starts

I bought a used 94 750. It had an aftermarket exhaust on it. It also had the starting problem. I am not a loud person so I changed the exhaust system back to stock. I couldn't believe the difference it made. It starts well now. If when the exhaust system is changed the carburetor is rejetted in might be ok, but if not you will have problems. By the way I really like the bike. It is older but had had a good home and looks good and now runs good.
 

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Sparky!!!
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ok i spoke too soon, thismorning tried to start her... took full choke and half throttle... when cold... won't start when hot at at all.. with the normal start button.. with my aux. start switch it starts right up when hot... this is a first.. my aux start swich shouldn't work at all.
 

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AGM battery is going to solve most of that issue alone. More cranking amps gives your plugs more spark, along with what the starter takes to turn, giving you quick, hot starts. For whatever reason, when the engine is hot, it seems to take a bit more voltage to get a hot enough spark to fire off the engine. Your starter is going to pull a big part of what your battery can give. If your battery is a wet cell, or an older MF, it is probably weak enough that the starter is pulling down your voltage going to the coils and your spark is weak. Weak spark gives you a rich mixture in the chamber, resulting in frequent, LOUD backfires and the engine doesn't want to fire off.
A good combination of a quality AGM maintenance free battery and NGK iridium plugs, will cure nearly all hot start problems.

Some have had great success rebuilding the starter, and setting the gap in the ignition coils, but you should start with getting the right battery in the bike, and do yourself the favor of buying the iridium plugs, and if that doesn't fix your problem, then go with the more involved fixes. You need the AGM battery anyway! No more acid boiling out of the battery and crapping up your electronics and your shiny parts.

You may also want to relocate your R/R to the side of the bike, and out from under the battery where it gets cooked by the goatsbelly. The few degrees of heat you save might also give your electrical system a boost.
 

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Sparky!!!
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ok i spoke too soon, thismorning tried to start her... took full choke and half throttle... when cold... won't start when hot at at all.. with the normal start button.. with my aux. start switch it starts right up when hot... this is a first.. my aux start swich shouldn't work at all.
found my problem... I was messing around with my tank last night to do some more custom electrical work... I hastely put it all back together, and pinched a fuel line... both fuel lines actually.
 

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Sorry if I am the only one here who doesn't get this, but what auxillary start switch? Assuming it is something you added, then my question is why? I figured I would ask and maybe learn something....
 

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Sparky!!!
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look at my sig pic.. the aux start switch is located in my left air box... I am running a custom wiring harness, because the one I had on my bike was toast... A member tried to help me out and sent me another harness, but I had so many other electrical problems, the harness wasn't going to fix my problem. My stock ignition switch wouldn't come loose, and was broken... I ordered a replacement ignition switch, but when it came it... it was in worse shape than the one on my bike, so it was either shell out another 65 bucks for the oem one... or spend 10 bucks and get a universal one. Since I am making this bike fit my personality, I went with option 2. I also removed the stock fuse box, igniter box, R/R, Reserve Lighting Unit, and headlight. For the Headlight and Fuse box, I made my own. The fuse box is now located in my left ear. I don't remember what i got my new igniter box off of, it was some 4 cylinder car that used a wasted spark ignition. The R/R well its an ongoing project... for now I am running the Shindengen FH012AA (Chirron and I did a write up on this look for it in my scribd pages).

Now you are probably wondering why I went to all this work... well here it goes... wait for it... wait for it... Because I can. It might sound like everything is hosh poshed together, but it isn't. I still need to go in and clean up my wiring job. but then again I am not done with my wiring mods so it will stay as is until I finish installing new switches, a custom dash, and re-work my lightbar.
 

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Sparky!!!
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ohh and the reason my auxiliary start switch shouldn't work... I never put a wire from the start terminal on the switch to the start solenoid. the reason it was working... because one of my test lead wires was touching the start terminal making temporary connection.. i fixed this by taping off the test lead.
 

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i did the coil mod that l2fish is talking abt and boy did it make a world of difference eng turns over maybe twice when hot and roars to life
 
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