Bought A 93 Vfr750, It Wont Start Anymore

in regards to jumping your bike for your starters sake DO NOT JUMP YOUR BIKE WITHA CAR!!!!!!!!!!! I learned this the hard way it WILL COOK THE ARMETURE IN THE STARTER!!!! Car/truck's produce way more amps than your bike cost me about 400 in '94. just a word of warning

 

WELL, i've done it many times without probs, so was i just lucky???

(the car/truck should NOT be running)

 

A car battery in itself won't cook your starter. Engaging it for long periods of time without letting it cool COULD however. A larger capacity battery would make this easier if you're not careful. Or if your armature is leaking current already I would guess it could make a short to the case or the core show up where as a weaker one wouldn't be able to jump the gap. If that's the case your armature is faulted anyway.

 

Jumping your bike off a RUNNING car or truck is the best way to COOK a regulator/ rectifier. Squirrelman is right on the money.

 

AN impotant point was mentioned that many ignore or don't think about:
A starter has a "duty cycle," meaning that it must be allowed to cool after brief ( 10-12 seconds) use.

FOR example, holding the starter button for a continuous 30 seconds is enough to damage it from heat build up.

IN this same way a bad ignition switch, failed fuel pump or pump relay, fouled plugs, etc. can ruin your starter from over-use.

 

I've found the best way to damage your reg/rect or your stator windings is to jump a battery that's too weak or discharged to spin the starter properly, then go for a ride expecting the bike's charging system to act as a battery charger. That'll get stuff hot for ya.

Something I come across every so often is a customer's bike that will spin the starter at a decent pace, but starts hard or starts at the instant you let up on the start button. Often a good fully charged battery will fix this. The large demands of the starter drops the VDC of the battery so much, there's just not enough leftover to operate the battery type ignition. I'm not makin' that up, you can see it with a multimeter.

You know...jumping a vehicle is sometimes necessary, but it's always kind of a risky procedure. There's a lot of resistance in those clamp type connectors, connections are often corroded or oxidized, causing execessive heat and sparks to jump. People are a little stressed because their vehicle is not starting so due caution is not always observed. It's really easy for a hanging pos jumper cable to brush a ground, not to mention hooking the cables backwards.

 

so turns out some of the coils were bad, so it was only runnin on 2 cylinders. its going great now. thanks for all the input

 

NOOOOO! although it runs much better and theres a ton more power, it still start really hard. it was sitting all day sunday and on monday it took like 5 mins to get it to hold an idle. its back like it was when i first got it. press the starter and it runs for like 2 seconds and dies, repeat 10 times untill it gets some warmth in it and then itll be fine.

 

another weird thing thats happening, no engine braking, itll just kind of coast when i let off the throttle.

 

Jay...what is the outside temperature when you're trying to start it?

 

about the mid 40's

 

im going to try to check the compression in the next couple days. i cant think of anything else.

 

Sounds like a really bad sync or your choke is still "on".

 

Compression test is a good idea.

Try a new set of plugs. They can foul easily in cold weather.

Go back to the basics. When it's starting hard, check spark...note if the new plugs are wet or dry. You need to narrow down the possibilites a bit.

 

Sounds like a carb sync issue to me. Did the techs at the shop check that when they were "fixing" it?
My 86 VF500F and VF500C did the same thing until I synced the carbs.

 

was gona do a compression test but the none of the adapters that came with the gauge seem to fit.

it was 60 outside today and it started up fine with no problem at all

he said he reset the carbs but i called and told him whats going on and he is gona fix it sometime this week (no charge)

 

There's nothing wrong with your bike. Under cold conditions mine will do the same thing. You need to figure out which starting technique to use when it's cold. Try and just crack the trottle maybe a 1/4 turn when you first crank it. Do it when you engage the starter NOT before.

 

if thats true i am very dissapointed then, even my little baby ninja starts just fine in well below freezing temps.

 

Your bike should start fine in the 40's. Now if it were single digits or teens...and you hadn't run your bike for several weeks, that would be another thing.

RC has a point about technique though. I've usually had the best luck full enrichener, NO throttle with the older VFR's I've owned. The mixture has to be right for a good start. It may help to know that there's nothing in a 93 VFR (no accel pumps) that you can do to the throttle to allow more gas on start up. Think of the throttle as an air valve instead. If you have to open it to start the bike it's 'cause the spark plugs are on the verge of flooding or fouled with gas.

Cold weather requires RICHER mixture for starting a cold bike. My experience has been opening the throttle at all is the wrong thing to do. Or if you 'blip' the throttle prematurely the bike often kills.

 

on a cold start i always set my choke to full on, then i hit the starter. if it fires right away and goes to high idle i leave it alone. if it cranks for more than a few seconds or coughs without starting then i crack the throttle a little bit. In either situation i dont touch the throttle or choke once it starts or it will stall. I find this is what works for me. We're not dealing with fuel injection here and different bikes under different conditions will require different starting procedures. Does you're owners manual suggest the use of hotter plugs for you're current temps?