Starting problems. New starter, bendix, battery

[johnwohl]

Starting off this season with a fizzle.

Last year before winter I got a "100cc" bbk but I never got it farther than starting and idling.

The starter was beginning to go out when I put it away for the winter so I kept a mental note of that.

So far this year I rebuilt the bbk with new gaskets, studs, nuts, washers and a new torque wrench to make sure everything was ready to go, and I changed the battery to an agm, got a taida high torque starter, and a new starter bendix.

The problem I am having now is that where before the stock starter would just kind of chug and not turn it over fast enough to start the new starter setup will not engage for tmore than one revolution 95% of the time and when it does it gives only a few revolutions before spinning freely again.

See the video:

When it does happen to catch, the scooter will start and idle for a while.



I didn't get a chance to mess with the jets last year so it obviously needs to be tuned, but I can't very well do that if I can only start it 1 out of 100 tries.


I don't get it. The starter motor is very beefy and shouldn't have a problem at all, the engine isn't hard to turn over at all, you can turn it through a full cycle by hand pretty easily. The bendix is brand new, the old one gives the same problem. What else is there? Could the flywheel be bad somehow? Here are some pics. Anything look weird?

[Mustang 64]

These may be obvious suggestions,but I'll make them anyway.
Put fresh oil in the engine.
Try the starter motor without the spark plug.
Is the gear on the starter meshing perfectly. If the gears are mis aligned , they will bind.

Is there a burr on either gear.

[johnwohl]

The starter works and turns the engine over fine with no plug in. I started thinking maybe the compression was too high on the bbk even though it has the cut outs on the head to lower the compression so I got a compression test kit.

I'm only getting like 40psi.. WTF.



I know my rings are on correctly and clocked, the compression test fitting was in tight, I know my cam is lined up correctly. What else? Valves?

Now I remember how frustrated I was with this thing.

Read more: http://49ccscoot.proboards.com/threa...#ixzz5mKBmPVqI

[sc00ter]

We do multiple compression test with 2 sets of gauges and average the numbers because we can never get them to seal 100% of the time. I find the compression gauges so frustrating, but I get results with a little patience. Now when we do bbk kits on 2 stroke Zuma's the stock starter does not have enough torque to turn the motor over anymore. We just kickstart them. I know they make high-torque starters for GY6 4 stroke motors. Last thing to check is cold cranking amps on the battery. You said you got a new one, but is it enough to turn over the now-larger motor? I honestly know very little about GY6 motors. My friend and I have built a bbk Genuine Buddy but its been awhile since I messed with one.

[sc00ter]

Ok, I just read your post a bit more. Only thing thats popping in my head is the bendix thingy needs a tad of grease. I had a Genuine Buddy 50 that will not turn over when cold. Only seems to start when the motor is warm ot=r its warm outside. Someone told me to put a dab of grease on the bendix shaft and it worked one time cold. Still "sticks" I think but its summer now so it seems to be working now. I purchased the biggest battery I could cram in the battery compartment and made sure all the connections were tight and clean. Still have to use the kickstart when its cold.

[Roscoe]

What I'd probably do.... check voltage drop at various points along the starter circuit. Maybe jump from a known good battery right to the starter, if that doesn't spin the starter like it should you have starter mechanical issues or some other mechanical issues. If it does spin like it should when jumped then it's a starter system issue. Could be the starter solenoid, could be a bad connection, could need larger wiring, bad ground. Diagnose and fix. This looks like a good video on the subject....