starter motor vs push starting??

My 82 305 CSR has issues with starting. It starts when cold with some finesse required but it is fairly reliable. When it is hot it will not start. The starter motor cranks fine but there is no fire.

Last night after a quick trip to WalMart it would not start. A passerby offered to help "compression start" it. I asked what that was, he said "push it". His friend said she had an old Kawi and they are difficult to start. I thought it would not make any difference: mine cranked but would not fire. But it couldn't hurt to try. He pushed me and it fired right up. I then remembered when I bought it the guy had to push it to get it to start, because it would not fire up from cranking.

So, why is it easier to start when pushing it? Just spins faster? Maybe I just need to park on downhills.....

Thanks,
HH

With electric start, the battery voltage drops. Maybe you should start looking for voltage losses in the ignition system.

loudhvx wrote: With electric start, the battery voltage drops. Maybe you should start looking for voltage losses in the ignition system.

Exactly.

The starter pulls current from the battery. If the battery is not fully charged, or if there are voltage losses (high resistance, etc.) in the ignition system there isn't enough current getting to the coil to make a hot spark. By push starting the bike nearly all the current from the battery is available to the coil so it produces a hotter spark.

How old is your battery, and is it holding a full charge? Ed

Although push starting works great in jam, I doubt it is good for your bike.

That's just silly. Bad battery or coils. Maybe the igniter if you have one. I wouldn't ride it that way.
Steve

I have a bike dedicated to bumpstaring only. It's probably the one I've ridden most often for the last 8 years. Doesn't seem to be suffering any ill affects from bumpstarting. The key is to not ride it immediately after it starts. You have to let it idle for a few moments to let the oil pressure build a little before, just like you would with starting any other vehicle.

I owned my BSA for 11 years and bump started it 40-50% of the time. It didn't hurt it. Ed

Can you guys give a quick stepcby step on bump starting? What gear to do it in, estimated minimum speed to do it, things to be careful about, ect ect? I've never done it, but would love ntontry it on my starter clutch dead bike...

First - it helps a lot to have a hill to drift down unless there is someone to give you a push.
You don't need to make the bike move very fast. If you can get it rolling along in neutral at 5 mph or so you should be able to start it. With the fuel on and the ignition key on get the bike rolling in neutral, pull in the clutch and shift it into first or second gear (second gear should be fine), then quickly let out the clutch. If you let the clutch out slowly you may simply bring the bike to a stop. The bike should start. A cold engine will normally require the choke just as if you were starting it with the electric starter. Once it starts you should be good to go. If the engine is cold you may want to let it warm up a bit before normal riding; again just as if it started with the electric or kick starter.

Do this on dry pavement. If the pavement is wet the rear tire may simply skid. If you try this on pavement that has snow on it, the rear tire will skid for sure (guess how I know). :laugh: I once had it snow while my BSA was parked at school and when I came outside the road had about 2" on snow on it. I had to wait for a car (that had been there since before it snowed) to leave so I could bump start in the dry spot that had been under the car. Oh what fun! Ed

Many years ago, the charging system on my 1982 GPz 1100 lost one of the windings on the alternator, letting the battery run down, during some street riding about 30 mph.After letting it sit for a while, the battery regained enough voltage to allow me to bump start it.

To do it, I had the gas on, the ignition on, and in first gear. With the clutch pulled in (squeezed) Got the 500 pound + bike rolling down a slight incline, jumped on, and the same time my butt hit the seat, popped the clutch, and it fired right up.

I had to keep the rev's up as the charging system lost on of the three phases, but being I lived about 1 mile away, made it home ok.

Years ago I had trouble for a while on the first start of the season and had the wife and son help push start mine ...... after that it would start fine the rest of the year.... not sure if I was flooding it or not getting the carbs filled before flooding it or .....but it saved me more than a few times. :laugh:

I've had to do it too. I said HAD TO. Not something I would choose to do and definatly not on a regular basis. First is not an option. Best in second. On these bikes you have to roll it in first with the clutch in then shift to second to start it.
Fix the bloody starter.
Steve