Runs great but real pain to start

Wilf · Post by **Wilf** » Sun May 17, 2009 9:07 pm

I've got a megajolt lite junior running a xflow 1700 with TPS and twin 40s. Once it's running it runs really well, but it is a real pain getting it to start. Got starting advance of 4 degrees so no kickback. With the distributer ignition it was always two pumps on the accelerator and it would then start if a little reluctantly. Same with the MJ just seems to flood. Using a spark tell tale between the lead and spark plug 1 shows the spark during cranking to be a little erratic, nothing at all if flooded then rock solid once running.

Coil pack is new, starting behaviour is the same with the new coil pack and a previous second hand one

My questions are:
What spark plug gap should I be running?
What else is worth checking - the install itself seems to be fine as it goes really well once running, everything inc TPS works fine. I've got another EDIS and VR sensor on the way to rule out issues there.

Any comments appreciated!

david jenkins · Post by **david jenkins** » Sun May 17, 2009 9:39 pm

I have a 1660 xflow with bike carbs + tps, and Megajolt. Mine starts first go almost every time, Summer or Winter! (but I'm sure you don't want to know that!

)

I leave my plugs as they come out of the packet - 0.8mm I think - not sure what that is in Imperial.

Maybe you need a bit more starting advance - mine's around 8 degrees (but I doubt whether it'll make much difference).

Are you using the mechanical pump, or an electrical one? My engine used to be hard to start with the mechanical one, as it took quite a few cranks to get fuel up to the carb (Weber down-draft). Now I feed the bike carbs with an ex-bike electric pump - turn on the ignition, wait a couple of seconds for the pump to stop puttering, then start the engine.

HTH,
David

Wilf · Post by **Wilf** » Mon May 18, 2009 5:01 pm

Got an electric pump so no issues with it taking a few revolutions to get sufficient fuel. It has always been a pain to start from cold if left for a few weeks, and I hoped the megajolt would improve it. It may be the starter is not quite up to the job?

david jenkins · Post by **david jenkins** » Tue May 19, 2009 3:52 pm

You say that it's not a good starter if it's been left for a while - how healthy is the battery? They do lose charge over time, especially if they're not so new.

Mine has a maintenance charger permanently plugged in when it's in the garage - one of those 'intelligent' chargers that senses the state of the battery and charges accordingly. This means that the (standard) starter can work at its best when cranking over from cold.

Even then, it does have to work hard when the weather's cold and the oil is thick!

Wilf · Post by **Wilf** » Sat May 23, 2009 9:10 pm

I have it on a battery conditioner so it's always fully charged. I do think I have solved it now though. It appears that my VR sensor works both ways (polarity). I did do some tests before wiring it up that suggested it should have been OK the way I had it originally, but having switched the polarity it not only runs great but now starts without requiring easy-start as well.

Starts much better than on points which is one of the reasons I switched over, guessed it had to be a fault on my part as it works so well for everyone else.

Thanks for the assistance david!