Scooterotica

Afternoon all,
I've got a problem with my scoot, it keeps killing spark plugs. The first one it did was when I first put the motor in the frame and put that down to a bad plug, but so far I have gone through around 6 and only covered 600+ miles.

I've tried different makes of plugs bought from different suppliers and different heat ranges, and still they die.

I replaced the regulator as I wanted to run a pathfinder (for info for anyone wanting to run these the BGM 120 isn't up to the job).

I replaced the HT cap for one without a supressor in (from AF).

I guess the next stop is the coil, and then the stator.

When I take the plugs out they are well and truely dead without a glimmer of a spark (I've even tried them in another bike)

Has anyone else had any experience's like this / knows how to resolve it?


For info the setup is:
BGM 120 Stator (iginiton set at 17 degrees BTDC)
MB Lightened flywheel
MB Loom
Earth connections @ engine to frame, regulator to frame x 2, coil to frame, and lights to frame x2 (I've used a volt meter to check that they are good earths)
vespa 5 point regulator
ducati cdi
Spark Plugs tried NGK, Denso (long and short reach as I had the head skimmed, heat ranges 7 and 9)
Tried different HT Caps

Cheers
Mike

If it was mine I would check how the electrics are, Impedence on wires etc or wrong choice of plug cap (Impedence too high)... The piston to head clearance if its a skimmed head (I have seen a couple where once the engine is reving high the plug has been hit by the piston after skimming) and missively high compression can give ignition problems.. and on some engines an over large combustion chamber can give rise to detonation which can damage plugs, breaks the porcelin insulator causing it to track to earth.... But sometimes its the way the plug is gapped damaging the plug in the process... There is a tool that bends the electrode without the need for tapping in and bending back which prevents damage... I run my plugs at between 17-19 thou, and try not to beat the into submition, but bend the tip to the correct gap using the spark plug tool I bought off a Champian plug dealer many years ago...

Hope somthing here helps,

Hi Mike did you find the problem yet? i am having the same problem.

Hi all (been on my jollies hence no reply)
The squish was set at 1.3, head reprofiled by MB (22.5 cc plus sqiush), so all should be OK on the head front.

Since my last post, I have changed the cdi, I also recrimped the cables that come off the stator, just to try an eliminate poor connections.

If it blows one more spark plug the stators off back (I have an indian stator on standby)

I'll keep you posted

Mike

I thought the 5 pin regulators were for battery setups?

corrado wrote:I thought the 5 pin regulators were for battery setups?

Hi Martin,
The extra connector is for the pathfinder (it worked without a battery...but not very well) so I added a battery and this connector now charges the battery for the pathfinder to run off.




Mike