hello all,

I stripped my sons gas gas 50 boy engine to replace a broken gear selector shaft. After rebuilding the engine I cant seem to get a spark at the spark plug. The engine started and ran ok up until the gear shaft breaking. So what have I done wrong or damaged. I am pretty certain I put all the wires back in the correct place - but there again maybe not. I also cleaned the earth leads as I was told on a previous post that this is a common problem on these bikes - still nothing. I cant see anything broken or damaged. When I stripped the engine I removed the stator (not realising this was unnecessary). I put it back in exactly the same position. I also read that others have removed the ignition system and fitted a better system - does anybody have any info on this.

Any help is much appreciated.

http://www.trialspartsusa.com/electrical.html

You should find a wiring diagram for your bike at the above.

Gasgas change the system for 2006, the original being very poor - you can see its bound to fail if you see some of the internal connections. I was told the updated system needed a change of crank, making the parts bill in excess of £700 total.

I would contact PVL and selettra ignitions direct to see what they can offer. I think there is a UK kart supplier where these can be obtained.

Alternatively do a web search for Bradford rewinds.

thanks dadof2, my problem is that I don't know what is wrong or how to diagnose the fault. It may just be something simple.

hello dadof2, checked out trialspar but they do not have a wiring diagram for the 2005 boy.

Apparently so, I see they say it is coming soon.

Can you post a photo of your stator

I have found these 4 faults in the past.

1) the source coils earth was making poor contact with the stator laminated segments where it is held by the fixing screw

2) the wire on the HT coil had necked off unseen inside the insulation near where the connector was crimped on

3) internal coil HT failure

4) internal coil HT failure

The HT coils are not just LT and HT winding's, they contain electronics, don't know the present situation but Beta coils used to work OK and were about 1/2 price of Gasgas.

I expect your stator will have two coils with windings of heavier wire - these are for the fan

The 2 coils with the finer windings are linked and provide the ignition power. Find the wire that comes off them and spin the motor (plug removed) with a battery drill. Should get over 20 volts AC between this wire and earth. It is the internal connections in theses coils that usually fail lowering source coil output.

Edited October 15, 201312 yr by dadof2

thanks dadof2, I am struggling to add a picture, but if you look on page 5 of this section and scroll down to the 14th entry you can see a picture at the bottom of the posts.

thanks again for your help