No spark on h100

[burnleytony]

Hi ppl on my 1989 h100 I have no spark at plug .but get spark when I touch H T to earth. Why is this happening? Most parts are new. HELP pls

[eastanglianbiker]

well if you are getting a spark by holding lead to earth but not once the cap is on and plug fitted i would take the plug and cap and replace them both and see what happens then also trim the ht lead back a fraction before fitting new cap

[burnleytony]

I have fitted a new ht cap and cut back lead and new spark plug? Really sun my head in even redone Points.

[eastanglianbiker]

when you look around the rear engine mounting bolts can you see an earth wire going from mounting bolt to frame normally down on the right hand side to make sure the engine is giving a good earth for the engine,might be worth checking out and if not just drop a mounting bolt nut off and put an earth tag from bolt to frame and see what happens

[Stu]

Let me get this right

You are getting a spark at the plug when you earth the lead?

[eastanglianbiker]

that was how i read it as well stu hence saying change plug and cap

[burnleytony]

Yes that's right. I get a spark from the lead when grounded bit not from spark plug when its connected. Even when I just put the plug directly to the ht lead.

[eastanglianbiker]

have you dropped the plug at all as this can damage the ceramic part and cause the failure to spark

[burnleytony]

Have got brand new plug just going to put another earth on engine and see what that does. Woodruff key looks nackerd but carnt be that.thanks lads.let you know what happens

[eastanglianbiker]

Have got brand new plug just going to put another earth on engine and see what that does. Woodruff key looks nackerd but carnt be that.thanks lads.let you know what happens

can be that if its not allowing the rotor to spin properly when kicking the engine over it wont generate a good or proper spark as the h100 relies on the rotor to spin to operate the points

[burnleytony]

Thanks mate overlooked that.its 1.5 mm out. Doee! Dont i feel daft. Will order new one. Will do the earth lead just incase. Grate advice forum .and thanks again..

[Stu]

Sounds like you need new HT leads too if they are sparking when grounded they are designed to insulate from that

[Tango]

This may be a really stupid question.....but are you grounding the outside of the plug when you're checking it?. You won't get a spark unless the body of the plug is grounded.....

[burnleytony]

Nice one EASTANLIAN BIKER..! Got my spark back!! Thanks mate. Such a simple thing to overlook. Just got to redo points ( misfire now) thanks again to all. Stay safe