Bad Luck.

[den35]

I've been working on getting a 79 Honda CT70 running for a while now.Finally the carb I had ordered came in today and I got right on it.After spending most of the day tweaking the new carb,I was only one more tweak away from getting it dialed in.Then it happened.:blink:


The spark plug blew out of the head,taking the threads with it.:doah:
Thank god it was idleing at that moment.

Now I have to wait till Tuesday to take the head in to a machine shop and have the threads repaired.Much cheaper than buying a Heli-Coil kit($45 for the shop repair or up to $100 locally for a kit).A new head is way out of the budget.

If it weren't for bad luck............

 

[smallbikes88]

WHat? how does the spark plug blow out when at idle? If you want i have some ct70 motors you can swap out the heads

 

[bandit 40]

I've been working on getting a 79 Honda CT70 running for a while now.Finally the carb I had ordered came in today and I got right on it.After spending most of the day tweaking the new carb,I was only one more tweak away from getting it dialed in.Then it happened.:blink:


The spark plug blew out of the head,taking the threads with it.:doah:
Thank god it was idleing at that moment.

Now I have to wait till Tuesday to take the head in to a machine shop and have the threads repaired.Much cheaper than buying a Heli-Coil kit($45 for the shop repair or up to $100 locally for a kit).A new head is way out of the budget.

If it weren't for bad luck............

The threads had to be already in bad shape you'd think or cross threaded if the plug blew out that easy, it might be easier to just take Smallbikes88 up on the head he if offering:thumbsup:

 

[ogygopsis]

Lucky you weren't sitting on it at the time !

 

[den35]

WHat? how does the spark plug blow out when at idle?........

I asked myself that very question.This bike had the snot beaten out of it before i got it.The only resaon I can come up with is the threads were weak from past abuse,and it was just a matter of time before it let go.


Ogy...I was on it at the time.Had just done another test run.Luckily for me the threads didn't give while at higher rpm and that the plug is mounted pointing forward and to the right of the bike,away from the rider.But even then,I thought I was building a bike,not a gun:gunsmilie:

 

[josh]

:doah: i have seen it happen on a race car plug came out the hood

 

[Tom S.]

I remember that happening to my pal's CL175 in high school. Bike made a noise and quit running. The right side spark plug was just hanging from the wire. I don't remember what he did to fix it. Did they even have heli-coils back in the early 70s? Speaking of heli-coils, I have a bunch of 'em in my '71 Ducati 450 flat tracker. It's been apart several times. At the last rebuild, we installed heli-coils on all of the holes in the aluminum cases and cylinder head.

 

[swamperjmb]

Lucky you weren't sitting on it at the time !

LOL,, ya thats one hell of a butt plug!!!!!!!!:lol:

 

[minibikedude]

That sucks, I had that happen on a Kohler 8hp engine before, Someone been over tightening the spark plug over the years. If you can not get it fixed a E22 70cc Lifan head will bolt right up to it.DRATV.com has them.

 

[den35]

I hope it can be fixed.A friend of mine has a friend who works in a machine shop.He may be able to get a cut rate for me,which would be great for me.I'd rather not spend any more coin than nessessary.I'm on lay-off and the funding is running out!

 

[den35]

It runs.After a $45 spark plug thread replacement,my old CT70 runs.Did a bit more tweaking on the carb hopeing for better performance,then I remembered it's only a 70cc engine and 3 speed tranny.It won't win any races,but it will cruise the trails nicely.