Newb here in ATX

[spanky]

Hi all! I've been lurking on this forum for years, poring over everyone's builds and soaking up as much information as possible. I have a background in bicycle repair, but am very new to working with small engines. I've been working on my build using the Skyhawk aluminum frame with the integrated gas tank built into the top tube and a dragon fire 66cc/80cc 2 stroke China girl. I've found that the petcock that was included with the engine kit doesn't thread into the skyhawk tank. I'm pretty sure the petcock is an M10-1.0 but can't determine the female thread in the frame's tank. Has anyone had this issue? Any and all insights are welcome! Thanks so much!

 

[spanky]

I should add that this is my first build.

 

[ericbowie]

Aluminum threads - could be tight or beat up, or thinkmaybe you crossthreaded it?

If you can bring it to Cedar Park I'll help you out. We can measure the thread pitches in the frame and the petcock; if they match we can chase them out. If not, at least you'll know what they are.

It would help me too, as I'm curious about that frame.

 

[spanky]

Hi Eric! Thanks for your reply! I agree... The threads could just be funky in the frame. I went ahead and bought both an m10-1.0 bolt and an m10-1.25 bolt just to see if I'd have any luck threading something in there that's not an awkward shape like the petcock, and no luck. I've been really careful to not strong arm anything in there out of fear of damaging the aluminum threads. I may take you up on some help if you have some free time! I set up a temporary gas canister out of an aluminum water bottle in the meantime (homemade, but I vented the cap). Now at this point I've been trying to fire the darn thing up and am getting nothing.

I think I have a compression problem as well. I've got spark from my plug, but the fuel is not reaching the inlet manifold from the carb. The carb's jets and float look real clean but it's not getting out of the bowl. I'm pretty stumped.

 

[ericbowie]

Hi Eric! Thanks for your reply! I agree... The threads could just be funky in the frame. I went ahead and bought both an m10-1.0 bolt and an m10-1.25 bolt just to see if I'd have any luck threading something in there that's not an awkward shape like the petcock, and no luck. I've been really careful to not strong arm anything in there out of fear of damaging the aluminum threads. I may take you up on some help if you have some free time! I set up a temporary gas canister out of an aluminum water bottle in the meantime (homemade, but I vented the cap). Now at this point I've been trying to fire the darn thing up and am getting nothing.

I think I have a compression problem as well. I've got spark from my plug, but the fuel is not reaching the inlet manifold from the carb. The carb's jets and float look real clean but it's not getting out of the bowl. I'm pretty stumped.

I have time. I often work a little late so you may come by the shop.
AFA your carb problems, I'd check the venting first. Generally speaking, if you vent tube (or cap on these little carbs) to the bowl is kinked or plugged, the gas can't flow out.
You'd be surprised how many experienced mechanics get stumped by this exact problem.

 

[spanky]

Okie dokie, Eric. I'll take a closer look at the vent. Thanks for the insights.

 

[ericbowie]

Cool. Hope you get it going without too much effort. Carbs can be a real PITA sometimes.
BTW, I'm a n00b here too; my intro is a couple below yours ("newkid").

Let me know if/when you want to get those threads looked at. PM or reply here - I'll respond.

 

[Agreen]

I have a Skyhawk frame as well... and I also fell for gasbike.net's stupid trap. They offered one for an extra $7. I bought it and it was female threads. Well, so is the bike. Turned out, the one that came with the engine kit that fits in the peanut tank fits as well.

But it is a regular metric thread. Not BSP, not NPT, but straight metric thread. I think it is 10mm, but I think it's 10x1.5, not 10x1.0.

And don't forget, there's got to be a sealing washer for it, or it'll leak.

 

[spanky]

Agreen... Aha! That was my suspicion. Really good to know. I'm pretty sure I could tap it to a different thread pitch then? I have a feeling that is what is going on here. I did the same as you and got the frame super cheap on king's website. Were you able to find a solution or a fitting that worked?

 

[Agreen]

Yeah, the fitting that came with the engine kit works. Not the one that comes with the frame.

Don't tap it! You'll end up with no threads at all if you tap different pith threads over the same size bore.