fuel line up against spark plug

D

Dougan

New Member
With my small frame on my bike, I noticed that the fuel line is bumping right up against the spark plug. It's so close to the motor that I feel I should probably get some kind of heat shielding. Any tips on what I should use to shield the fuel line from heat? Also, should I be worried that it's up against the spark plug for electrical reasons?
 
There is some heat shield tubing out there. It is braided and looks kind of like those chinese hand cuff toys. I could only find it online and usually in large quanaties. I found one site that sold it in 3 foot lengths. I can't remember which site it was and I tried searching for you but couldn't find it. I have some left over but want to save it for future projects. If you only need 3 inches or less I will mail it to you if you give me your address in a private message. The site said it resists up to 1200 degrees F. And it is black in color. Let me know
 
You could also just take another hose thats a little larger and can take heat and make a slit down the hose and slide it over your fuel line.
 
Why not just use a longer fuel line and route it away from the plug. The shielded hose mentioned is probably not a good idea because the sheath is stainless steel, a conductor of electricity. You don't want spark jumping to it for obvious reasons.
Try rerouting the fuel line before shielding it from the plug. Maybe a 90 degree elbow at or near the tank petcock?
Tom
 
2door said:
Why not just use a longer fuel line and route it away from the plug. The shielded hose mentioned is probably not a good idea because the sheath is stainless steel, a conductor of electricity. You don't want spark jumping to it for obvious reasons.
Try rerouting the fuel line before shielding it from the plug. Maybe a 90 degree elbow at or near the tank petcock?
Tom
Click to expand...

This is what I'm doing now, sort of, but it's easier said than done. You see, the frame on my bike is small, small to the point that if i want to take the spark plug out, i will have to unmount the motor. So the nipple on the petcock is literally maybe 1/2 inch away from the spark plug just due to the size of the bike and the way everything has to be mounted. So, i'm currently doing what I can to space the fuel line from the plug, but it's impossible to get it at an "ideal" distance. So some sort of heat shielding will still be preferable.

Thanks for the offer, Tadd. Hopefully I can figure something out before I have to ask you to mail me anything!

I suppose the idea of putting a bigger tube around it might work, if i can't find anything else around here, and it's not made of metal..

Thanks so far guys.
Scott
 
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The heat tubing I offered is made out of some type of nylon or plastic not really sure but it is not the stainless steel that 2door thought it was.

2door, I know what you are talking about when you say stainless steel I have seen it at the parts store before but this is a non conductor synthetic material.

Dougan, if you can't figure it out let me know and I will send it to you. It would help if you can post some pics so we can try to help you figure out a way.
 
Two thoughts here. 1) would using a shorter plug help in your clearance issue? I am using one due to my frame being a 24" Mtn bike. 2) have you thought of using a different style tank? I don't know your level of mechanics, but Rockenstein has a post here in the forum about an apple juice tank....

http://motorbicycling.com/f26/apple-juice-tank-11720.html

Silver Bear makes his own tanks too. I have even tried my hand at it and didn't do that bad. Sorry no pics.

With creating/buying a tank you then have the opportunity to mount it elsewhere on the bike therefore eliminating that fear. I know I would feel a lot better.

If you have any more question let us know that's why we are here.

Post some pics. it will give us a better idea of what problems you are facing.
 
dag has a good idea; try a shorter plug. I've had good luck with the Autolite 2976. I built a 24" bike for my nephew and the plug clearance to the top tube was like yours. If not for the short plug he would have to pull the engine off to get it out but the short plug worked great. The Autolite should be available at most auto parts stores.
Tom
 

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I dunno if this tip is much help either, but on my build we used zip ties to keep the fuel line away from the engine and my legs when pedaling. Maybe some longer fuel line and zip ties would work in your situation?

-AZ
 
I very much appreciate the smaller spark plugs. I dont' think it will help my current situation in this thread that much, but it looks like it will definitely help my annoyance of having to unmount the motor to get at the plug.

I'll post pictures, but probalby not tonight. I appreciate the help so far.
 
What about going to the auto parts store and buying some silicon tubing to go over your fuel line? The stock fuel lines normally end up cracking from sun exposure anyways. What I did for my fuel line was use black rubber fuel line for a car, then put corrugated wire loom over that, it gives it a nice look and protects it as well. The wire loom I bought at Wal Mart it was about 3$ for 6 feet of it. Here is a picture of what I am talking about.
wire_loom_big.jpg
 
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I think you can do a combination of things to make it safe(r).

WIRE/PLUG: A short plug may help with the routing. Use a high quality silicone wire and boot. Sleeving it with the purpose made woven glass is a good idea. I have used these sleeves on turbo cars, you can get them at speed shops/catalogs.

FUEL LINE: Use the best fuel line you can buy, then use the idea above - slip it into the next size hose that will fit.

Short Plug link

Silicone Plug wire and boot link

Insulate Spark Plugs, Insultherm Spark Plug Boot Insulators, Spark Plug Boot Insulators, Insultherm Sleeving
 
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