Engine Trouble Quick question CNC “Racing Heads”.

[Carl Walichnowski]

Well I'm basically troubleshooting right now and I'm hoping this will resolve my problem. I've switched the carb as I mentioned, double checked all the wiring, and this weekend my plan is to clean out my tank and check the petcock since ity seemed like the gas was flowing poorly. I'll take some pics to see if you guys can tell by the photos if it's the lengh of the plug that's the issue. If it's not the spark plug then I'm at a loss.

 

[FurryOnTheInside]

Sorry for the delay, your correct the bike will simply not start. I’ve tried everything I can think of. The bike has spark, I put a new carb on and went back to the stock head. Can’t figure the problem. Here are pics I took of my spark plug in the head. Thx for any advice.View attachment 82420View attachment 82421

That's really screwed in all the way? Eek. Okay so measure the threads that are left over and get a plug that is that much longer threaded section. Presumably the E code, but you'll measure to be certain..

 

[Carl Walichnowski]

That's really screwed in all the way? Eek. Okay so measure the threads that are left over and get a plug that is that much longer threaded section. Presumably the E code, but you'll measure to be certain..

Yup it’s screwed in all the way. Doesn’t the spark plugs simply some in 1/2” or 3/4”? There is about 1/2” thread space but I’ll get the actual size soon.

 

[FurryOnTheInside]

Yup it’s screwed in all the way. Doesn’t the spark plugs simply some in 1/2” or 3/4”? There is about 1/2” thread space but I’ll get the actual size soon.

Without re-reading page 1, I think we decided those were the popular NGK sizes, H and E. But I expect there will be other sizes (and other brands!). Might be worth visiting an actual scooter and motorcycle shop and showing them the head with the plug in so they can find a plug that will suit it.
That's the H length in there now? It won't matter if there's one or two threads still left over. You might be able to use a (P) projected tip in that case. Like the NGK BPR7EIX that I had for some reason.

 

[Street Ryderz]

The NGK b7es is what fit's that head,You said you went back to stock head and it still didn't start so the problem is else where.You say there's spark but is is correct? The magnet(rotor) can be on backwards and still show spark but wont start.Is there ample air/fuel go thru everything you can you'll find it,check all gaskets and connections.

 

[gary55]

It's the head. Go buy a 1034 BP7ES. Try it and you should be happy.

 

[Carl Walichnowski]

Ok yea I replaced the stock head in an effort to troubleshoot and still no start. I figured the electrical was ok cause the bike was riding a short while, like 1/4 mile before it died at idle and wouldn’t start back up. The bike previously started but died at idle often and the idle screw was turned in way to much, about 90%. Since then I replaced the carb with a brand new one and the idle screw is where it should be but no issue. Now there was an obvious issue of the fuel not running through the line properly, it seemed to stop at the filter despite the filter being brand new. So I’m order to get the fuel line filled up I blew into the gas tank to push the fuel along. Is it possible the there’s a pressure issue in the line and the carb isn’t getting the necessary fuel/oil mixture?? Any suggestions would be appreciated I just want to ride!!!

 

[FurryOnTheInside]

Ok yea I replaced the stock head in an effort to troubleshoot and still no start. I figured the electrical was ok cause the bike was riding a short while, like 1/4 mile before it died at idle and wouldn’t start back up. The bike previously started but died at idle often and the idle screw was turned in way to much, about 90%. Since then I replaced the carb with a brand new one and the idle screw is where it should be but no issue. Now there was an obvious issue of the fuel not running through the line properly, it seemed to stop at the filter despite the filter being brand new. So I’m order to get the fuel line filled up I blew into the gas tank to push the fuel along. Is it possible the there’s a pressure issue in the line and the carb isn’t getting the necessary fuel/oil mixture?? Any suggestions would be appreciated I just want to ride!!!

I suppose you could take the bowl off the carb and test the fuel inlet (into a cup) by gently pushing the tangs upwards to open the valve. I wouldn't be able to tell you what the ideal rate of flow is, but obviously more is better than a drip. Check it shuts off properly too, of course.
And you have presumably already made sure there's no vacuum being created in the tank by a cap that seals too well?

 

[gary55]

Ok yea I replaced the stock head in an effort to troubleshoot and still no start. I figured the electrical was ok cause the bike was riding a short while, like 1/4 mile before it died at idle and wouldn’t start back up. The bike previously started but died at idle often and the idle screw was turned in way to much, about 90%. Since then I replaced the carb with a brand new one and the idle screw is where it should be but no issue. Now there was an obvious issue of the fuel not running through the line properly, it seemed to stop at the filter despite the filter being brand new. So I’m order to get the fuel line filled up I blew into the gas tank to push the fuel along. Is it possible the there’s a pressure issue in the line and the carb isn’t getting the necessary fuel/oil mixture?? Any suggestions would be appreciated I just want to ride!!!

 

[gary55]

Take the gas cap off, hit the tickle button under the idle screw about 10 times real quick, and see if it fires up and keeps running without the cap on. If so the cap is defective. Rarely does this happen, but it does happen. I really need to look back through all your symptoms. If you get the chance to write down what has happened and has been checked or changed since it was last running well in order and how you checked then it will help. Things like "I figure the electrical is ok" doesn't work. It has to be "I checked for spark and it was good". Sometimes you can even have spark when testing but after a short ride the CDI stops working right and starts running like crap and dies. Things can be tricky.