If it says 18 that is 18cc domes, I run them in mine, but am at 6500ft elevation, and they work well at 4000 also. If you are in texas, I am assuming you are close to sea level, so you need more octane.

It was probably detonation, but not really sure from here. Check the compression with a tester and if it is over about 160 then you should be running some race fuel, of course that is not always true, if it is ported the cranking compression does not always tell the whole story.

Give us some more info, but I would plan on a rebuild now.

Bat

 

There is know way i can do a compression test now (the head, jugs, pistons, and carbs are out/off) .

So im guessin that the 18cc domes on 93 octane caused this??!

 

That would be my guess, what altitude are you at?

Yeah, after I typed that I thought you probably had it apart. Anyway, I would guess too high of compression for the fuel.

Could also have been agravated by a lean mixture. But sounds mainly like a compression problem to me. The piston I saw that had been attacked by detonation had a lot of little dents in it, kind of like someone took a hammer to it.

Bat

 

From what i saw on the internet is that grayson county, tx *where i live. Is at 700-900 ft. elevation

There is one big divet into the right piston that blew chunks that stuck into the exhaust port.

I dont know if my cylinders can be honed or have to be bored. I dont have a digital camera either to take pics[img]i/expressions/face-icon-small-sad.gif[/img].

 

If she burned down and you dont know what jetting is in it I would check that to see if it is too lean. Then rebuild it and check the compression. Then if it is higher than 160 PSI or so I would change domes.

 

IT ran almost spot on b4 it broke, plugs just a little on the white side. I have ot buy new domes b/c i cant get aholt of 100+octane around here. Plus the right dome is almost toast.

DId the wrong octane fuel for 18cc domes cause this??

 

Yes

 

Check to see if there is an aftermarket timing plate in it. Seeing as how the other parts have been added, someone could have put a plate in it or even modded the stocker. Since the plug was melted, I am guessing TOO much timing along with too low octane.

 

18 cc domes are almost certainly all or at least a major part of the problem. SInce the dome is damaged anyway I would order some 21cc domes. 21 cc is safe to run at sea level with premium pump gas. I ran 21cc domes, +4 timing advance at Glamis on 91 octane and was OK. Still you want to check your timing and jetting when you get it back together.

Also, I would have a serious talk with the guy that sold you the Banshee - he should have told you about the 18cc domes.

 

Oh I am going to have a "sit down" w/ him tonight. The guy is outa bohnam, tx and sells yorkies for a livin. He had this for his 10yr. old son!!!