howdy gents,

I've got a loaner fantic from a friend who's convinced me that trials is the best thing since.....well....er....you know. Anyway, I don't know a thing about it, don't even know if it's called a 301 or not, but I am informed it has a 250cc mill. The carb is a dell orto and I have a known carb to airbox boot cracked and letting air in. There are tons of little niggling issues that I'm going to have to pursue, but the greatest of them right now is that I'm constantly fouling plugs. I'm running silkolene synthetic premix at 50:1 and I don't know if that's right or not. I haven't fettled with the carb internals yet, but the fuel/air is 2 turns out from seat and the idle is set by ear to a steady burbling stacatto. I' m sure the carb/airbox leak is playing havoc with the fueling somewhat, but I'd really just like some general advice on tuning one of these so when my new carb boot comes in I can take the big muddy throttle response out and replace it with some nice crisp, clean response.

Jimbo

the leak you describe would make it run weak, not rich...if you dont want to pay lots for a new piston, nikosil plating, mains etc etc, get a rubber (BILL PYE OR BOB WRIGHT MOTORCYCLES) and then strip the carb as r2 says. Chances are the o ring on the cold start jet is knackered (Lid off carb, long thingy in brass in one corner with an o-ring on it) and this will cause the plugs to foul. A complete carb overhaul kit will cost about 15 quzid. I took my kit to a bearing suppliers and coppied all the o rings in the kit 5 times each for another fiver. May want to think about it.

It may take three attemps to replace the o ring without tearing it...a real bitty. push it over with the slot 90 degrees to the push direction, if ja see wot i mean!!!

HTH

lee

the leak you describe would make it run weak, not rich...if you dont want to pay lots for a new piston, nikosil plating, mains etc etc, get a rubber (BILL PYE OR BOB WRIGHT MOTORCYCLES) and then strip the carb as r2 says. Chances are the o ring on the cold start jet is knackered (Lid off carb, long thingy in brass in one corner with an o-ring on it) and this will cause the plugs to foul. A complete carb overhaul kit will cost about 15 quzid. I took my kit to a bearing suppliers and coppied all the o rings in the kit 5 times each for another fiver. May want to think about it.

It may take three attemps to replace the o ring without tearing it...a real bitty. push it over with the slot 90 degrees to the push direction, if ja see wot i mean!!!

HTH

lee

I will certainly take the time to get a new "rubber" from Bob on his fantic site. I've already got a concern over a certain noise I hear in the top end that I'd describe as valve noise if it was a 4 stroker.....hmmmmmmmm.

Jimbo,

I wuz listening to your bike this weekend and I thought it sounded remarkably quiet and smooth. I did see you on the sawmill creek rd with a fouled plug (I thought).

Yep, that wuz me. I was installing the last of 3 plugs I'd brought along for the weekend. guess If i'm going to get the fantic reliable, I'd better get to some maintenance pronto.

Hope to see you back at TTC again soon.

James