Big Guy

5 replies to this topic
  • Robbydalejr

Posted January 20, 2009 - 04:55 PM


I own a 2000 YZF 426. I know it has a big bore kit but I don't know what size. Last weekend was 1st ride in a few months. Changed oil,spark plug and filter previously and rode only once and it ran amazing. Last ride however I dumped it a couple of times and it seemed to flood easily. Could kick it out before but now I had to wait 8-10 mins both times. It has sinced leaked gas from the lines coming out of the bottom of the bike.( over flow lines?) Don't know much about bikes! My gas is off and it is still leaking. Any suggestions would greatly be appreciated. Also, if someone knows the size of the big bore kit for my model I would love to know. I ride with two guys both on KTM EXC 520's I pull them on hills and keep up on the straights and I'm 6'4 300lbs. I will be looking to buy a new bike when mine finally kicks it. Would love some suggestions.

  • DMC707

Posted January 20, 2009 - 08:11 PM


Problem with the float height maybe? Pinhole in the float? Just spitballin here

If your lookin into a new bike, why not keep it Blue. I am a heavyset critter myself and have no problem with the power of my '08, plus an Athena big bore will put it at 480 cc with a ton of torque.

Besides that option,the Suzie FI 450 is about the torquiest thing around , but the drawback is it takes nerves of steel to keep the pro level chassis on the bubble.

I've decided a little extra weight is not the kiss of death on these things i thought it once was after watching an expert quad rider on a stock YFZ 450 clear a massive double that i wouldn't even attempt. The rider was more skilled and weighed less than me, sure, but he was riding a 400 lb quad with at least 5 hp less than my YZF

  • DeeCee

Posted January 21, 2009 - 12:02 AM


Chances are you have some dirt in your float valve and it is not sealing properly. You will have to take off the carburettor and clean the valve. At the same time I suggest you blow out all your jets.
If it was running OK before, and you have not done anything to it, the carburettor clean out should solve your problem.

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  • curthall11

Posted January 21, 2009 - 05:06 AM


The big bore kits available for the 426 is a 444. Does you cylinder have any markings on it?

  • MikeyT750

Posted January 21, 2009 - 06:45 AM


YUP. You definitly have something in the Float. I went to start mine up the other day and turned the gas on. It free flowed gas out of the lines like you said. I pulled the Carb out and found crud all over the peice with the rubber tip that seats up in the carb which controls the float. Anyways, Fixed it and runs like new. :thumbsup:

  • Robbydalejr

Posted January 21, 2009 - 09:58 AM


Thank you very much. I'll try cleaning out the float this weekend. Big bore info sounds right. I'm still suprised how much power I have! The KTM 520's I ride with are supposed to be the baddest but I'm right there with'em !

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