2003 Yamaha Blaster power issues

[ricsrx]

i have had both my crank seal leak (dry side) and my reed valve leak (did not seal on the case), they both created a lean condition that increased power on the top end that i loved until the piston melted....

im sorry i am not much help

 

[Jared]

Well, it's fixed. It was missing a $2.09 washer from the main jet. Apparently the previous owner rejetted the bike when he installed the pipe, and neglected to reinstall this washer. Leaving it out allows fuel to be sucked past the main jet, causing the bike to run outrageously rich. I never knew it had that washer to begin with because it was gone when I first disassembled the carb. I was looking at a parts fiche of the carb and very luckily noticed that washer. The guys at Carey's Cycle Center confirmed that would cause the bike to run super rich.

What a PITA... But, I'm glad it's fixed. I tossed in a 310 main jet, and after a 30 second test I think it might be a tad rich. But I can fine tune that in 20 minutes. Thanks for all the replies guys.

 

[Gravy]

lucky

 

[Corban_White]

Wow. I've worked on carbs with and without that washer. I will file this bit of knowledge away for the future.

 

[Jared]

It caught me off guard too. I've never had a machine with a washer under the jet and didn't expect it to have one. If I hadn't noticed it on the parts fiche I'm sure I'd be doing a leak down test and swapping ignition components this weekend.

With just that washer it will now break the tires lose in dirt in three gears, even jetted rich.