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Old CV carb question, wierd jetting changes

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We picked up an old 92 Suzi Bandit 400, Great original condition, 7k miles, garage kept beauty.

No, its not a thumper or a dirt bike but the issue is odd and I bet you guys have a better explanation than anyone else so here it goes.

It had an erratic idle, floaty, wouldn't always come back down from revs. It did however absolutely rip from about 6k up to 14k redline.

I pulled the carb bank off, found some cruddy discolored stuff as expected in the bowls but also found a rubber plug, OEM, inserted in each of the pilot jets capping them completely off!

OK, I expected clogged pilots but not intentionally clogged!

Out they go, everything clean. Bike rips with nice smooth torque and idles perfectly, drops to idle as it should but now it slows in revs above 8k, stutters at 12k and will not pull to 14k redline unless it gets a very slow throttle fed to it. Slowly feeding throttle will allow it to pull clean thru the 12k and right to redline but its very, very slow and a hint of too much throttle kills it hard. WOT brings an abrupt stutter/bog like its out of fuel or the kill switch was thrown.

It is absolutely awesome from idle to 8k with operational pilots.

Now, this feels like a lean main to me. My question is how can actually opening the pilots up to allow them to function affect WOT and why isn't rich up there with the additional fuel. Am I misreading it and its actually rich?

Thanks for any ideas.

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the plugs need to be there. the feed for the fuel to the pilot jets is a small passage in the casting of the carb.

yes,its rich.

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Well I'm glad I didn't toss them out! Thank you for the info!

Back into the carbs again. :smirk:

Just for the sake of asking, now that it runs absolutely flawlessly without the pilot plugs till it is on the mains, any harm in just leaning the mains down a few sizes? I honestly never expected it to run this well below 6k rpms.

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Eddie, thanks for the guidance. It was in fact rich on the main, removing the airfilter for a test made it almost perfect. Jets ordered! Appreciate the advice! Jim.

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