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post #1 of 5 (permalink) Old 10-30-2009, 10:20 AM Thread Starter
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carb confusion

I recently purchased an 88 vn750 and the bike had sat for 2 years. Right before the guy put away he had $1300 in tune ups done to it by a mechanic that i actually use as well. After he had the work done he said the carbs would surge and eventually flood out, so he put it up after only putting 500 miles on it after the tune-up. The carbs were rebuilt within that tune-up and the mechanic said he remembers that it ran very well back then.

Well when i bought it it ran "ok". I did all the things you should do when you buy a vehicle (oil, plugs, etc,etc) and rode the bike up and down the street. it had hesitation and would flood eventually, like the previous owner said. There was also small amounts of smoke coming out of the right exhaust. I had the carbs pulled and cleaned very well and put them back on the bike. It ran great but then after about 30 minutes it started smoking again, but in a smaller amount. The next day i tried to ride it again to see what it would do and after it warmed up it wants to die when i give it any throttle. It also will only run with the choke on (which is a sign of the pilot jets being clogged? im not 100% on that though.)

Sorry this is so long but i have been researching in the website and i cant come to a conclusion on what is wrong so i decided i would state the whole case to see if some of you guys may know whats going on lol. Could it be out of sync? The mechanic said he would check the adjustments but i have not tampered with them and neither did the previous owner. what is this a sign of when it dies when i give it throttle?
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post #2 of 5 (permalink) Old 10-30-2009, 11:11 AM
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Could be a number of things. How old is the gas? What does the inside of the tank look like? Spotless, or rusty? When the carbs were "rebuilt", were all the rubber parts replaced or did it just get a thorough cleaning? Have you drained the carbs into a clean container to see what the fuel looks like? If there's crud in it, inline filters may be in your future, 'cause it's coming from somewhere. As lance noted on another post, the petcock could be breaking up and letting rubber crumbs into the carb.

I'm keepin' all the left over parts. I'm gonna use 'em to build another bike!
"Black Beauty"
1989 VN750 acquired December, 2008, 6,711 miles
Currently 23,298 miles

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2001 Honda CMX250 Rebel acquired July, 2008

1987 VN750 project bike, acquired August, 2009, 33,000 miles and balancer sticking out of the case, currently awaiting attention and parts
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post #3 of 5 (permalink) Old 10-30-2009, 11:15 AM
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Also check your carb vent hose for bugs nesting. Hose goes to the right ear.

02 honda sabre 1100
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post #4 of 5 (permalink) Old 10-31-2009, 01:30 PM Thread Starter
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ok thanks a lot. the tank is in perfect condition and i drained all the gas before i attempted running it. all the hoses were replaced when it was rebuilt, but i replaced them again when i got the bike. the carbs were rebuilt with a kit b/c and not just cleaned. i will check all hoses and then double check them again to see if i can find anything.
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post #5 of 5 (permalink) Old 10-31-2009, 03:38 PM
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Lots of folks say they've cleaned the carbs, but don't open the float bowls to see what's going on in there (often means drilling out the screws in the back of each float bowl and replacing them). Ask the mechanic if he did that - if not, and you can pull the carbs, check the floats - easy enough to get crud in there and it'll gum up the works (as you describe).

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