Shortskimpre Posted July 26, 2022 #1 Posted July 26, 2022 As the title says. I found this motorcycle. It had been sitting in the Tennessee sun for the last 6 years. I've rebuilt the entire clutch system (and cleared the clutch hoses, those are NOT fun to get to). Rebuilt the entire front braking system. Rebuilt the entire rear braking system. I've put a TON of work in to this thing. Now, for the problem: I've rebuilt the carbs. And when freshly putting them in and power cycling the first time. All is well. Bike fire up and idles smoothly! except. I turn the bike off and the next time i go to fire the bike up. The pump primes and BOOM. I get 4 jets of fuel that would be going right in to the airbox shooting a solid 12 inches above the carb bodies! I did the all balls rebuild kit. It has new needles, new seats. Basically new everything. Anyone have any ideas on what could be allowing the carbs to overflow that much and in that particular spot (the hole with the brass fitting closest to the top of the carbs). I'm kind of at a loss here. I can post video or photos if needed. I'm new here so i'll have to figure out how to do that! Thanks again!
cowpuc Posted July 26, 2022 #2 Posted July 26, 2022 did you take a close look at the interior of the fuel tank before you pumped fuel into the freshly rebuilt carbs? What year/model of bike? Some bikes employ a vacuum operated fuel petcock that, if the petcock diaphram gets a hole in it I have seen do similar things.. If we are talking about a Venture here and it were mine I would probably drain the carbs into clear jar, let the jar set for an hour or so and then look at the bottom of the jar to see how much tiny particled gook was in the carbs.. I would say yeah, you probably got a stuck float in your rebuild but highly unlikely all 4 would stick at the same time.. Sounds suspiciously like ya got a rusty tank routine going on there.. Take a peek.. Puc
Shortskimpre Posted July 26, 2022 Author #3 Posted July 26, 2022 2 hours ago, cowpuc said: did you take a close look at the interior of the fuel tank before you pumped fuel into the freshly rebuilt carbs? What year/model of bike? Some bikes employ a vacuum operated fuel petcock that, if the petcock diaphram gets a hole in it I have seen do similar things.. If we are talking about a Venture here and it were mine I would probably drain the carbs into clear jar, let the jar set for an hour or so and then look at the bottom of the jar to see how much tiny particled gook was in the carbs.. I would say yeah, you probably got a stuck float in your rebuild but highly unlikely all 4 would stick at the same time.. Sounds suspiciously like ya got a rusty tank routine going on there.. Take a peek.. Puc Hello puc! I have taken it apart twice as that is what I assumed as well. The third time I primed the fuel pump in to a gas can (to clear the lines of debris) and used a fresh canister of fuel. So I believe we can safely rule out debris. Although I do plan on taking it apart AGAIN to double check. And of course, before I put them back in the bike. I did the "blow in the fuel intake as hard as you can and operate the floats". They all passed that test. It's a 1999 Yamaha royal star tour classic. I'm not sure whether I have a vacuumed petcock. Would you know by chance? Could this be a symptom of a TPS set incorrectly? I just used witness marks to put that back on the carbs. 1
Shortskimpre Posted July 26, 2022 Author #4 Posted July 26, 2022 Also! The tank is extremely rusty and is currently getting professionally sealed and coated. Should have it back in a few days. 1
cowpuc Posted July 27, 2022 #5 Posted July 27, 2022 2 hours ago, Shortskimpre said: Hello puc! I have taken it apart twice as that is what I assumed as well. The third time I primed the fuel pump in to a gas can (to clear the lines of debris) and used a fresh canister of fuel. So I believe we can safely rule out debris. Although I do plan on taking it apart AGAIN to double check. And of course, before I put them back in the bike. I did the "blow in the fuel intake as hard as you can and operate the floats". They all passed that test. It's a 1999 Yamaha royal star tour classic. I'm not sure whether I have a vacuumed petcock. Would you know by chance? Could this be a symptom of a TPS set incorrectly? I just used witness marks to put that back on the carbs. 2 hours ago, Shortskimpre said: Also! The tank is extremely rusty and is currently getting professionally sealed and coated. Should have it back in a few days. And a mighty HOWDY right back your way @Shortskimpre! I just looked your scoot up on a parts fiche and saw no sign of a vacuum operated petcock there so we can cross that off our list. Rusty fuel tanks create teeny tiny particles that easily slip thru fuel filters, even double filters cant catch them all, and those little varmints can/will cause issues like you are experiencing cause it dont take much to gather on the float valve needle or seat and give an uncontrollable fuel flow into the carbs. I think once you get your coated tank back and those needles recleaned you should be good to go. If it were mine I would tinker with the carbs while waiting for the tank. I would drain the carbs, close the drains then take some fresh fuel in a large ag syringe and squirt it into the carbs thru the output line detached from the pump. Do that until I either felt the valves close so I couldnt force more fuel in (meaning the needles/seats were working again) or I seen raw fuel entering the carbs again. If that failed I would try air pressure applied to that output line again (after draining the carbs again of course) and then redo the cleansing attempt with carb cleaner. All with hopes I didnt have to remove the carbs to hand clean those float valves. On another note, be sure and check the oil in your crankcase just to be sure the case oil has not been contaminated.. Puc
Shortskimpre Posted July 27, 2022 Author #6 Posted July 27, 2022 Thanks so much Puc! I tore them apart again last night. I tightened up the primary holders (They might have been too loose?) and pulled the seats out and recleaned everything in the bowl. A small amount of sediment (I'm thinking at this point, it may be the old fuel pump that keeps releasing it in to the line) was found inside the bowls. I bored out out (with some green scotchbrite) where the needle seat o-ring sits and put everything back together and tried it again. It has gone from a sky rocketing fuel overflow to just a weeping overflow out of the top of 2 of the carbs now. I think between those 2 items and a cleaning. I may be on the right path! 1
Shortskimpre Posted July 28, 2022 Author #7 Posted July 28, 2022 Well... I spoke too soon. Got home from work tonight and just for giggles wanted to make sure the carbs were holding out. Power cycled the key. The moment I turned the key over, fuel started spraying out of the top of the carbs again. Time to take them off for a fourth time... When I checked them last night. There was a very small amount of sediment in them. Starting to feel like it's hopeless...
RDawson Posted July 28, 2022 #8 Posted July 28, 2022 8 hours ago, Shortskimpre said: Well... I spoke too soon. Got home from work tonight and just for giggles wanted to make sure the carbs were holding out. Power cycled the key. The moment I turned the key over, fuel started spraying out of the top of the carbs again. Time to take them off for a fourth time... When I checked them last night. There was a very small amount of sediment in them. Starting to feel like it's hopeless... Contact @eusa1 Mike Eykamp. He’s the carb guy, if he can’t talk you through it he offers a carb rebuild or carb exchange. It’s not hopeless.
Shortskimpre Posted July 28, 2022 Author #9 Posted July 28, 2022 (edited) You're all not going to believe this. The air vent hoses on the top that equalize pressure on the top of the carbs were completely clogged with mouse feces where they "plug" in to the motorcycle. I unclogged that. The carbs are running amazing gand this bike has officially moved down the street under its own power for the first time in 6-7 years! I'm so excited! Edited July 28, 2022 by Shortskimpre 1
Shortskimpre Posted August 23, 2022 Author #12 Posted August 23, 2022 Does anyone happen to have documentation on the TPS and how to properly set/tune it? Can't find too much on it and my check engine light is on. I had to remove it and set it by eyeball which CLEARLY wasn't close enough!
saddlebum Posted August 23, 2022 #13 Posted August 23, 2022 (edited) Check the tech section under manuals https://www.venturerider.org/manuals/RSVservice.pdf http://www.venturerider.org/manuals/1996-2001 Royal Star LIT-11616-VZ-01.pdf Edited August 23, 2022 by saddlebum
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