reachn' out for help - Yamaha FZ6 Forums - International FZ6 Motorcycle Community Forum

xv920 · 07-30-2008, 05:38 PM

i have a 1981 xv920 with troubles it starts up and idles fine but when given the throttle it falls on its face and dies. if anyone can help i would be greatful

tolgatt · 07-30-2008, 05:40 PM

sounds like a carb issue,,,you should do a good clean up on the carbs and also spark plugs too

**Nelly** · 07-30-2008, 05:44 PM

Sounds like a card issue. Sticking float needle or split diaphragm's?

**reiobard** · 07-30-2008, 06:03 PM

nice looking bike

I agree that it is a carb problem, also could be a clogged intake if the bike has sit for a while. check for obstructions in the airbox

**FZ6inNH** · 07-30-2008, 06:17 PM

It means she's either starved for air or fuel. The easy one is to check the air path all the way to the carbs. Then, drop the carbs and give them a good cleaning. Check to see that the floats actually do float. Check the needles as Nelly pointed out. Remove the jets and be sure nothing is obstructing them.

Then throw in some good fresh plugs.

Last is the gas tank. Sometimes a foreign object can get into the tank that may not clog the outlet enough to stall the bike, but when you start a higher demand on the flow (twisting the throttle), that little bugger will stop up the fuel flow. When it stalls, the piece will float free. Start it up and the whole process starts all over... Take the tank off and dump it into a pail. Flush it out with more fuel into the pail. If the petc0ck is removable, take it off and check for clogs. Filter the fuel into another container with the finest filter possible then put it back in the tank.

Let us know how this turns out cause that's a COOL bike!! Good luck!

Cali rider · 07-30-2008, 06:42 PM

Check the inlet manifolds between the carbs and the cylinder heads. Unless they have been replaced within the last 10-15 years they WILL leak air. Just spray them with WD40 as the motor idles, if the revs change you have found at least one problem. Getting replacements might be a bit of a challenge but not impossible, there is a lot of NOS still out there for 20-30 yr old Japanese bikes.

Fred · 07-30-2008, 06:50 PM

Assuming it's a CV carb, the slides aren't lifting. They might be stuck, or the diaphrams might be torn.

Heck, just tear the carbs apart and rebuild them. You'll be glad you did.

**Bill** · 07-30-2008, 06:55 PM

Quote:

Originally Posted by Cali rider

Check the inlet manifolds between the carbs and the cylinder heads. Unless they have been replaced within the last 10-15 years they WILL leak air. Just spray them with WD40 as the motor idles, if the revs change you have found at least one problem. Getting replacements might be a bit of a challenge but not impossible, there is a lot of NOS still out there for 20-30 yr old Japanese bikes.

K.I.S.S. Start there and then go into the carbs like everyone else has said.

mdr · 07-30-2008, 06:57 PM

I agree that carbs are most likely culprit but don't forget to check battery as well. They don't last forever and it's easy to check for fluid levels and voltage. Amperage might mean removal and a trip to an auto-parts store but still not hard and usually they do check for free. I'd do the easy stuff first then move on to carbs if needed. I had similar problems on a Ninja and it turned out I apparently had spark blowout from weak battery. Still betting on carbs though...

And I'd advise you to not put the gas back in bike if it's the least bit suspect. Use it in your lawn mower, they're a lot more tolerant of funky gas.

**FZ6inNH** · 07-30-2008, 07:05 PM

Quote:

Originally Posted by mdr

And I'd advise you to not put the gas back in bike if it's the least bit suspect. Use it in your lawn mower, they're a lot more tolerant of funky gas.

I was assuming it wasn't funky gas, just a foreign object in it. This actually happened with a used car my son bought. Drove off with it but when he got to 1/4 tank of fuel, it quit. Started back up, ran a couple minutes and quit.... long story short, the garage pulled the tank and drained it. Out came a short piece of rope! It was clogging the fuel pickup. All better now.

07-30-2008, 05:40 PM	#2 (permalink)
tolgatt Goodfella Join Date: Nov 2007 Location: Windsor , ON Bike: 2007 FZ6 Posts: 466 Rep Power: 12 Member #876	Re: reachn' out for help sounds like a carb issue,,,you should do a good clean up on the carbs and also spark plugs too __________________ 07 FZ6 S2 Candy Apple Red

07-30-2008, 05:44 PM	#3 (permalink)
Nelly UK Moderator Join Date: Jul 2007 Location: Reading, Berkshire, UK Bike: 2005 FZ6 Silver & black Posts: 4,179 Rep Power: 49 Member #274	Re: reachn' out for help Sounds like a card issue. Sticking float needle or split diaphragm's? __________________ "Some say......... His cardiac output is equal to the FZ6's 4 cylinders at 13,000rpm. All we know is he's called the STIG".:UK: Mods: K&N Airfilter, Datatool system 6 alarm, Bikerdude headlight harness, 12V power socket, Data tag, 15T Front sprocket, Speedo healer, Puig frame slders, front & back Crash bobbin axel sliders. "Dont ask me I got it from here"? Forum FAQs... My Resume...

07-30-2008, 06:03 PM	#4 (permalink)
reiobard Postaholic Join Date: Nov 2007 Location: Concord, NH Bike: 2007 FZ6 (The Faster Blue) Posts: 5,205 Rep Power: 70 Member #991	Re: reachn' out for help nice looking bike I agree that it is a carb problem, also could be a clogged intake if the bike has sit for a while. check for obstructions in the airbox

07-30-2008, 06:17 PM	#5 (permalink)
FZ6inNH Moderator w/ Twisted Fate Join Date: Mar 2007 Location: New Hampshire Bike: 2008 FZ6 Cobalt Blue Posts: 2,959 Rep Power: 49 Member #18	Re: reachn' out for help It means she's either starved for air or fuel. The easy one is to check the air path all the way to the carbs. Then, drop the carbs and give them a good cleaning. Check to see that the floats actually do float. Check the needles as Nelly pointed out. Remove the jets and be sure nothing is obstructing them. Then throw in some good fresh plugs. Last is the gas tank. Sometimes a foreign object can get into the tank that may not clog the outlet enough to stall the bike, but when you start a higher demand on the flow (twisting the throttle), that little bugger will stop up the fuel flow. When it stalls, the piece will float free. Start it up and the whole process starts all over... Take the tank off and dump it into a pail. Flush it out with more fuel into the pail. If the petc0ck is removable, take it off and check for clogs. Filter the fuel into another container with the finest filter possible then put it back in the tank. Let us know how this turns out cause that's a COOL bike!! Good luck! __________________ -={FZ6inNH}=- . . Member #9 . . 2008 Cobalt Blue FZ6 -My Rider Resume Mods: Yamaha Lower Cowl, Racetech Springs w/15w oil, FAZR6 F.E. Kit, Puig Smoke Racing Screen, Tank Camera mount, Cortech Sport saddle and tail bags, dual headlight mod, Shogun Sliders, Yamaha Comfort Seat, Mild Airbox Mod, De-Stickered, and Custom Carbon Fiber SwingArm Decals

07-30-2008, 06:42 PM	#6 (permalink)
Cali rider Tequila connoisseur Join Date: Oct 2007 Location: Orange County, California Bike: 04 FZ6, 07 R1 Posts: 281 Rep Power: 8 Member #681	Re: reachn' out for help Check the inlet manifolds between the carbs and the cylinder heads. Unless they have been replaced within the last 10-15 years they WILL leak air. Just spray them with WD40 as the motor idles, if the revs change you have found at least one problem. Getting replacements might be a bit of a challenge but not impossible, there is a lot of NOS still out there for 20-30 yr old Japanese bikes.

07-30-2008, 06:50 PM	#7 (permalink)
Fred M em b er e d Join Date: Nov 2007 Location: Austin, TX Bike: 92 K75 Turbo, 07 Yamaha FZ6, Custom chopper (Pocketbike rear end, K75 front end.) Posts: 843 Rep Power: 25 Member #872	Re: reachn' out for help Assuming it's a CV carb, the slides aren't lifting. They might be stuck, or the diaphrams might be torn. Heck, just tear the carbs apart and rebuild them. You'll be glad you did. __________________ I don't know anything about motorcycles, but I just love little kittens. 1990 BMW K75 Turbo (Eternal project bike) 2007 Yamaha FZ6 (Modifications: Stebel Nautilus horn, Valentine 1 hardwired with remote display and audio, Mix-It sound mixer modified for hidden installation, Mayer saddle, true dual high/low headlights. Relay, fuse panel and lockdown blocks for all additional wiring.)

07-30-2008, 06:57 PM	#9 (permalink)
mdr Junior Member Join Date: May 2008 Location: Portsmouth, Virginia, USA Bike: FZ6 2008 in Blue Posts: 392 Rep Power: 5 Member #2760	Re: reachn' out for help I agree that carbs are most likely culprit but don't forget to check battery as well. They don't last forever and it's easy to check for fluid levels and voltage. Amperage might mean removal and a trip to an auto-parts store but still not hard and usually they do check for free. I'd do the easy stuff first then move on to carbs if needed. I had similar problems on a Ninja and it turned out I apparently had spark blowout from weak battery. Still betting on carbs though... And I'd advise you to not put the gas back in bike if it's the least bit suspect. Use it in your lawn mower, they're a lot more tolerant of funky gas. Last edited by mdr; 07-30-2008 at 07:00 PM..

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