Carb flooding question

[mschor]

I've been slowly getting this 81 Special together after 20 yrs in a garage. About to hook up fuel and try starting it up, but a little concerned about fuel flooding into the crankcase if the floats aren't perfect or the float needle doesn't seat well. I replaced the needles and seats, did a pretty thorough carb rebuild. Is there a good method to check that fuel won't overflow through the carb with it off the bike? Thanks! I'm getting pretty excited to fire this thing up.

[motoman]

I've been slowly getting this 81 Special together after 20 yrs in a garage. About to hook up fuel and try starting it up, but a little concerned about fuel flooding into the crankcase if the floats aren't perfect or the float needle doesn't seat well. I replaced the needles and seats, did a pretty thorough carb rebuild. Is there a good method to check that fuel won't overflow through the carb with it off the bike? Thanks! I'm getting pretty excited to fire this thing up.

Flip carb bank upside down and remove bowls. With carb bank upside down, which closes needle seats, hook fuel lines to carbs using a portable fuel tank ABOVE the carbs. Any leaks by the needle seats will immediately show.

[mschor]

So if the needles seat well then it will overflow elsewhere if the floats are off?

[mschor]

Off as in not set perfectly

[motoman]

Off as in not set perfectly

Gotcha.........no, if floats set to low(carb bank inverted), actual fuel levels will be too high. I'd advise, while carb bank is off to check those static float heights. Should be 23mm from carb body(gasket removed of course) to highest portion of float. Also, make sure floats set straight and not crooked. If not parallel to carb body, a float can hang up on float bowl. Also, set bowl gasket on carb body. If any of gasket protrudes beyond bowl inward, take a razor blade and trim gasket while it sets on carb body. When bowls are tightened, gasket being squished somewhat can cause protrusion of gasket to inside of float bowl, which will also hang up a float.

[mschor]

Thanks, also just read the suggestion to tip the bike back so fuel flows to the airbox instead of the engine if anything sticks. Going to take off the carbs again tomorrow and go over one more time. Lots to learn on these threads

[motoman]

Thanks, also just read the suggestion to tip the bike back so fuel flows to the airbox instead of the engine if anything sticks. Going to take off the carbs again tomorrow and go over one more time. Lots to learn on these threads

Never had a bowl overflow myself, but for good measure mine sets covered in man-cave with a shorty 2"x4" under front wheel while on centerstand. Just an acquired habit the past few decades.

[mschor]

That was a great method. I went through the carbs again today. One float was hitting the gasket & I fined tuned the levels again. Needles are sealing well. Put it on the bike and tried to start it. It turned over a couple times, then just a click, and now not a sound. Ignition lights are strong, and battery is good checked it today. The engine spins smoothly by hand. Thinking to replace the fuse box to start, then go through the electrical. Any thoughts where to begin?

[BA80]

Check fuses for good connection or blown, starter relay (solenoid), kill switch in right handlebar switch.

I believe the 81 has a kickstand and/or a clutch safety switch also.

[JeffH]

It turned over a couple times, then just a click, and now not a sound. Ignition lights are strong, and battery is good checked it today.

Sure you got 12.5v or more on that battery?

I know you still plan on going completely through the Electrical but crank then click then nothing is maybe bad ground connection(s).

Check the ground cable connections. Look for corrosion. Terminals tight. Likely its not a fuse. That might be what you need at this step just to get it started to check your carb work.

Hope you can find the problem without too much hassle.

Jeff

[mschor]

Thanks ya'll, I will check the grounds first, then other spots listed. After 20 years sitting (garaged) I'm sure there are a few bad connections

[BA80]

Likely its not a fuse. Jeff

If he still has the old glass fuse panel a bad connection there is the most likely. Especially since it's been sitting.

[mschor]

Okaaay, it was just the battery contacts not screwed on tight enough duh. Started right up with some fluid, now starts easy but idles a little high. I guess the carb work was good because it runs smooth. I let it run for a minute or less and it heated up pretty quick, started smoking off the #4 pipe close to the engine. Not sure if too hot or just burning off old ****. Pretty hot to touch tho. You think this smoke is normal? Can't believe how fast things came together after about 3 months

[mschor]

Choke was a little stuck so idles good now. How long is ok to run it without a fan cooling it?

[DiverRay]

Only about 3-5 minutes MAX!! A cheap 20" box fan is what I use, set up on a 4X4. It'll keep the engine cool while doing a sync and setting everything on the carbs.
You DO have new oil in it, correct. IF so, run it for about 500 miles and then change it and the filter. The old sludge in the engine will be loose and ready to come out by then. Also, do NOT worry about doing a compression check until you have at least 500 miles on it, as it may take a while for everything to get back to working properly.
If it was my bike, the next two things I would be doing is a T.C. fuse block and the ACCT from a newer Yamaha. Both will save your sanity and don't cost much.