Hanging throttle/low idle/bike dying/etc

[brockd]

Hey all,

So I've finally got her on the road! Noticed a few things today:

1) old battery wouldn't hold a charge and wasn't powering the ignition properly - so I bought a new one. Went with a Motomaster AGM 12A-A which corresponded with the manual. Seems to have fixed the electronic issues.

2) Cold start is a bit of a problem. Just read that I'm not supposed to touch throttle on a cold start - so I'll try again with choke out in the morning.

3) Been fiddling with the idle screw. Before getting the new battery in I had to crank it up considerably to get it hovering around 1500rpm. It would idle for a minute or two then drop right off and die. In addition to this I'd rev up to about 5000rpm to get it juiced and then the idle would hang around 4k for about 30secs

4) As I'd get driving everything seemed mostly fine though when I'd drop it down to 1st to try some slow-speed stuff the throttle wouldn't respond, the engine would almost sputter to a stop and then it'd finally catch and jump up to 3500rpm while I had the clutch in.

Also added a coupla capfuls of Seafoam to the tank in hopes of cleaning out any hidden gunk in the lines.

I've thrown a couple vids on youtube showing some oddities while it's idling here:
This one fluctuates up and down a bit, then I rev near the end.

This one goes up and down of its own accord:

On the second vid note the OIL light on - is this normal...?

The shop synched the carbs as close as he could with the manometer setup they had in the shop.

Everything else is pretty well stock save for repro air filters, new carb boots, and a fuel line change. I have to replace my petcock as it's leaking in the Res position and it looks like my gas cap seal is cracked from age so I'll need to get that done too.

Now that she's officially in my possession I'm a) pissed with how much work and money I've already unexpectedly sunk and b) excited to get into this crazy world of carburetors, moving parts, and rubber

Y'all have been super helpful thus far and I look forward to whatever info I can get here

 

[xschris]

Make sure the carbs are fully cleaned. This would mean they should be completely taken apart. New butterfly seals also. Check the diaphragms for holes and cracks. Make the the tips of the idle mix screws are not broken off in the carbs. How many turns out are they? 3 turns is a good starting point. Stock air boxes and mufflers with no holes? The oil light should be on if the motor is NOT running.

 

[brockd]

Carbs have already been fully cleaned - squeaky cleaned.
Haven't taken them off the bike a second time - but might have to adjust the floats and check the needles n whatnot.

Discovered quite a bit of gas in the oil - so we bled that out and drained the float bowls. Not sure if theres gas leaking into the carb through the vacuum tube - I suspect there is - or whether we're some choke issues/goosing the throttle too much to start her.

Just waiting on a petcock rebuild kit, a new gas cap, and an oil filter before she gets put back together to see if all works before tinkering with the carbs.

Have a look at the deconstructed petcock - how would you guys recommend cleaning the drain plate - you can see it's all gunked up. Would CLR be too strong?

Tx!

 

[brockd]

Chris - Can you point to the butterfly seals and the idle mix screws...

 

[xschris]

The seals are located at the end of each carbs shafts. Two per carb. The mix screws are at the top front of the carbs. Make sure the tips are straight and pointed still and have NOT broken off in the carbs, this is bad!!

 

[brockd]

Chris - you're the best!
Any recommendation on cleaning out the gunk in the petcock drain bowl? Should carb cleaner or CLR do the trick?

 

[xschris]

Soda blasting and a sonic washer. Then 150 psi of air through all the holes would be the best.

 

[brockd]

Happy May all!
Alright - finally got to the carbs myself.

Luckily the idle screws are completely intact

The butterflies also look like they're in good condition.

Checked the float height and they're bang on 26mm. Also did a little blow test with a fuel line to confirm the needles are doing their job well.

I'm wondering if most of my problems are with my faulty petcock just pissing fuel into the bowls constantly. I'll be picking up the repair kit this eve at the FedEx depot and will be headed back to the machine on Sunday to pop in a new oil filter, fill 'er up, and see what happens!