Author Topic: no firing in cylinders 3 and 4? (Read 8586 times)

KSUGreggy · « **on:** April 01, 2006, 10:30:28 PM »

well had my bike up and running good the last couple days. Today i go to start and it sounds funny so i turn it off....sounds like its not firing on all 4...and i was right....go ahead and feel the header pipe. Cylinders 1 and 2 are warm.....3 and 4 feel cool to the touch...not nearly as warm as 1 and 2.

Firied it back up to make sure again....stuck my hand behind the exhaust and had raw gas spray. I just replaced the plugs so im not thinking that is this issue. Pulled them and they didnt seem very fouled at all. Any ideas for things to start checking?

Red01 · « **Reply #1 on:** April 03, 2006, 11:37:53 AM »

Did you put the plug wires on the wrong plugs?

#1 & #4 should come from the same coil, and obviously, #2 & #3 from the other coil.

KSUGreggy · « **Reply #2 on:** April 03, 2006, 11:44:09 AM »

yea checked all that....ran fine yesterday after i tinkered with it..maybe a loose connecetion somewhere...who knows...works now

Red01 · « **Reply #3 on:** April 03, 2006, 11:52:21 AM »

That's good to hear!

99er · « **Reply #4 on:** April 07, 2006, 06:18:31 AM »

Be careful with those "Works now and I don't know why" solutions. They could strand you who knows where. Like Red01 said, it doesn't make sense to have 3&4 go out when they're on different coil circuits. That would at least point to the carbs. Something to think about - have the carbs ever been removed and cleaned, tank drained of sediment, etc...

That said, my 12er ran like crap once, back in 2000??? after checking the valves. I found that it was arching to the case and that the ignition wires had to be kept as high as possible in those bendable routing clamps that Suzuki supplies. Solved.

Take another look and rule out the obvious. Nothing worse than not being sure you can make it home once you leave the garage. After all, it's not a Harley (ouch).
Marc/Atlanta

Doch80 · « **Reply #5 on:** April 07, 2006, 10:39:07 AM »

I kind of have the same problem as you KSUGreggy. When I start the bike up after sitting for a week or more it sounds like it's running on 2 cylinders. That and the choke has no effect on rpm's like it usualy does. After about 10 min or so the other two cylinders pick up and it runs fine. This has only started happening this year after I let it sit for about 2 weeks one time... took about 30 min to just get it idling after and another 30 min just to get it running right. Prior to this year after sitting (cold mornings or warm) it just ran rough for a few min then warmed up. Back in April 2005 after storing it for 10 months with Stabil in the tank it started up just fine.

Guess I need to clean something... or just get a jet kit...

... in about another year

Chad

KSUGreggy · « **Reply #6 on:** April 07, 2006, 10:41:14 AM »

i bit the bullet and just bought a holeshot stage one the other day...should be here today. Figured it cant hurt to pull the carbs and might as well stick a kit in while im cleaning them out!

rider123 · « **Reply #7 on:** April 07, 2006, 02:02:15 PM »

Put the bike on prime for 20 secs before starting up when you leave it for more than a week. Some cylinders will have slightly more fuel pressure(usually middle ones closest to the fuel line) than the two outer carbs which are the ones that usually evapourate the gas first. This will make sure that all carbs have equal gas.

KSUGreggy · « **Reply #8 on:** April 07, 2006, 02:37:12 PM »

thanks for the tip

rider123 · « **Reply #9 on:** April 07, 2006, 02:42:21 PM »

In adition if you've left the bike on the side stand 3 and 4 will have less gas than 1 and 2 due to gravity. Put the bike on the centre stand, prime it, and enjoy the ride!

Red01 · « **Reply #10 on:** April 07, 2006, 04:49:34 PM »

Quote from: "rider123"

Put the bike on prime for 20 secs before starting up when you leave it for more than a week. Some cylinders will have slightly more fuel pressure(usually middle ones closest to the fuel line) than the two outer carbs which are the ones that usually evapourate the gas first. This will make sure that all carbs have equal gas.

If your carbs are working like they're supposed to, the pressure will be the same. On a closed (non-vented) system like the one between the petcock and the float needle & seat, the pressure will be the same everywhere in the system. That's just basic physics.

Quote

In adition if you've left the bike on the side stand 3 and 4 will have less gas than 1 and 2 due to gravity. Put the bike on the centre stand, prime it, and enjoy the ride!

Again, not if it's working like it's supposed to and the bike was shutoff in any attutude where the gas tank is higher than the floats.