SOS Bogging bad from a stop, very choppy while cruising

[CivilPenny]

Bear with me here, there is a lot of material to cover. 1979 XS1100 Special.
Bought my bike from a guy a while back, every thing worked perfect. No lagging, throttle response was perfect, no bog, no issues present at all. I rode it for most of the season with no issues aside from having to rebuild the brakes.

One day after class I rode home in a VERY heavy rainstorm. Unfortunately, there was no stock air box, pod filters are on the carbs. The rain really got to my bike, and i was bogging down starting from stops and even stalled it a few times. I finally parked for a bit, let the rain pass, and rode it home with the same bogging issue.

After this, everything was Fu*ked. Every ride, starting from a stop, the bike would bog,jerk, and backfire through the carbs until it finally got up to 3-4k rpm's where it then took off no problem. This was a huge problem, and affected everything about riding. Even pulling in the clutch to rev match, i just got bog instead of a rev. Cruising at any speed I can hear the bike popping and really struggling to run properly and it KILLS me.

To try and fix this, I started with the fouled plugs and put new ones in, and gapped them. That didnt help much. Then, we turned the vaccum advance clockwise a little, no change, then went counter clockwise from where it was at, no change. The other day, I turned in the Fuel/Air mix screws all the way in, backed them out to 1.5 turns, no change, 2.0 turns reduces the bog and backfire a little, but it was still present. Also, every time I hit the throttle hard (in any gear/rpm) all it wants to do is bog down for a bit, then will take off. It will even stall sometimes if revved too quick.

Where do I go now?? . Everything seems to be working fine inside the carbs, slides, floats, diaphragms, clean jets. I have been balancing the carbs after adjustments are made.

PS. The rubber stopper in the cam chain tensioner keeps popping out and leaking oil. Tried to epoxy it back in, but it keeps popping out under engine pressure. Any ideas? Maybe this could be part of the bogging issue.

[JeffH]

Sorry to hear you are having trouble. For starters let's try to dissect this a bit. Have noted some 'initial thoughts' and then some other ideas based on a couple re-reads. I'm sure others will join in with their ideas too. Also, it might be the old domino effect deal where things are changing as you work on one thing it is effecting something else.

So it apparently ran GREAT until is got WET. Curious how long between the time it got water logged and the time you started working on things?

I rode it for most of the season with no issues aside from having to rebuild the brakes.

I rode home in a VERY heavy rainstorm.
My initial thought was Coils or Plug Wires or Plug caps. But then you said runs great above 4,000 rpm. Kill switch too. But then you say it runs fine above 4,000 rpm.

Unfortunately, there was no stock air box, pod filters are on the carbs.
To confirm, you have taken apart and cleaned the carbs after it got wet and starting doing the Jerk n' Pop on you.

btw: Broken pickup coil wire also gives you the Jerk n' Pop ride


The rain really got to my bike, and i was bogging down starting from stops and even stalled it a few times. I finally parked for a bit, let the rain pass, and rode it home with the same bogging issue.

After this, everything was Fu*ked. Every ride, starting from a stop, the bike would bog,jerk, and backfire through the carbs until it finally got up to 3-4k rpm's where it then took off no problem. This was a huge problem, and affected everything about riding. Even pulling in the clutch to rev match, i just got bog instead of a rev. Cruising at any speed I can hear the bike popping (but running steady above 4K rpm it runs perfect?) and really struggling to run properly and it KILLS me.



Chasing some of this stuff might be counter productive. Would rain really change the vacuum advance if the bike was running aok before you hit the rain?
To try and fix this, I started with the fouled plugs and put new ones in, and gapped them. That didnt help much. Then, we turned the vaccum advance clockwise a little, no change, then went counter clockwise from where it was at, no change. The other day, I turned in the Fuel/Air mix screws all the way in, backed them out to 1.5 turns, no change, 2.0 turns reduces the bog and backfire a little, but it was still present. Also, every time I hit the throttle hard (in any gear/rpm) all it wants to do is bog down for a bit, then will take off. It will even stall sometimes if revved too quick.
And you are sure the Pilot Jet are clean-clean and Pilot jet circuits are clear?
Where do I go now?? . Everything seems to be working fine inside the carbs, slides, floats, diaphragms, clean jets. I have been balancing the carbs after adjustments are made.

PS. The rubber stopper in the cam chain tensioner keeps popping out and leaking oil. Tried to epoxy it back in, but it keeps popping out under engine pressure. Any ideas? Maybe this could be part of the bogging issue.

So it starts up just fine? Curious, with choke or no choke? Then idles fine and smooth? Just won't take any throttle between 1,100 rpm and 3,500 rpm without the Snort & Pop?

> battery up to 12v?
> pickup coil wires are ok?
> changing the timing hasn't been a factor?
> unlikely but tensioner is adjusted properly?
> using fuel filters on the fuel lines?
> rust in the tank or clogged vent?

Jeff

[CivilPenny]

I have read many other threads but can’t seem to find the exact issue.

I believe I started working on it within that first week. I didn’t let it sit too long. I would ride it to a guys house who knew xs11’s pretty well for help. During these rides, it would bog down just like before. At one point, the problem disappeared like nothing even happened. I was happy because the problem seemed to have fixed itself. That lasted for a few days, then the problem came back. Then went away, and now it has come back and remained that way. The power seems to strike at 4K and above but it’s still poppy/choppy. It starts with and without choke with ease, idles just fine, smooth as butter. I am using inline fuel filters and the gas tank is sparkly clean on the inside. I opened up the carbs and cleaned them after the problem as well.

I will take a look at the pick up Coil wires because many other people have had issues with them.

[Schming]

P.U. Coil wires sound like a good place to start also when these engines backfire through the carbs the rubber caps get blown off the carb manifolds make sure they are still there.
Sounds like you have the correct pods on if the bike was running good before.
There are some restictive pods on the market to beware of.
The nuetral switch wire is in the same harness as the P.U. coil wires and when wet sometimes shunts to ground.
Most have done the ACCT mod to solve the stock cam chain tensioner shortcomings.

Oh Welcome to the Obsession

[CivilPenny]

I’ve heard the ACCT’s aren’t such a good idea because they put constant tension on the shaft when so much tension isn’t always needed, causing wear a lot quicker. However It sounds a hell of a lot better than constant adjustment. I tried following a thread on here on how to adjust the CCT but when I did it, I didn’t hear and sounds or clicks telling me that the spring snapped back to its proper place. Maybe there shouldn’t even be a sound, I wasn’t really sure what to expect.
When I did this, I Removed plugs, Turned the dial to “C”, loosened CCT nut, backed out CCT screw a good amount hoping to hear a click or pop of a spring, didn’t hear anything so I figured it adjusted itself. Tightened screw and nut back up. Did I do it properly?

[motoman]

I’ve heard the ACCT’s aren’t such a good idea because they put constant tension on the shaft when so much tension isn’t always needed, causing wear a lot quicker. However It sounds a hell of a lot better than constant adjustment. I tried following a thread on here on how to adjust the CCT but when I did it, I didn’t hear and sounds or clicks telling me that the spring snapped back to its proper place. Maybe there shouldn’t even be a sound, I wasn’t really sure what to expect.
When I did this, I Removed plugs, Turned the dial to “C”, loosened CCT nut, backed out CCT screw a good amount hoping to hear a click or pop of a spring, didn’t hear anything so I figured it adjusted itself. Tightened screw and nut back up. Did I do it properly?

Yes, done correctly. Schming's suggestions would be a good start. Also, after removing the ignition cover, using both hands pull each of those pick-up coil wires every inch. If insulation of wire stretches a bit, wire is broken internally making intermitant connection only. If a wire is broken internally, cut connection, first slip a really short piece of shrink tubing over a wire, then use a SHORTENED naked butt connector to re-attach wire(no soldering allowed). Then slip shrink tubing over connection and shrink it with a lighter or such. If you solder the wire, the heat from soldering will weaken the teeny copper wires and will break again from movement of the vacuum advance assembly.
Acct's create no additional wear, period. Pinch screw of original adjuster will not hold under a heavy decell, which ends up forcing adjuster back out of adjustment again. Is a common issue with the stock cam chain adjuster. Ideally, if you can locate one of the two self adjusters from a v-4 Yammy Venture, any year model, that one IS the best option to use. If you get both self adjusters from a Venture, that gives you an extra self adjuster fpr future use.

[jetmechmarty]

Do you still have an airbox for this bike? If it was me, I'd put it on. Everything was fine until your pods got wet.

[motoman]

Do you still have an airbox for this bike? If it was me, I'd put it on. Everything was fine until your pods got wet.

Agree, pods previously getting wet didn't do the filter material any good.
With ignition cover off, unhook vacuum advance arm and check that advance assembly rotates very freely. If the least bit stiff, has to be removed and backside where mechanical advance/springs are located, all needs to be cleaned. A slow or non moving mechainical advance assembly changes correct ignition firing time, till it may, from vibration rotate fully advanced at higher rpm ranges.

[CivilPenny]

I do not have the original airbox, but I have access to a few. I’ll slap it on and give it a shot

[thumperjsa]

I don't think taking the pods off to see if they are choking and making it lean would help in testing since you say it runs good above 3k or so. I'd think it would be one of the air circuits in the carbs blocked. Once you get to about 3k, the main starts opening and let's much more air/fuel in. Those lines are so small a drop of water could block a passage. Did you pull the carbs and clean them real well to make sure there's no blockage of any of those tiny air passages.

I don't think it would be in the fuel circuit because that should have cleaned through and you said it runs good at higher RPM.

One other thought. Open and clean some of the electrical connectors under the tank. Possibly water got in it and caused corrosion. Just thinking maybe with enough RPM, voltage is high enough to overcome the resistance from corrosion allowing it to run better at higher RPM than lower RPM. Just a thought anyway.

[motoman]

Good thought thumper, and also unplug and clean connectors behind fuse panel if not already done.