Spit back into carbs video and POLL

[dan filipi]

Ok so I've done a video showing the effect the typical spit back has on the cylinder vacuum.
You can clearly hear the clunk in the engine when this spit back happens, though vacuum doesn't always get affected.
When it does though there is a profound affect on vacuum. Seems to be most evident on #2 and #4 (opposite coils).

Please vote in the poll if yours sounds like this!
I heard it happening on every 1100 at the meet.

For info, there is a problem in the number 2 carb I haven't done anything with because I know how it runs.
Garage temp is 85 degrees and this is a cold start.
Coils are Mp08's from a 1500.
I'm playing with the throttle to get it at the point it spits most.
My intention here is to figure out exactly what it will take to fix this spit back problem and use this video as a reference before installing the C5 ignition.

[video]https://youtu.be/5elmRCwldys[/video]

 

[backlander]

I'm thinking. 2 questions, does this occur only while on idle circuit and does each carb on 1100 have an air cutoff valve or do they use a single valve for all four carbs like the 1200.

 

[dan filipi]

backlander » Mon Sep 02, 2013 1:26 pm[/url]":2c3slcgk]
I'm thinking. 2 questions, does this occur only while on idle circuit and does each carb on 1100 have an air cutoff valve or do they use a single valve for all four carbs like the 1200.

Well in the video I held the throttle just off idle where it typically spits the most.
It will spit at idle though not as much, it will also spit at 2-3000 rpm but not as much.
Above that, spit rarely happens though it has happened.

1100's have a cutoff valve on each carb. They are new in these carbs.

 

[zman]

I have to say no but I need to qualify that a bit, When cold it is smooth as glass and throughout the day it is fine but once in ahile when i`m going red light to red light and acellerating away I hear a "just audible" sneeze., It doesnt interfere with the launch seemingly and will stop doing it once I get on an open stretch.
I have been tossing it up to the engine being loaded up by the stop and go traffic but also there is the fact the stator output is really up to max at idle conditions and with the fan running at the red lights maybe running lower volts?
I plan on buying one of those Gunderson color tune`s and make certain the idle circuit is getting what it needs before I go guessing or replacing.

 

[dan filipi]

Can rule out any stator effect in my video because I'm running an external alternator. Voltage at idle is at least 13.5 at the battery.

 

[zman]

dan filipi » Mon Sep 02, 2013 3:34 pm[/url]":3l3cllqw]
Can rule out any stator effect in my video because I'm running an external alternator. Voltage at idle is at least 13.5 at the battery.

How do the plugs look? That is allot of coughing.

 

[dan filipi]

zman » Mon Sep 02, 2013 3:41 pm[/url]":2ijc1uz0]

dan filipi » Mon Sep 02, 2013 3:34 pm[/url]":2ijc1uz0]
Can rule out any stator effect in my video because I'm running an external alternator. Voltage at idle is at least 13.5 at the battery.

How do the plugs look? That is allot of coughing.

Tan.

 

[zman]

I have no doubt you have it set up very well so I`ll forgo the elementary things, How about throttle shafts?
You can sometimes see the effects by removing the intake manifold and looking up inside, A fan shape will be present spreading from the shaft itself and getting larger as it reaches the end of the carb. Usually this can be corrected by opening the fuel mixture screw but in worse cases it becomes impossible to tune.

 

[brianinpa]

Mine will run like that when I first start it up, but once it is warm, for the most part, I don't notice it anymore. Maybe I am just accustomed to and ignore it because to be honest with you Dan, I was first thinking that this is how mine sounds when I am riding in a major rain storm. Gerry and I were discussing that and i am going to be changing the plug wires and spark plug boots. What are yours like? Maybe it isn't in the fuel...

 

[Omega Man]

Old Girlfriend would do that in the morning until I got on the open road(60-90seconds from where parked, down driveway to road) where I'd ride at 45-50 mph. After warm up it was gone.

~O~

 

[joedrum]

well in everyway possible the oldwing has built in lag time not only with carbs and vacume slides but also ignition that's vacume advanced and mechanical .....this is never most present than at idle and just off idle ...cdi iggy is very inaccurate and the system realy heats the coils a everything else up ... there thirty yrs old ... they wasted spark system that sets up spitting back in carbs ... at idle there not much gas to begin with or to much .. bad timing in spark weak spark idle and screwy carbs from things spitting cause a lot of power waste in oldwing motors ... it huge problem of many sources to deal with wires and ends mention

 

[skiri251]

Mine does it when cold.

 

[AApple]

I don't really know how to answer, or vote in the poll. Mine will do something similar on first start in the mornings, but it's not the SAME thing. And it only does it a couple of times while idling/warming. Mine sounds/feels more like it has a minor hydro-lock on one cylinder for a split second, than spitting back thru the carb(s). Can't really say it is poppin back thru the carb(s)...but it IS doing something weird. Once it runs for a minute, it don't do it again, until it sits over night, and even then it may not do it every cold start. From the responses here, it(whatever "IT" is) :headscratch: appears to be a common malady....

Moving the throttle on mine doesn't make it do "it" more, or worse....the throttle doesn't seem to make any difference in my case.

 

[jpwinger]

+1 on what Joel said I have the same thing on my 80 but I have 82 carbs on it. Tried to just floats several times, I think its getting worse. And now I think floats are leaking, keeping a very close eye on the oil level. Gonna have't to pull carbs and look at floats and needle's and seats and do the float leak down test again. As well as fuel level i n bowls Jerry

 

[westgl]

With my stock Carb rack, Mine is the same year bike as yours Dan, a 83' GL1100.

It does have a slight spit when started and till it warms to operating temp. after that it is occasional, or if it is a Hot day out, it will do it more.

Dan,
I would like to see, another test video, with that single carb conversion, you are working on, and see if you get any spitting with it, before you install the C5 Ignition.

This would tell us for sure, if it is the OEM Carb. Rack, or the Ignition.

 

[mcgovern61]

When I had these carbs on the '81, it did the same thing plus they leaked and I did not know that I had a vacuum leak at one of the intakes. After a carb rebuild and installing the '83 engine (plus new O-rings for the intakes) it does not ever spit back now.

Here is a cold start up on the '83 engine for comparison:

[video]https://www.youtube.com/watch?v=s-SnkdhcdII[/video]

 

[dan filipi]

Sounds great Gerry.

When you had the problem with the carbs after getting them back from Pistol Pete, was it the float levels that were too high (too high gas level in bowls) or too low (too low gas level in the bowls)?

 

[mcgovern61]

The problems I had were related to overfilling. The floats were all out of whack and the seats were leaking gas. I had to pull them three times to get them clean enough to seal. One float is adjusted at 17 mm to get it to work correctly. I am not sure if all of the needles are OEM or not which might explain why 1 was so far out. As far as the floats being out of adjustment otherwise, they were actually more twisted than level which made the original adjustments pointless. I had to straighten all of the floats first before adjusting them.

My guess was, the shipping company dropped the box several times between the airplane ride and the ground crew to mess the floats up that much. I find it hard to believe with Pete's reputation (and apparently how many of these sets he has worked on) that he would have let them out of the shop set like that. Although, I would have thought the seats would have been cleaned better and seals well.

That video up there is after I set everything, no leaks, sync performed, valves adjusted. It was the first start of the day and it still pretty much starts like that today. I do have to give that little bit of choke every start though? Always have. I just think the '81 carbs are cold blooded?

 

[joedrum]

sheesh :shock: reputation dosnt mean much today ... nope I don't see how seats get dirty from droping while packaged up at all :nea:

 

[westgl]

I am not getting the spittback at all with the single carb. and the MP08 coil conversion

My idle is very smooth.