popping in the exhaust-carbs?

[Steve]

Synching the carbs is the LAST thing that needs to happen, after adjusting the valves and CLEANING the carbs thoroughly.

If you have to have the "choke" on for more than a minute, something is not cleaned or not adjusted properly. It is recommended to clean first.


What couldn't I read?
Just the single, incomplete, run-on sentence in the first post.
No, we are not grammar police, but that post is VERY hard to read.

.

[bubby]

sry im bad with grammar and run on sentences. Let me start over lol I bought the bike it did not run. i put new points on it, reshimed the valves, cleaned the carburetors, adjusted the air fuel to 1 and 1/4 turns out synchronized the carbs and this is what i got a bike that idles poorly and is cold blooded and like i said it pops around 2700-3200 rpms ........ my compression gage only goes up to 100lbs and all 4 cylinders max it out.... has good acceleration and runs its best over 3600 rpms hope this helps you help me lmao

[Steve]

Sorry, I am similarly bad with bad spelling, bad grammar and TEXTING.

You say you have "adjusted the air fuel to 1 and 1/4 turns out". How far out is the FUEL screw? How far out is the AIR screw? If your fuel screw (the one on the bottom of the carbs) is not out far enough, it won't really matter how far out you turn the air screw (the one on the side of the carbs). "1 1/4 turns out" could possibly be a correct setting, but would require the fuel screw to be turned about half that amount, or 5/8 turn. Generally speaking, for a stock bike, the fuel screw should be about 3/4 turn out, the air screw should be close to double that, as a starting point. Slowly adjusting it from there to acheive best idle speed will determine its ultimate setting.

.

[OldVet66]

The air screw in your photo of carb #1,and #4 is way more than 1 1/4 turns out. At 1 1/4 turns, the screw head is still in the beveled area. You look like you are more than 2 1/2 out. Some of it could be camera angle, but the last picture looks like the screw is ready to fall out.

[TheCafeKid]

Those aren't stock VM26SS carbs either. Perhaps VM28 or 29 smoothbores maybe? Popping on decel is usually a symptom of an intake leak. Likely the orings behind the intake boots on the engine, dried out and rotten seals in the airbox etc. or an overly lean mixture particularly in the pilot and needle transition area.

Those look absolutely filthy by the way. I'm. It sure how you cleaned the carbs but it likely wasn the "correct way" to do it.

By the way, do you have a manual for your bike? And is it the correct manual? You keep posting questions that don't pertain to your model.

[bubby]

old vet i think it might be the angle i seen your post and checked all four screws the screw on the side of the carb is 1 and 1/4 turn out from seated position on all 4 carbs there is a line in the carb casting that the flat head notch in the screw is lined up with ......... the only other screw i see on the bottom of the carb is what i thought was the drain screw if you loosen that fuel comes out the hose the screw and hose im talking about can be seen in the top picture on cowboyup3371's post #12 of my pictures when i said air fuel i assumed that the screw adjusted the mixture witch it does but i think only the air flow some one correct me if im wrong.... i may be lol

[bubby]

the manual i have just says gs 750 service manual not sure which questions dont pertain to my 77 750 and you should have seen them before i cleaned them with mineral spirits, carb cleaner, and compressed air they where bad but my focus was more on cleaning the internals... if you know of a better method i would like to hear it besides a ultra sonic dip witch i didn't do but thats my plan if i can find some 1 who has a ultrasonic cleaner .....

[OldVet66]

OK, You have basically just cleaned the surfaces of the carbs that you can see. Carb cleaner and compressed air will not clean the internal passages. They have to be totally disassembled and soaked in carb dip and then replace all the O-rings. The inside passages look like a plumbing commercial. When you dip them you will be able to see the this stuff as it melts before the dip gets too dirty to see it floating out of the carbs.

[bubby]

the carb dip is good stuff? i should be able to get that from a local parts store rite is it called carb dip and is there a brand name that works better than others.... the stuff i found is chem dip carb and parts cleaner $23 for 3/4 of a gallon pricy stuff lol

[koolaid_kid]

You can get it from any auto parts or even Wally World. The most popular brand is Berryman's, but I suspect any brand will do. Probably made in the same factory and rebranded to suit the trends.
Yes, it is pricey. And it works. And you can keep it around to do more carbs (yes, others will know) so it is not a one time throw it away type experience.

[chuck hahn]

AND...while you have them off the bike for a proper cleaning, check the inside diameter of the throats ON THE ENGINE SIDE. This will tell you what VMXX they are. Some pics of the bottom of the carbs ( unless i missed them somehow ) would help too. If they have that tamper proof plug youll want to remove that so you can get the pilot screws out so the carb dip can get thru there as well. This will allow you to replace the oring that is "usually" on them.

[chuck hahn]

ALSO....Check the exhaust gaskets at the head and pipe joints for any leaks. Leaks and holes allow cold air to be sucked in on decel and that too causes popping.

[tkent02]

Not sure what motorcycle those carbs are from, but if whoever put them on your bike didn't jet them correctly for your engine there will be problems until it is done.

[bubby]

im thinking about putting gs 850 carbs on it yay or nay?? i have a set that my buddy gave me i wasnt sure if this was a good idea or not... im putting a dyna ignition on it (waiting for the kit to be delivered wed) and i im gonna get some pods for it to

[chuck hahn]

If it were mine, I would get a stock set of the original VM26 and get it straightened out. Maybe PM The Cafe Kid as he seems to have a bunch of stuff in the bin.