Throttle butterflies dont retract?

If it's broken or just needs tweaked

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Thu Mar 15, 2018 1:42 am

I would most definitely avoid using any of the brass parts from a carb rebuild kit as they seem to cause more problems than they cure. Just make sure that if your original jets are still usable that you get them nice and clean first. If your plugs are a light tan/brown colour then that is fine.

EDIT, Just looked at your picture and it looks like you are running a bit rich to me. I'd swap those jets first then see what your plugs look like.

MEHall
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Re: Throttle butterflies dont retract?

Postby MEHall » Fri Mar 16, 2018 8:10 am

I can say for a fact when spark plugs look like that it IS to rich.
Had the same problem on a CB 250n superdream and when i changed to a smaller jet the spark plug looked as it should. :wink:




8)
Riding bikes? I ride where ever i want and whenever i want. :wink:

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Fri Mar 16, 2018 1:26 pm

I havent had enough time to get to the carbs yet but I can confirm that the jets are old 90 mains. I left the new ones in the box and never installed them cause they were stamped 95 but I did install the pilot screws that came with it because mine have limiter tabs that get in the way. Im wondering if the size of the pilot screw is different since some parts did not fit like the paper gasket for the top covers. One last thing, I never replaced the little rubber air cutoff valves that are on each carb but I took them out and soaked them to soften them up since they look like the originals (to expensive at the time). They are soft now and theres no popping on decel but im wondering if theres some kind of air passage that I didnt clean down there. Ill post some pictures tonight of the carbs to see what you think.

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Sat Mar 17, 2018 10:42 pm

So I was finally able to get through the carbs today and everything was still clean. I polished the brass seats with a qtip in a drill so now there smooth and shiny. Hopefully the needles will appreciate it. When was dissasembling the carbs and floats I measured the height and they looked to be too high (holding it upside down) so I tilted the carbs at a slight angle and got a different measurement at 12.5mm. This is how i measured it https://www.flickr.com/photos/83017157@N08/27000105138/

Also when the floats are resting down not closing the flow of gas they hang a little low is this okay? Heres a pic of them hanging freely not closed or anything
https://www.flickr.com/photos/83017157@N08/39060658190/

Lastly, I dont think ever cleaned the pilot screw holes thoroughly so I removed them and found two o-rings in each hole oops. I removed the little metal washers in past with all four and put in new orings never realizing there was left overs in the bottom. Maybe this was shortening the reach of the needle giving me a false reading of "lightly seated"?

Anything else you guys would suggest?

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Sun Mar 18, 2018 4:09 am

Hi WT, it doesn't matter how low your floats hang because they never will be that low when you have fuel in your carbs. When I set the float height I hold the bank of carbs in my left hand and sort of roll them until the float "settles" without putting any pressure on the float valve then measure with a vernier gauge in my right hand. I've come across the too many o-rings problem just recently on some Kawasaki carbs :roll: I have developed the habit of shining a torch into the mixture screw hole and firking around with a bit of wire, if there is a washer in there it can still look like the bottom of the hole. I'd say that finding two o-rings in there is definitely going to mess up your settings :lol: Do you have access to a Gunson Colortune http://www.gunson.co.uk/product/G4074 ? can you borrow one from somebody? Some people refer to them as glass spark plugs.

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Sun Mar 18, 2018 12:04 pm

Thanks for the fast reply. I don't know anyone with a colortune plug but I will probably buy one in the near future for the bike since its not that expensive. I forgot to ask what are those tiny little holes at the air intake throat of the carb by the choke flaps? Theres 3 in each carb. I cleaned them out too just in case since I just they were just cosmetic the first few times :? . Hopefully I can get the carbs back in tonight since it sounds like I measured them right.

Heres a recent pic of the bike all stock
https://www.flickr.com/photos/83017157@ ... otostream/

After sanding and buffing the aluminum on all the covers and forks.
https://www.flickr.com/photos/83017157@ ... otostream/

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Sun Mar 18, 2018 1:42 pm

Wow! 8) I thought mine was shiny! viewtopic.php?f=2&t=14452 That is very nice, have you got any before pics? As far as I'm aware the 3 little holes in the carb throat are air passages, I know that one goes to the air cut off valve but I'm not sure of the other two without actually holding a carb in my hand. I clean those out with plenty of carb cleaner and lots of compressed air after the carbs are stripped, then the carbs are put through the ultrasonic cleaner.

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Sun Mar 18, 2018 11:57 pm

Yeah Im trying to keep it stock like a museum piece :D I like stock. I have to send my pipes out to Mexico to get patched from a rust crack and everything re-chromed. Ill try to find some old pics before I started cleaning it up. Yours looks nice and clean especially the tank, good rich color. I going to add additional clear coats to fill in some fine scratches in order to preserve the original candy muse paint as it is quite nice looking in the sun. I will get some more pics of it before I started polishing her up.

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Mon Mar 19, 2018 7:28 am

Stock is Best! 8) but I think we may be in a minority :D I just wish that these bikes were more common in the UK as finding reasonably priced spares here is a real problem :cry:

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Tue Mar 20, 2018 7:02 pm

Looks like it did not make a difference cleaning those holes and removing those extra washers in the pilot screw. It started easily with choke after a second although its 74 degrees here in CA. I turn off the choke within a few seconds because it stutters like its going to die if left choked, the idle rises when choke is open. It still smells a little at idle (i have a crack in the baffle not sure if its that) and now that air hissing noise is more clear by the airbox. Theres no air leaks I checked by spraying. Should that idle raise after turning off the choke at idle? Does it mean its lean or rich?

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Thu Mar 22, 2018 2:08 am

Did you put the original jets back in the carbs? The idle should lower when the choke is switched off. I remember reading on the interwebby about some guys having bikes that ran too rich and the solution seemed to be to run the bike with the air filter cover removed, the air filter was secured by three penny washers on the cover screws. Now I'm unsure as to why there bikes were running so rich in the first place as the type of fuel and altitude were brought into the discussion.

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Thu Mar 22, 2018 1:58 pm

The jets in carbs are the original 90 main jets I never installed the other ones. The bike needs the choke to start but only briefly. If i try starting without choke the bike will start for a split second then stop. After it starts with choke I turn it off after 2 seconds and the rpm rises. Im going to take it for ride eventually but its raining here so theres no much I can do right now. I have 2 air filters, a K&N one from the PO and a stock EMGO paper filter I bought and am using currently. Is one of them more restrictive to airflow than the other?

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Fri Mar 23, 2018 2:45 am

Have you checked your carb boots for leaks by spraying easy start around them when the engine is running? I admit this doesn't sound very likely as your problem sounds like it is running rich, I'm thinking about why the revs would rise when the choke is off. How does the bike rev when you give it some throttle? does it accelerate smoothly?

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WiseTurtle
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Re: Throttle butterflies dont retract?

Postby WiseTurtle » Sat Mar 24, 2018 9:49 pm

I got to ride the bike a little today and it was able to start relatively easy in 72 degree weather. It doesnt smell as bad like it did before. When it started it idled around 1100rpm. Did some light riding and when I held the throttle open at a fixed position the acceleration picked up gradually even though I wasnt feeding it more gas. Is this how its supposed to be because I've never felt that? Usually I have to open the throttle more as I pickup speed. After doing some slow riding in a parking lot practicing for my dmv test for 10mins is was cruising beautifully and taking slow turns in 2nd gear with no stuttering like it used to. I was going less than 10mph in second gear without it stumbling but I noticed the idle was now at 2000rpm when it was now fully warmed up. Before I left the lot I lowered the idle with the adjustment knob back to 1100rpm and it ran like shit at idle and taking corners in 2nd gear slow with it was now stuttering. Whenever I started off from a stop it stuttered unless I gave it a considerable amount of throttle(Maybe Im babying the transmission?). When coasting in neutral down a long hill the engine kept dying maybe this is a clue. It did this a few times while coasting where as before I went down the same hills and it was perfectly fine, never died once. Sparkplugs was still fouled. :evil:

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GeorgeSweety
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Re: Throttle butterflies dont retract?

Postby GeorgeSweety » Sun Mar 25, 2018 6:45 am

It really does sound to me that you may have an air leak at the boots or your exhaust. Have you tried running it without the filter cover on to see if it makes a difference.


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