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Discussion Starter #1
Has anyone has come across seized carbs before? I recently bought a 2001 750 that sat for at least 5 years and the carbs show it. I have soaked them in PB Blaster and let them sit overnight in Chem-Dip and the choke valves are still stuck. I noticed there is a cap on the side of the carbs where the choke valve shaft gets installed but it doesn't look like this is meant to be removed. Anyone out there with experience in this?
 

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Knock off with the chem-dip for now, it’s only going to remove any penetrant and make your job harder. I’ve read that a mixture of lacquer thinner and ATF works very well. Bike restoration guys use it. Don’t force things , but try to move them back and forth to loosen them up. I wouldn’t remove those plugs until you have the replacements in your hand. Your Yamaha dealer can get individual carb parts, they were fitted to the tdm850.
 

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Aerokroil is another good penetrant to try. Take the carb apart as much as possible. Every time you can get something off , spray the holes. I rebuild carbs in a cake pan to catch everything. Remember there are rubber diaphragms inside that you don’t want to soak in anything because they are really expensive. Take the big plastic covers off and remove the slides and keep the diaphragms out of any cleaners but soap and water.
 

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Discussion Starter #4
Just to clarify, at this point I have pulled the diaphragm slides out (not without breaking one of the slides first...) and have pulled the floats out. I started with soaking with PB Blaster for a few days, spraying a few times a day and letting them sit. That didn't seem to do anything. I then tried the Chem Dip over night and again, no real help.

Last night I removed the choke valve screws from the shaft and was able to get the actual brass valve out. I was thinking maybe the valve had some corrosion that was causing the interference within the casing. After removing those, still nothing. At this point I am able to use some brute force and get the choke shaft to rotate but it is pretty rough. I am hesitant to continue rotating so that I don't completely gall up the casing.

I suppose I will trying to soak some more with penetrating oil and hope for the best. If no success there, in my mind I have two options, pull the exterior cap off of the choke shaft port (again, not sure if this is designed to be done or if they even sell replacement parts for this) or split the carbs apart and hope that I can get the shafts out from the inner faces.
 

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Patience, Grasshopper. Strip as many parts off of the carb body as you can and maybe try some different penetrants. Maybe even a little heat , but take care. It’s frustrating, I know. Keep lubing it every time you get something to move , back and forth to increase movement without too much stress on the parts. Make sure you spray into the passages from the float bowl in order to get lube inside the Enricheners.
 

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Discussion Starter #6
Guys, I realized that I made a goof. What I have been referring to as the choke valve is actually the throttle valve. Doh!

My only experience in working with moto carbs is with my old Honda and the Mikuni throttle valves resemble the Keihin choke valves. I just didn't think about it too much obviously.

Anyways, I picked up another set of carbs yesterday pretty cheap on eBay to swap some parts between so between the two sets I should be in business. I'll update once I get something figured out.
 
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