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Discussion Starter · #1 ·
Need help guys. Trying to do a full rebuild on my carbs, but cant find the throttle shaft seals. Any ideas?
 

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Discussion Starter · #3 · (Edited)
Doug, they are replaceable, 100%. Ive not replaced them, but I have had carburetors torn down for a deep clean, seals are replaceable.

I suppose I should have added more info with my question. Bike has 46000 miles, bought it 2 months ago, runs like a rocket - fastest bike I have ever owned. When I test rode it I knew there was an issue but thought it would be an easy fix - at an idle RPMs gently surge up and down, from about 1000 to 1700. Thought for sure just a small vacuum leak, maybe sync the carbs, no biggie. Got it apart, found nothing obvious. With the bike running, sprayed carb cleaner around the intake boots, idle would drop. Picked up a set of new boots, no change. Spraying around the area of the boots and throttle shafts, idle drops. Spraying around the vacuum slide covers made no change. Attempted to sync the carbs with a digital tool - all 4 cylinders are constantly up and down, carbs would not sync. Oddly enough, bike runs amazing. Take off from a stop is smooth. From a stop will run up to 140 without any effort. Throttle snap is not what it should be - if I snap the throttle open, the RPMs dont come back as fast as it should. Have owned many bikes over the years and watched a shitload of youtube videos, my bike isnt right.

So, unless somebody can redirect my focus because Im missing something, Im stuck on the carbs.
 

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Doug, they are replaceable, 100%. Ive not replaced them, but I have had carburetors torn down for a deep clean, seals are replaceable.
I guess I should have phrased it differently. They are removable but Kawasaki didn’t intend them to replaced which is why they don’t show on a parts diagram…along with the throttle shafts and butterflies.

Later, Doug
 

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Discussion Starter · #5 ·
You are correct. But I know the seals are available. Those seals were and are used on a shit ton of bikes, just a matter of sourcing who sells them.
 

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WOW! 10 years of ownership and 70,000 miles and I NEVER needed throttle shaft seals..... let alone even knowing what or where they are.

WTF possessed you to need or want to replace those? If you have OEM carbs and have NOT installed a decent jet kit, imho, u r wasting your time. Buy a Factory Pro jet kit, K&N air filter, and Ill almost guarantee you all your carb issues will disappear.

Maybe something in this kit will fit...

 

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Discussion Starter · #7 ·
Blaine

This is what I have learned after 30ish years of riding and turning wrenches - most riders wouldnt even bother with an issue like mine since its not critical and the bike runs fine otherwise. Im sure your 70,000 mile bike runs like a Swiss watch, happy for you. I've isolated a vacuum leak at the carburetors, specifically the throttle plates. Appreciate the link for the o-ring kit. But the seals I need are called, I believe, D-rings. O-rings would bind the throttle shaft. Re-jetting the carbs wont fix a vacuum leak.
 

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Blaine

This is what I have learned after 30ish years of riding and turning wrenches - most riders wouldnt even bother with an issue like mine since its not critical and the bike runs fine otherwise. Im sure your 70,000 mile bike runs like a Swiss watch, happy for you. I've isolated a vacuum leak at the carburetors, specifically the throttle plates. Appreciate the link for the o-ring kit. But the seals I need are called, I believe, D-rings. O-rings would bind the throttle shaft. Re-jetting the carbs wont fix a vacuum leak.
I've never torn down carbs to this extent either. Worst case scenario, you might need a set of bare carbs to build upon and salvage what you can off of your set.
 
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What would cause such an uncommon leak? Corrosion? Damage? Age? Factory flaw?
What is the material made of? I am asking out of curiosity and future reference.
 

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Discussion Starter · #12 ·
What would cause such an uncommon leak? Corrosion? Damage? Age? Factory flaw?
What is the material made of? I am asking out of curiosity and future reference.
The seals are made of rubber. Over time the rubber gets hard and cracks, just like the intake boots and vacuum hoses. Normal wear and tear.
 

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Discussion Starter · #13 ·
By the way fellas. Im very open to different ideas as I dont look forward to doing a full tear down of the carbs.
 

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Since it's a 40mm Keihin, you might search for other bikes that have that carb, like Harleys.

I don't know what this is?
 

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Discussion Starter · #18 ·
I dont think the Harley seals will work, but it gives me ideas. As you suggest it looks like I may have to remove for measurements.

I'll keep this thread active with my findings. Thanks Haybaler!
Since it's a 40mm Keihin, you might search for other bikes that have that carb, like Harleys.

I don't know what this is?
If you get the old seals out, pictures and measurements might help locate a set?
 

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Yes, thats the seal. Theres one on each side of the throttle shaft, 2 per carb.

Last I read, round rubber rings were called "O" rings, not "D" rings..... :D :D :D :D

What am I missing here Ed?
 

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The seals are made of rubber. Over time the rubber gets hard and cracks, just like the intake boots and vacuum hoses. Normal wear and tear.
Allowing rubber to soak for at least 24 hours in a solution of three parts isopropyl alcohol and one part methyl salicylate, will soften them up
 
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