Vacuum Leak?

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SirHuthALot

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Hi all,

My bike has been running rough no matter what I do. When I try to tune the carbs, even with the restrictors, the indicators are really bouncy. Guy at a local shop listened to it and is pretty sure theres a vacuum leak. Thought I'd start by replacing the carb boots. Can anyone recommend a place to order a new set? Or a better place to look for the leak?

Thanks,

B
 
Hi all,

My bike has been running rough no matter what I do. When I try to tune the carbs, even with the restrictors, the indicators are really bouncy. Guy at a local shop listened to it and is pretty sure theres a vacuum leak. Thought I'd start by replacing the carb boots. Can anyone recommend a place to order a new set? Or a better place to look for the leak?

Thanks,

B
Possible leak areas are the rubber caps on the synch ports, 4 vboost boots, manifold to carb boots, carb to air box boots.

Boots can be purchased from any dealer (local or on line) or you could support a forum vendor like Sean Morley.

I buy most parts from Sean or Ron Ayers, Partzilla, and Boats.net.

An unlit propane torch can be used to pinpoint leaks. Listen for rpm increase.

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Thanks for the advice. maybe I should see if i can find the leak first. The propane from the unlit torch will get sucked in via the leak if its there and rev the engine (is that the idea)?
 
Thanks for the advice. maybe I should see if i can find the leak first. The propane from the unlit torch will get sucked in via the leak if its there and rev the engine (is that the idea)?

Yes. Also,the boots get hard and crack. They need replacing every few years. They aren't cheap, but make a big difference when they are right.
 
In that case, I'll prob buy new boots. Mine are the stock ones (almost 20 years old). I see a bunch on eBay for $20, but others for $80. I can't tell the difference.....
 
In that case, I'll prob buy new boots. Mine are the stock ones (almost 20 years old). I see a bunch on eBay for $20, but others for $80. I can't tell the difference.....



I seen them $20 ones too. I'm bought a set to see if they're even close in material. There is one guy that is a U.S vendor, this should be interesting. If they are the same materials, then why a $60 mark up.. right?


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Had a vacuum leak a couple of months ago. Used the propane torch but the starter fluid worked better. My main problem was the vboost boots.

http://vmaxforum.net/showthread.php?t=44645

Sean said he could tell from looking at the picture that the other boot was ripped as well due to the gap between the edge of the boot and the clamp, I guess.
 
I seen them $20 ones too. I'm bought a set to see if they're even close in material. There is one guy that is a U.S vendor, this should be interesting. If they are the same materials, then why a $60 mark up.. right?


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I'm not sure of quality from E-bay,and I'm sure I'd try them too. I bought replacement carb diaphragms there I'm happy with. But believe, Yamaha marks up EVERYTHING sky high. When I worked for a Yamaha marina dealership, I got all my bike parts at cost plus freight. The difference was huge.
 
Soak your boots in oil of wintergreen for a day first. Also it'll help if you find the leak so you know exactly how much stuff you have to take apart.
 
Honestly.... Just buy the Yamaha stuff.
It lasted al these years, so u know what quality u have.

Everyone I talk to whoem bought the aftermarket stuff can do it all over in a year or 2. Yust my two cents
 
Thanks for the advice. maybe I should see if i can find the leak first. The propane from the unlit torch will get sucked in via the leak if its there and rev the engine (is that the idea)?

You got it but as Mr Billy 1 Ear says, starter fluid is better.

Is this a new problem?; did it develop suddenly or over a period of time?; have you been doing anything to the bike?

Rule #1 of diagnosis is 'Don't guess, base your decisions on facts'. That way you will save a lot of time and money.
I wouldn't replace anything until you are sure that you have found the culprit.

Some surface cracking on the boots is normal and probably won't have gone right through the rubber. If this is what you suspect then the best way would be to take them off and probe the suspect area with a thin wire.
 
I'm not sure of quality from E-bay,and I'm sure I'd try them too. I bought replacement carb diaphragms there I'm happy with. But believe, Yamaha marks up EVERYTHING sky high. When I worked for a Yamaha marina dealership, I got all my bike parts at cost plus freight. The difference was huge.



I got those $20 boots in today. They look just the same as stock ones. I'm thinking that ya can't really go wrong with them [emoji848] especially for the [emoji385]


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I got those $20 boots in today. They look just the same as stock ones. I'm thinking that ya can't really go wrong with them [emoji848] especially for the [emoji385]


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I'm thinking it would be a great addition to the forum if you were to start a new thread in the carb forum about these alternate $20 boots.

Post multiple photos showing any differences between them, and OEM.
Provide a review, good or bad, once installed.
Provide purchasing info for anyone interested.

Just a thought to help out other maxxers.
 
I'm thinking it would be a great addition to the forum if you were to start a new thread in the carb forum about these alternate $20 boots.

Post multiple photos showing any differences between them, and OEM.
Provide a review, good or bad, once installed.
Provide purchasing info for anyone interested.

Just a thought to help out other maxxers.



Yeah, I agree!! I I will do that tomorrow. Bike is sitting at work, along with the new boots. My boots don't look the best, and why not replace them. Reason for purchasing these anyhow.







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