Issues with 98 vmax

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Bruceb

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Jun 14, 2017
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I bought a 98 v max with 3,700 miles on it.
Typical issues, former owner left gas in it for over 4 years.
I tore down the carbs and cleaned them and then put the new parts in out of the k and l build kit.
I did not replace the vacuum diaphragms as they looked good.

I took the gas tank out and cleaned all shit out of it,
I also installed a new fuel filter.
And new plug wires.

The issue I am having is I am getting gas misting up out of the air intake of carb #2. you can defiantly feel like air pressure pushing the gas up.
I trying to figure out if the Diaphragm could be bad and cause this issue. also when I back out the air /fuel mixture screw on this carb there is no change in rpm.
At idle the diaphragm shutters.

I started to wonder if sitting so long I could have stuck rings or valves.
I did a compression check and all cylinders were low. lowest being 135psi and highest being 144psi. These numbers are way below minimum level.

I ordered a leak down tester and should be here this week.

I looking for advise on this issue.
Thanks
Bruce
 
How torn down did you go? sounds like a clogged pilot jet with bad sync at least.

Also, I've been wrong before.
 
I did a compression check and all cylinders were low. lowest being 135psi and highest being 144psi. These numbers are way below minimum level.

Did you have the throttle wide open when checking compression? It's important that it is to get accurate readings.

Also make sure it's spinning good and fast......battery must be fully charged. Removing all of the plugs will help as well.
 
i tore the carbs down all the way and shot carb cleaner in every hole multiple times and then blowed them out with air compressor.
I have tried to sync them but it just wasnt helping.

I did the compression check with wide open throttle and a freshly charged battery, and all plugs removed.
My thoughts were stuck rings from sitting so long so I put oil in the all cylinders and let it set for 2 weeks and then turned it over a few time.
I did a compression test after that will a little amount of oil in the cylinders and the compression did go with indicates worn rings. but with 3,700 miles i just cant believe they could be bad. stuck maybe. idk

The bike runs just runs like shit. Bogs down when you give it gas. makes me think the carbs arent functioning correctly still. im just stumped on why its misting out fuel out the carb.
so much for my good deal of $1,300.
 
i tore the carbs down all the way and shot carb cleaner in every hole multiple times and then blowed them out with air compressor.
I have tried to sync them but it just wasnt helping.

I did the compression check with wide open throttle and a freshly charged battery, and all plugs removed.
My thoughts were stuck rings from sitting so long so I put oil in the all cylinders and let it set for 2 weeks and then turned it over a few time.
I did a compression test after that will a little amount of oil in the cylinders and the compression did go with indicates worn rings. but with 3,700 miles i just cant believe they could be bad. stuck maybe. idk

The bike runs just runs like shit. Bogs down when you give it gas. makes me think the carbs arent functioning correctly still. im just stumped on why its misting out fuel out the carb.
so much for my good deal of $1,300.

Some of those holes do not like carb spray-:bang head:
Have you tried a shotgun technique? :clapping:
http://vmax.lvlhead.com/tips/shotgun.htm
 
With buying the bike for 1300 dollars (which in my opinion is a good deal), I would take the carbs off and have them sent somewhere.

My recommendation would be to Dannymax. That way you will know that they are done right...the first time.

Several years ago, it was apparent that it was time for a carb build on the 07. I know that I could do it, and probably do a pretty good job of it, but i wanted it done right, and done right the first time.

So, even if its a couple of hundred dollars, when you add that into the purchase price, you still WAY ahead of the game.
 
I would like to +1 to dave in suggesting that it needs a carb synch if carbs were off and apart. I noticed mine doing some strange things when they were way out. The K&L kits or Yamaha OEM are nice quality Japanese made parts, there has been plenty of documented cases where the Chinese aftermarket carb parts and kits end up not ever working properly and getting replaced with the Japanese made parts.

Welcome! MT is my favorite state to end up in when I ride aimlessly. It's so wide open and much of it is just too beautiful for words.
 
I will try and sync the carbs again. Its weird when I tried to sync them last time it was pushing air out the vacuum ports on carbs 1 and 2 which isnt right and sucking on carbs 3 and 4 which seems right . the readings i was getting on the sync was weird.
I think i will try the shotgun method before taking the carb rack off again.
its just odd how carb 2 mist gas up out of the air intake.
 

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