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Discussion Starter · #1 ·
HI all

2000 Marauder VZ800 22k mi no idea what previous owner did, but Im figuring it out

I just performed a valve adj and all the valves were so tight I could not even get a .003 feeler into any of the valve tappetts
I set all the intakes to .003 and all the exhausts to .008,,,,,,My PSI per cylinder went from 145 before to 165 after, and bike seems to have more power now, HOWEVER I feel like I am hearing some tapping, like the valves are loose, but maybe its hitting parts of the metal it never did before,,,,ALSO, all the backfire and popping upon decel has disapeared after this adj

QUESTIONS
1. can some concur or verify what these valves should be set at,,,,one manual says .003 - .005 and another manual says .003 - .005 intake and .007 - .009 ex

2. after valve adj I can now park the bike in garage without smelling gas fumes stinking up garage, any idea how a valve adj would make the gas smell go away?

2. It looks like someone drilled holes in the stock xhaust and I also have the K&N filters in there, I cannot read the MJs in the bike as the markings are not visible,,,,The bike should come with 90 and 100MJ,,,,,I totaly feel this bike is lean,,,,,I have on order the 92.5 and the 105MJs from mikuni,,,,is anyone willing to reccomend what jet based upon this setup I should try? This at least will give me a starting point

TY all
 

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The tapping sound is likely coming from the .008" exhaust clearances .

The smell has been 'contained' by your new 'no leak' fuel lines and valve . Not anything to do with the motor valve adjustment.

What do the spark plugs tell you about the bikes combustion ? Feelings are great for lovers , but machines require physical 'measurements' .
 

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Bike was slightly lean from the factory, and the K&N filters likely made it more so. Holes in the exhaust just made it louder. But, it can be a real PITA to get these carbs tuned with anything but stock filters.

Old saying "a tappy valve is a happy valve"; when they go quiet you have a problem.
 

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Discussion Starter · #6 ·
Hey Guys, TY for response,,,,I think I got it right with the valve adj then,,,,not only did it eliminate all the popping and backfire upson decel, but I got 20 PSI more per cylinder

When you say its tough to tune with the K&Ns is it a jetting issue? what else can come into play in terms of tuneing the carbs with those filters?
 

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It's the interaction of the change in air pressure in the carb intake with the needle jet/jet needle, along with the CV piston. All CV carbs can have this issue, but somehow, these carbs are just a little worse. I can't easily tune the carbs on my old CB450 with low-restriction filters, either, so just gave up and put repro stock filters on.
 

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You might search for an official service manual on your exact year model, they can change the valve clearances as they go and sometimes because cams got changed in some way for durability reasons commonly. The exhaust is the one that will bite, the fact the clearances are closing up says valves are probably receding and doing it on exhaust will burn the valves. Why the compression came back up. I'd run the bike a little hard for a bit to beat through any carbon that built up on the exhausts, sometimes you do and then suddenly you need to set the valves again when they beat through carbon and got closer again. I drove a certain bike that you might have to set the valves twice before they settled in to stay after the carbon was gone.
 

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Discussion Starter · #9 ·
Yes, I am going to do that,,,,Im thinking of putting a bit of Berrymans B12 in small amount in tank as well

I though I solved the fuel smell issue when parked in garage but no,,,,,heres what is happening, when I fill the tank 3/4 of the way or more then park in garage, the garage then the house will slowly smell of light fuel, if I walk into the garage where the bike is it smells fuely,,,,there are no leaks,,,what is this indicating? IS the tank not breathing properly is it off gassing? how would I go about resolving this issue? Im thinking maybe take out a couple hex screws in the cap and put a small hose to vent out of cap,,,any ideas?
 

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Discussion Starter · #10 ·
IN terms of jet,,,,,,I am looking to upgrade the jets,,,,jets are us seems to have all the jets, EXCEPT the rear carbs MJ, these carbs for the marauder are slightly different and Im not sure if MJs are the same physical size in each carb, they may be different, any ideas where I can find MJs for this bike, preferable Mikuni, I could always to dynojet

 

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Discussion Starter · #12 ·
UPDATE

So today I am getting somewhere, I decided to tear apart the carbs and inspect the floats,,,,I set the rear float as close to spec as I could, the diaphram and needle looked good, I cleaned all passages, removed the mixture screw, cleaned and reset,,,,HOWEVER, this time I was able to read the rear MJ and it was a 165! Someone put that in there, I knew It was an issue,,,,I had some spare jets and decided on a rear 120MJ and put it all back together,,,,NOW the bike has more power and more midrage torque, I got it up to 78mph no issues,,,so I know Im on to something,,,,I was out of time so next time I will inspec the front carb closer,,,given the OEMs for this bike are 90 and 100 MJs with the no snorkel K&Ns spacer Jim says 120 or 130 MJs,,,,,,today was a big win as I am on to something
 

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Discussion Starter · #14 ·
If you look at spacer Jims fourm they have many Marauders rejetted with those filters in, with great perfrmance, they came with the bike, and the previous owner did a half a$$ attempt at upgrading it,,,I think the whole tricky key is proper tuning and jetting, what I found out today was huge and I didnt even touch or inspect the front carb, a simple rear carb cleaning, adj of float height and a rejet from 165 to 120 did wonders for this bike,,,the midrage power and top end is so much better and Im not even close to fine tuning it,,,,this bike has been sputtering at 70mph, which makes sense with a MJ of 165,,,today the bike flew through the gears to nearly 80 with ease,,,,it was so rewarding,,,,,I think with those after market filters you have to reallly tune it properly and listen to your bike,,,later tonight Im gona push the bike again and see what it does
 
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