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My Vfr 750 Project < Lots Of Questions >


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pump it all the way out.. remove piston. polish the sucker with 4000 grit sandpaper. clean out the slave add a new ring seal

put back together. :beer:

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It's not uncommon for the slave piston to stick. What usually happens is it will still move far enough to actuate the clutch, but it won't ever retract right back into the cylinder - so it always keeps some pressure on the clutch rod, and the clutch never fully engages and suffers premature wear.

It sticks due to lack of maintenance - the clutch hydraulic system sucks crap in a lot quicker than the brakes, and the fluid gets muddy, and being hydroscopic it holds water, and the water causes corrosion on the slave cylinder bore.

You have to get that piston out... try not to score the bore, but other than that, whatever it takes...

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It's not uncommon for the slave piston to stick. What usually happens is it will still move far enough to actuate the clutch, but it won't ever retract right back into the cylinder - so it always keeps some pressure on the clutch rod, and the clutch never fully engages and suffers premature wear.

It sticks due to lack of maintenance - the clutch hydraulic system sucks crap in a lot quicker than the brakes, and the fluid gets muddy, and being hydroscopic it holds water, and the water causes corrosion on the slave cylinder bore.

You have to get that piston out... try not to score the bore, but other than that, whatever it takes...

Ok so update. Got the slave out, used a rear brake master etc I had sitting in my spare parts that was partially bled, in less than a minute it popped out. So I suspected the master, which isnt stock, it has a clear bowl. (Giving you this information due to you giving me such thorough instructions) So i start looking over it, had a greasy liquid around the lever where the bolt goes through it. (Where it articulates?)

I suppose it could of been some spillage but it was greasy. So I take it apart, the booty from the piston isnt sitting on the push pole thing, I feel a thicker ring on the end of the boot and see where it looks like it should set on the pole so 2+2. Sorry for lack of terminology, first time here.

So, all in all, slave is cleaned little rust where the spring sets down inside of the slave nothing major.

The master is in pieces currently as im not sure how to get this booty to sit on right, its a right rascal for lack of other language.

Sounds like your master cylinder is toast . It should build enough pressure to pop it out .

Maybe?

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Ok so the guy before me took the fuel pump out and it's gravity fed now. I am getting gas in my oil somehow, I pulled the carb off and inspected and cleaned in today. The floats seemed very good, the carbs were in good shape.

He definitely cleaned them before I got the bike they looked good, all the jets were in order and clear etc.

None of the floats had gas in them, that eliminated a hole.

Should my next step be a compression test?


These 2 things are the last 2 of 3 big obstacles im facing to finish this bike, the last will be trimming up the wiring harness but thats on hold, we've got bigger issues ;).

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I don't know if this is the issue or if there is more likely causes, but the needle valves and seats can get worn and cause issues… or even just a tiny bit of debris can get stuck in them.

For now, if you shut off the fuel when your bike is parked (if your fuel shutoff valve functions properly… I'm not sure mine is completely effective, based on small drips while having my tank off the bike) and the problem doesn't return you know either you fixed the issue, or narrowed it to the carbs. I think...

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I held my tank up. Cut off works fine

I'm going to pull the carb again and recheck the floats. Also do a compression test

Need to replace my boots that the carb sits on hard as a rock and sync this bad boy

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While you have the carbs out, remove the floats and needle valves and have a look in the valve ports. Make sure they're clean.

If it were my bike, I would go ahead and put new needle valves in. They are cheap, and if you don't know how old the current ones are, just chalk it up to preventive maintenance.

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So here are the plugs the test was a bust have to order the right adapter. These all seem good to me by looking at a plug chart. Comments?

post-29573-0-61090700-1396311185.jpgpost-29573-0-11103100-1396311215.jpg

I mean Good as in all similar. Experienced advice and comments needed

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the ceramic part of the plug should be tea colored.. a nice tan..

this is too rich..

toorich.jpg

this is too lean

toolean.jpg

this is just right!

bikinibikenight116.jpg

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I know the bike needs rejetted & balanced. Been knowing but that's on the back burner at the moment.

Love the pictures haha, we're so much alike in taste haha.

But seriously, I would know if I had a piston ring or something out correct?

My worries are about the gas in my oil, if I can eliminate the engine we'll assume it's the carburetor and I can rest easy.

Carb rebuild kit is in the mail and getting replaced anyhow, but just in the mean time tinkering and elimination.

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dude this is a VFR

the plugs arnt THAT bad.

drain the oil and clean the carbs and if you keep it gravity feed add a remote inline gas cut off valve

gasvalve_zps2b634363.jpg

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dude this is a VFR

the plugs arnt THAT bad.

drain the oil and clean the carbs and if you keep it gravity feed add a remote inline gas cut off valve

gasvalve_zps2b634363.jpg

Dude I'm glad you're knowledgeable because I'm not. Learned tons in the past week working on this bike. Would be no where without this community. Thanks for your comment. I have gas in my oil and it was pure cream 2 days after I changed it.

Ok with that stuff being said. I'm going to sum this up to being the needle valves.

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that would be my guess. if it been sitting for a while the float needles are hardned or stress shaped by now. and need time to seat themselves. or just get new ones...

oh and a pm sent. :wink:

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The only way petrol can get into the oil is if it leaks from the carbs through the intake tracts and down past the piston rings.

The rings themselves can't be considered a culprit so don't worry about that.

The petrol in the oil is due to leaks within the carbs. Sort that, and you're sorted.

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It has a built in petcock.

which is a pain the butt to get to.

add the one in the pic and it can be hidden behind a vent hole for easy on /off

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Current state of the bike

I think you missed the pic :P

3M Invisible Cloaking wrap, it's all the rage with the kids these days

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