Power Valve Cleaning Cagiva' Mito '

[WannaBeDude]

I have a 2009 Raptor 125, which is a naked Mito really. Despite having the workshop manual, i can't find the section about cleaning the powervalve.

Anyone know where it is, and any advice taking out and putting back in, i know i need to clean it of carbon deposets.

edit, it's the exhaust power valve it looks to be the valve i can see as the exhaust is off at present, if it is that part, i can see it has a layer of carbon build up on it.

So do i need to remove it to clean, and if so, how ? as the workshop section refering to it, is no use as it just says clean it.

This action is all part of ME actually servicing the bike.
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[Kickstart]

Hi

With great care!

The power valve is above where the exhaust bolts to the barrel. From memory 4 allen key bolts hold it in place..

Now the nasty bit. The Mito power valve has an adjustable stop (you will see a tiny allen key bolt with a lock nut on it). Get this wrong and the power valve will be too close to the piston, and thus probably touch when things are at the right temperature.

Trouble is to adjust this you need the head off so you can check the clearance between the valve blade and the piston.

If you remove the power valve then reusing the same gasket WILL result in less clearance. If you use a new gasket then you are relying on luck.

All the best

Keith
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[WannaBeDude]

Can i just take it out and just clean as best i can, bikes only done 5400 KM.

And if i can do that as i read you don't have to reajust, what grease of the following shall i apply to the valve spring.

Gen purpose lithium
Red Rubber
Wurths batt / electrical grease

Or is it some other form, i also have exhaust high temp paste.

As i can see the valve is carbon coated, i need to do this, esp as at present the exhaust and rad are off.

The pipe going back on is decoked, acf50'd and being VHT sprayed today. I also have new vitton rings to use, but NOT a new manifold gasket.


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Jogging on, destination living.

[Kickstart]

Hi

Problem is you can't just take it out (cleaning it is the easy bit). You will affect the clearance between it and the piston. If that clearance is too tight (which it almost certainly will be if you reuse the gasket) then you will trash the power valve and piston, and quite possibly the barrel.

Think I would just lube it with 2 stroke oil, although not sure what Cagiva recommend.

All the best

Keith
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[WannaBeDude]

Can i clean the bit i can see through the pipe hole, and if so is scrapping it with say a screwdriver ok ?

I also changed the nickel allen bolts that hold the power valve housing, one at a time, please don't tell me i could of moved anything inadvertently, as if so, i'm not gonna try and start her, and she will be going to MME as planned if i could not get her running right ?


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Jogging on, destination living.

[Kickstart]

Hi

Should be fine to clean it through the exhaust. The carbon should be blown out of the exhaust rapidly.

As to the bolts, will probably depend how much you tightened them.

By the way, valve touching piston is something I have had happen on a Cagiva.

All the best

Keith
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[WannaBeDude]

Not too tight, so one side of the valve will be clean but i wont have access to the other side ?

Starting to think more and more about taking it to MME, get them to set it up right, at least it's spotlessly clean and stripped ready for them !
____________________
Jogging on, destination living.

[Kickstart]

Hi

Other side won't matter that much. It should cycle on start up to keep fairly clean, and the effective exhaust port height is the important bit (and you can clean the bit that affects that).

All the best

Keith
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[Frost]

From someone who has owned an old school RGV250, power valves and pistons need to be kept as far apart as possible! Neither survives the encounter and the barrel get trashed too.

[WannaBeDude]

So i CAN use a flat head screwdriver to clean the carbon off the visible side of the valve.

If so then i may be able to continue with getting her back on the road, and then get it done properly when i get the rings changed in a few thousand KM, and or depending on compression test, which will be undertaken soon when i buy one !

Would rather not have to take it to MME just yet, as i need to learn how to set the carb up, service the breaks and see if she runs !


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Jogging on, destination living.

[Kickstart]

Hi

Not the side, the end.

Personally I would have just left it until I was taking the top end off again.

All the best

Keith
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[WannaBeDude]

I'm never taking the top end off !

I can see the blade, it has a layer of carbon on it, so i should leave it, but go round it's edges with a small flat end screwdriver.

Sorry for noobness, this is fucking brain surgey for me !
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Jogging on, destination living.

[Kickstart]

Hi

Bottom edge. Ie, any bits hanging down vertically from the bottom of the blade.

The side of the blade facing you should be kept reasonably clean from the power valve opening and closing.

All the best

Keith
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[Robby]

A little bit of carbon build up is normal, and doesn't need to be cleaned off. If you do clean it, it'll be back in a few miles anyway, it's a 2 stroke. As long as the valve can move through its travel (which the self-clean thing when you switch on the ignition should ensure) then leave it.

If you want to de-carbon something, the exhaust is worth doing.

[WannaBeDude]

Thanks, i was having some intermitent problems with the powervale self check on turning the key seeming to play up, which can point to clogged partially seized valve or another electrical gremlin.

I shall just run a driver on the blades bottom edge, refit everything over the weekend, and then see about getting her up and running.

This valve trashing engine parts is V off putting !
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Jogging on, destination living.

[Kickstart]

Hi

The self check playing up is a touch worrying. The older Mitos had an issue with the power valve control unit going pop (which new was sold with the servo unit, hence a £200+ bill) when the valves stuck. Newer ones have a fuse I think, so the fuse goes pop instead of the control unit.

Not much you can do without stripping it and cleaning it properly, beyond taking it for a good few thrashes.

All the best

Keith
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[WannaBeDude]

Electrics can be a nightmare, so much so, that over the next year or two, i shall be cutting the middle man out, and buying leky parts of fleabay so i can fault find and replace as of when.

The above is why i'm taking her to MME of London, soon or defo in future, as they can sort it out in no time compared to any old garage.

Something my pay 600 quid for a triple service bro can't for the life of him fathom, to a point of failing out over it. He's relented and agreed van transport. But he still thinks i should take her to Coventry Honda !!

Thanks again, i've learnt some more through this thread and are one step closer to being back on the road.

Learning in the sun on the bike is fun, and the silver lining i'm familiar with is that when without my bike for a month or two at a time, when i do get her on the road again, it's all ' special ' again !


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