Powervalve Problems - Fixed

[simon1221]

The powervalve on my bike broke (might not have been yesterday) in half and then as I was going along the cover shot off the side of the cylinder (with a big BANG!) and the broken half went with it.

Apart from me being stranded in a village for 3 hours having broken down.

So now I need:

Complete new powervalve including cover for the rhs of the cylinder head. ~£100 I think.


This is probably the cause of my past problems, as the Pv is servo controlled (moves around), if it was only moving one half, then it would not be closed properly at low revs. Thats why I get poor acceleration and dodgy firing occasionally and why it has a flat spot between 4 - 5000 revs when it is not supposed to.

Is there any reason why it might fly out of the side of the cylinder like that? Detonation?

Any help would be appreciated.

(at least I dont need my bike for another 2 weeks as it is easter holidays )
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[stinkwheel]

That would certainly explain things.

Never heard of it happening before. My old powervalve used to 'flutter' the valve if you fitted unsurpressed sparkplugs due to rf interference. Made riding quite interesting.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Kickstart]

Hi

The power valve is a 2 piece unit, split in the middle. Think there are 2 pins locating the 2 halves together. Suspect it would have strange effects if they are not aligned.

All the best

keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Git]

Two pins and a bolt going up the middle, at least this was the case on 250.

Have some pictures, I posted these last night but I think the forum threw a wobbler so they went missing, here thay are again.

[tatters]

so does the powerband clip on to the clothes peg
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Past:NRG50,AF1125(x2),NSR125RR,ZZR250,CX500,VFR400,KR1S,ZZR600(x2),CB400N,YZF1000(x2),KH125,Z200,FX400R,CBR954RR(x2)GPZ500S,GT550,VFR750F(x2),RD350N,XR650R,CBR600F,CB250,KDX250,YZF750R,CRM250,400EXC,KLR650,TTR600RE,DR350S,R100GSPD,RGV250,VMAX1200,DL650,KZ750 Present:G650XC,C12,CRF450X,1190ADV

[cagiva gezzer]

[simon1221]

I investigated, turns out there was not a bolt holding it together, and also I had to whack it out with a hammer from the rhs as it was stuck by the amount of crap that was in there.

Photo:

https://img.photobucket.com/albums/v236/simon3_2000/85e5a356.jpg

The plastic bit on the right was broken anyway.

The bottom left piece is the bit that broke off the cylinder.

I also managed to bend an allen key trying to undo some of the bolts, thats why it is there.

As there was no bolt holding it together im not surprised it fell apart.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

Anyone know how much a new one is roughly, or where i can just get a bolt and pins, as I may be able to just bodge the old one
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

UPDATE:

Gave the parts a clean (as well as I could) in petrol and scraped most of the carbon off including the huge amount inside the screw holes.

https://img.photobucket.com/albums/v236/simon3_2000/b2fb3f2b.jpg

Using a bit of creativity, I was able to restore the parts to a pretty good condition (even if this photo is terrible), so all I need to do now is go down to west end (hardware store) and get me a screw that is long enough to go through all of it!

I still need a powervalve cap though, which i cannot get around. Looks as if it will be about £20. Not that much really.
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

Managed to bodge the cover on, so i only need a bolt for about 30p, woohoo!
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[simon1221]

Fixed the Pv today as well.

After a bit of grinding and drilling to return the broken half to a proper state, I was able to 'create' some pins out of some old nails, which I glued into one half then placed the other half in the other side and bolted it together, simple. The pins didnt fall out as they were glued in (see what a good idea it was).

Reattatch pther bits etc.

Now the bike is:

More responsive
More powerful at lower revs (and higher revs too I suppose, havent got there yet)
Sounds a lot better, smoother and doesnt misfire.
I dont need to get into the powerband to go anywhere at high speed, (unless over 55mph of course)


And it only cost my a grand total of £1, not £100
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[ojilynn]

u can get a pv that don't have a separate part so u don't have to think how to assemble it... and u can get a bush that have double o-ring.... that can give u something less to work with... have ever heard about TZM150?