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Dt125 power valve stick


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Hi all,

I believe my power valve is in need of a clean however I lack the know how to do it myself and also the money to have it done immediately,

Does anyone have experience of freeing up and cleaning them via the exhaust port??? I'm think a rag and some carb cleaner or wd40 will be a poor man's quick fix?

Any input appreciated lads

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Aye whitley" go on u-tube, thers lots of tricks in dismantling and cleaning, its the must watch manual nowadays, :yeah:

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Thanks pal will give it a go , the manual says it can only be done by stripping cylinder head and cylinder which I don't have time for , got some carb cleaner today so Il try taking exhaust off and giving it a good spray/scrub hopefully it unsticks it , probably only a temporary solution

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Nope. Take it out clean it and put it back with new o rings.

It will be choked with carbon which doesent come off easy. When it does it will have worn your seals.

Its not too drastic. Exhaust off. Tank off and a handfull of nuts/allen bolts to remove.

It rarely siezes though. Check your battery, the fuses and the cables/pulley boxes before starting on the pv.

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Update: Had the exhaust off today tried cleaning in and around PV seems quite clean,took the side cover off and the cables are correctly aligned however there was some rust visable on the cables so I applied good ole wd40.

When I started her up the cables moved to closed position and fluctuated open/closed as I revved it (as per normal) and then stopped in the closed position,no longer responding to revs??

Switched off the ignition and it stayed closed until I turned it on and it did the self cleaning thing, upon starting ignition it did the same thing where it would open and close to the revs for a few secs then stopped in closed position, not responding to revs anymore hmmmm

I'm thinking the motor could be buggered or will rusty cables have an impact?

Any help or experience here would be spot on so frustrating on having half the power ggrrr

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Nope. Take it out clean it and put it back with new o rings.

It will be choked with carbon which doesent come off easy. When it does it will have worn your seals.

Its not too drastic. Exhaust off. Tank off and a handfull of nuts/allen bolts to remove.

It rarely siezes though. Check your battery, the fuses and the cables/pulley boxes before starting on the pv.

Sorry Cynic didn't see your post before my last reply

Il check the pulley box tomorrow to see what's going on, I think it's not clogged as the PV moves freely .

The rusted cables are a bit concerning , I take it the pulley box is the box the PV cables labeled 1 and 2 lead into right??

Taking the tank/exhaust off is no bother however I'd need to take the cylinder head/ cylinder off also which would require new gaskets and I've just had the cylinder head gasket replaced and cylinder/head mating points skimmed due to a shoddy head gasket made by previous owner lol

Any ideas what to look out for when I open the pulley box? Cheers lad

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You have checked your battery. That can cause some wierd pv operation.

Yes that is the pulley box. If your saying the pv moves freely why did you say its stuck. You have said you have opened it already?

Sounds more like the motor/cables under the tank. Or electrical.

Why do you keep refering to removing the head and barrel?

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I haven't checked the battery, I don't have the equipment to do so I assume I'd need to some sort of testing device.

The PV moves smoothly through the self cleaning operation however I was unable to move it with my hand but the cables were connected so I presume i couldn't move it by hand anyway,

I keep referring to the head and barrel because Mr haynes is telling me that these must be removed in order to access and service the PV however I've just read a post in the workshop that gives instructions on how to remove it without touching anything :-)

Il try charging my battery for a few hours if I can get hold of a battery charger today !

It has been quite cold and wet recently and I haven't been using the bike everyday like a usually do due to snow/ice and being off from work so that could be the issue.

Il try cleaning the bullet connectors that come off the PV motor, slackening and re adjusting the cables as they may be set to tight, charging battery , and if that doesn't work Il have to strip the PV down for a clean , new o rings etc

Failing that Il just pin it open until I can afford to throw my money down the drain at a garage

:(

Cheers bud

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If its doing the cleaning cycle then its not that wrong.

That tiddly battery will take all the spare juice if its buggered as there is not much spare when the lights are on. That will make the pv motor turn slow, get out of sync then stop. To protect its self.

My tdr did some right wierd stuff when my battery went.

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Ok cheers pal , it's a motobatt AGM sealed battery so I've had it on a 10amp charge for 2 hours , I would have put it on longer but I've been reading AGM batts need specific chargers(bloody typical) so I've given it a quick boost and I'm gonna take it out for a spin see what happens, if problem persists Il make a video of the pulleys and stick it on here

I will probably buy the specific charger at some point or put a new batt in anyways just im penniless due to the aftermath of xmas!!

Will update ASAP cheers

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The little charge has done nothing so Il have to get hold of a volt meter and see what power it has....

I was going to take a vid but there's not much to see as now the pulleys just move to the closed position when you fire it up and don't move at all even when you apply throttle... :/

It's strange as it still does the cleaning thing so there nothing wrong with the PV itself so it's got to be the motor or connections/ battery etc

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Starts fine, accelerates well up to 1/2 to 3/4 throttle then just when it should hit the power band it sort of bogs out and loses power....

Originally thought lean main jet which it could well be but a plug chop suggests it's ok plug isn't Aah white or anything,

Air air filter is oiled and held in place with lithium grease , I've checked system is air tight around filter/carb etc (don't think it's an air leak as it wouldn't idle well but it idles fine)

After watching vids of PV pulleys on YouTube I definitely no something is wrong as the pulley doesn't move at all expect for once when you fire it up and it moved into the closed position

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Update:

Definitely something up with PV motor/battery as shes a monster with the PV pinned open, nearly had me off a few times when the power suddenly kicks in, especially in the snow haha just have poor bottom end but I can live with that at least I can maintain road worthy speeds :)

Took the cover off the servo motor and I noticed that there was what seemed like excessive play in the cables, however when I tightened them up and loosened them slightly as per Mr haynes instruction the motor was barely able to operate the self clean function and sounded very slow (zzzzzzt zzzzzzzzt instead of zzzt zzzzt) in other words it took longer...

Any one had any experience with motobatt AMG batteries? Because if mine has gone im not sure what replacement to get as they require a specific charger seems like a bit of a waste of money to me

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I have the Oxford optimser battery charger, cost about £45 and keeps the battery charged right through the winter plus it keeps it from doing the usual thing of over cooking like most cheap chargers do, if your going to buy a good top of the range battery then you need a good top of the range charger, cost is expensive to start out but if it saves you buying a new battery every year or so then it really is worth it. Just my 10 pence worth you understand but I would not be without it now.

You can use it on the Motobatt batteries, just cos they sell one don't mean you have to use theirs.

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You may wish you hadnt. Your engine is very different power wise to the 90's rocket ships.

Your engine makes its power without any major restriction. The old engines were good for 25hp with a pipe some jets and some teenage bogettery.

Yours will ride without any oomf. General less allround except for the point where the pinned valve causes a sweet spot.

In short. You really need to fix it. That valve controls the fuel mixture in the cyl in a complex 2strokey way and that may damage the upper cyl if it leans off at the wrong revs.

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It's just a quick fix to get me going I Will be fixing it as I already miss having bottom end power !!!

Hopefully it's a battery related issue rather than the PV motor being knakard but if the PV motor was the problem it wouldn't do the self cleaning thing surely?

I don't plan on riding it unless absolutely necessary, doing my driving lessons now so hopefully this will be my last winter on a bike

It's quite violent when you hit the sweet spot I wish it was like that all the way through the rev cycle

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