Right powervalve stuck on 89 KX125

[queen of spodes]

I was stripping the cylinder to send it off to Millennium but sadly discovered that the right power valve doesn't turn and won't budge.  Looks like the top part of it was broken off at some point likely due to the same reason.   Also, the valve on the front of the cylinder is stuck as well. 

I have some Kroil soaking in the right powervalve and sprayed a little around the front valve.   My feeling is that neither of these valves are coming out easily.

What's the procedure for removing locked up power valves?  At what point do I break out a dremel?   

[queen of spodes]

One other thing, what other cylinders could I potentially use for this bike?  I'm not seeing any 89 cylinders on FleaBay and haven't in the last few months.

My question is will other year models (like the 90/91 or even the 88) actually fit and still work OK with an 89 bottom end?   The 88 bottom end I have looks nearly identical to the 89 bottom end where the cylinder attaches (same water ports, ect).

[sandblaster]

I would not resort to the dremel just yet.
Can you post a pic of the offending exhaust valve?
The 89 KX125 cylinder and part number are unique (1565 FITS 89 KX125  11005-1565) but I bet someone here knows what else will fit...

[staffylad]

white spirit or gunk slowly remove the carbon build up 1st ,surprised its not the l/h kip seems to be common that,i need a left kip for next build like 

[queen of spodes]

I got the valves moving, but I need to replace the right valve as the top post is broken off from it being stuck previously.   Do you have to take out the center valve in order to remove the side valves? 

Will valves from a KDX200 fit the KX125?

[queen of spodes]

So there are different part numbers for the 89 KDX200 and KX125 power valves and components.  Thought I might get lucky there, more of that on Ebay.   

I need the right side powervalve if anyone has one let me know.

[sandblaster]

I don't have any but, you might want to run 3 different searches on eBay
1989 kx125 exhaust valve
1989 kx125 power valve
1989 kx125 powervalve
Spelling is everything.
Once you run one of the searchers look for the words "Follow this search" in green, about 2" down from the top of the page directly in the middle.
Click on "Follow this search"
Then eBay will automatically email that search result once a day anytime that search result is listed on eBay.

[staffylad]

ya have to take out the guvoner rod to get the valves out,check for ware on the cogs 

[queen of spodes]

Do you mean the rod that lays across the top of the exhaust port, with gears on it?   It only comes out so far.. then stops. 

[yeomans]

Pull the main exhaust valve (one below your exhaust port) out of cylinder until the groove in the valve lines up with the edge of the cylinder.
Lift the small idler gear out of its hole.
Then lift both the right and left valves until their gear surfaces are flush with top of cylinder.
Then your operating rod will slide out.

I use oven cleaner on stuck valves. I broke one once, so I have become much more patient when they get stuck.

[yeomans]

The power valves are specific to the 1989 kx 125 model.
1988,1989,1990 all have different part numbers for the valves, so you can't switch them out for a different year.
The part number for the 1989 right hand valve is 12005-1113.
You could cross reference this # to find out if they were used on the KDX maybe.
Sometimes you better off trying to find someone on ebay selling an old cylinder/core with the valves still inside, rather than trying to wait for a set to come up by themselves.

[staffylad]

agreed ther all different ,never tried oven cleaner but will in futre I usualy use thinners or white spirit just the same as gunk takes it off nice n clean valves n ports makes all the difference gives it some rattle but apparently they all do this 

[queen of spodes]

Power valves disassembled. 
Note, fwiw.. right valve came that way.   P.O. also welded the countershaft sprocket on, among many other "fixes".   This bike was past roached.  I am foolish for trying to restore it!!!

Anyway- no oven cleaner or heat needed.  I let the cylinder soak in diesel for a week.  The valves were spinning free, but I couldn't pull the center bushing & valve assembly out.  So a week soaking in diesel, followed by some generous application of Kroil it finally pulled out.   

Everything but the right side valve looked serviceable, but I ordered some replacement valves (right center and left) and will probably install those.  Rod looks good. 

[queen of spodes]

Striking out on the right side exhaust valve (part number 12005-1114).  Many OEM fiche sites say they have it, but actually don't after I place an order for it. 

Found one on ebay that ended/sold March 16, 2014 just a month ago.  Wish I'd known!

[Motorrad]

Power valves disassembled. 
Note, fwiw.. right valve came that way.   P.O. also welded the countershaft sprocket on, among many other "fixes".   This bike was past roached.  I am foolish for trying to restore it!!!

Anyway- no oven cleaner or heat needed.  I let the cylinder soak in diesel for a week.  The valves were spinning free, but I couldn't pull the center bushing & valve assembly out.  So a week soaking in diesel, followed by some generous application of Kroil it finally pulled out.   

Everything but the right side valve looked serviceable, but I ordered some replacement valves (right center and left) and will probably install those.  Rod looks good. 

Mmmm Mexican coke