Power valve reassembly issue - Help!

Discussion specific to the 1989 - 1994 (E Series) KDX200 model sold in the USA
Post Reply
User avatar
Kawboykid
Supporting Member I
Supporting Member I
Posts: 15
Joined: 03:58 pm Nov 17 2013
Country: United States

Power valve reassembly issue - Help!

Post by Kawboykid »

I am reassembling the top end on my '92 kdx200 (now that the cylinder has been resealed and honed) with new power valves from BDK. I got the valve assembly timed correctly, and it operates perfectly by hand... that is, until I go to install the main/center valve cover and bolt it tight against the cylinder.

As soon as the O ring (I replaced all 3 o rings in the powervalve assembly with OEM) inside the cover contacts the aluminum carrier for the main valve, the valve assembly binds up and will not operate, even with the main valve cover bolts only finger tight against it.

What gives? The only thing I can think of is that Powerseal USA (reputable local 2 stroke engine shop who did my cylinder) did some welding & machining on the exhaust port to build it back up from excessive wear, and perhaps left too much material or a burr, where the main valve gets stuck once fully pressed into its journal by the cover bolts.

I felt in there by hand and thought maybe the one edge feels burred, but I don't want to start going at my cylinder with a file or dremel unless I absolutely have to.

Has anyone experienced this issue? Where the power valves work perfectly until the main valve cover is installed?
User avatar
Kawboykid
Supporting Member I
Supporting Member I
Posts: 15
Joined: 03:58 pm Nov 17 2013
Country: United States

Re: Power valve reassembly issue - Help!

Post by Kawboykid »

Update: I called powerseal and the guy thinks that when he did the welding repair on the exhaust port area where it was cracked he may have built up a little too much material and it is causing the main valve (ref 12005B in diagram) to bottom out in the journal. He suggested grinding the main valve to clearance it. Thoughts on that?

Reference diagram - https://www.bikebandit.com/oem-parts/19 ... 7#sch53656
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Power valve reassembly issue - Help!

Post by KDXGarage »

I think you are going to have to remove material from the cylinder or valve. For me, which is cheaper to replace if I mess it up? :grin:
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
Molly's 70
Platinum Member
Platinum Member
Posts: 563
Joined: 04:29 pm Jun 18 2017
Country: USA
Location: Wichita, Kansas USA

Re: Power valve reassembly issue - Help!

Post by Molly's 70 »

I'd send it back to power seal, but that's just me.
If you lend someone $20, and never see that person again, it was probably worth it.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Power valve reassembly issue - Help!

Post by KDXGarage »

You aren't the first with overgrowth and won't be the last.

If you can clearly see where it is on the cylinder, that is one thing, but I would be sure to use some machinists blue spray or similar to check, sand and re-check 100 times.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
Kawboykid
Supporting Member I
Supporting Member I
Posts: 15
Joined: 03:58 pm Nov 17 2013
Country: United States

Re: Power valve reassembly issue - Help!

Post by Kawboykid »

Thanks for the input guys! I think the best first move is to take it back to Powerseal and show them the issue. They are professional machinists and should be able to fix it best, plus they did the job, so they should finish it for free.

My other thought was potentially trying to space the whole main valve assembly out just a hair with a copper or aluminum crush washer, or additional o ring inside the outer lip of the aluminum main valve carrier/collar. I like to ask "what can I try that is reversible?" first before going to the bench grinder.

But when it comes bench grinder time, the old "which is cheaper to replace when you eff it up" is definitely a good order of operations hahah. In this case both bits are no longer available from kawi, so I'd rather not go there until I absolutely have to as a last resort.

Thanks again. I'll post an update (hopefully a resolution) once I get the jug back in front of the guys at Powerseal and can talk to them in person.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Power valve reassembly issue - Help!

Post by KDXGarage »

I forgot you said they were local. Grab your keys and go (with all parts).

I assume they will use fine emery cloth to enlarge it after a test fit.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
User avatar
Kawboykid
Supporting Member I
Supporting Member I
Posts: 15
Joined: 03:58 pm Nov 17 2013
Country: United States

Re: Power valve reassembly issue - Help!

Post by Kawboykid »

Resolved!

I took your advice and drove back out to Powerseal yesterday morning before work.

The interference was in fact where he had made a weld repair, and he clearanced it while I waited, no charge and a free t shirt for the trouble!

10/10 recommend Powerseal's customer service. Jamie, the one owner is also the president of the ECEA. They are real enthusiasts, not a shop out to make a buck.

Thanks again for your advice on this! Glad i didn't take a dremel to it myself, they did a much nicer job than I could've, well worth the hour drive.
User avatar
KDXGarage
KDXRider.net
KDXRider.net
Posts: 14047
Joined: 06:45 am Nov 01 2004
Country: United States of America
Location: AL, USA
Contact:

Re: Power valve reassembly issue - Help!

Post by KDXGarage »

SWEET!

I am glad it worked out well.
Thank you for participating on kdxrider.net. :bravo:
To post pictures from a device: viewtopic.php?f=88&t=24128
Post Reply