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Hey guys, I just bought a 1991 KDX 200, and after getting plenty of information from here for restoring parts of it, I decided to make an account and ask this question. The bike is a pain in the ass to start, like BADLY. We're talking 20m of kicking the damn thing, so naturally I thought it was poor compression. Taking the top end apart seems to confirm that, the cylinder walls and piston are both in pretty rough shape. However, upon disassembling the rest, i discovered that the power valves are incomplete! None of the smaller gears are present, just the long toothed horizontal bar that pushes through.

So my question is, can I run the bike without these? It did actually run before the tear-down, and power felt alright (Although its been a long time, not sure how it should feel), and secondly, would these missing parts be responsible for it being such a pain to start? Or is that likely entirely the bad cylinder and rings.

The missing parts are p/n 12005 A/B/C and 59051.
Heres the diagram: http://www.bikebandit.com/oem-parts/199 ... 0#sch47948

Welcome aboard! If everything else is sorted, it oughtta run without the Kips valves, though it won't exactly break the butt-dyno. I'm actually theorizing alloy toys. I know it'll run if the valves are stuck open or closed, but I don't know if having them missing entirely would provide too much open space and adversely affect airflow.
Nevertheless, if you're going to replace them, they're notorious for breaking and it's worth getting the steel ones made by BDK racing.

Sent from my SM-P600 using Tapatalk

Welcome to the forums.

Sorry that the bike is in poor shape.

You may have other issues besides the power valves, so be check it all.

Alright, thanks for the replies! Yeah I definitely have other problems, i just had a moment disassembling it where I went "Isnt something missing here?...". Ill try finding those steel power valves you mentioned.

There was a member on here just a couple of weeks ago that had a set for sale.

Keshyoma wrote:Hey guys, I just bought a 1991 KDX 200, and after getting plenty of information from here for restoring parts of it, I decided to make an account and ask this question. The bike is a pain in the ass to start, like BADLY. We're talking 20m of kicking the damn thing, so naturally I thought it was poor compression. Taking the top end apart seems to confirm that, the cylinder walls and piston are both in pretty rough shape. However, upon disassembling the rest, i discovered that the power valves are incomplete! None of the smaller gears are present, just the long toothed horizontal bar that pushes through.

So my question is, can I run the bike without these? It did actually run before the tear-down, and power felt alright (Although its been a long time, not sure how it should feel), and secondly, would these missing parts be responsible for it being such a pain to start? Or is that likely entirely the bad cylinder and rings.

The missing parts are p/n 12005 A/B/C and 59051.
Heres the diagram: http://www.bikebandit.com/oem-parts/199 ... 0#sch47948

Hi,

last year I bought a 1990 KDX200, looks well used but mechanicals are in good order.
After the first ride, with the stock expansion chamber which is well beaten up and the header section was a little split, I was very very impressed with the low to mid range torque of the bike. I assumed this was due to the KIPS.
I have since purchased an FMF fatty for the bike. When I had the old pipe off to fit the new one, close inspection up the exhaust port on the engine revealed the lack of any of the KIPS valves (centre or sides). Obviously removed by a previous owner probably because they were broken.
Now with the FMF pipe fitted and a slight rejet (it was waaaay rich), the bike is a real screamer. It's got guts right through the rev range and really winds out well. All I can say is, that a KDX200 with the KIPS intact and working must have very good low down grunt.

So long answer to your question, it should run fine and it shouldn't be a major cause of your starting issues.

Cheers,
Dave

2vdave, welcome to the forums.

Jason wrote:2vdave, welcome to the forums.

Thanks Jason! Long time reader, first post above!