power valve screw up

Before I make myself look like a complete idiot let me clarify this is my first go at a two stroke.

I recently bought a 99 rm125 with a scared cylinder and a fragment welded to the stock piston. I got into it super cheap and sleeved the cylinder and went with a 56 mm wiseco piston. Knowing I would have to remove some material from the power valves for clearance. Here is where the dumb ass moment comes into effect. I dropped the valves in marked them and proceeded to grind them down. Did some final tweaking with the piston in the cylinder to get a perfect fit. Notice I did not say anthing about the valve retention plate.:prof:

When I reassymbled everything with the plate now in place, my valves have about a 1.5 mm clearance. !!!!!DOOOO!!!! :smirk::smirk:

Went ahead and finished the reassymbly after checking and finding some people actually run these engines with the power valves locked open or completely removed.

Motor runs strong. I don't know what is was like before as I bought the bike already disassembled.

So any suggestions as to wich way to go. I am having dificulty finding a set of powervalves. Will running it as set cause any problems other than being a little boggy at low rpm.

Thansk for any help Trey.

1st-Welcome-2nd Nice score on your RM.

Power valve was designed for range of Power thru-out the power-band.--Im sure that there is a butt-load of better explanations.

I have alot of Two strokes.i had a Power-Valve issue in my Sons mid 90's RM 125.I took the Power-valves out. The bike would Scream if you kept in the throttle and kept putting in a fresh plug.It sucked for Family/Bud trail riding.Never less- kept it that way till new parts got here.

Since you brought it to this point-Do her up right-You scored a great ride and it will last you along time with proper service


If anyone has a set of old stock valves for this application I would be interested in taking them off you hands for the right price. This time i think i will add the plate to get the spacing correct.

New valves are running about $200 a set. ouch!!

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