125-200cc Exhaust valve inoperative after actuation

Hey everybody, got the 144 put together on a new '09 cr125 and after about four hours started to part throttle it into the band. I had the PV linkage cover off and could see it operate. Then a little later it didn't feel or sound the same and saw the linkage was sort of flopping around and investigated and found the shaft inside the case was not meshing with the splines on the regulator/governor. I saw the flat spot and thought a lot of grinding had been going on and then thought how can a round governor grind a flat spot in the gears? I then determined the factory installed the shaft about 180 degrees out of time and when I went to full valve actuation the geared shaft and splined regulator/governor disconnected. Thought I had a lot of metal shavings inside a brand new bike at first. So just thought I'd let people know in case. Seems to run okay with 35 pilot and 1.5 air screw at 3000 feet and 80-90 degrees. Big fat bog at half throttle or more so raised the needle one clip(at fourth) and went from 460 to 440 main after opening her up and all she did was stutter. Can't remember if I did this before I noticed inop P.V. so need to take it easy at first. I'm putting it back together(I need to salvage my water pump gasket, waiting on a new one) and see how it goes from here. Noticed some bad machining in my taken off 125 cylinder(floor of one transfer port is 1.5+ mm lower than others and looks like it would disrupt flow banging into side of piston) and had to machine off casting flash in my case reed port, way inside next to crank, afraid it would vibrate off while in operation. Are these machining operations some possible reasons why some bikes just don't run as well as others?

wow! Thanks for the info. Can you inspect the gear mesh through the little 3 bolt cover abover the pump outlet?

Went out for a couple of hours and the PV linkage stayed together(as I thought) Raised the needle to top and some of the bog went away. Deciding between RM needle and slide or 38PWK. The pilot may be too big also. I'll see if the bog goes away, if not get some PV springs. I have the compression damping full out and have only used half of the travel and its extremely harsh on small stuff. At 134 lbs, probably not going to get away with lighter oil and a preload adjustment and cutting the spring spacer, trying to find the best source for fork springs now. The progressive springs I'm reading about sound good. Hey montgob 1, on my cr125/144 the governor/regulator is under the cone shaped cover held on by two bolts on the right side. I'm no expert on this machine but if you take off the cover you might see the shaft(with a flashlight) in there above the gov, and if you disconnect the bolts on the lever on the front of the shaft you can pull the gov/reg assy out. Mine just came out without disconnecting the lever(see original post) The factory grinds a flat spot into the shaft gears for assembly purposes, not sure if its really needed. I just clock the shaft so when I push in the gov the splines/gears mesh and the lever lines up with linkage. (had to take off the lever and replace 180 degrees) If anybody is still reading this why is my carb dripping fuel? I set the floats at 6mm. Stock setting was around 15mm, I set it according to what I read here.

I have a direction guide for installing the power valve governor. Marc, actually they were probably only off by a spline or so. You want to be able to remove the governor by turning the shaft 90 degrees. When re-inserting it will find its place back in the proper spline. If it was off a spline then it also was affecting the throw. JFYI
I have only had the governor out and re-installed about a thousand times and that isn't an exageration.

yup, 6-7mm is the spec on sudco website. Mine was a hair off also, doesnt drip now. I run a 450 main, 45 pilot with a 5 slide and RM needle in middle clip. runs nice i think. Was top 3-4 out of 12 into the first turn all weekend lined up against a bunch of 450's.

Hey Walt, I had the linkage disconnected and with a marker drew on the inner housing the limits of travel for the upper lever put it back together and winged the throttle as I squatted to see and looked like I had full throw, I'll see again what you mean by lever throw. Also my lever with two holes in it is positioned around 3:20ish. I'm thinking it was a little different before. Thanks for info, also how does one get the direction guide and what are some of (if any else) guides you have? I understand the directions for checking ignition timing but how does one know that is the instant the plug fires? Is there a buzz box or light that can be setup to double check?

Marc,
I don't know of any timing light kind of application that will work with our bikes. There just isn't a reference point. You could figure it out yourself using the husky curves but I tend to just trust the case mark or you can get the tool and check it yourself. I have the tool and can send it to you if you want to check your case mark. If you have full linkage throw then you are good to go. That is the important part having the governor putting just a bit of pressure against the upper spring to keep the valves closed when they should be and still having full throw when they are open.
Keep us informed about how it runs and where you end up on jetting once you have it running good with the 144.
Walt

Walt, I've got the linkage set up like you described. I've got a dail indicator and can find the proper position for the piston, thanks for your offer, much appreciated, I'll probably take you up on the special tool. I've been a little leary of trusting the mark. Haven't built enough trust in this bike yet. Rung its neck a few times and it hasn't blown up yet so trust is building. Been reading a lot on jetting and I think you mentioned you finally went with a PWK and others were able to find joy with rm needles,etc. I've been able to work with mikunis before but you seem to be the guru, so probably go with the keihin with the ktm needle, that you're running, if I recall correctly. Have lots of keihin brass. Have to go out to socal for business/pleasure so won't have much to update until I get the PWK and fork springs. Anybody know of good sources for these items? Hey montgob1 what were temps and altitude? Wondering about the mainjet. Mine went a little lean as the temps dropped. Unusually cold the other day and got colder. Anyway was time to pack it up. So long everybody.

Mark, this was in spokane. 2000 ft maybe?? temp ran from 55 to 70. I think i am still rich, power dropped off in the third moto on saturday when the temp was highest. Although it never blubbered on the pilot?? I might mess with a 47.5 pilot at sea level. I also think the 16chy rm needle is to rich, i want to try one of the leaner profiles, i think it would run better especialy with the 144 kit. I also might machine out a leaner slide than the homemade 5 i have. I might make up a 5.5 or 6. One thing i am confused about though is Keihin slide numbers are based on the cutout ange. I was told mikuni slides are based on a diameter. I spent better part of 5 hours last week trying to get a shorty PWK to run better than my mikuni with 3 different slides, 4 different needles and 3 pounds of brass. No dice, mikuni went back on at the end of the day. I was hoping for less temp sensative carb but i might have to do some more homework. I realy dont want to buy a $80 needle from JD.

Marc,
I think that some of the guys here have had good luck with the TMXX using one of the RM needles. I actually had much better experiences with the TMXX than I ever did with the TMX. My issue is always getting it to work reasonably as well at 8000' as it does at 4000'. For that it is hard to beat an airstriker PWK. Just let me know on the tool. It has been shipped around quite a bit.

I got my TMXX working fairly well with the RM needle. Then I had RB Designs do a divider plate and low speed mods with his air screw. It is super crisp now. Of course this is not a cheap fix. Also I do not ride big elevation changes so I don't know how it would handle it.

I think Rob and Rb told me a #5 Mikuni is 5/8" from a certain point, a #6 is 6/8, etc.

I used wallybeans tool to make the timing mark (thanks again) but really do not get too hung up on having it set exactly to the stock position. It is real easy to adjust on the CR so I went with what runs best. I am about 2 degrees advanced now for maximum midrange pull. About 2 degrees retarded makes it real easy to ride in slick stuff. So you might want to experiment. Of course if you are running pump gas you probably want to pay more attention to how far advanced you go.

Hey everybody, just popped in and saw more responses. I talked to Kelly Wednesday and he's sending a PWK here. He assured me this is the ticket and I Just Want To Ride! I don't normally just start swapping major parts out on bikes(until some experimenting) and being a highly stressed small bore I'd like the jetting to be more consistent during the day. And its probably not good to keep running it the way its setup now.(dead lean bog right in the middle) It would be nice if it came with identifiable needles in case I have issues. On that timing mark I adjusted it a little retarded( figured it would give me more on top?) in case it was off and I use with 99 RON fuel I mix up. I'll move it around as soon as I can determine if its correct now. Walt, I'll PM you as soon as I get time(trying to pack) and find out how to PM on this site. Thanks again.