125-200cc 09' CR125 RM needle first impressions

Stock cr125. TMXX carb. PV adjusted up in the slot with about 1.5mm gap showing above the bolt. All jets stock. Ran a few practice moto's yesterday (300' elevation, 40-60* f) with the stock needle in clip 4. Ran good.

Put in the 6 CH 16-62 needle in the middle clip (3) and did a few pit runs, noticed a slight dip around 1/4 throttle that wasnt there with the stock needle, but once past that it pulled harder than stock. Raised needle to clip 4, no good, terrible mid range. Clutch burning a plenty. Dropped the needle to clip 2, same as clip 4, no good. Back to the middle clip for the last few moto's and all was good. Didnt actually notice the low end bog on the track but im sure its still there. Is this where the 5.0 slide comes into play, or did the RM needle cause a pilot issue? Im thinking the 1663 or 1664 needles might work better in some conditions.

I will be running my 144 kit in a few weeks but i would like to get the 125 cylinder dialed before hand.

The stock jetting has (at least on my bike) a 35 pilot and the #4 slide. The recommended jetting for the RM needle is a 45 pilot (richer) and the #5 slide (leaner), so there is a battle going on in the pilot department. I think we should try some different pilots tomorrow with the RM needle and see if we can find something that works with the RM needle and #4 slide. I think I have pilots from 32.5 to 50 and a spare carb for easy testing.

Did you mess with the air screw at all? I have found this carb to be very sensitive to air screw adjustments.

Giles said we could ride at his place tomorrow, the track wont be freshly prepped but that will be good practice for PIR Thursday anyway.

Later,

I think you will have to go leaner once you get the 144 kit. I run a 40p, 5.0 slide and RM needle-3 and once the engine is warmed up it runs great on the bottom end.

I need to get that slide, or just cut mine. I need to somehow make a template off of your 5.0 jake. I did do some air screw turning, but had little affect on the stand. I typically can get a idle change with the air screw, and i got none sunday, which tells me i am way off on my pilot most likely. I have my jet kit as well for tomorrow. Although i gave a bunch of jets to some old guy on an early 80's husky sunday.

Mike, other than 144 kit what modifications have you done to your engine? An is it a Cr?

Bone stock 144 except for PV adjustment and springs - Walt's silver inner and stock spring. It is a WR.

I tried the RM needle on my WR and still had a bog, but it wasn't consistent. It would only appear at the most inopportune times. I changed to the stock CR jetting on the recomendation of another WR owner, and have been happy with it. I haven't ridden a CR model, so maybe ignorance is bliss, but it runs clean, has minimal spooge, and the plug looks good.

RB Designs up on Bonney Slope can cut the slide for you. Not sure how much he charges, but it'll be quite a bit cheaper than a new one.

I'm struggling with my cr125 jetting too. Rode it once at eddieville (bone stock) and it was a major hurdle to get past 'the bog' and into the power. Once into the power it pulled nicely, but it was not easy to get into the power.

2nd ride was at D Mill (where Jake broke my RT shroud ), but this time I had the FMF system, PV linkage adjusted all the way up and the RM needle in #2 clip (rest of jetting stock) and the bog from the pilot to needle was BAD. I lowered the needle to #3 and it was better, but still there. By this time the group came back to get me and we started the ride, so needle testing was over.

Once we started climbing up the jetting was WAY off and I'm not talking about major elevation... about a 1000' climb. I would have jumped off and played with the air screw, but Jake wanted to ride it and I was tired of fighting it, so I let him have it.

Once we got back to around staging area level (700') Jake said the bike ran noticeably better. I know its a 125 and not a 300, so I'm trying to be realistic about power loss, but having the jetting fall that far from a 1000' climb seems pretty extreme. I'm going to pull the PWK carb from my 300 and see how that feels on the CR. I'm assuming its going to be an improvement (it was on my 300) and I'll probably end up buying one for the 125 too. I'll gladly pay $170 to not have to adjust the carb multiple times every ride for the life of the bike.

PC, my bike was 100% rideable with the bone stock jetting and PV adjusted. No bog to speak of. Sure, the midrange wasnt like my kx250f but a touch of the clutch and i was hurtling to the next turn. The only reason i tried the RM needle was because everyone says it is the ticket. And i think it is better than stock in the middle clip (stock in the 4th clip was best for stock needle on my bike). I wouldnt say i have a bog now either, just a slight hickup at 1/4 throttle but in moto i get through that portion of the curve quickly so it isnt a killer. I have only ridden at woodland and my house so i cant speak for elevation changes. BTW, i have a 38 PWM and a shorty 38 PWK you are welcome to borrow for testing if you want. I can give them to jake to forward to you if you want. The shorty PWK is dimensionaly identicle to the PWM, just different slide and the pwk has a slide stop screw where as the PWM uses the cable as the slide stop. I really cant complain about my TMXX though at this point, so i am going to keep working with it.

Frustrating update..

rode a friends track yesterday that has a couple steep hills right out of corners. You have to hit the turns in second and bang third as soon as it revs out on the hill. I was running a machined 5.0 slide (could be machined wrong but it looks right) and the 16-62 needle in clip #3. Bike was a dog on the bottom, this was my first ride on the modified slide. I swapped back to a 4.0 slide with the RM needle middle clip. Still not very impressive, and i had ran there before but not with the steep hills so i was fooling myself. I ended up putting in the stock needle 4th clip, with the stock slide. Bike ran the best there. I was lean on the bottom still but didnt know it until the day warmed up to 68* (was probably 55* when i started riding). The bike pulled better as the day went on and the air warmed. Funny thing is i was setting the air screw properly all morning, i would pull off the track with the bike hot, and back the air screw out until there was no noticable RPM change. With a 35 pilot this was about 1 3/4 turns. I think this bike wants to be Fat on the pilot?? I was surprised how much better the bike ran as day went on, i think i might need a 37.5 pilot since with a 40 i run the airscrew about 2.5-3 turns out, but obviously the 35 is lean. The sensetivity of this bike/carb combo can bum a guy out. I also think the 62 needle is to fat unless i take up ice racing, i was told by someone who ran the 64 and the 62 that they prefered the 64, and my experences are pointing to the same thing.