Don't intend to pop any one's bubble here, but those are some really weak numbers for a CR125...sorry JMO
You think so? It makes roughly half the horsepower as my Aprilia RS250 I dynoed my 250s on the same day. I was expecting it to make half the power my 250's make. It did exactly that.
Getting closer to Honda RS125 HP there. I think my 98 RS125 made about 44hp with the MOTOBUM cylinder.
I remember the very first CR125s after rejetting the stock carb, would put out a then-astonishing 19+hp.
On this same dyno a CRF250R Does like 34. Once I put in some serious time RIDING and ENJOYING this little thing, then I will worry about more power. Trying to get it to 190 pounds now. 190 lbs and 31 at the wheel? Bring on the ninja 250/cbr 300 / RC 390
If the rest of the bike is sorted well and its 190 lbs and 30 whp then you will smoke the Ninja 250/ CBR 300 class bikes. They make the same 30 whp but its tough to get a ninja 250 under 300 lbs for most class rules. At 300 lbs a bike would have to make 48+ whp to match your power to weight ratio without a rider.
Sorry...yes. By the looks of the A/F curve, the RS pipe might not be the best choice IMO. With a kart cylinder/pipe/timing combo with the right jetting you could be in the high 30s hp range. Keep dropping the jetting till the hp flattens out...you might be surprised how lean you can go. 38-40hp CR125 on a DJ is not that hard to achieve on a DJ...JMO
Please show me some of these 38-40hp cr125 dynos, lol. I have not seen many at the rear wheel doing that much.
Got the second 125 swapped aprilia running today, it's a blast as well. I think i'm going to take these two to the 1/8 mile dragstrip on wednesday to see how they do, haha
i built that one out of the spare parts and stuff that i had after i got a second frame and polished / welded / heat treated it to make it look kind of like a works frame.
Sorry, but I do not have access to the graphs anymore...but I can assure you that I did not pull the numbers out of my ass. My 125s won 7 straight AMA Grands titles and they did not do it running in the low 30hp range. Hell, my 85s turn 28hp (with a 18hp stock baseline) on DJ SAE CF... I tried to offer some suggestions but you came back with doubts...no worries.
I have heard lots of wonderful stories on the internet. It's funny though, when we ask for real numbers they actually disappear every dyno is going to read different, even with correction factor. I made improvements and that was what I was after. I hope to continue the trend of making more power the next time I go to back, by making small changes here and there. For sure, the ignition timing is something to look into because I am sure that it can be advanced given the fact that the bikes are running AVGAS. Also, I am nowhere near 600C At the end of the dyno pull so perhaps the timing or jetting can be looked into. The cylinder head temperature is climbing at a similar slope to the egt so I know there isn't too much timing into it down low or through the meat of the torque plateau. I do not have a power valve on this cylinder so I have to remember that any tuning I do for more peak will very likely affect my low end in a significant amount. If I were racing I would have to make sure it is a compromise I am alright with. What did Aprilia RS250's do on your magic dyno? 80hp? Haha
Matt.... Errrrr.... you do know who you are talking to right? If just about anyone on here says something about a 2 stroke dirt bike, most you can blow off. Not his statements. I am guessing you missed the part where he mentioned the AMA part. Jake Lewis... Heard of him? That guy^^^ Above, build his motors.. Cool project none the less though. I dig it.
Matt, less talking more listening. Jake Lewis is just one of many many great riders to have benefited from Tdubs knowledge. He has no reason to lie and nothing but results to back it up. I'm sure you've read lots of stuff on the Internet, and really have this motorcycle stuff figured out, but take a minute to listen to a real professional freely sharing his knowledge and maybe you'll end up with a faster bike.
LOL ....... Gee Tryce ya just don't get any respect anymore. Whats with that? Tdub is correct. In fact I have a KX 100 mini motard I need to sell along w/ a KLX 173 sitting in the garage. The KX pushed 31+ hp w/ Billy Wiese WRW Racing building and tuning it. Keep digging on that Aprilia Matt. It does have some room for improvement in the motor dept. Tryce, you see Jake and Bobby pass on a hello to them. Let Jake know Kevin is racing 600cc micro sprints at the Houston and Dallas dirt tracks. We'll do the Tulsa Shootout in December. He's as tall as Jake is now. Best to ya. T. Johnson TDK Motorsports Conroe, TX.
Like I said I haven't seen a stock Moto cylinder do a lot Rs/05 cr piston, base gasket spacer, wider transfer windows, and cleaning everything up a long with a programmable ecu and I will see more power for sure, but I don't think this stock cylinder had much more in it without jamming a ton of compression and timing into it and losing all the over rev and smoothness it has right now. I'm sure I will break out mr ccspecialtytool at some point but I want to drag elbows on this thing first, it has enough power to get me to 118mph already
Pfft, what does that Tdub guy know. My local chainsaw guy said he could squeeze 20hp out of my Poulan pro. Ha
