dajogejr Posted July 18, 2012 Report Share Posted July 18, 2012 IMO a good running cub @ sea level is at 120ish on HP. If you're coming in just under 110 at 7200 feet without any kind of correction (sorry, I just kinda browsed this thread) I'd say you're doing outstanding. Apples to apples, you're going to be down 10 to 20% on HP compared to a sea level read, there's no way around it. However, I don't know what correction map you used or was used... 120 is a good number to shoot for on a 10 cub on alky. The rest is chassis, gearing and clutch tuning. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted July 19, 2012 Author Report Share Posted July 19, 2012 IMO a good running cub @ sea level is at 120ish on HP. If you're coming in just under 110 at 7200 feet without any kind of correction (sorry, I just kinda browsed this thread) I'd say you're doing outstanding. Apples to apples, you're going to be down 10 to 20% on HP compared to a sea level read, there's no way around it. However, I don't know what correction map you used or was used... 120 is a good number to shoot for on a 10 cub on alky. The rest is chassis, gearing and clutch tuning. This was the first time I have been on a dyno & i don't know much about the correction factors he had set up on it. I want to bump up the compression and see if I can get a few more hp out of it, and help my launching a bit. Thanks! -Jared Quote Link to comment Share on other sites More sharing options...
dajogejr Posted July 19, 2012 Report Share Posted July 19, 2012 Throw a little more timing at it before you raise compression. What is it at now? You'll know when you have too much timing when your ET stays the same but your MPH dips off....then you hit the wall. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted July 19, 2012 Author Report Share Posted July 19, 2012 Im sittin at the 6 or 7 deg mark right now. What do you think, +9? Quote Link to comment Share on other sites More sharing options...
dajogejr Posted July 19, 2012 Report Share Posted July 19, 2012 Are you running down a track, or just in the dunes? If you're running a track, bump it. If you're duning/riding, leave it. Too much heat to sustain. No problem with a few second run. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted July 19, 2012 Author Report Share Posted July 19, 2012 We are at the dunes with it. Mostly flat straight-line drags about 500-700ft. Some up-hill stuff, but the up-hill runs are shorter. I do want to get the compression up above the 150 mark with some smaller domes. Thanks! Jared Quote Link to comment Share on other sites More sharing options...
dajogejr Posted July 20, 2012 Report Share Posted July 20, 2012 Yeah...leave the timing where it's at for now. Those are long runs on a two stroke...make sure you can supply the fuel it needs with smaller domes, and it doesn't heat up too much. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted July 20, 2012 Author Report Share Posted July 20, 2012 Yeah...leave the timing where it's at for now. Those are long runs on a two stroke...make sure you can supply the fuel it needs with smaller domes, and it doesn't heat up too much. I put a pump on it a couple weeks ago. Its not the black hex pump, but one of the smaller 35Lph pumps. I also have chariot billet bowls on my mikuni's. I'll have to check the heat on the plugs next time we take it out now that we played with the jetting a little bit on the dyno. -Jared Quote Link to comment Share on other sites More sharing options...
dajogejr Posted July 20, 2012 Report Share Posted July 20, 2012 I put a pump on it a couple weeks ago. Its not the black hex pump, but one of the smaller 35Lph pumps. I also have chariot billet bowls on my mikuni's. I'll have to check the heat on the plugs next time we take it out now that we played with the jetting a little bit on the dyno. -Jared I ran a pump, the hex pump, DF62, which is 65Lph pump for a long time with billet bowls on Lectrons. Not needed, but good insurance. I switched to a 35Lph pump because no matter what I did with the 62...it would push fuel out the overflow. I never had an issue again. You can get a little more or less pressure by lengthening or shortening the pulse line hose...or putting a small jet in the line. They operate at 4 to 6PSI I believe, so don't mistake fuel pressure with fuel volume... With that long of a run, I think you're making a safe bet with the insurance. Quote Link to comment Share on other sites More sharing options...
Bigcarb Posted September 1, 2012 Report Share Posted September 1, 2012 10mil cub ported by Tim @ Titan Domes cut by Tim, but they were cut for las vegas elevation, so the compression is way down at our elevation (130lbs static compression) 6deg timing 35mm mikuni carbs with a pump and billet bowls .118 dumps .116 mains K&T / Racers Edge pipes 7200ft elevation Alright, I know some stuff on my setup is not optimal, but I am pretty happy with the numbers I got. The green run was the first run of the day with my "seat of the pants" jetting and the other two runs are after playing with the powerjet. (went from wide open and ended up at 2 turns out in the end) His sniffer wasn't working right, or didn't like the methanol. Its readings were off, so we were just going by the plug readings and the sound of the motor. This was the first time I have ever been on a dyno. It was fun & we had a great time screwing around. I want to get some domes cut for our elevation and get my compression up a little bit and take it back. The air/fuel curve is not correct & I think we ruined his sniffer. 109hp and 55tq. I really like how flat the curve stays once it seems to top out. It looks to me like the motor is not happy at peak. From 10-11k the curve little variation indicating that the motor is struggling. Timing and compression might the wrong way to go. I would guess the pipe is holding too much heat. A pipe change is what I would guess would yield the best results. And if I am right, you will have reliability issues with the setup you have now. The plugs porcelain, and the pistons might be frequently failing. LOL(oops, that's no laughing matter)... And as to the elevation/corrected power: the potential for higher dyno readings are better at elevation. Peak cylinder pressure is the most common limiting factor on a two-stroke's power, and it is lower at higher elevation. So you can abuse things further (ie. timing/compression etc.) And while the power is substantially less, (about 25% at 7500ft) your SAE/DIN/or STD correction is adding that 25% back in to simulate sea-level power-automatically. You can see the observed power by looking at the runs on the dyno "uncorrected". Try it. But you likely won't want to post that number. Quote Link to comment Share on other sites More sharing options...
N2DEEP Posted September 4, 2012 Report Share Posted September 4, 2012 Man the racers edge pipes are imo the best pipe you can run on a cub! I will gladly buy them back if he dose want to sell the I will buy them! I ran the timing at 8 on this motor I think by the way. Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted September 6, 2012 Author Report Share Posted September 6, 2012 Man the racers edge pipes are imo the best pipe you can run on a cub! I will gladly buy them back if he dose want to sell the I will buy them! I ran the timing at 8 on this motor I think by the way. I am really happy with the way these pipes hit. We made probably 50 passes over labor day weekend with this setup and ran about 500ft on most of the runs. I like how this thing runs. -Jared Quote Link to comment Share on other sites More sharing options...
Paulie B Posted December 15, 2012 Report Share Posted December 15, 2012 Whats a .116 main jet? This combo mirrors my own and I run Mikuni carbs. Quote Link to comment Share on other sites More sharing options...
Finch Posted December 15, 2012 Report Share Posted December 15, 2012 its drilled to .116 Quote Link to comment Share on other sites More sharing options...
Paulie B Posted December 15, 2012 Report Share Posted December 15, 2012 Oh. I'm an idiot. This must be for Meth? Quote Link to comment Share on other sites More sharing options...
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