TeamRealtreeHD Posted July 30, 2008 Report Posted July 30, 2008 As most of you know, I am having some problems with my bike. It has a badlow end problem. Just doesn't want to go. After speaking with the motor builder, and a guy around here who also does the motors, they think I am running too high of octane. I was running 116 and only had 185 PSI in the jugs. So would this cause a bog down low, like the rpms aren't high enough to burn the fiel fast? It wasn't missing, just taking a long time to get on the power. I drained it as both recommended to run lower, around 104-105. I now need to get some. If that doesn't solve this, then I don't know what to do. I want to run +6 timing like the builder says, but I hear that takes alot away from the low end. Then I have guys saying advancing the timing will take away from the top end. Hell if advancing the timing is taking my bottom end away I'll take the plate right out and put the stock one back in. But I never played with timing before so I couldn't say from first hand experience. You want to talk about being confused? Quote
No Limit Powersports Posted July 30, 2008 Report Posted July 30, 2008 What jetting are you running in the carbs... Sounds like a jetting problem to me ... Quote
TeamRealtreeHD Posted July 30, 2008 Author Report Posted July 30, 2008 It's not jetting for sure. I currently have 155 mains and 48 pilots in. I had it as rich as 162 mains and 52 pilots and as lean as 45 pilots and 150 mains. And i had the air screw 1.5 turns to 2.5 turns out on every jetting trick I tried. Just please guys, take my word here... this is not jetting. Quote
okbeast Posted July 30, 2008 Report Posted July 30, 2008 Sounds like jetting LOL I never had a problem on Kevin's motor doing this, never really messed with the jetting either now that I think of it. I just stuck a fatty in there and rode it and it was fine. I'd take Kev's experience, he built the motor, he knows what's gonna get it running right. Quote
blowit Posted July 30, 2008 Report Posted July 30, 2008 (edited) check needle position and sync carbs. I agree, jetting. 116 WILL run fine with that compression but you will want to bump the timing a bit to get the most out of it. It will NOT make more power but you can use it. If you did have to choose, anything over 100 oct will be fine. You also NEEED to drop your plug gap if you have not to .020 from the OEM .028. That WILL cause this problem. You can be all over the map with jetting and never get spark snuff out without dropping the gap. Brandon Edited July 30, 2008 by blowit Quote
okbeast Posted July 30, 2008 Report Posted July 30, 2008 check needle position and sync carbs. I agree, jetting. 116 WILL run fine with that compression but you will want to bump the timing a bit to get the most out of it. It will NOT make more power but you can use it. If you did have to choose, anything over 100 oct will be fine. You also NEEED to drop your plug gap if you have not to .020 from the OEM .028. That WILL cause this problem. You can be all over the map with jetting and never get spark snuff out without dropping the gap. Brandon What's the reason for closing the gap some? I know why you'd do it, but what about his motor setup would require it? Quote
TeamRealtreeHD Posted July 30, 2008 Author Report Posted July 30, 2008 (edited) I appreciate the help guys. 1. This is not a jetting problem. 101% not jetting. 2. The NGK plugs right out of the box are gapped right for this motor. That is is coming from Kevin's mouth. As of right now, in terms of power, this has about as much as my 2 into 1 setup had. It screams but nothing like people would think or what guys claim of this portwork. I know what it had before, and I know what it has now. A port job and all of this stuff I did should make it run and that's just not the case. My last setup would beat this one probably. That is why I know something is wrong. Edited July 30, 2008 by TeamRealtreeHD Quote
TeamRealtreeHD Posted July 30, 2008 Author Report Posted July 30, 2008 This is not a drag bike. This is a playing bike that I climb with and drag occasionally. So why would I bump my timing higher? Quote
TeamRealtreeHD Posted July 30, 2008 Author Report Posted July 30, 2008 (edited) What I have to do is just stop trying to tell myself I can fix this and just have the guy that built one for a local guy that runs really good look at it. He talked with my engine builder and both are on the same page. This is beyond me. I spent 11 days trying to do it, and keep starting over and over. And coming back here asking the same questions. I think the problems will shock most here, I really do. This is something that most of us wouldn't think... It is just dying at the low end, and the top end isn't as impressive as I would think. It doesn't pull all the way through the gears like it should. You really have to clutch it and such. Edited July 30, 2008 by TeamRealtreeHD Quote
TeamRealtreeHD Posted July 31, 2008 Author Report Posted July 31, 2008 Well Kevin said with 116 and my compression, the motor is only calling for 104 (roughly). The low rpm's can't burn the high octane points fast, but in high rpm's, it could and not be noticed. My exact condition. So it all makes sense. But if that's not the problem, since I am getting the lower octane gas tomorrow, I am doing a leakdown to check for air leaks, etc. I am not running this until she is good to go. Until then, she will sit. Quote
deerekillr Posted July 31, 2008 Report Posted July 31, 2008 Instead of going through the trouble of getting 104 octane why dont you just mix some 93 pump gas with what you have and lower it that way? Might save you some running around. james Quote
deckheight Posted August 2, 2008 Report Posted August 2, 2008 Your main problem (probably only problem) is the 116 octane fuel... 104 sounds about right w/17cc dome and stock deckheight. What your doing with the 116 and your compression is very similar to retarding the ignition timing. Maximum combustion chamber pressures have to happen at the right degree of crankshaft rotation. Too early and the piston is working against the expanding fuel charge, too late and the piston is already traveling away from it. Since the flame front with higher octane fuels travels at a slower speeds, you are not getting a complete burn before the exhaust port opens. Just spitting part of the fresh fuel charge out the exhaust port along with the rest of the exhaust gasses... I personally would have listened to Kevin from the start, sounds like he knows what he's talking about... Quote
shanYE west Posted August 2, 2008 Report Posted August 2, 2008 Just out of curiosity.. how do you know 100% its not jetting? was it dyno tuned? Quote
KEVSWS6 Posted August 2, 2008 Report Posted August 2, 2008 Butch got a hold of it. It had a small air leak, pickup gaped wrong, tightened and gaped the plugs. Put the timing at +4 and then changed jetting cause of the other stuff. It runs well from what Butch told me. TeamReal should be a happy camper now! Quote
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