|
|
Post by rcq92130 on Oct 6, 2014 19:30:33 GMT -5
Have a bit over 400 miles following the BBK upgrade, so it's time to do some WOT checks and do what is needed to tune this thing.
It's a 150cc GY6 with 60mm piston, A9 cam, stock valve size, Uni intake, big exhaust, 30mm carb with 125 mail. I forget the idle jet --- 38 maybe. Large variator w/ 11g sliders.
Have PLENTY of off the line acceleration ---- no interest at all in more there. Top end seems low, though can probably get into the 60+mph range on flat if given enough room.
But the main thing i would like to ask Ally and others is about RPM.
Form rest, at WOT, the RPM goes up to but never beyond about 6700 or 6800. By the time I'm at 40mph (still WOT) the RPMs are down to about 6100. The only time I get up to 7K is downhill when I'm up to maybe 60 or 65 mph.
That means (I think) I'm always operating below the max power and max torque range.
So, before starting ---- isn't there anything i can do to get this thing to skip into a better RPM range?
|
|
Freshman Rider
Currently Offline
Posts: 59 
Likes: 11
Joined: Oct 3, 2014 20:29:15 GMT -5
|
Post by katastroff on Oct 6, 2014 19:36:23 GMT -5
Stiffer contra spring maybe?
|
|
|
|
Post by alleyoop on Oct 6, 2014 20:43:32 GMT -5
I will tell you this with 11 gram weights it should be pulling in the 7K range. I don't think you want to again hear my .02 on your setup and tell you what your problem is, I believe I said my peace on your original thread on this build.
Alleyoop
|
|
|
|
Post by rcq92130 on Oct 7, 2014 15:35:58 GMT -5
Guess I'm not welcome here any more.
Anyone have a suggestion of another forum site similar to this one? I'm new to scooters and know only this one forum.
|
|
|
|
Post by xyshannen on Oct 7, 2014 16:08:46 GMT -5
alleyoop Will too large a carb prevent higher RPMS?
|
|
|
|
Post by alleyoop on Oct 7, 2014 16:55:38 GMT -5
Guess I'm not welcome here any more. Anyone have a suggestion of another forum site similar to this one? I'm new to scooters and know only this one forum. RC, you are for sure most welcome here, the problem is I told you before but you did not listen you are over carbed and over jetted now your paying the price. I have been doing carbs and motors for DECADES and not these little 1 cylinder jobs the big boys I know what makes them tick. I was a HOT RODDER built my own hot rods still have one left a 1969 firebird with dual quads 462 hp at the rear wheels runs like a bracket car at the strip 11.73 -11.78. Just so you know and understand where I am coming from, I am not the only one that tried to tell you, Millsc knows his stuff and tried to clue you in but you also did not listen to him and you went and did you own thing. Check out our setups and compare to what you have and the problem your running into. My motor 157qmj has a 62bbk and a 60mm stroker crank with a 24mm carb and it took a 122.5 main and a #38 pilot jet to get the most power out of the motor started with a 125 main but was to much fuel, tried a 120 and it ran but it was on the edge of being LEAN so went with a 122.5 and runs like a raped ape. MILLSC has a 157qmj as well and he went with a 61bbk so he would not have to bore the case and a stroker as well and he TRIED a 30mm carb and took it off could not get it tuned right and put in 26mm carb and I believe a 120 main and his runs like a raped ape. And here you are with the same motor and with less displacement than either Millsc or I and slapped in a 30mm with a 125 main jet. I believe Millsc also chimed in and said something I can't remember but like a lot of folks people believe dumping a lot of fuel into a motor and it will produce a lot of power. A motor can only take so much air and fuel and burn it efficiently if to much it blows it out and less power is produced. You can get them to run but with a lot less power. Alleyoop |
|
|
|
Post by alleyoop on Oct 7, 2014 16:57:27 GMT -5
alleyoop Will too large a carb prevent higher RPMS? Yes, due to the motor not making power to much and you actually loose power. You can get them to run descent but the motor will produce less power a combo of fuel and air and how it is now moving through the bigger venturi and creating different pressures and velocity. Also if the intake is now bigger than the heads intake now creates a lip and disrupts the flow of fuel and air. So there are several things you have to consider before slapping in a bigger whatever. Just a simple example take a simple free flow filter put in to big butt free flow filter and you will have problems with getting to much air and not enough fuel. So then what do most do they slap in a bigger main and or pilot jet and then they have problems starting and running at different speeds. Alleyoop |
|
..BAD TO THE BONE..
