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Post by vegaslightsss on Sept 12, 2012 13:51:34 GMT -5
Just added the Carb yesterday.bbk with stock head, cdi & performance. Coil,iridium,installed new 80.00 CVT 23mm flat slide Carb with 88 main,and 32 pilot jet. Idles nice and runs WOT the rest off the rpm range is a 125 two stroke on or off.
Mixture screw or where do I start? Thanks,Vegas
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Post by felliott on Sept 12, 2012 17:29:44 GMT -5
I would adjust adjust the needle. Move clip down richens and clip up leans. the needle controls 1/4 to 3/4 throttle.
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Post by usmcdoc on Sept 12, 2012 19:41:50 GMT -5
Just added the Carb yesterday.bbk with stock head, cdi & performance. Coil,iridium,installed new 80.00 CVT 23mm flat slide Carb with 88 main,and 32 pilot jet. Idles nice and runs WOT the rest off the rpm range is a 125 two stroke on or off. Mixture screw or where do I start? Thanks,Vegas First off...carb is WAY too big...that is what 150 size scoots use...#88 jet is WAY small for all the airflow that MASSIVE carb sucks in. Not to sound rude....but bottom line is...you over did it...even the pilot jet is too big. Men always think..'Bigger is better'...lol...even women will tell ya...it's how it's tuned and how ya use it... ;D Sounds like you are trying to build the ultimate racer. Old timers besides me will tell you...one piece at a time..that way when you have a problem...the last thing you did..is what caused the problem. Scooters are NOT like Crockpots..where you can toss 10 things in at once..and come out with a nice stew. Do that with a scooter and...well you now see what happens.  |
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Post by vegaslightsss on Sept 12, 2012 22:56:42 GMT -5
First of all,its not way too big,just way too big to run out of the box. I have the 130 Pipe,I have the 50mm bore,I have a Uni On it. the 88 Jet is what It cam with. It idles perfectly,and runs at WOT perfectly, and at WOT it not just running,its constantly pulling. It is a matter of setup. When I went to scrappy I tried to buy the 20mm but they were out of them,so I went for the 23mm which they advertise as the Best Carb for their BBk. I need to get a big valve head or the A9 cam to increase lift and duration slightly in my opinion. I am simply looking for someone with some advice,not to be told its hopeless when the forums are full of folks that have them working just fine. Yes I agree a smaller carb would have worked out of the box,but I disagree that the situation is hopeless. I am sure there is a jet,needle valve,mixture combination that will improve midrange performance and make it driveable.....Thanks,Vegas
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Post by usmcdoc on Sept 12, 2012 23:10:08 GMT -5
First of all,its not way too big,just way too big to run out of the box. I have the 130 Pipe,I have the 50mm bore,I have a Uni On it. the 88 Jet is what It cam with. It idles perfectly,and runs at WOT perfectly, and at WOT it not just running,its constantly pulling. It is a matter of setup. When I went to scrappy I tried to buy the 20mm but they were out of them,so I went for the 23mm which they advertise as the Best Carb for their BBk. I need to get a big valve head or the A9 cam to increase lift and duration slightly in my opinion. I am simply looking for someone with some advice,not to be told its hopeless when the forums are full of folks that have them working just fine. Yes I agree a smaller carb would have worked out of the box,but I disagree that the situation is hopeless. I am sure there is a jet,needle valve,mixture combination that will improve midrange performance and make it driveable.....Thanks,Vegas Never said it was hopeless...settle down Hotrod. Just saying...just because they gave you an #88 jet does not mean that it will work with all the other stuff.Which it isn't... Best wishes in your endeavors to make a NASCAR speed scooter out of a 50cc engine... |
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Post by peteyparado on Sept 13, 2012 3:04:09 GMT -5
for me i run a 50mm bbk with big valve head etc... i use to use that same 23mm scrappy carb an it was too big.. the scoot ran fine.. just couldnt get it dialed in i tried main jet sizes from 85 to 105 an pilot sizes from 28 to 40!! an i couldn't get the bottom to mid range pepp... i changed to a 18mm with a 98 main with 35 pilot an bingo.. vegas if u just gotta get a bunch of jets an test an tune...
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Post by usmcdoc on Sept 13, 2012 7:57:35 GMT -5
for me i run a 50mm bbk with big valve head etc... i use to use that same 23mm scrappy carb an it was too big.. the scoot ran fine.. just couldnt get it dialed in i tried main jet sizes from 85 to 105 an pilot sizes from 28 to 40!! an i couldn't get the bottom to mid range pepp... i changed to a 18mm with a 98 main with 35 pilot an bingo.. vegas if u just gotta get a bunch of jets an test an tune... peteyparado....Your setup is what many here run..as you said..." i changed to a 18mm with a 98 main with 35 pilot an bingo" I am just trying to help him. He claims many on here run the 23mm carb setup. I have YET to see one that does... The 23mm carb may work if you have a stroker crank...giving you a true 100cc vice the 83 you get from 50mm BBK..thanks for your input. :thumb: |
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Post by vegaslightsss on Sept 13, 2012 14:17:02 GMT -5
Ok Guys, In Either of your opinions,would either a A9 or some other cam benefit me,or a Big Valve Head? I have another customer thats wants BBK but has limited funds,I could give him mine with a quick hone and re ring and then I could go for the 52mm with Big Valve Head. Its running much better than what I started with but it is still "loaded up" and I have to pump the throttle until it "catches" at about maybe 1500 rpm and takes off. So as far as jetting would anyone estimate that I would go larger like a 95 or 105 or it was suggested I raise the needle a bit. Would that help. It is getting better,I guess I will change the needle and experiment.Vegas
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Post by vegaslightsss on Sept 13, 2012 14:18:32 GMT -5
So do I need to raise the needle or lower it if it is loading up from 1/4 - 3/4?
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Post by usmcdoc on Sept 13, 2012 16:18:15 GMT -5
Ok Guys, In Either of your opinions,would either a A9 or some other cam benefit me,or a Big Valve Head? I have another customer thats wants BBK but has limited funds,I could give him mine with a quick hone and re ring and then I could go for the 52mm with Big Valve Head. Its running much better than what I started with but it is still "loaded up" and I have to pump the throttle until it "catches" at about maybe 1500 rpm and takes off. So as far as jetting would anyone estimate that I would go larger like a 95 or 105 or it was suggested I raise the needle a bit. Would that help. It is getting better,I guess I will change the needle and experiment.Vegas A9 cam and Big valve head...you would be flowing even more air with the 23mm carb. and really have a hard time getting it to run right. Or if you are talking an A9 cam and 52mm head on a stock engine...the cam will give you more boost...but the 52mm head would not. Most likely it would cause compression to be to low to run. 52mm heads are made for 50-52 bores... Regardless..no matter what you do..that massive 23mm carb is gonna cause you problems..IMO.. |
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Post by felliott on Sept 13, 2012 17:08:16 GMT -5
You lower the needle. Do it one notch at at a tme. In other words do small adjustments.
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Post by vegaslightsss on Sept 13, 2012 21:11:47 GMT -5
Hey usmcdoc, I have a 50mm bore,and I have the 120.00 "High Dollar" free flowing pipe. I feel my motoer is "bottle necked" at the stock valve size. I realize my options are limited. On Scrappy's site for the BBK gy6 50cc upgrades,the first thing is a big valve head that goes from the stock 18mm to 22mm on the intake,and they increase the stock 15mm to 17mm on the exhaust. They claim it is "Hand Ported" with proper 3 angle valve seats. I doubt they are Stainless Steel valves,with 4130 Guides but better than stock. They say 149 for just the head or 179 with a 24mm "Run Tong"Carburetor and a matched larger intake to go with it. That sounds like it is worth the extra 29.00 for a carburetor and larger intake,even if I just off it on Fleabay or Craigslist. Does Anyone have "ratio rocker" arms for these motors or because the cam is right there they just go that route. They also are selling them with the longer 69mm valves my 1P39QMB "6B" Motor came with. I was reading a thread where a guy did the big valve head and the cam and didn't check valve clearance,started it and heard "Bang-Bang".He shut it right down ,and claims he bent nothing and all is fine but has to run his stock cam. So he was told to do the modeling clay in the valve reliefs in the piston and to keep adding base gaskets until he wasn't seeing the valves marking the clay any longer. Another guy suggested he take an angle grinder and flatten out the lobes on the cam...WTF are these folks nuts! Anyway,I will figure it out,going to mess with the needle valve a bit and see what that does for me. I also say they have a 4-valve head for these GY6 50's now but it is being said that the Big Single Valve heads work better,I am sure that these guys don't know anything more than the order of which the parts go onto the motor and things like "deck height" and "compression ratios" are going to be adversely affected by stacking base gaskets up under the cylinder to clear the valves with the Big Head and Cam Combo. Anyways this is a hobby to me,not my sole source of transportation. After just buying the 80.00 card,i sure wish I would have opted for the big valve head. I am hoping all these cool "Top end" parts will be good when my stock crank lets go prematurely. Thanks everyone for your suggestions and comments,I will post my success when I find it.Vegas
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Post by usmcdoc on Sept 13, 2012 21:27:58 GMT -5
Vegas..."Another guy suggested he take an angle grinder and flatten out the lobes on the cam...WTF are these folks nuts!" <---- omg...yer kidding right??.. Charles Darwin would have loved to have that dude as a 'Lab Specimen'.... :lol:
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Post by vegaslightsss on Sept 14, 2012 0:42:45 GMT -5
Really Wish I was kidding there usmc...My Oldest Boy now 20 is in the Navy and assigned to the Nimitz which was recently transferred from Dry Dock in SD to it's and my Son's new home up in Washington State. He is a "Nuke" really Bright Kid,sure making his Dad proud. My Twin Boys Graduate HS this year and one of them is talking about joining already to take advantage of all the perks they have these days for Exceptionally Bright People. Nothing to do with Scooters there sorry,I guess I just thought of my Boys when you were questioning the "Custom Makita Cam Shaft Man...
Anyway,I just got in from 25 miles of blazing around Vegas with a Mag Lite and a long fine standard scredriver doing 1/4 turn adjustments to the mixture screw. I will pull the plug tomorrow and see what the last 10 miles at what I found to be the best performance adjustment looks like. So here is the Deal.It is now idling perfectly. When I take off I have to give it two good "Blips" of the throttle to get it up to about 1500 RPMs with the clutch taking a bite and putting a load on the motor.From that point,it now pulls exceptionally well and runs up to 50mph (gps)and is pulling all the way through the powerband,no flat spots or sluggish behavoir at all,I can actually back off when I get up to 45+ to about 80% throttle and maintain that speed up slight grades and all.Om a slight downhill,it is scary fast for those stock tires and brakes. I really have no interest init going any faster,I would just like to make it more driveable.If you dont clean it out off of the line It will bog out,and I mean out,But open it up and it pulls from 10-50 with Zero hesitation. I jst need to figure out what I need to do with the Main Jet and the Needle. I suppose I can just start experimenting with the needle and buy a bag of jets,I was just hoping I would run accross someone with close to the same setup or experience with the 23mm CVK as I am stuck with it for a while,and really quite happy with the way it is running on the performance side of riding,I pull away from all but the fastest Cars in Traffic and can pretty much stay with most everything. Guess I will try the "belt sander to get a nice even grind on my cam eh??? Vegas
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Post by peteyparado on Sept 14, 2012 1:49:24 GMT -5
i also run a A9 cam in engine setup.. i gain mid range power some top end...as for your 23mm carb it sounds like it drowning in fuel/air..u should drop the needle if possible an or lower main jet/pilot jet... try using a stock air box instead of a uni filter... u can also play with the air fuel mix screw..
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