usfmarine
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SJA, Scooter Rebellion
Posts: 74
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Post by usfmarine on Nov 16, 2009 17:45:37 GMT -5
Who knows, I have yet to see any standard on what defines an A9 vs A12 etc.
Am I supposed to recheck my valve clearances after re-torquing the big 12mm nuts holding the cylinder together?
My valves were perfect at .004 after putting it all back together. Then I went for a 10 minute drive, came home and retorqued the head nuts, should I have rechecked my valves?
The lobes on my A9 were about 1mm higher than on stock camshaft. Doesn't seem like a big difference. Another waste of money.
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usfmarine
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SJA, Scooter Rebellion
Posts: 74
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Post by usfmarine on Nov 16, 2009 20:06:02 GMT -5
The intake port on my head was about 25.5mm, my exhaust is now ~26mm. I don't think what I did was very dramatic. So Kliff, when do you tell me how to use each one of them there tools? I figured a cam upgrade would have done something noticeable. That's what I had been told since day one. Since I used your better springs, I should have gone with a more aggressive A12 cam. I'm kind of scooter'd out right now. The springs, the cam, the prodigy variator, many different sliders/rollers and I don't think I have any performance gains to show for it. I think I should have stopped after the exhaust, uni, and flatslide carb upgrade. I'll never learn.
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usfmarine
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SJA, Scooter Rebellion
Posts: 74
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Post by usfmarine on Nov 16, 2009 20:07:38 GMT -5
Separate question, if I was one tooth off with the timing would I necessarily know it?
Can a slight mis-timing create stagnant performance, or would be belching and barking at me?
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Post by kliff on Nov 17, 2009 6:38:22 GMT -5
Separate question, if I was one tooth off with the timing would I necessarily know it? Can a slight mis-timing create stagnant performance, or would be belching and barking at me? Not necessarily. It would be mildly lethargic, if retarded one tooth, to the point it may never reach it's torque curve, so top end would suffer too. If it were advance a full tooth, that would be about2 - 3 times what would be useful, as that cam is already advanced on the intake lobe. Might wanna re-visit your clutch too, these cams work best with some rpms... 1500 rpm clutch pills. stock variator drop weights by about .5-1 ounce, 115mm var, drop 1- 1.5 ounce, and start experimenting all over again. Also, and I really hate to tell you this, the "A" series cams prefer a shrt pipe. Yours is the first I've seen that length combined with an "A" cam....could lead to some rejetting also. On a stocker, it is a plug and play improvement provider. But on an enine that already has carb, jets, pipe..... then you gotta start tuning to get more. The more you have, the more you want, the more you want, the harder it is to find. But you could have as much as 5-10% lurcking in there, just gotta get it out. and once you have, the nest 3-5%, will be even harder!
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Post by kliff on Nov 17, 2009 6:57:19 GMT -5
The intake port on my head was about 25.5mm, my exhaust is now ~26mm. I don't think what I did was very dramatic. So Kliff, when do you tell me how to use each one of them there tools? I figured a cam upgrade would have done something noticeable. That's what I had been told since day one. Since I used your better springs, I should have gone with a more aggressive A12 cam. I'm kind of scooter'd out right now. The springs, the cam, the prodigy variator, many different sliders/rollers and I don't think I have any performance gains to show for it. I think I should have stopped after the exhaust, uni, and flatslide carb upgrade. I'll never learn. Nah, don't give up....ole numbski went through a lot worse than that, including illness, and my sometimes over bearing attitude, thrown in for good measure, but he didn't quit, you won't either. You have all the good chit now( 'cept for the porting....hey I remember MY first porting effort 35 years ago....ATROCIOUS....bad, terrible...all eff'ed up!) And I ain't picking on you about the porting, it's a skill, a steady hand, and an ability to "read" what you have now, vs what you can change it too. A flow bench works wonders here....unfortunately, I sold mine 15 years back. But these are individual heads, cast by who knows how many different companies, so I treat each one as an individual, and just sorta "wing it." Hardly the best you could get, but they work. My days of flowing eirght intakes and eight exhaust ports, to withinin 5cfm across all eight are over....it was fun, but stressful at the same time. Now with CNC machine porting, very few hand porters are left, and in about 50 years, I'd say we'll be gone. I really don'r know how to tell you to start, other than hit ebay, and buy 2,3, or 4 used heads, clean 'em, and start porting. take some notes on each head, then start installing them on a scoot, and run each for a week or so, noting any and all performab=nce quieks or plusses. Pick your best head, and start refining. .. No trying to be evasive, but it is a hands on skill, I can't teach, nor show you why I do what where.... unless you were here to see a specific area, and how on shape, slope or incline, maybe 1/4 to 1/2" square will effect 50% of the entire port flow...
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usfmarine
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SJA, Scooter Rebellion
Posts: 74
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Post by usfmarine on Nov 17, 2009 10:02:55 GMT -5
Thanks Kliff, you or my cup of coffee just motivated me
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Post by performancescoot on Nov 17, 2009 11:12:32 GMT -5
usfmarine
Here is my 2 cents. You need to port out the head completely. Remove the valves, and grind grind grind.. it easily takes me 3 hours to get it to where I want it and I've done many.
Something else that isn't mentioned here, but if you mill the head 30thou, it bumps the compression a point. A Scoot with a properly ported and milled head with only an upgraded exhaust will out run any stock engine with all the "bolt on's" including a cam. And it's a very noticable difference.
CDI's, cams, bigger carbs, exhuast are easy but do very little to a stock engine. Plus there is the feedback from those who bought it convicing themselves and others it made a difference instead of tossing money away.
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usfmarine
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SJA, Scooter Rebellion
Posts: 74
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Post by usfmarine on Nov 17, 2009 13:10:53 GMT -5
Thanks for the advice performancescoot. I'm sure there is hidden power in the head. You guys have me convinced of that. I can buy those tips that Kliff linked me to, but I would just be guessing as far as the shape of the intake and exhaust. I am completely scared to touch the combustion chamber. And to be honest, the process of tearing down the scooter just to remove the head is a 2+ hour ordeal. The good part is, it isn't a mystery anymore, I don't have to worry about head gaskets and all of those other questions I had before. I think over Christmas liberty I might tear it all down and do it more deliberately than the quick valve spring mod I did with Doug the other day. By then I should have a real dremel with all of the tips. It may be worth my time just to send Kliff my head though. $125 seems pretty good for a port/polished head. Kliff has to promise me a performance boost though Kliff's advice about cleaning the mating surfaces between the cylinder and the head I think paid off big time. Doug and I both used some sandpaper to get all the gunk off and get it nice and smooth. Neither of us have oil leaks from the head gasket which we are both pumped about. Those tips Kliff posted appear to be quite able to dig into the aluminum. They have me scared. The tips I was using I think is called a grinding stone or something. It was shaped like the polishing tips Kliff linked us to. Are each one of those tips intended to be used in a specific way? If it is obvious to you, I apologize, b/c it is not obvious to me. I'm glad I didn't get the abuse Numbski got I try to do everything methodically and with plenty of advice from here.
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Post by Rebel on Nov 17, 2009 13:26:57 GMT -5
Numbski may have had a little abuse, but he proved himself able to take it like a man and keep coming at the problem. The ability to do that, gives him a position of respect.
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Post by kliff on Nov 17, 2009 17:30:07 GMT -5
Thanks for the advice performancescoot. I'm sure there is hidden power in the head. You guys have me convinced of that. I can buy those tips that Kliff linked me to, but I would just be guessing as far as the shape of the intake and exhaust. I am completely scared to touch the combustion chamber. And to be honest, the process of tearing down the scooter just to remove the head is a 2+ hour ordeal. The good part is, it isn't a mystery anymore, I don't have to worry about head gaskets and all of those other questions I had before. I think over Christmas liberty I might tear it all down and do it more deliberately than the quick valve spring mod I did with Doug the other day. By then I should have a real dremel with all of the tips. It may be worth my time just to send Kliff my head though. $125 seems pretty good for a port/polished head. Kliff has to promise me a performance boost though Kliff's advice about cleaning the mating surfaces between the cylinder and the head I think paid off big time. Doug and I both used some sandpaper to get all the gunk off and get it nice and smooth. Neither of us have oil leaks from the head gasket which we are both pumped about. Those tips Kliff posted appear to be quite able to dig into the aluminum. They have me scared. The tips I was using I think is called a grinding stone or something. It was shaped like the polishing tips Kliff linked us to. Are each one of those tips intended to be used in a specific way? If it is obvious to you, I apologize, b/c it is not obvious to me. I'm glad I didn't get the abuse Numbski got I try to do everything methodically and with plenty of advice from here. Like performance scoot says, it takes almost, and sometimes more, than 3 hours, just to get to the polishing part.....then you're on the down hill trek. From the pics I've seen, Performancescoot does some jam up porting too. Don't over look this man's skills. Just from looking at those pics, I'll tell ya, he's been around the block a time or too. ;D The more expertise we pile on, and welcome here, the better off we'll be in the future. #1, "stones" work on cast iron heads, they "load up" with molten aluminum, making them virtually useless. When and where you can use burs designated for aluminum. Larger just can be taken without fouling the bit. finer burs are used at slower speeds, when less cutting is desired, and you are nearing the polishing stages. If you had the capability of using 1/4", I'd have also suggested some spiral taperred sanding rolls, another excellent tool. But I sorta narrowed the feild, figurring you'd only be buying one tool. I have 4 that I use on every job, 3 pneumatics, one electric, 2 for 1/8" shanks, 2 for 1/4" shanks. But even an intricate porting job, with a mirror polish can be done with one dremmel, a selection of bits, and time....don't rush. The rubber bits are for polishing, and 100% expendible, but a little smear of white lithium grease every few minutes will make the rubber last longer, and allow some higher speeds, without melting, or shreading. But pease, find an old head, 50cc or 150 to practise one....even an old VW head... bigger ports, easier toi figure out how your bits work for you.... 50cc with it's smaller ports, will teach you finess, and feel.
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Post by Rebel on Nov 17, 2009 18:23:11 GMT -5
with a burr, couldn't he use a 1/4 inch drill? One of those is pretty cheap at H.F.
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Post by kliff on Nov 17, 2009 18:53:12 GMT -5
Yes, but he better have SuperMan's fore arms and wrists. That 1'4" drill is gonna get heavy, and hard to control. When fatigue starts creeping in, that's when a guoge occurs, a nicked valve seat, and sometime even a bent shaft on the bur.
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Post by Rebel on Nov 17, 2009 19:50:59 GMT -5
Hey, he is a Mah Reene, he can do anything, leap tall buildings and all that stuff.
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usfmarine
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SJA, Scooter Rebellion
Posts: 74
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Post by usfmarine on Nov 17, 2009 20:15:03 GMT -5
Thanks Kliff. Do you have any before/after shots of a port/polished head? That last photo's exhaust port looks REALLY clean and perfect!
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shiftless
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SFC Indy, IN, 2nd DIV, So. Symperthisers
Twist n Go !
Posts: 177
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Post by shiftless on Nov 18, 2009 0:59:23 GMT -5
I took a pic or 2 of the head Kliff did for my dragscoot before I installed it It was a filthy stock qmj head when I sent it Intake (matched to my mrp manifold) Exhaust Valves top Bottom
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