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Post by humanshield on May 3, 2015 14:11:13 GMT -5
Has anyone installed the 50mm BBK along with an A9 cam and a Big Valve Head on their originally 49cc scoot?
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Post by Silar on May 3, 2015 14:48:32 GMT -5
I don't have the big valve head, but everything else. What's going on?
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gscootnsouth
Scoot Member
Recovering from a very bad accident :(
Posts: 63
Location: South Carolina
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Post by gscootnsouth on May 4, 2015 1:30:47 GMT -5
yep right here bud. 50mmm piston (they say its 100cc but when you do the math they advertise it rounded up too much. its actually in the low to mid 80's as far as cc's are concerned. I went above and beyond and also installed a hoca 44mm stroker crank and that adds to displacement getting me to the upper 80's near 90cc.
But I installed more than the bbk piston, cylinder, head, and cam. I did exhaust, intake, carb, and more...its in my signature what i upgraded. But I already had the longer valves on my stock 4 stroke TaoTao. If your engine code has a "P" (example..there is a 139QMB AND a 1P39QMB). All the 1P39QMB's I've seen have the 69mm valves and the 139QMB's have the 64mm valves. Brent has a very excellent detailed video breaking down the differences between them.
...and the rumors of BBK's wearing out real fast... lol hogwash. As long as YOU KNOW what YOU are doing, and are mechanically inclined....in other words, installing your BBK kit properly and checking squish clearance on your piston to head...and maintenance your bike regularly and give it GOOD LUBRICANTS...not cheap walmart oil and lubricants...It WILL last.
As of tonight...I have 5,000 kilometers (which is 3,100 miles I do believe) and I'm still hitting 50mph+....lol hell, I got pulled over tonight for just that...going over 50mph on a bike thats only supposed to do 30mph. not all cops are equal. I was able to leave without a ticket or incident. But I got a reasonable cop and he told me I should tag it for motorcycle class.
So now that you got a match from some of us that have what you are asking...what's your question(s) regarding the 50mm BBK kit?
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Post by humanshield on May 4, 2015 12:58:30 GMT -5
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Post by humanshield on May 4, 2015 13:02:29 GMT -5
yep right here bud. 50mmm piston (they say its 100cc but when you do the math they advertise it rounded up too much. its actually in the low to mid 80's as far as cc's are concerned. I went above and beyond and also installed a hoca 44mm stroker crank and that adds to displacement getting me to the upper 80's near 90cc. But I installed more than the bbk piston, cylinder, head, and cam. I did exhaust, intake, carb, and more...its in my signature what i upgraded. But I already had the longer valves on my stock 4 stroke TaoTao. If your engine code has a "P" (example..there is a 139QMB AND a 1P39QMB). All the 1P39QMB's I've seen have the 69mm valves and the 139QMB's have the 64mm valves. Brent has a very excellent detailed video breaking down the differences between them. ...and the rumors of BBK's wearing out real fast... lol hogwash. As long as YOU KNOW what YOU are doing, and are mechanically inclined....in other words, installing your BBK kit properly and checking squish clearance on your piston to head...and maintenance your bike regularly and give it GOOD LUBRICANTS...not cheap walmart oil and lubricants...It WILL last. As of tonight...I have 5,000 kilometers (which is 3,100 miles I do believe) and I'm still hitting 50mph+....lol hell, I got pulled over tonight for just that...going over 50mph on a bike thats only supposed to do 30mph. not all cops are equal. I was able to leave without a ticket or incident. But I got a reasonable cop and he told me I should tag it for motorcycle class. So now that you got a match from some of us that have what you are asking...what's your question(s) regarding the 50mm BBK kit? I see where you installed a head with 69mm valve length, but I was referring to heads with larger diameter (big valve) heads. Did the exhaust do much for the scooter? I'm not worried about longevity. I have several spare 49cc motors and I also build car engines so these tiny QMB139's I can practically build them in my lap.
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gscootnsouth
Scoot Member
Recovering from a very bad accident :(
Posts: 63
Location: South Carolina
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Post by gscootnsouth on May 5, 2015 1:35:44 GMT -5
lol thats so true...but yes the exhaust made me safer by being louder and yes, there is a performance gain. but remember to upgrade intake flow to equalize all the airflow in the engine. As far as the big valve head...I know what you are talking about now, my bad lol.. scrappy has some 4 valve heads for 4 strokes I was looking at I work on cars too, we have a very nice shop and tools for lots of different jobs....I like being a grease monkey ha ha ...oh and yeah don't forget...after all that upgrading...you will probably need to upjet. Stock scoots come lean already to make emissions lower.
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Post by peteyparado on May 5, 2015 2:44:33 GMT -5
I'm running a 50mm bbk with a HOCA BVH, an recently changed that stock Chinese 50mm flat top piston to a HOCA dome type piston. Without no valve to piston clearance issues..
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gscootnsouth
Scoot Member
Recovering from a very bad accident :(
Posts: 63
Location: South Carolina
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Post by gscootnsouth on May 5, 2015 14:22:26 GMT -5
That's awesome ... im wanting to do something similar...i want to go over scrappy's 4 valve head. i still have the Chinese 50mm piston, and has 3000 miles on it now. but i bet a really high quality dome piston and 4 valve head would rock.. lol I'm flying 55mph gps verified...i can only imagine going to a really nice piston, 4v head, and porting the engine might just get me to the 60s
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Post by humanshield on May 5, 2015 15:01:50 GMT -5
Great info guys. Thanks Gotta tell ya, I added an A9 cam yeterday and quite honestly, I'm impressed. But noone has done the BVH + A9 Cam + 50mm BBK ?? Maybe I'll be the first? (unless I misunderstood....which is possible)
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Post by TurboTyler on May 6, 2015 1:02:07 GMT -5
I have all three but haven't had much luck with the A9 cam. I even tried a cam that was between the A0 and stock. After many re tunes, valve adjustments etc. I still can't get much if any power out of an A9 cam over the stock throttle response and smoother operation. Also it causes a short dead stop in the throttle that I can't tune out of the A9 ; what gives sometimes.
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Post by humanshield on May 6, 2015 18:04:25 GMT -5
Tyler, the A9 cam made an absolutely astonishing improvement over the stock cam on mine. I'm wondering if you got the timing right or if you got a bad cam.
Something isn't right.
I will not lie....the A9 is probably as good or better than any thing I have done so far....including the BBK
My scoot starts better now because the A9 reduced the compression duration. (The higher lift and longer duration shortened the time the cylinder is at maximum compression) It is smoother, and MUCH more powerful across there entire range from low to high. I'm at a loss how you could not have similar results.
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Post by humanshield on May 6, 2015 18:05:53 GMT -5
Tyler, I haven't installed my Big Valve Head yet...that's why I installed things one step at a time.
There is always that possibility that modifications won't like each other. I wonder if there's some conflict with the A9 cam and the Big Valve Head.
Did you do the modifications all at once? Maybe you have a problem with the head?
Can you tell me the order that installed your components, first to last and whether you did them in stages or all at once?
Did you do any clean up work on your BVH? Is it a Hoca or standard BVH ?
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Post by TurboTyler on May 6, 2015 22:14:44 GMT -5
I actually figured it our earlier. I feel like a terrible mechanic sometimes but I had the timing marks mixed up. My GY6 requires it to be at the F and the 49cc requires it to be on the T. I had the timing wrong for some time now lol but oh well. I am now maxing out the speedometer again with flawless starts. I installed the A9 well after the bbk and head. The cams aren't worth but $5 imo. I am going as fast now as I was b4. 64mm valve length not a 4v either.
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Post by humanshield on May 6, 2015 23:30:16 GMT -5
I actually figured it our earlier. I feel like a terrible mechanic sometimes but I had the timing marks mixed up. My GY6 requires it to be at the F and the 49cc requires it to be on the T. I had the timing wrong for some time now lol but oh well. I am now maxing out the speedometer again with flawless starts. I installed the A9 well after the bbk and head. The cams aren't worth but $5 imo. I am going as fast now as I was b4. 64mm valve length not a 4v either. Hmmmm.....ok After I install my BVH I will let you know what I get. I will say this....there are fake parts on the market. It is not so simple fo the average person to tell the difference between an A9 cam and a stock cam. A dirty seller could sell you a stock cam and call it an A9 and most people would never know the difference. I have opened up a similar can o worms with fake 20mm carburetors. You would need to measure the lift and duration of the cam you have that supposed to be an A9 to tell if its real. Mine made an enormous difference. Hands down... there's absolutely no way to mistake the difference. Sorry your experience wasn't similar.
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Post by TurboTyler on May 7, 2015 0:21:57 GMT -5
Naw, mine is a real A9 from a US distributor. I measured it and another I have compared to stock. The cheaper A9 was in between the stock and real A9 but heavier than both.
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