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Post by Deleted on Nov 4, 2016 13:33:57 GMT -5
Can't remember if this has been mentioned already but maybe part of the varying results could also be from the condition of the scooters prior to adding the BBK. What I mean is....take a scoot with 1,000 miles on it, do a BBK...then take a scoot with 15,000 miles on it and do the same. My guess would be that, everything else being equal, the high mileage scoot will be more prone to failure as you have just increased stress on very worn  con rod bearings and crank bearings, etc. Also, for what it is worth, my manual, such as it is, calls for compression to be 210 psi. Bill |
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Post by humanshield on Nov 4, 2016 14:13:32 GMT -5
The reason your launches are slow is due to low compression. My scoot will walk away from a 47mm BBK all other things equal. If you can get the compression up to about 160 to 180 with that head, and get the cam you will be blown away at the difference. Your scooter will nearly be as fast as a 150cc scooter up to about 55. It would be unlikely that you would come across a 2T scoot that could beat you. Only the really highly modified, big money 2T's would have a chance against you. Look at the video I posted of my race on my fast 150cc scoot vs the guy on the modified 4T with 50mm BBK and cam (plus a few other mods such as straight through custom pipe and 24mm carb). It was close and he did not have the 23mm big valve head. Hate to burst your bubble there, but a mild 2T (Athena basic and Leo Vince pipe) is faster than a 150. With the right gearing it will even have more top speed. A lot of 150's are slugs. The ZNEN ones have bigger heads and will surprise you compared to normal 150's. Try your luck with a TGB 4 valve head 150.....you'll be seein tail light all day long and twice on Sunday  Haha...yeah, I keep hearing that and every time it comes down to let's go...it doesn't work out that way There are not that many who put much into their 2T's. So ya, it'd be "rare" to come across one as I said. BTW, I haven't been beat by another 150..... yet.  But a 4 valve TGB would probably do it. That said, I just had to replace the head on my 150 and it is definitely slower right now. I'm getting another head and flycutting it to raise the compression back up. I'm down probably 15% on HP :-( |
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Post by humanshield on Nov 4, 2016 14:16:46 GMT -5
Can't remember if this has been mentioned already but maybe part of the varying results could also be from the condition of the scooters prior to adding the BBK. What I mean is....take a scoot with 1,000 miles on it, do a BBK...then take a scoot with 15,000 miles on it and do the same. My guess would be that, everything else being equal, the high mileage scoot will be more prone to failure as you have just increased stress on very worn con rod bearings and crank bearings, etc. Also, for what it is worth, my manual, such as it is, calls for compression to be 210 psi. Bill Interesting post Bill. Note that somewhere here I posted that I took a really abused motor out of a practically abandoned POS scooter and used it for the 50mm build I have now. So I've put about 6,000 miles on it since I got it....4,000 of those on the 50mm BBK It's really hard to judge. I just got lucky but I also checked for crank free play and rod wear before I used it. All was good. Oil pressure might be some really critical. |
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Post by spaz12 on Nov 4, 2016 14:29:44 GMT -5
Hate to burst your bubble there, but a mild 2T (Athena basic and Leo Vince pipe) is faster than a 150. With the right gearing it will even have more top speed. A lot of 150's are slugs. The ZNEN ones have bigger heads and will surprise you compared to normal 150's. Try your luck with a TGB 4 valve head 150.....you'll be seein tail light all day long and twice on Sunday Haha...yeah, I keep hearing that and every time it comes down to let's go...it doesn't work out that way There are not that many who put much into their 2T's. So ya, it'd be "rare" to come across one as I said. BTW, I haven't been beat by another 150..... yet. But a 4 valve TGB would probably do it. That said, I just had to replace the head on my 150 and it is definitely slower right now. I'm getting another head and flycutting it to raise the compression back up. I'm down probably 15% on HP :-( A "180" can't beat my 08. |
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Post by humanshield on Nov 4, 2016 20:55:24 GMT -5
First 40 feet you're talking? Because a 180 should be able to hit 80mph
Do you have any idea the HP your 08 makes? Ever been on a dyno?
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Post by spaz12 on Nov 4, 2016 20:59:54 GMT -5
lol a 180 does 80? It takes a 250 or larger 4 puke scoot to go that fast. Check out the speed list.
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Post by humanshield on Nov 4, 2016 21:05:50 GMT -5
lol a 180 does 80? It takes a 250 or larger 4 puke scoot to go that fast. Check out the speed list. check your numbers...a Ninja 250 can hit 100 - 105 (actual, not indicated) routinely Yes, a properly tuned 180 with a good breathing head can hit 80 mph. What's the biggest displacement bike or scooter you own? |
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Post by spaz12 on Nov 4, 2016 21:12:16 GMT -5
A Ninja is not a scooter.
And if you want to compare motorcycles, take an Aprilia RS (not sr) 50, make it an 80 and it will wipe the floor with that Ninja 250.
We're getting off the subject. You said that it takes a highly tuned 2 stroke to beat a 100cc 4 stroke. It does not. Like I said, a mild 70 will easily beat them. That's a fact and not an opinion.
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Post by humanshield on Nov 4, 2016 21:26:33 GMT -5
AH...you did say "scoot"...I took the 4 puke to mean any 250cc bike. I didn't exactly say that about the 100cc thing. What I said was, it is rare that someone riding a fast 150cc 4T scoot will come across someone on a 2T scoot that is as fast or faster. But last time I was on a race track, it wasn't on a scooter. It was on a 175mph sportbike. (4 Puke) haha Almost as fast as your 08 |
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Post by 90GTVert on Nov 6, 2016 7:53:32 GMT -5
Sure, the 4Ts can be fun, but I just don't think they should be compared to the 2Ts when we're talking about the scoots we typically see. A real engineered 4T that wasn't made with practicality in mind may be compared, but who is going all out designing a 49cc 4T to make max power when they're in a market often limited to 25-40MPH or to some low HP number to be legal? In real life with our little scoots, with rider weights equal, both in a reasonable state of tune, and so on... 2T wins. That's not me being biased, it's a fact of life at this point.
Scoots vs bikes is so unfair. I've been looking at 250-650cc scooters for some time now and the difference in output is depressing... but if you wanna ride a lounge chair with real storage space around, you have to make some sacrifices. I don't own any big bikes, but I've had a little seat time on a 600cc sport bike. They're fun and I love to look at them and hear them as they're essentially street legal racing machines in the super sport class, but I'd rather ride the scooter for 10 hours straight.
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Post by Deleted on Nov 6, 2016 20:56:31 GMT -5
Put about 75 miles on the scoot today, it does not like to start without a hint of throttle that should go away when I do the final tweak on the carburetor, had the same issue with the other carburetor when it was new, also an intermittent idle issue that is most likely related to the carb as well.
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Post by spaz12 on Nov 6, 2016 21:20:35 GMT -5
lol a 180 does 80? It takes a 250 or larger 4 puke scoot to go that fast. Check out the speed list. check your numbers...a Ninja 250 can hit 100 - 105 (actual, not indicated) routinely Yes, a properly tuned 180 with a good breathing head can hit 80 mph. What's the biggest displacement bike or scooter you own? Just noticed that you edited your reply. I have an 07 Aprilia RSV 1000 R and a 2000 Yamaha WR400F. Haven't ridden the Aprilia yet because of my foot, but have racked up a gazillion miles on the wr. I've had a gsxr as well, but that was many moons ago when they first came out. I have no idea how much hp my 08 Zuma make. 10 - 12? I honestly don't know, but it's quick. Brent of course is so much better with words, but like he said, the little scooters I think are better with a 2 stroke. Liter bikes are sweet asf and I have no problem with them being 4 strokes because they make a lot of power, and that's what I love; fast toys. Just a personal preference  |
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Post by Deleted on Nov 8, 2016 20:31:28 GMT -5
Got the A9 cam installed this morning, took her for a spin and wasn't all that impressed. A bit more top power but less low end. So just for giggles I pulled the carb and swapped it for the old one, same model, just had the float level set properly, reset the idle and mixture and took it back out. New engine... 0-30 is still around 10.5, but now it keeps pulling all the way to 40 and beyond.
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Post by tortoise2 on Dec 13, 2016 11:02:24 GMT -5
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Post by humanshield on Dec 13, 2016 19:00:28 GMT -5
Got the A9 cam installed this morning, took her for a spin and wasn't all that impressed. A bit more top power but less low end. So just for giggles I pulled the carb and swapped it for the old one, same model, just had the float level set properly, reset the idle and mixture and took it back out. New engine... 0-30 is still around 10.5, but now it keeps pulling all the way to 40 and beyond. So the cam worked much better with old carburetor (or am I misunderstanding)? |
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con rod bearings and crank bearings, etc.
