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Post by rcq92130 on Aug 20, 2014 21:53:49 GMT -5
Scooter said: You said the ScpDg was 170 and this says 163, so that's 7cc's difference.
Scoot - this has gotten a bit confused.
1, MY scooter is 150
2. We were speaking first about Scrappy Dog's Gy6-200. But then Korn said he HAS one of these and it's not at all 200cc but, rather, a 150cc engine bored out to 170cc. But he said he can easily get to 65 MPH, and I would give my left nut for that.
3. I then asked about a 163cc BBK that i could duct tape onto my engine, and if that would give me about the same performance as the ScrpyDg 200.
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Post by scooter on Aug 20, 2014 22:15:34 GMT -5
Scooter said: You said the ScpDg was 170 and this says 163, so that's 7cc's difference. Scoot - this has gotten a bit confused. 1, MY scooter is 150 2. We were speaking first about Scrappy Dog's Gy6-200. But then Korn said he HAS one of these and it's not at all 200cc but, rather, a 150cc engine bored out to 170cc. But he said he can easily get to 65 MPH, and I would give my left nut for that. 3. I then asked about a 163cc BBK that i could duct tape onto my engine, and if that would give me about the same performance as the ScrpyDg 200. I understand. It's hard to tell who is talking to whom and I thought you said Scrappy's told you the engine was a 170cc. I was giving you the possible horsepower difference between the 163cc and the 170cc displacements. You could conceivably get almost half a horsepower more out of the 170cc as opposed to the 163cc, assuming they are similar and that the 170 is actually 170cc. Obviously there's a lot more to it, like tuning, exhaust, timing, cooling, etc. |
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Post by korn858 on Aug 20, 2014 22:41:41 GMT -5
I think for the price, unless you plan on driving it a lot, I would go with the 163cc option. I went with scrappy's only for the oil cooled part, as I'm hoping to get 15,000+ miles on this engine. So far, I have 2,000 and it's broke in, running strong, and I have no reason to think I can't get that type of miles out of it.
But, then again if price is not that big of an issue, the scrappy engine is very plug and play. But note, I also have his performance exhaust, up jetted to 120 and a uni, so that helps my performance too.
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Post by rcq92130 on Aug 20, 2014 23:02:45 GMT -5
Already have a Uni, drilled out my exhaust (and am adding a large bore exhaust header, and a dr p. variator. My stock carb is teensy, teensy with a 115 jet.
The main question i have is if your block accommodates a larger diameter variator than the standard 150cc GY6 block.
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Post by rockynv on Aug 20, 2014 23:32:29 GMT -5
Oh - yeah, mine is a 1576QMJ also. So ............. with 163cc would I get about the performance of the ScpDg "200"? You said the ScpDg was 170 and this says 163, so that's 7cc's difference. We can go WAY out on a limb and say that since the engine lists as 150cc for 8.6 HP @ 7,000 RPM then that could be said to produce 8.6/150=0.0573 horses per cc, so 0.057 * 7cc's = 0.4013 or 4/10's horsepower difference. But that's a real WAG. (Actually, I used that number to calculate the 125 and 50 cc motors and it's not a bad ballpark figure for the stock motors. .0572 hp per cc (or 1HP for every 17.5cc's) is the average of the 3) Besides, if they mean 170 when they say 200, what do they mean when they say 170?  The design of the piston top and head volume below the valves also comes into play so its not all black and white. I have the Piaggio 250 in my bike and with the 4 valve head it is 244.29cc however that same engine with a different head and piston can also be 249.9cc while the stroked Piaggio 300 is really 278cc however it is considered a 300cc class engine and design . Sometimes they also round down too. The Chrysler 440 was for example sometimes really 500 cubic inches which helped in some racing events when it was put against say 460's or 455's from other makers so that restrictions would be assessed against the cars with the apparently larger engines when in fact the Chrysler was larger due to the number game that they played. It's nothing new and has been the case for years. The quality of the components and the care with which it is all matched up and put together is more important then if it is technically more CC. The Scrappy 200 with potentially a better head and more compression may perform better than another engine that is technically closer to being 200cc but made up with less care or lower quality components or potentially mismatched components that although high quality don't work well together. There is also that little bit of wisdom that comes with experience that tells you that if you scale back just a little you will get close to the same performance along with more than double or triple the reliability. Dropping cc with a piston crushing more fully into the head can greatly increase performance with the higher compression ratio. The 244.29 cc engine in my bike comes in at a 11:1 compression ratio so it will be higher performance than the 249.9 cc with a 8:1 or 9:1 compression ratio. Some 200cc Piaggio bikes are really 180cc however at 12:1 compression with a 4 valve head they put out more horsepower and torque than many of the truer 200cc or even some of the 250cc engines out there. |
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Post by korn858 on Aug 20, 2014 23:53:04 GMT -5
Well it sounds like your ready for the bbk. If you were close I would let you take my scoot for the day, so you could feel the performance. However, since that is not possible all I can convey is what I have. I've never ridden a bbk 163cc to give you a comparison. As far as the variator, and what not is concerned its all interchangeable, so no worries there. Just one thing I wish I knew is that the 11 pole stator takes some electrical work. I ended up taking the easy route and just swapping it out with my stock one. Your 24mm carb will fit fine. All I had to do was adjust the needle, and put in a 120 jet.
Off subject, but I plan on trying a 30mm carb when the weather gets bad. Another member has given me a lot of encouragement, and is willing to walk me through it. I think if I do that I'll get close to scrappy's claim of 18hp. I'll post my results when I give it a go.
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Post by rcq92130 on Aug 21, 2014 0:13:52 GMT -5
Yes, I've been following your chat with GEH. I'm 2 months into a scooter, so on a very, very steep learning curve, starting from zilch.
Yes, I'm a ways south of you in san diego, but your offer is really generous and nice. Thanks!
Even without that, though, your 65mph is pretty compelling. I have no problem at all with the low speed performance I'm getting, but my top end ---- 50 to 55, normally ---- just leave me unhappy. But getting a BBK isn't clear .... I could sell my stock GY6 - only 700 miles; very well broken in .... and use that for part of a scrpydg 200. Or go with a BBK. Or just live with things as they are. Had no idea when I got this thing the can of worms i was opening!
Wouldn't it be nice if there were some really ... true ... comparisons of these engines!
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Post by geh3333 on Aug 21, 2014 0:53:35 GMT -5
I'm not sure but I think the only difference between the regular gy6 engine case and the B case is the stud spacing for the cylinder and head . They're spaced further apart on the B case so that there is more metal between the cylinder hole and the cylinder studs " makes it a little more solid when bored out for 200cc + " . Other than that I think they are the same . Hopefully someone will correct me if I'm wrong . So Unless your gonna bore to an actual 200cc or more the B case really won't make a difference " that's just in the case " . I think scrappy adds the whole " the 150cc is built from a 125cc engine case " just as a selling point because though it's true there is really no performance difference . I'd like someone to design a new case that holds a little more oil . I really don't like the fact that these engines are air cooled and only hold less then a quart of oil . That's why at some point I'm gonna install an oil tank . I wanted to start the project already but it's been put on the back burner for now . The gy6 200 does sound like a good deal .
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Post by geh3333 on Aug 21, 2014 1:08:14 GMT -5
I will also add that korns gy6 200 still has plenty of potential , from the input I've got from him he isn't pushing it to hard and has some room for more gains . Not everyone wants to push these engines to there max and I don't recomend always running the you know what out of them but it does sound as if the gy6 200 engine has plenty power for just about any driving . I run mine pretty hard and have over 12,000 miles " 12,000 miles over almost 3 summers" just keep an eye on them and the fluids changed and they should last . Also it's wise to know the tempof the engine " even if it's just the oil temp " so I do recomend a temp gauge , it could save you some big problems .
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Post by scooter on Aug 21, 2014 16:03:52 GMT -5
You said the ScpDg was 170 and this says 163, so that's 7cc's difference. We can go WAY out on a limb and say that since the engine lists as 150cc for 8.6 HP @ 7,000 RPM then that could be said to produce 8.6/150=0.0573 horses per cc, so 0.057 * 7cc's = 0.4013 or 4/10's horsepower difference. But that's a real WAG. (Actually, I used that number to calculate the 125 and 50 cc motors and it's not a bad ballpark figure for the stock motors. .0572 hp per cc (or 1HP for every 17.5cc's) is the average of the 3) Besides, if they mean 170 when they say 200, what do they mean when they say 170? The design of the piston top and head volume below the valves also comes into play so its not all black and white. Thanks, I understand. This was a comparison between 3 stock gy6 motors listed on wikipedia and is a good starting point for people like myself who want to get a rough idea of how cc's relate to horsepower on the standard gy6 engines. I was surprised to find they were all so close on that ratio. Performance mods will increase the power to displacement ratio for sure. Engine Displacement Power Bore x Stroke Compression Ratio 139QMB 49.5 cc 2.  hp at 7,500 rpm 39 mm × 41.4 mm (1.54 in × 1.63 in) 10.5:1 152QMI 124.65 cc 6.8 hp at 7,000 rpm 52.4 mm × 57.8 mm (2.06 in × 2.28 in) 9.2:1 157QMJ 149.6 cc 8.6 hp at 7,000 rpm 57.4 mm × 57.8 mm (2.26 in × 2.28 in) 8.8:1 |
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Post by rcq92130 on Aug 21, 2014 16:18:38 GMT -5
Now THAT is interesting, Scoot! So the QMJ - which I have - is a very low compression version.
Hmmmmmmmmmmm.
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Post by geh3333 on Aug 21, 2014 19:58:24 GMT -5
Some claim they can get 65mph " straight run" from a 57mm bore stock 150cc . I do believe it's possible because cc's is one thing and HP is another . You can run the horse power up on a 150cc high enough to get those results . So when some say " your at such and such cc's , there is no way to run that fast or good " this statement holds little to no water when it comes to horse power . It may make it easier with a bigger bore but a bigger bore is not always necessary . And yes compression is one way to up the horse power and compression is one not mentioned much on here " other then lowering it " . I think many here would rather not up the compression thinking they will destroy there engine " which can happen if not done right " . Just like many other upgrades .
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Post by rockynv on Aug 22, 2014 12:19:07 GMT -5
The other measure of performance is lbs per hp. So say you get a 12:1 compression 250 that generates 1 hp for every 10cc and put it in a standard 250cc frame and compare it to my Sport City at 11:1 which puts out about 23 hp. Most would say the 25 hp bike would be faster however the 25 hp bike weighs 425 lbs while the Sport City is only 326 lbs. The 23 hp bike is pushing roughly 14.2 lbs with 1 hp while the 25 hp bike is pushing 17 lbs with 1 hp. With equal riders the 23 hp bike will generally be faster.
I wear a full face helmet with no sun bill which will also cause less drag and increase top end on the highway compared to someone on an equal bike with an open face or half helmet which could make a 5 to 10 mpg difference. No tall windshield either but a more compact sport fairing and another potential 5 to 10 mph speed difference. Now zip up the jacket and cinch the sleeves so they don't flap in the wind again you should see some increase in top speed. It all adds up.
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Post by geh3333 on Aug 22, 2014 12:47:33 GMT -5
Very true rocky , I also wear a full face helmet . I'm not sure why some do not wear helmets . I've Been smacked in the face before by rocks and bugs and both suck , so unless u like eating bugs and being shot in the face then a full face helmet is the way to go , and yes it's much better for aerodynamics. When you have such a small low powered engine the slightest difference in weight , wind resistance, incline and decline will have an effect on the performance .
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Post by rockynv on Aug 22, 2014 22:19:32 GMT -5
In Florida we have swarms of what they call love bugs and when they mate they swarm in mass like a dark cloud of locusts. If you get caught in a swarm they impact and hurt even though your gloves and then they start soaking into your clothing, etc. Open face and its not going to be pretty. They are attracted to anything warm and will completely envelop even a medium sized truck when its stopped so that all you see is a squirming mound of bugs in the outline of a truck.
If you get caught out on a bike by them you'll want to strip naked and toss everything your wearing in the trash. Get them all mashed up in your hair, face, eyes, etc is going to make for a really bad ride.
Here are some (actually pretty mild) examples:
Some freak out:
Put on your rain suite:
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hp at 7,500 rpm