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Post by 4950cycle on Nov 2, 2012 8:39:00 GMT -5
Hi, I really liked the way Banditms explained the only two 250cc engines that could be on "any" Chinese 250 scooter. But in my incessant seaching of scooter related technical stuff (especially 250) I have yet to uncover any proof that the 300 (275cc) Linhia has any bigger head than the 250 (257cc) Linhia that all of us JCL and Roketa 250 riders have (if equipt with Linhia instead of CF Moto engine). Not to say that there is not a bigger head on the 300. I'm just saying I have not seen any proof yet. One has to wonder at this point weather the scooter sellers (the ones that actually know anything) don't want us to know that the only difference between a 250-260 (257cc) Linhia and a 300 (275cc) Linhia is only the bore size  If so, All one would have to do is put a 275cc cylinder kit (I've actually seen these) on a Linhia 250 (257cc) to make theirs a 300 ;D But let me say this, I actually hope that they do make a bigger head for the 300. Because a bigger better flowing head makes all the difference in the world to engine performance. Slight bore size increases rarely if ever increase performance that noticably IMHO. I hope someone out there has some pics. PLEASE prove me wrong guys and gals  What I am saying at this point is that a 257cc and a 275cc Linhia share the exact same head. And at that rate there would be very liitle difference in performance with only an 18cc cc difference with no other changes. But don't get me wrong I'll take that 1 hp ;D |
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Post by EPAhater on Nov 2, 2012 20:49:31 GMT -5
There is no difference all parts fit and bore is the only difference and there are kits that push it to 290cc with a 75mm piston.
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Post by 4950cycle on Nov 2, 2012 21:43:25 GMT -5
Thanks EPA, I thought so. That might be a good power bump !
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Post by prodigit on Nov 3, 2012 0:14:05 GMT -5
Same engine, bigger bore will get your engine wasted faster.
Speed difference is negligable, MPG difference is a few MPG's to a few tens of MPG's.
IMHO a 250 is the perfect balance between high MPG and power.
A 300 is a serious decrease in MPG, while only a marginal increase in power; and since the engine is largely the same, parts will wear faster on a 300, than on a 250.
If they would only equip a larger engine, with matching gears, having a 6th gear for instance, that would allow the engine to run eg: 4k RPM while driving 60MPH, is much better for MPG and lowers engine wear, than having only 4 or 5 gears with (or a CVT limited to) the engine running at 6k RPM @60mph.
Larger gears does not always have to mean a faster bike. Yes, top speed could increase, but it could also mean better fuel mileage.
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Post by macktheknife on Nov 3, 2012 7:08:14 GMT -5
Same engine, bigger bore will get your engine wasted faster. Speed difference is negligable, MPG difference is a few MPG's to a few tens of MPG's. IMHO a 250 is the perfect balance between high MPG and power. A 300 is a serious decrease in MPG, while only a marginal increase in power; and since the engine is largely the same, parts will wear faster on a 300, than on a 250. If they would only equip a larger engine, with matching gears, having a 6th gear for instance, that would allow the engine to run eg: 4k RPM while driving 60MPH, is much better for MPG and lowers engine wear, than having only 4 or 5 gears with (or a CVT limited to) the engine running at 6k RPM @60mph. Larger gears does not always have to mean a faster bike. Yes, top speed could increase, but it could also mean better fuel mileage. I presume you're basing this on owning the 300 linhai? I own both the 257 and the 300 and like anything else MPG depends on all the factors, weight, terrain, speed etc. I easily get 65MPG + on my 300 just like on my 257 and I ride with common sense and not trying to see how fast I can ride. I have both my linhais tuned with sliders haven't touched the gearing and have over 13k on the 300 and 11k on the 257 and they "both" still run nicley. I ride in the hills and the extra little HP the 300 has pulls the hills better than the 257 even though the 257 does fine. The 300 scooter weighs no more than the 257 one and actually pulls the weight better. I run at 60MPH at about 6k RPM which is what the engine was designed to do. All engines have a HP to RPM curve and a place where they perform the best at the range they were desgined to do so. Where I ride if you gear it so high like you suggested the engine will lug and not perfrom in anyway correctly on MPH and MPG. Won't make it to the top of the hill. Lugging a engine drastically decreases MPG and MPH. The linhai at 4k and 60 MPH will not have enough power to blow the hat off of your head, might be alright on a perfectly flat surface but you're working the engine harder to get to 60 MPH than if it was geared to meet it's proper operating range. Bumping up the same engine a little doesn't necessarily hurt it an example the small block Chevy of the past, started as the 265 in the 50's and evolved over the years. Yes I'm that old. Exact same engine over the years with just different piston sizes, the 283 actually out performed the 265 in MPG and MPH. As far as it wearing out quicker? The difference in the piston on a 300 versus a 257 is 2mm on the stock ones and if you buy a kit it's 5mm at the most, not going to hurt or stress a quality engine like the linhai is. |
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Post by 4950cycle on Nov 3, 2012 19:12:20 GMT -5
Thats why I have a 6th gear on my Ninja 250 twin. BUT, it's just more motor than this Linhia single. It will comfortably pull the taller gear. Even though it is a high revving motor. I've always got 5th if I run out of torque for what ever reason. There is an RPM that any particular motor is at it's most efficient. Weather it be high rpm or low rpm depending on the design of the engine. Over head cam engines are almost always rather happy at Higher rpms. That being said all modern scooter engines are over head cam. To gear a 17 hp motor to the point of inefficientcy just thinking taller is better is not always the right answer to MPG. And as far as 300 vs 250 Linhias with same engine crank and head I doubt 300 or actually 275 or 290 is going to beat the motor to death. Now if it was punched out to 350 or better there "might" be concern IMHO.
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Post by macktheknife on Nov 3, 2012 21:12:11 GMT -5
The 257 linhai mhas been known to come in 3 piston sizes, 68, 69, and 70mm. 68 downsizes it to 244cc and 70 = 257cc on the button. All the 300 linhais I've dealt with come with a 72mm piston and again you can look around and get it up to 75mm.
Not enough to make any difference on the rest of the engine, no hardships on it at all again this is based on what I see by owning one.
300
Displacement: 275.00 ccm (16.78 cubic inches)
Bore x stroke: 72.5 x 66.8 mm (2.9 x 2.6 inches)
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Post by 4950cycle on Nov 3, 2012 21:39:37 GMT -5
I will say back on the original subject, Jim J. I believe his name was, Said that the heads were bigger on the 300. It was a post from 2008 and he sold scooters . His company was Bandit motorsports. Now I have heard that info repeated since. But you say Macktheknife that that is a bunch of Huuey and the heads are the same. Good to know
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Post by macktheknife on Nov 3, 2012 22:04:03 GMT -5
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Post by 4950cycle on Nov 3, 2012 22:32:14 GMT -5
Boy ! They want enough for it ? Don't they. I hope someone comes out with a kit to compete at a more competitive price. I have sites with kits for half that I think. I will have to go check to make sure I know what I'm talking about though. But thanks for posting it.
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Post by 4950cycle on Nov 3, 2012 22:54:06 GMT -5
No, the 275cc kit for $299 now at scootertronics . Boy thats a lot of extra money for 12 ccs more on the Polini kit
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Post by macktheknife on Nov 3, 2012 23:06:56 GMT -5
Stay away from Scootertronics. Yes there are good kits cheaper out there, was just using that one for reference.
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Post by leo on Nov 13, 2012 8:05:02 GMT -5
Bumping up the same engine a little doesn't necessarily hurt it an example the small block Chevy of the past, started as the 265 in the 50's and evolved over the years. Yes I'm that old. Exact same engine over the years with just different piston sizes, the 283 actually out performed the 265 in MPG and MPH. the same can be said of the ford small block 289. different heads gave the 302 and a bigger bore gave the 351. all 3 of these engines were great and used the same block. |
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If so, All one would have to do is put a 275cc cylinder kit (I've actually seen these) on a Linhia 250 (257cc) to make theirs a 300 ;D But let me say this, I actually hope that they do make a bigger head for the 300. Because a bigger better flowing head makes all the difference in the world to engine performance. Slight bore size increases rarely if ever increase performance that noticably IMHO. I hope someone out there has some pics. PLEASE prove me wrong guys and gals 
What I am saying at this point is that a 257cc and a 275cc Linhia share the exact same head. And at that rate there would be very liitle difference in performance with only an 18cc cc difference with no other changes. But don't get me wrong I'll take that 1 hp ;D
