Let's talk engines..

[akumabito]

Alright, I'd like some opinions on which engine to select..

For starters, let me clarify again that the engine will NOT be for a minibike. Instead, it will be mounted on a modified Honda C70. The aim is to come up with a street-friendly performance bike. Since I am likely to invest a reasonable amount of money in this project, I have given myself some performance benchmarks which I'd like to match or exceed.

There are two performance oriented light motorcycles for sale here in Thailand - the Honda Nova Sonic, and the Honda CBR125. Both use almost identical engines, and offer very similar performance. These bikes are the weapons of choice for the young racers around here. I'd like to have a bike with classic looks that can take on the boy-racers and leave 'm in the dust. So I am looking for plenty of torque and Hp, which in turn means I am looking at the 150cc up class of engines.

I am confused by engine specs though. There appears to be a lot of hocus pokus around with some dubious claims... the engine that initially caught my attention was This YX 160cc engine which is claimed to have an output of approximately 20Hp. It sounded great, until I found This 150cc YX engine which doesn't even produce 12? Certainly a mere 10cc wouldn't make THAT much of a difference? Then there is the GPX 160cc engine, but no Hp figures.. and the RSR R150 engine - which looks very similar in design to the YX 160cc engine posted above? And then comes Lifan with their 140 and 150cc engines.. what do those produce? 12 to 13 Hp?

I wish there were larger horizontal engines available.. 200, 250 perhaps even as big as 300 cc. I couldn't find any though, so I assume they just do not exist, or they are prohibitively expensive. Are there any big-bore /stroker kits for any of the above engines that'll bring the engine to 200+ cc? I am sure such kits must be around somewhere.. after all, the Yamaha Mio (115cc stock) has plenty of big bore kits, 150cc, 200cc.. even seen one bringing it close to 300 - although granted, that kit costs more than the entire bike..

Whew! Sorry for the long post! Everybody keeps telling me I talk to much..

 

[Ingleburn]

nothing wrong with talking to much.The more you add the more people here can help you. Better than just posting "what engine do I need."
I,m no engine expert but sure a lot will give you their opinion.

 

[tubes380]

the gpx 160 is the same as the yx 160, and the 20 hp is wrong,
if your looking to build big cc engines, the yx 160 is the best base as there is alot of bolt on kits from the klx110 thatll fit,

try looking aroung Planet Minis for more crazy builds and advice, there has been a couple 194cc builds and a couple 187cc builds. should get you started.

 

[Pittin]

The only way to get a genuine HP figure is to test it yourself! Only problem i see is the main issue will probably be the gear ratios as they are motors for dirt bikes not for the road so you would need i reckon at least 250cc's to take on the cbr's if not more

well thats just my opinion

 

[Cactus Jack]

The CBR will be hard to beat (with a 4 speed chinese motor) since they have 13.3 hp , 6 gears and can pull 125 KPH from a 125 cc motor ....... I think someone's cocked up the weight tho ' (115 kg / 253.5 lbs) ???????????

Honda CBR 125 R 2006: technical specifications

Honda CBR125R Honda's latest learner legal pocket rocket

Yes there's a hell of a lot of tossers BS'ing the HP figures for horizontal 4 stroke engines ...... a 20 HP four stroke will be competitive against an 80 to 85cc two stroke ....... ask the ******s claiming the 20 BSHP if their bike is as fast as a KX/CR/RM/YZ 85 or a stock CRF150R and IF their answer is NO ...... then tell them to get their hands off their joystick .......

 

[arkark]

i would go with the 150cc motor ,,,

 

[corey58]

how much u looking to spend?

 

[akumabito]

Thanks for the replies so far!

About top speed though; I'm not sure if you need big CC's to get a decent top end. I have a Yamaha Fino, and the stock 113cc engine pulls it to 110kph on the speedometer - so I guess 95 to 100 real life km.. I have heard others pulling all the way to 125 on the speedometer, although my nerves gave ot long before that. (my wheels aren't balanced right, it feels downright dangerous once you pass the happy side of 90kph!)

My budget is pretty flexible. I am planing on spreading major expenditures over a longer period. One thing I noticed though is that there can be some pretty big price differences between apparently similar engines.. is a 350 euro Lifan engine really only half as good as a 700 euro YX engine? Somehow I doubt it..

What causes the difference in price? Are the more expensive engines better build quality? Stronger? More durable? Do they have more tuning parts available?

 

[Cactus Jack]

What causes the big differences in price ? Have you heard of the word "GREED" ??????

Here's a link to a thread where they're all saying that the new Lifan 150 is more powerful than a YX150 .... But I'd say the YX might be better for a road bike due to the shorter stroke ...... short stroke engines like to buzz along on momentum whereas long stroke motors like to have the gas kept up to them ......


Battle Of Lifans!! - Page 2 - Planet Minis