Is it worth it?

[BlackIceBicycleWerks]

Hello guys I am mostly just a reader on this site and have got tons of great info from here! Now its my time to post.
I have built 8 bikes so far and each one has been better and better. My current bike has an aftermarket DAX carb, the SBP tuned piped, port matched and opened the ports up. smoothed up the casting burs on everything, shaved the head and shaved the piston. The bike is fast but just i think could use a couple more newtons to push me up some of the bigger off road trails i like to go on. SOOOOOOO my question is should I supe up the china girl even more or move to a morini.
China girl would be
reed kit
transfer port correction
crank case stuffed
Hi Hi head
balanced crank as well as all the stuff I already have.

Morini/ KTM clone
this would be on its own steel frame with down hill wheel sets hydraulic disc brakes and a high dollar fork as well as the top hat sprocket adapter.
I figured the morini build would cost around 1500 and the suped up china girl would be $800.

SOOOOOOOOOOOOOOOO what do you guys think? is it worth it?
HAPPY RIDING

 

[bairdco]

you're the only one who can judge it's worth, since you'll be the one riding it.

if you can do most of the work on the china yourself, the main cost is in the bike itself.

you could always switch to a morini later, after you blow up the china...

 

[bigbutterbean]

Any particular reason it has to be a two stroke? I just built up a 98cc cruiser for $800, getting some parts free or at a discount, thats an actual value of 1200. I'm happy with the torque of the engine so far, but predator engines have even more torque than my minibike engine, and can be built for about the same price. Or if you wanted a smaller 4 stroke and a shift kit, you're still not looking at more than about $1500. If money is not the limit, then a 4 stroke is just as doable as a 2 stroke, maybe even more so. Much less fab required for a 4 stroke unless you want to make all your own custom parts. I had to modify my suzuki motorcycle forks to accept a bicycle wheel, and fit a longer front axle up because the suzuki forks are a bit wider than a standard front axle, and I also had to make a few other minor modifications, but no actual fab work was required. Basically, for what I spent, I'm very happy. You can mod a china girl to your heart's content, but eventually you'll break her. But of the two engines you mentioned, I'd go with the morini/ktm clone. If you treat it right, its not as likely to break you heart as quickly as a china girl.

 

[Huffydavidson]

If you allegedly have done all this work yourself then you should be able to answer your own question . But for a streetracer that joined 11/12 and still has newbie status , kinda make wonder????hhhuuummm???

 

[BlackIceBicycleWerks]

Well I may be a newbie on here but not to mechanics. I have a motorcycle a truck and a car I do all my own work on I love to tinker with things. I am most certainly not a street racer! That's what my ninja 500 os for. I am just kind of bored and looking for a fun new project for summer. Maybe the right question would be what would you guys pick? I didn't really think about a 4 stroke. I figured it would be almost the same build time as the ktm clone and only net me 3 or so Hp. So what would you guys pick?

 

[misel]

If I had built 8 bikes, I knew I would want to try building a morini or ktm clone for tinkering sake.

 

[fatdaddy]

No matter what you do to a China girl it's still gonna be a chinese engine. Yeah, I know, MOST engines are made in china today. But I think if your gonna go 2 stroke high performance you should start with a Morini. If you want a 4 stroke perhaps a Predator build would be better suited.
But in the end, I think gearing is your issue. It's not impossible to get low end torque (for the trails,) AND a good top speed, just a little harder to do. You might want to try a shift kit to get the best of both worlds.
fatdaddy.

 

[bigbutterbean]

Well I may be a newbie on here but not to mechanics. I have a motorcycle a truck and a car I do all my own work on I love to tinker with things. I am most certainly not a street racer! That's what my ninja 500 os for. I am just kind of bored and looking for a fun new project for summer. Maybe the right question would be what would you guys pick? I didn't really think about a 4 stroke. I figured it would be almost the same build time as the ktm clone and only net me 3 or so Hp. So what would you guys pick?

The predator is 3.5hp at 3600 rpm, and thats with the governor installed. Without the governor, I'm guessing its closer to 5 or 6 hp. I guess if you're really looking for a high powered machine, maybe a 4 stroke won't cut it. But like I said in another thread recently, you can gear a ktmn/morini clone to do 65mp, but its going to take forever to get there and be a dog on hills, because at that gear ratio, its not going to have very much torque. If you're able to gear it low enough to do about 45, it will have much better torque.

 

[16v4nrbrgr]

Actually, it should have plenty of torque geared to go 65. Mine acted like a HT and went 60 geared with a 44t that theoretically would do 110 in a dragless environment. If you gear it right, it will be about as fast a riding a KTM 50 Adventure Senior, which is considered much faster than a CRF 50 four stroke due to the two stroke power density advantage. Adults can go typically 55 on an Ad Sr. and it won't feel "slow". You just need a ridiculous rear sprocket, the one I'm putting on the bike today is 13" in diameter.

The advantage of the clone motor is that you really don't need to add much to it , just get chain and a rear sprocket. The Predator engines require adding a transmission to it. The three shoe clutches can be tuned to work well if the gear reduction is appropriate so the drum will spool up faster, which drives the output gear reduction.

 

[BlackIceBicycleWerks]

Ya I understand the principals of gearing and that to go off road im going to need to gear it low. I was more in favor of the 2 stroke builds because that are simpler less parts working less things to break. Plus isnt the predator pretty heavy? I think just 5 to ten pounds more would make a big difference in handling and durability of the bike. I tried shift kits on two of my separate bikes and they never impressed me. I was ever so careful and meticulous about the install, checking all alignments and such but id get out on the trails and it just did not hold up at all. It wasnt that great on the street either always gave me problems when I was out riding. I personally like the idea of building up the china for simplicity sake but it seems you guys think she wont last very long? It makes sense I suppose because the build quality on those engines is just so piss poor. I imagine the KTM clone motor is a much better quality?

 

[BlackIceBicycleWerks]

The purpose of adding more power instead of just gearing for me is just all around better performance. The engine running smoother and more powerful and still being able to cruise home going 30 to 35 mph without winding the engine up too much.

 

[bigbutterbean]

On the subject of handling, the weight difference mostly depends on how you mount the engine in the frame. My 98cc weighs about the same as a Predator, but it handles just as good if not better than my chinagirl bike did. Part of the reason why is because I mounted the engine as close to centered in the frame as I could. I also used different forks (Suzuki K10 motorcycle forks) which added rake and positive trail. Adding a little rake will make up for any weight difference/higher center of gravity. Now, I don't go offroading at all, so extra weight may make a difference in trail handling, not sure. But the ktm clone is likely to be at least a little heavier than a chinagirl anyway. As far as simplicity and less moving parts to break, if you start with quality components and maintain them properly, you'll have a lot less chance of failures. If you want something that's bolt-on and go, stick with a chinagirl and replace it when it blows up. A custom bike is going to need more maintenance than a kit bike, but the difference is that the maintenance on the custom bike will mostly be preventative or routine.

 

[BlackIceBicycleWerks]

Ya i dont mind maintenance but what I do mind is when my bike brakes on the trail. That really sucks because you gotta ride out or carry it out and back home. It seems like the 4 stroke build would be just as much money and even more work than the KTM clone build. All of the extra parts like the gearbox and such would cost so much. I do like the quietness of the 4 stroke. Has anyone on here ever built both and compared the two? that would be a very interesting read. Like I said i dont mind tinkering and doing maintenance and i understand higher performance means higher maintenance. (Hmmm kinda reminds me of women) So anyone ever build a high performance 2 stroke and a predator?

 

[BlackIceBicycleWerks]

How much did your lifan end up costing you if you dont mind me asking. I was thinking about 1300 for everything?

 

[magrider]

I've built and raced a few bikes. I've built stock 2stroke Chinas up, raced them. Raced heavily modified chinas.Built and raced My Italian H20 Morini 2stroke and built my brothers (buckO) Honda 4stroke 120cc and his 212 predetor 4stroke HF bike, raced his Honda 120.

Out of the 5 engines I feel what gets the most intrigue is the China POS, because you can take a terribly tuned engine and make it faster. It won't last long, I had to take my engine to the builder after every race for rebuilding, with only 2 hrs max on it.

As far as I know Morini's factory is closed, the factory got bought out and they are revamping it with no real date for when they will be back online so it is very hard to get replacement parts for them. I think you can still purchase the H20 from Herdan around $800 with no radiator, and I replaced the stock clutch with a Tomar $450, clutch fluid gets changed after every moto and clutch gets adjusted, 20 min each race time. I love my Morini.

The HF 212 is heavy and if you want to get major HP out of it lots of $$ ask Scotto or jeff (CCC), its very fast and powerful.

Headtrama built a KTM clone and it did very well at the last race, I don't know what getting replacement parts are like. the bike sounded and ran very good, It has a Tomar clutch.

I liked my brothers honda 120cc, there seems to be some aftermarket parts for the engine. He says there are enough parts to get it over 12HP? you have to build a gear reduction like a jack shaft, or buy one from AGK that the karts use. If I build another bike for racing or riding to the store it will be powered by the Honda 120cc and it will go into my China racing chassis.

just another thought don't let the $$ be the deciding factor.

 

[bigbutterbean]

How much did your lifan end up costing you if you dont mind me asking. I was thinking about 1300 for everything?

I spent $800, started with a bare frame. Keep in mind though, I got some parts for free or at a discount. I estimate the actual value of parts to be about $1200. I built this bike from the bare frame (no forks, no wheels, no seat or seatpost, not even bearing cups in the bottom bracket or the head tube). If you ask me, the amount of work required is more than a chinagirl, but probably a lot less than a morini/ktm clone. I did not have to fabricate anything, just make some minor modifications really. With a ktm/morini, you'll have to fab the motor mounts and figure out a pipe mount, since the exhaust port is dead center on the cylinder, the frame is kinda in the way. As far as your bike breaking on the trail, it doesnt matter what engine you're running. A breakdown is a breakdown, and its possible with just about any engine, albeit more likely with some than others. This is where quality components and mechanical ability come into play. Build it right the first time, and you'll have no worries. And unless you have your own machine shop to fab all the parts, a ktm is going to cost you a lot just in fabrication costs. So if you don't want to do a lot of work or spend a lot of money, you're better off modding a chinagirl till it blows up, then replacing it and doing it again. Of course, over the long run, that's going to cost you the same anyway. I had over $1500 altogether in my chinagirl before I euthanized her to build my 98cc bike, and she was worth over $600 as she sat.

 

[Technocyclist]

Is it worth it? you say... How about calculating your costs in terms of Power gain? like how much would it cost for each horsepower or kilometer per hour gain... on the other hand you can also calculate your mileage, like if you gain horse power, how much mileage would you loose, so you can play around with the figures until you can get sweet spot then you work around the budget... I've been working only on HT, but it seems the technology on electric is catching up, more power, less weight, but more expensive. However, if you calculate on cost per horsepower, it would seem to be cheaper...

 

[magrider]

I haven't built an electric yet. thought about it, looked into it, that was about it.

 

[BlackIceBicycleWerks]

I cant do that because each engine has something that is not a quantitve value. WHen I said worth it I was not only talking about money but qualitty time break downs reliability etc. The 4 stroke is quiet and smooth but is an expensive build, the KTM runs like a raped ape but is super loud, the HT can be made the cheapest but runs pretty sloppy. See what I mean? not only taking about quantative values of each build but also qualitative.

I also looked into electrics but I dont like the idea of alsways having to charge the battery and worry about it running put of juice. They also seem very expensive to upgrade for minimal gains. Maybe when prices come down I would build one. I think half the fun is hearing the engine and modifiing it.

 

[BlackIceBicycleWerks]

I really dont mind the fabrication part. I am an ok welder so I could just weld mounts on which should not take that long there is only a few simple welds I would need to make. For the pipe I was pretty sure I saw a custom pipe for sale just for these builds. I understand what your saying about building with the best components. I always do because they are worth it of course. How long do you think the China girl would last with the mods i mentioned? I really dont want to be rebuilding engines every week. If she lasted 500 miles I would be happy is thqat too much to ask for this powerlevel? my current ride is sitting right around 500. and still runs great.