looking foward to my motor arriving!!

crazyhorse

crazyhorse

New Member
hi to everyone....
I have a "big mo" chopper style bike and found a motor supplier here in new zealand so have ordered a motrax two stroke kit for it. The motor looks very similar to the common ones that i have been seeing here referred to as a ?china girl? but with the importers sticker on the side.

I have been spending allot of time reading posts here to try and get a bit familiarized with motorizing a bicycle and have found this site to be a wealth of info. A big thanks to all the contributors.

I was wondering if anyone could tell me what sort of rpm range these engines peek out at normally. I have seen peek power quoted at 6000rpm but what sort of rpm do they tend to get to before flying apart?
 
HI,

My owners manual for the Power King engine rates the engine at 5000 RPM and lists peak power at the same 6000 RPM you found.

I have had my Dax 70 up to 6400 RPM (shown on Sen Dec Fas Tach) BUT something (not sure what and didn't hold it that high to find out!) sounded "rattly".

Hope this helps.

Andrew
 
thanks for that info.
I have been doing alot of reading here so much good info.

I havent felt like such a kid for a long time.... whens my engine going to get here!!!

Probably a good thing its takeing so long as it is giving me a good chance to look at what others are doing out there.

does anyone have any suggestions where to look for some discussion on running in. I have been doing some looking and am struggling to find anything major on it except fuel oil mix and keeping the top speed down for the first 500.?
I am trying to remember stuff about it that i learned 15 years ago when i got a new two stroke ringless model airplane engine...
keep fuel to air ratio rich?
extra oil
but i cant remember about throttle whether its best to run at different levels of throttle? whether its ok to use full throttle ocasionally at moderate to low rpm during run in etc.

any advice appreciated
 
I use the ten minute idea. First ten, ride gently, then stop for ten. Don't bog the motor.
Vary the rpms. Let it cool off. Second ten, 15 mph and after 10 minutes stop and cool. Check for loose bolts! Motor mount bolts! Check your bike! After about a tank you can burst the gas a little. Don't do it long. After 3-4 tanks you will know what you can do, and what you can't. This is how I do it. But thats just me. I use Dax motors for my two wheelers. Honda for the trikes.
 
crazyhorse said:
thanks for that info.
I have been doing alot of reading here so much good info.

I havent felt like such a kid for a long time.... whens my engine going to get here!!!

Probably a good thing its takeing so long as it is giving me a good chance to look at what others are doing out there.

does anyone have any suggestions where to look for some discussion on running in. I have been doing some looking and am struggling to find anything major on it except fuel oil mix and keeping the top speed down for the first 500.?
I am trying to remember stuff about it that i learned 15 years ago when i got a new two stroke ringless model airplane engine...
keep fuel to air ratio rich?
extra oil
but i cant remember about throttle whether its best to run at different levels of throttle? whether its ok to use full throttle ocasionally at moderate to low rpm during run in etc. YES, but at moderate to high rpm. Don't give full throttle @ very low rpm.

any advice appreciated
Click to expand...
Start with the needle clip @ the second from the top for most applications, even for break-in. 24:1 Oil mix, and vary the engine speed and rpm. Where some folks differ (that's me) is that I run up the rpm to 75-90% after the engine has had time to warm up, say 5 minutes. Always with a light load, and always de-cellerate slowly too. That will get the rings seated right away. After the first 15 minutes, then let it cool and ride it varying the throttle and rpm for a tank of fuel. After that, just ride it!
Important points- Always let the engine warm up with a light load and moderate rpm. Avoid prolonged down hill runs with the throttle closed- best to pull and lock the clutch. Check your plug periodicly for a "read" of how the engine is running.

..............................
 
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Its finally arrived. yahoo!!!!


thanks for the run in advice that gives me a clearer idea of how to do it.

Have decided not to go for mounting it in the chopper just yet and have got it mounted in my mountain bike instead.

should have everything mounted by bed tonight and ready for testing tommorow.

i am going to have make up a different tensioner as the one supplied does not even have a bearing in it.

I am really glad i have been reading so much here as i was expecting to be able to use the engine for braking down a few long steep descents i do regularly but now understand that this aint a very good idea due to closed throttle therefore lack of lubricant and i suppose cold running the engine. Shame but at least i found out the easy and cheap way not the hard and expensive way.

I now have a bit of a delema because those long descents i use to tackle by just using my "air brakes" by going 60-70kph (38-44mph) but i am worried that if i do that with the clutch in i will be asking for trouble as if the clutch for some reason accidentally engaged my engine would be toast and me probably to.
I am a big boy ~300 pounds and chew through the brakes if i try to use them on long descents.

oh well i better get back to it
photos tommorow i hope
thanks again for all the advice
:D :D :D :D
 
On the long downhills just hold in the clutch (don't lock it, just hold) and you should be fine. It would be a very rare freak accident if it magically engaged....either the lever or cable would need to break for that to happen most likely.

As for the brakes...I know what you mean (260 here). I think it's just one of those things you gotta deal with.
 
weeeehooooo its in and running

a dream i have had since i was a 8 year old has finally come to fuition.


these things are beyond cool.


the clutch needs some tweeking in order to be able to be fully disengaged and fully engaged I think i will have to work on a better clutch lever tonight.


what a feeling.

as far as the down hills are going to go i suppose brake pads are cheap when your not using much gas at all.

140kg is what i weigh in new zealand 2.2lb/kg * 140kg =308lb

i am heavy but fit thanks to cycling but i do tend to stress them a bit as they are not really designed for much over 100kg
 
very very fun!!!

off to get new spark plug now.
the rubber seal on the end of the spark plug cap has started to melt already and you can smell it i can smell it as soon as i stop.
The color of the electrodes are a nice chocolate brown so don't really know if the plug would be said to be to "hot" i will have to do more reading but figure if i am going to be able to choose hottor or colder in the future i have to start with a brand i can actually get here, The plug it came with doesnt even have a brand name on it.
 
Yeah the stock plug is crap. Most people recommend NGK (B5HS or B6HS). I couldn't get it locally, so I ended up with a Bosch plug. much better.

While you're out and getting a new plug, pick up a good quality 7mm plug wire and boot as well.
 
got the ngk b5hs plug and the auto shop was so impressed with the setup they gave me some of ther highest quality wire for free.
now the plug is a definite chocolate without the hint of carbon it had before. The plug has a much smaller gap than the one supplied, I wonder if i can find my plug gap gauges??
More torque down low now and sounds and feels more responsive now to.

Many many heads turning as i putt around people are just loveing it all i am getting is complements, so far so goood.

i reckon i could shift some of these engines easily around here.

time to figure out the mounts for the chopper a little bit of rubber i think .

i found that all except the steepest inclines are top gear so i cant see the single speed of the chopper being a problem at all.

i met someone today who ordered one and it died before he really got it going then instead of returning it pulled it apart(engineers eh we cant help ourselfs gotta find out how it ticks or doesnt in this case). Anyway the guy said its probably heading for the dump but i might be able to have it for parts.... sounds like a spare new clutch at the minimum.
:D:D:D:D
 
here is my first build i slapped together to break in the motor.

runs sweet ......real sweet

i am a total addict already.
 

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next projects....

the big mo chopper i was lucky enough to win from the local liquor store two years ago. Gonna try and get it mounted in there soon but with some rubber mounts i will make.
 

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i think i am going to need more motor kits or maybe finally use those old weedwacker engines i have been collecting.
 

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just put my seat down and it looks and feels like a completely different bike. I had the seat at the correct height for peddling efficency because i try to go as far as possible on the engineless bike but these things are so different with engines in that i realise i am going to have a very different riding strategy for these motor assist bikes.

as far as looks go now the seat tank and handle bars are all lined up horizontally which i think looks really cool.

but damn i cant start it up now as its just about midnight and i dont think the neighbours would appreciate it.

and its sunday morning tommorow so cant start to early though......o well the next time i hear a weedwacker or lawnmower go i will get to test it out .
i am pretty sure it will be eawsome though, less weight on the arms will be much more relaxing ..... bring on the cruiser.

did my first engine mod today. I probably shouldn't of but i cant help myself.

The supplied muffler has a final tube that allows the exaust out and picks up the exaust from about 1/4 the way down the muffler. The first thing i thought was that this was a rather long thin tube for all the exaust to travel and like a pan pipe would only have one very strong resonant fequency makeing for a loud sharp note and not much broad help on power curve.

I just plain didnt like it so off to the drill press i went. I put about five tiny holes in the tube at various points on the length and put it back together.

I havent ridden it enough to descern any power differences but it is now allot more pleasent to hear than it was before with now great loss in power.

I want more motors!!!!
 
by the way i have been casting aluminium for a few years now and was wanting to know if its something that others are doing for mods for the engines.

I am already looking at putting a bit of extra weight on the clutch cover to quieten the gear noise that resonates in it.

I have a couple of castings that will fit perfectly in that space and add my signature to the build as well as being functional and looking good.
 
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