Can you answer any of these questions?

[mrsaxman99]

1) Check out these pics of my engine internals:

http://chas.servehttp.com/bike

Is the black stuff on the top of the cylinder head normal? This was still when I was running <20:1, so I know the oil was building up. I am now running 40:1. Could the black stuff hurt performance? The engine seems a little less powerful than everyone here on the boards is talking, and I haven't noticed all that much of a performance improvement since I leaned out the oil.

2) I read somewhere about mixing r/c fuel (5-30% nitro in the r/c fuel) to the gas/oil fuel. Anyone tried this? Any info on that?

3) It seems that the choke can change a/f ratio a bit. if I am going up a hill at mid rpms, sometimes adding a bit of choke seems to richen up the bike and give it a little more grunt. But at wide open throttle, any choke hurts performance (i'm sure because of breathing issues). I HAVE played around with changing the a/f pin. When I set it for a good mixture at high rpm, it STILL seems like a little choke helps the engine in the midrange under heavy load. Any thoughts?

4) I read about getting a thicker ignition wire. Can I get any >7mm wire and screw it on? What about the coil pack? anything worth upgrading there? Or how about the spark plug boot? I have heard the type of spark plug doesn't really matter, so I'm not even going to open up that can of worms.

5) I have also heard there is a brand of oil that is formulated to be run at 100:1 in all engines. Does anyone know where to find this? I imagine as long as it lubricates like it should, that might help performance of the engine a bit.

My bike just seems to be a bit underpowered, so I'm trying to track down any possible source.

thanks in advance!

 

[srdavo]

hi mrsaxman99,
nice job on your photos. I've never opened one of my engines up, so this is cool to see. I am sure the guys here can answer your performance questions.
I use Amsoil 100:1 formula oil, but I mix it 40:1

http://www.motoredbikes.com/viewtopic.php?t=639&postdays=0&postorder=asc&start=0

one question.... did you replace the sparkplug when you switched fuel/oil ratios?

One fact I know! the sparkplug boot that comes with our china kits WILL fail. Change it to the automotive type before you have to pedal home.

dave

 

[chieflets]

To me looks like carbon deposits do to unburn't fuel in simple terms ur motor might be running to rich

2 things u can try which also improve

1. A Hottor plug NGK B5HS
2. Semi or full sensythic oil

Chieflets

 

[Cookie]

YUCK

Chief hit it on the head your are running to rich on the oil ....I took my motor apart a few yrs ago after a run in with a car (that motor never did run right after that SUV played with it ) but I had over 1000 miles on that engine and did not have 1/2 the slug you have the spark plug tip looked ok from what I could see but it is not normal to have the build up around the threads.When you clean the cylender make sure not to scratch the thing and use a good gasket material the ones that come on them are not worth a hoot.
Cookie

 

[thatsdax]

Looks Really Good.

That is really really Clean. Must be low miles..Sitck to the 20:1 unless you are running synthetics.

 

[Guest]

Adding RC fuel will destroy your engine unless you know what you are doing. Since you are asking very basic questions, I will have to assume you aren't familar with the dynamics of carb tuning and mixture settings.

RC fuel which contains methanol and nitromethane requires it be run at a VERY rich setting compared to gasoline. This requires rejetting of your carb at a minimum to achieve the appropriate stochiometric ratio of fuel to air.

I blend a little nitro and methanol to my fuel only because I am at 7200 feet altitude and the relative lack of oxygen with same carb jetting causes my engine to run pig rich. Running nitro and methanol at a specified setting solves this problem for me and regains performance lost.

So, in short, don't do it.

 

[mrsaxman99]

I know a whole lot about fuel mixture, tuning, and engines in general. Just don't know much about 2 cycle and THIS engine in particular. I was just curious if mixing in RC fuel, while fattening up the mixture a good bit, would yield good results...

 

[mrsaxman99]

Oh yeah, also...those pictures are taken when I was running richer than 20:1 gasil mixture...I have since leaned out the oil a bit...will the deposits on the cylinder go away with time? I switched out the spark plug when I leaned out the oil mixture as well.

 

[Saabsonettguy]

As for the carbon it's to be expected if you were running 20:1 of dino oil. The carbon on the piston won't hurt anything but every 200 miles or so you should check the plug, exhaust port and exhaust for carbon. I do notice you have a little bit of blow-by on the piston, though it doesn't look too severe. I'd replace all the gaskets with high quality gasket paper when you reassemble. Next time get a compression reading before you take it apart.

I wouldn't mess with the fuel unless you've squeezed every little horsepower you can out of the motor. A tuned 50cc engine can easily exceed the safe operating speed of a bicycle on pump gas.

 

[mrsaxman99]

yeah I agree with tuning other aspects before messing with fuel.

I'm going to swap to an NGK B%HS plug, get a new/better spark wire and boot, and I just ordered some Amsoil 100:1 fully synthetic oil. Looks like some good stuff. I might take a measure or two to improve breathing a bit. Like open up the exhaust just a tad, or get a better air filter.