my first case reed project
- Thread starter mrfubs
- Start date
mine too now that iv taken it apart 2 times for inspection. i have noticed small indents on top of the piston and my expensive head which is telling me we need to calm down on the rpm. These bottom end needle bearings are just not big enough to with stand 9000+ rpm. my bike still runs great but with it being case inducted the crank bearings are getting maximum cooling and lubrication and they still cant hold up.
Very depressing
Anyways my plug is showing signs of being too cold and my main jet needs to be bigger, from half to full throttle there is no difference unless i hold wot for 15 seconds it will start to bog and loose power untill i go back to half
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Mine too the case induction makes my bike run cold but with higher compresion it get normal... my exhaust port is at 70 % the diameter of the piston and duration is around 160... i am planing to buy a rse crank but need a seller in us... the second time i rebuilt my engine sounds the same as my first time very high rpm idle the exhaust duration is lower on my second engine. And idle the same there no other motorized bicycle here in puerto rico with the same sound. Last sunday i went to a clasic bicicle show and i started the engine every one started looking because sounds diferent even you can hear the air entering the carb... only at 130psi comp... what psi value are u runing...
I have no idea what psi im makin but because of the way i have the bike mounted in the frame no room for a tester. The only thing i can tell you is my squish is about 20 thou with 6.5cc of chamber. Im going to try a hotter plug but only after i jet up my main.
I'm not sure if it was mentioned but keep a real close eye on the rear hub. It'll eventually destroy itself and leave you stranded when you least expect it. That being said from first hand experience.
No big deal. Smooth the nicks out and ride it.
Mine has MUCH worse damage from a recent boo boo and it still works fine
These little chinese engines are way too fragile man! I follow these threads hoping to see folks have better luck...
Oh yes they are way fragile. I can tell ya what though im gonna fix it because i didnt get my moneys or times worth out of it **** it was almost broke in. It was also running when i took it apart, it was deffinetly a screamer! Sounded like a dirtbike had a bunch of torque and all around power.
too much pressure. Not necessarily compression. Are you still running a stock CDI? with such mods as case intake, you'll need to retard your ignition timing to reduce cranking pressures on your bearings. Your motor can now suck a full 66cc of air, maybe more if you have an expansion pipe. 66cc packed into a 6cc combustion chamber (idk if you run high compression or not), is 11:1 compression, but compression in a 2 stroke rises with your RPM, as the air has less and less time to escape out the ports, and as the expansion pipe comes into play to pack the extra air back into the cylinder, it raises even higher. I remember seeing a chart showing that 4-stroke high performance engines can experience a momentary 450 psi under compression, 600 with improper (advanced)timing. Get a jaguar, or Lightning CDI, they'll retard at high RPM's and save your bearings.
Yeah i was getting detonation if i cruised for a couple miles at steady throttle. Its a 6.5cc chamber. Freds gonna fix the indents and bore out the chamber bigger for less compression. I am running the stock cdi as well. I was also running the magneto magnet that has about 20 deg adv timing with the thinner plates. I have a magnet thats 20 deg retarded with thicker plates too maybe ill try that along with a hd lightning
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Nice thunk,,thanks Mew905. Had not thought of it that way with the cdi's but suspected they might be good with this application? ''breathing'' We should be running some good rpms on these motors. More especially because they are breathing now!
So you have been running these cdi's? Which would be your favorite?
So you have been running these cdi's? Which would be your favorite?
Iv heard from other members and the builder of the jag units that the timing is to retarded at the higher rpm even heard from fred, my engine was twisting 9500+ rpm. The reason the welds gave loose is because the lower connecting pin was too short when i got the crank, so instead of the pin grabbing the full half inch into the crank half it was only pressed 1/4" on either side because of the short pin. I believe the welds had a lot of stress because the guy who pressed and welded the crank for me said it didnt take much effort at all to press it together.
So to sum it up instead of having a total of a full 1" of gugeon pin pressed in both crank halfs there was only half an inch, quarter inch in each side... i didnt think of it as much of an issuse because it was welded but i am wrong now.
Once this issue is fixed i will move to the detonation issue. Plan of attack with either using my other mag thats has more retard or just get a hd lightning along with a 30t sprocket to go faster, keep the engine cooler at a lower rpm
So to sum it up instead of having a total of a full 1" of gugeon pin pressed in both crank halfs there was only half an inch, quarter inch in each side... i didnt think of it as much of an issuse because it was welded but i am wrong now.
Once this issue is fixed i will move to the detonation issue. Plan of attack with either using my other mag thats has more retard or just get a hd lightning along with a 30t sprocket to go faster, keep the engine cooler at a lower rpm