2 stroke questions

[Street Ryderz]

Yeah I think alot of this is seat in from heat cycles, & Lol, I get my digital torque wrench out & torque in a pattern in too. Balanced crank is next, I just dont know who's to buy, I really like the looks of RDM cranks that uses ktm50 magnet, but I dont know much about them. Im going to build a billet minarelli hybrid some day.

Rdm cranks for the ktm ignition in his hybrid case sure but they are not for regular china girl case or wire loop style ignition.

 

[DieselTech]

That's a down the road thing for me. When I got a big pocket of cash to spend. I'm wanting to learn from you guys on building the CG engines first. I've been building engines all my adult life, just dont know 2 stroke stuff. Like port timing & port shape, what cranks work & wont work. I'm hoping this being my 1st 2stroke bike, you guys will guide me/teach me the right way. I'm a gearhead new to 2 strokes & I'm loving it. I built that 49mm steel sleeve engine using your guidance & others on the forum & I'm happy as hell. This thing flat moves & got gobs of torque.

 

[Street Ryderz]

If you look at the ktm ignition the poles are divided by the two holes and the keyway is well beyond one o'clock which would give even more advance which is not wanted so I don't know why he say's it usable with a stock wire loop. Yes it will work but I would not want a high revving build with it!

 

[DieselTech]

Yeah I see what you are saying there, CG engine wise, who's crank would you recommend? Arrow has got them for a $100, I think Smolik are a $100 also. I would like to use this cdh110 case just because it looks a lot thicker & transfer area on sides of cases are bigger. I would like to use the minarelli 54mm horizontal cylinder & case reed it possibly if all possible or something similar.

 

[Cannonball3]

Its not very scientific but on all my engines I file the keyway in the rotor half a key width to the right to retard the
timing. Its makes a noticeable difference in the overall running. Nicer idle, a bit better bottom and revs a bit better. I have no idea how much I have retarded it, but it works for me.
I wedge a screw driver into the mags laminations to hold the rotor while tightening the crank nut. That rotates the
key against the rotor. The Jaguar ignition I had retards the ignition at higher rpms. Filing the keyway yields similar results. There is too much advance in the cdi.

Back when I raced karts, we lapped the flywheel to the crank and ran keyless. Set timing with dial indicators.
Running methanol timing approached 40 degrees advance. It was walking the razors edge on engine destruction
but thats where the power was.

 

[Karl Snarl]

Its not very scientific but on all my engines I file the keyway in the rotor half a key width to the right to retard the
timing. Its makes a noticeable difference in the overall running. Nicer idle, a bit better bottom and revs a bit better. I have no idea how much I have retarded it, but it works for me.

I'm just using an internal star lock washer with a flat washer over it, and a tab bent down into the magnet key way. I mark the outside of the shaft with a paint marker. Where the keyway is, so I know how far I'm going back. Long as the engine is hooked into the bike, chain. Just leave the clutch engaged as a way to keep it from shifting ( and a screw driver like you do) while you tighten. It holds just fine, and you can set the timing anywhere you want it.

 

[DieselTech]

The next time you are into your engine @Karl Snarl can you take some pics of your timing magnet set up & are you still using a key?

 

[Street Ryderz]

Yeah I see what you are saying there, CG engine wise, who's crank would you recommend? Arrow has got them for a $100, I think Smolik are a $100 also. I would like to use this cdh110 case just because it looks a lot thicker & transfer area on sides of cases are bigger. I would like to use the minarelli 54mm horizontal cylinder & case reed it possibly if all possible or something similar.

Both are good, they are done for the 47mm pistons weight though so with a bigger/heavier piston they will be off a bit, it's quite easy to do it yourself which usually yields the best results.

 

[DieselTech]

Thanks there Street Ryderz, I just pulled a good crank from a set of cases that the bolt holes were stripped out of. It's a ZMN crank, dont know if it will work, but I might try & figure balance factor for them 49mm steel sleeve engines I'm running.

 

[DieselTech]

Thanks for the video, I appreciate the time of you finding it. I found another video on the forum of someone drilling there crank to balance it but didn't know about it.