rod length vs port timing
i did it again. i made 75 changes at the same time and don't know which one fucked me. i don't even know where to start.
the first motor had a 50mm stroke crank that i built from a 40mm chinese crank, it broke twice. i got sick of the vibration and breaking and put a stock (chinese) crank in it. this changed my displacement from 79.8 to 63.5cc. and it ran great, except for the vibration at 8-10k. i pulled it apart and removed about 80% more material from the balance pad. while i had the crank apart i noticed the cracks in the big bearing cage and the trough in the bottom of the big rod hole. i had just found a rod that used cage free rollers (they grew up on a nice farm) in the big end but it was 3.9mm shorter. no problem i said, ill just chop 3.9mm off my 7mm cylinder spacer. how about a few ring land ports while i'm in there, YES! i probably did some other stupid thing that i cant even remember since i was too stoned to be working on motors anyway.
the cylinder is a 70cc kstar? with reeds and the carb is a vm22?
i strongly suspect my port timing is way off, when it had a 50mm stroke it had 178deg of exh. i never checked it with the 40mm stroke when it ran good with the other rod. where should i be with a shorter stroke than all of you guys. (besides with fat girls)
|Flagrant -||01/20/10 05:38PM|
|Flagrant -||01/20/10 06:37PM|
|Graham Motzing||01/20/10 10:22PM|
|mattology -||01/21/10 01:14AM|
|mattology -||01/21/10 01:13PM|
|Flagrant -||01/21/10 03:38PM|
|Flagrant -||01/21/10 05:21PM|
|Flagrant -||01/21/10 05:26PM|
|mattology -||01/21/10 08:08PM|
|mattology -||02/05/10 01:15AM|
|mattology -||02/05/10 01:17AM|
|mattology -||02/07/10 01:05AM|
|mattology -||02/07/10 05:58AM|