sstaton1983 Posted November 29, 2013 Report Posted November 29, 2013 The bike is suppose to be a 421 cub, 34 tm mikunies and cpi sb sf inframes. I know for sure it is a cub top end and ill check the crank when i tear it down. Im about to split the cases to cut the trans and beef up the clutch with a lock out and pancake bearing and inspect everything else. im wondering if i should have the cylinder ported or just go bigger on the carbs and get some shears. kicking compression is 145 psi on 22cc domes.The bike was not tuned very well and was rich, while correcting the jetting I swapped out the emulsion tubes and needles also. The bike runs great right now, but with the stock basket its a ticking time bomb. So is it worth the extra for a drag port assuming its stock casting? I ride sand mostly and sand drag alot at white field. Quote
J-Madd Posted November 29, 2013 Report Posted November 29, 2013 I would say no. Just clean up the casting flaws. Also, many builders wouldn't want to port it without replating after. Which adds to the cost. Quote
sstaton1983 Posted November 30, 2013 Author Report Posted November 30, 2013 (edited) I checked the plating when I first got the bike. I pulled the reed cages and looked around before I ran it. It looked ok even Though t he guy was pouring straight gas in and then chain saw oil right in the tank. I guess I'll prolly go bigger carbs and maybe change the exhaust. Trying to hit height 80s maybe 90 on pump gas. Edited November 30, 2013 by sstaton1983 Quote
5150banshee Posted November 30, 2013 Report Posted November 30, 2013 Can also swap the domes to 21/20cc domes and run race gas that will bring the compression up to 165/175 roughly. Sent using Iphone5 onTapatalk Quote
sstaton1983 Posted November 30, 2013 Author Report Posted November 30, 2013 Yep, trying to stay pump gas. I'm running 145 psi with 4 deg. Timing. Quote
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