HJR 4MIL PORT JOB @ 5000 FT

[SonOfSand]

Hey guys, what are you running for mains and needle, I have all the mods below, and I am running a 140 main @ 5000 feet. I still cant get it to scream up top. Any help would be greatly appreciated.

[SAVAGE420]

Do a plug chop and see what it tells you. http://www.dfn.com/benkaren/plugchop.html

 

Grab a couple sizes smaller mains. Start with the 135's if the plug chop is rich and go from there.

[KEVSWS6]

We thought it was a fuel problem at first. The cap is drilled out and the dual pingle is on it. The plugs have been gaped tighter at .025

Runs 35mm carbs with 140 mains CEL needles middle clip. Has trouble at the very top of the RPM band. I have been helping on the phone but the 140 mains at 5,000 feet seemed lean. What are you ported guys running at 5,000 plus feet? I know I have some Colorado motors running at this elevation but cant find my notes.

[SonOfSand]

Kevin, I re-gaped the plugs, tested the stator, it was fine, and moved the pickup for the stator closer to the flywheel, it might have been a little to far away. The engine ran great on top, However, I dint know if any of those adjustments helped, I say this because it was about 15 degrees cooler than when I first ran the 140's. So, was it the cooler temps making the jetting work, or the other stuff I did?

 

thanks for the link Savage.

[KEVSWS6]

Well that's good. Plug gap and pickup gap are very important. I'm guessing this was the problem. Now make sure your not lean on top.

[RagunCajun]

If the gap on the pickup is too big, it will breakup on top like that. Mine did that. Took i dont know how long to figure it out. Interesting how the littlest thing can cause that much bs.

Edited October 23, 2009 by RagunCajun