Stock carb jetting on 1982 CB650SC?

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Krtismo · #1 Unread post by **Krtismo** » Tue May 13, 2008 3:15 am

Anyone know what the stock carb jetting on 1982 CB650SC is? My stock exhaust had to be replaced, so I replaced it with some used 4-1 exhaust.
I was concerned that the bike was running a little lean before I replaced the exhaust. I took the bike for a quick ride after changing the exhaust and it seemed to run ok, but I would like to richen it up a bit, and I'm a bit inexperienced with carbs.

Please, let me know what you guys would do. I'm not sure what my stock jets are, and if I should replace them, I'm not sure what size I should replace them with.

And if you know any good websites with good info post them up please.

Thanks for the help!

-Kurt

Tue May 13, 2008 3:23 am

I would get either a clymer manual or a shop manual. Though if you call up your local Honda dealer and ask the service counter nice enough, they might just photocopy the pages from a service manual detailing carb setup and jetting for you.

Tue May 13, 2008 4:29 am

Run your bike down your street at 4k rpm. Hit the engine cut off switch, coast to a stop and pull a spark plug. If it's black, you're too rich, if it's brown your spot on, if it's white your too lean.

Next do a run at 3 more ranges of rpms (not sure what the range is on your bike but you want to see it across all jets being used). If they all show brown your golden. If not... well that's more fun. You can either research yourself which jets effect the power in each part of your rpm range so you know which ones to make bigger (if it's white) or smaller (if its black) or to adjust your needle length. The other option is that you can come back here and tell us what you find and we can tell you what to do in the carb.

Or you can pay a guy $300-$500 to jet it right.

Of course the easiest option is finding a group of guys (forum maybe) with your bike. See who has the same intake and exhaust as you and how they're jetted and start from there.

Enjoy!

Krtismo · #4 Unread post by **Krtismo** » Tue May 13, 2008 5:15 am

Thanks for the info!

-I do have a clymer manual, hopefully that will help me with some of the basics

-Can I remove just one plug, or should I check all 4?

Thanks again!

Johnj · #5 Unread post by **Johnj** » Tue May 13, 2008 6:04 am

Better check all four.

Tue May 13, 2008 6:04 am

One should do it more can't hurt