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Thinking of rejetting an 81

Posted: Fri Jun 25, 2010 11:01 am
by rekit
I'm at 60' above sea level (Houston, TX) and I'm sorting out a new-to-me CBX. Installed Accel coils and wires but 1 and 6 aren't getting fuel. Drained #6 bowl-pretty nasty and no new fuel coming in while the engine was running, so I'm going to pull the carbs. I've ordered the parts and book from Raddacks, and was thinking as long as I'm in there how 'bout a Stage 1 kit. Stock exhaust is staying on there. I just want it to run well, not too much high speed stuff (but I've said that before)<G>

Re: Thinking of rejetting an 81

Posted: Fri Jun 25, 2010 8:32 pm
by steve murdoch icoa #5322
If the stock exhaust, air box and filter are staying on the bike i would stay with the stock jetting. Save your money.

Re: Thinking of rejetting an 81

Posted: Fri Jun 25, 2010 8:38 pm
by EMS
I do agree with Steve. I don't really know if the altitude makes that much difference, it seems to be a concern, as you are referring to it. My 81 has stock jetting and runs pretty good. Even two-up. 8)

Re: Thinking of rejetting an 81

Posted: Fri Jun 25, 2010 9:21 pm
by rekit
Thanks. Raddack agreed with you guys. Got the carbs off today, went well as far as tilting the engine but pulling the old rubber manifold connectors off the head was interupting my drinking. WD-40 sprayed into the gap as I pried on the rubber eventually got em off. I'm gonna get new throttle cables and exhaust gaskets while I'm in there. Anything else?

Re: Thinking of rejetting an 81

Posted: Fri Jun 25, 2010 9:42 pm
by daves79x
You didn't need to take the rubbers off the head, unless you are getting new ones. If you are, make sure you get the correct ones for the late models. Now is the best time to adjust the valves and camchains - while the engine is tilted. Much easier to get the cover off.

As far as jetting the carbs - forget it. If you are able to get them completely clean and the accelerator pump working properly, they will be just fine stock. Getting the idle circuits clean is a major pain, and you'll think you have them done, but you probably won't. Learn exactly where each opening sprays and what is supposed to happen when you spray cleaner through the idle circuits. 2 or 3 attempts is not uncommon. Also bench test for leaks before installing. And reuse the original float valves if you can.

Dave

Re: Thinking of rejetting an 81

Posted: Fri Jun 25, 2010 10:10 pm
by rekit
Thanks. I am using the factory manual. On page 49 (4-3) it says "loosen the carb manifold bands", and below that it says "For easy removal, loosen the cyl head side bands". No matter-half came off on the carbs and half stayed on the head. It was a bitch to get em off! The thought of having to do this 2-3 times ain't gonna get it. Even hooking up the throttle cables back up looks to be a bitch. I'll follow the instructions in the book and do my best. Carbs + Ethanol= suck.

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 2:34 am
by alimey4u2
On assembly I always use Dow Corning 111 silicone grease. It feeds the "rubber" & makes the task a lot easier the second ( 3rd,4th etc.) time around...You can get it from McMaster Carr

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 8:12 am
by daves79x
Since you have the boots off - boil them in water to soften, then lube as Larry said and reinstall them on the head - keeping the index marks up. Then install all the bands and tighten the head side ones. Keep the carb side ones very loose as you'll need a lot of flex room on the end carb boots when reinstalling them. Heat the boots up well and grease them before reinstalling the carbs.

As for the throttle cables, if they are completely off, just install them on the carbs before sliding them in under the frame, then fish them out from there. Also, be sure you know which cable is which - it's a bummer to get everything back together and discover you installed the cables wrong. If your cables are still on the throttle, just slide the carbs under the frame (with a towel for a cushion), rotate the carbs rearward, and install the cables there. It's near impossible to install the cables at the carbs after they are on the head.

Dave

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 1:10 pm
by alimey4u2
Cables to carbs in situe ?? It can be done with a pair of these....http://www.medical-supplies-equipment-c ... d_full.asp Nurses uniform optional... :D

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 6:30 pm
by rekit
Gee, when we used those in 70's for holding other small items the word "rectal" was never mentioned, thank goodness! I've still got mine, they've been handy thru the years for all sorts of things mechanical.

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 6:35 pm
by EMS
....like replacing the windshield on a Prolink fairing and holding the nuts on the two bolts on the side :roll: :roll:

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 6:46 pm
by rekit
Exactly. But those two in the front-if only my 5 year old grand-daughter could know what to do-she could get her hand in there.

Re: Thinking of rejetting an 81

Posted: Sat Jun 26, 2010 6:47 pm
by alimey4u2
I have a pair that have long jaws bent at the ends., perfect for putting cables on Smoothbore Mikuni's. Especially when I forget the correct order of assembly... Hemostats though, not hemorrhoid clamps... :oops: :D