jet sizes for cb650 custom

If it's broken or just needs tweaked

Moderators: Volker_P, tidd650

hedlund65
Posts: 10
Joined: Mon Jul 23, 2012 4:20 am

Re: jet sizes for cb650 custom

Postby hedlund65 » Thu Jul 26, 2012 10:21 pm

Is there a chart somewhere that shows jet sizes?

cgswss10
Posts: 132
Joined: Mon Apr 30, 2012 3:17 am
Location: South east Michigan

Re: jet sizes for cb650 custom

Postby cgswss10 » Fri Jul 27, 2012 12:33 am

sorry- same place also has press in jets- I didn't look close enough

Well I guess you could just silver solder the jets and use a #80 drill to get where you want. If all is good, order new jets in that size. OR you could drill with a #83, test, drill with #82 Test etc. until you go past the point of best performance then order the small jet. I would also try shimming the needle to see if that helps (I would go to a smaller jet then try shims on the needle) When you don't have a stock air box you often have to get creative on tuning.

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Volker_P
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Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: jet sizes for cb650 custom

Postby Volker_P » Fri Jul 27, 2012 1:52 am

hedlund65 wrote:So like u said volker, a little choke going around the corners is all it needed.

So this has nothing to do with idle jets, as idle was fine before, right?

hedlund65 wrote: Being amateurs we are we grabbed a #78 bit and drilled it out causing the bike to load up and run like shit.

Now idle was too large and mains still too small. Probably worse than before as now nothing was all right any more.

hedlund65 wrote: So we tapped the jet and pulled it and it was a 35. Now do I replace them with 35s again?

If they were real 35 before, yes. You said idle was fine with them, right?
That's their job, more or less their only one.

But all of us sometimes learn things the hard way. :roll:

After correcting your mistakes, care for the mains to solve your problem.

Nowadays engineers probably would construct a pneumatic choke lifter and control it by some mixture sensor. :lol:
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

If you really like this site and you would not like to see it vanish soon, have a look there: Urgent: Future of HondaCB650.com Forum

hedlund65
Posts: 10
Joined: Mon Jul 23, 2012 4:20 am

Re: jet sizes for cb650 custom

Postby hedlund65 » Sat Jul 28, 2012 12:45 pm

the jets on the link you guys gave me are 1 1/8 " long and the jet i pulled is 7/8" long. am i talking about a different jet?

hedlund65
Posts: 10
Joined: Mon Jul 23, 2012 4:20 am

Re: jet sizes for cb650 custom

Postby hedlund65 » Sat Jul 28, 2012 1:14 pm

Here is a pic of the jet I am looking at.

hedlund65
Posts: 10
Joined: Mon Jul 23, 2012 4:20 am

Re: jet sizes for cb650 custom

Postby hedlund65 » Sat Jul 28, 2012 1:15 pm


hedlund65
Posts: 10
Joined: Mon Jul 23, 2012 4:20 am

Re: jet sizes for cb650 custom

Postby hedlund65 » Tue Jul 31, 2012 10:02 am

Does the length of the jet matter? I'm finding 1 1/8" jets and the ones in my carbs are measuring at 7/8"? Someone please help? I need to order so I can get back on the road!


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