Author Topic: Something's wrong.. CB650 carbs/exhaust  (Read 1450 times)

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Offline checkflag

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Something's wrong.. CB650 carbs/exhaust
« on: July 13, 2009, 11:29:49 PM »
Hi guys

Ok, so I was riding home tonight and at a stoplight I noticed that the left hand exhaust was
smoking more than the right. I also noticed the other night (I burned my finger :-\ ) that those
2 pipes were hotter than the other 2.

Also, the exhaust temperture was warmer on the left than the right.

What do you think?

Info about bike.. 1979 cb650. 4,500 miles, sat for 25 years.
1979 cb650. Mac 4-1 exhaust. Soon>> cb750 carbs.

Offline Hush

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Re: Something's wrong.. CB650 carbs/exhaust
« Reply #1 on: July 14, 2009, 12:04:34 AM »
More importantly how is the bike running?
The old touch test can be quite deceiving especially if you are sitting on the bike when you do it.
If one side of the motor was running hotter than the other you would guess at either an inbalance in gas supply from the carbs or oil supply to one side of the motor.
Either way it should be running like crap. :)
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline checkflag

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Re: Something's wrong.. CB650 carbs/exhaust
« Reply #2 on: July 14, 2009, 12:29:21 AM »
This being by first motorcycle, I would say it runs very smoothly.
My only complaint is that sometimes when I come to a stop, the bike idles at
around 3k. for this i turn down the idle knob.. that seems to quaff that.

The other thing is that I took her on the freeway, and in 5th gear going 60, it seems
that the engine was working way to hard for that speed. For all i know that is normal,
but i still feel that it should have another gear to go to at highway speed.
1979 cb650. Mac 4-1 exhaust. Soon>> cb750 carbs.

Offline MJL

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Re: Something's wrong.. CB650 carbs/exhaust
« Reply #3 on: July 14, 2009, 01:04:17 AM »
My first two bikes were 6 speeds, and for a long time I tried to shift my 650 up one more. You can get used to it, or you can find a smaller sprocket for the rear to bring the engine revs down some.
No matter how fast or how far I rode, I couldn't leave her memory behind.

Offline the technological J

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Re: Something's wrong.. CB650 carbs/exhaust
« Reply #4 on: July 14, 2009, 06:58:37 AM »
i had the same prob with a racing idle and it ended up i had an air leak and timing was off afteri fixed the leak, i timed it it stayed at the higher rpm i tuned down to a normal idle that problem was fixed...u can check for an air leak by spraying all around the carbs with starting fluid while shes running and listen for any changes in the idle( mine stalled)
« Last Edit: July 14, 2009, 07:03:27 AM by thegabrielj »
70 KO...sold to fund the ST http://forums.sohc4.net/index.php?topic=88800.0(Alpha)
74 Kaw 250 Enduro http://forums.sohc4.net/index.php?topic=124278.0
K4 added to collection! http://forums.sohc4.net/index.php?topic=104784.0
78 750K... http://forums.sohc4.net/index.php?topic=60257.0 (Omega)sold to fund the K4
94 ST1100..Gone
72 750 K2 Stay tuned!

Offline Hush

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Re: Something's wrong.. CB650 carbs/exhaust
« Reply #5 on: July 16, 2009, 02:33:28 AM »
Most of my bikes ahve been 6 speed up till now but the 650 seems to want another gear, 5 gears just seems one too few eh.
I have found that if you thrash the bike in all gears (don't worry the gearbox was made in a Russian tractor factory under licence to Honda I think) the speed is amazing, I tend to nanny around and don't do big speeds but every now and then I'll open her up in all gears just to frighten myself and clean the teeth on the gear cogs. ;D
As suggested you can regear them but you loose pick-up around town and from stop signs/lights to gain lower revs at higher speeds on the highway, it's not much of a trade as most of my riding is urban.
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!