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Author Topic: 72 cb500 tuning/issue?  (Read 1529 times)

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Offline Blackcobrajay

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72 cb500 tuning/issue?
« on: April 29, 2011, 11:31:14 PM »
hi guys

i have a 72 cb500. completely stock (from what i know) except for the head pipes have been chopped short and it has pod filters. so far i have raised the slide needle up one slot from center slot, added 42 slow jets and 115 mains. bike does not run right for some reason i need you guys to help me with. it sounds like when i give it some good throttle like the clutch is slipping but i know the clutch isnt slipping. its the sound the motor makes. i did file down the points flat and gapped them to .388mm. gapped plugs to i believe .026(whatever is stated in clymer). i first checked timing and i believe it was retarded so i advanced it to where the 1-4f line lined up with the casing line and it seems to run a lil smoother but has no power at all. here are a few pics of the bike.





thank you in advance for whatever help you can provide me with.

Jayson
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Offline Blackcobrajay

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Re: 72 cb500 tuning/issue?
« Reply #1 on: April 29, 2011, 11:39:41 PM »
here are some more pics if anyone wants to see them haha
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Offline dave500

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Re: 72 cb500 tuning/issue?
« Reply #2 on: April 30, 2011, 12:56:47 AM »
both points are lined up,as in the 2/3 set aswell?with your timing light on plug 4 and revving the bike steady higher and higher does the mark go to the full advance mark?do the same with the light hooked to plug 3,get this sorted first before you tinker with with carbs.
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Offline Blackcobrajay

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Re: 72 cb500 tuning/issue?
« Reply #3 on: April 30, 2011, 08:37:50 AM »
Advance is when the plate moves clockwise from the casing timing line right? I aligned the timing to where the casing line matches up to the line to the left of the "F" for 1-4 with induction wire hooked to plug #4
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Offline dave500

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Re: 72 cb500 tuning/issue?
« Reply #4 on: April 30, 2011, 03:29:42 PM »
thats cool,check plug 3 or 2 as well,get them the same,then as you slowly increase the rpm watch as the advancer moves the mark till it sits between the pair of marks further along,if you move the points plate clockwise(same as engine rotation)it will retard and visa versa,are the plugs new?or black?or clean?or old?
« Last Edit: April 30, 2011, 03:32:05 PM by dave500 »
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Offline Blackcobrajay

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Re: 72 cb500 tuning/issue?
« Reply #5 on: April 30, 2011, 08:24:58 PM »
ok i will try this out tomorrow. plugs were new but i will also pull them tomorrow and check to see what they look like and will post as soon as i find out. i really wanna get this bike running good asap as it is registered and insured lol
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