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my new bike progress


scottie.harris

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Ok some of you know already that I picked up a 73 cb500 for free, it needed work because it sat for 5 years with gas in it

and I have done most of it already with the help of my dad.

Starting from the beginning I cleaned the gas tank out, replaced fuel lines, and had my dad clean the carbs(I don't know carbs very well). Then I put new throttle cables on and my dad adjusted the clutch because the previous owner said it was slipping so hopefully it fixes it since there was a lot of play.

Yesterday at a swap meet I picked up a new exhaust because straight pipes are way to loud and coil with plug wires.

In the process of working on it the throttle sleeve broke so i went to iron pony and bought a new sleeve, had a front tire put on, and bought a battery for it. Once i get this thong running right I'll put a new rear tire on, but until then.

Currently the problem we're facing is cylinder 3 isn't firing, the header coming out is cold. We checked the spark plugs and they're sparking fine, so we think the carb is running lean, a burnt valve, or there is still some dirt in the carb(my dad said it was the worst). Were also gonna do a compression check but ran outta time.

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Good luck on the project...What are the plans, the get it into running reliable condition? or full on custom?

I have a cb500 im working on, just minus 2 cylinders. I have a thread started if you search Cafe Project. Let me know if i can answer any questions.

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pull that #3 plug out and ground it, see if it sparks. Put thumb or finger over spark plug hole and see if it has compression at all. If ok, pull carb and fix it...

btw, if I remember right.... #1 and #3 fire at the same time, on both compression and exhaust. You can swap the two and see if the cold cylinder moves. If it does, I'd say the spark plug wire is bad. I replaced mine with NAPA parts. But to do so, I replaced the coils with hot spark stuff.

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I'm mainly just gonna fix it for a bike to ride. The most id do for the time being it possibly change the handle bars to a cafe look.

Reconrat- the wires are good and getting spark, we've tested them and the plugs. We're gonna more tests but ran outta time. My dad said he's almost positive its in the carb.

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  • 3 weeks later...

Well i finally got the rebuild kit for the carb, but wanted to test the compression first. The compression tester was short so we rigged it a bit and we know it has about 90lbs.

Does anyone by chance know the compression needed, though we think compressions fine

gonna continue with the carbs and hope #3 fires.

Edited by scottie.harris
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Compare it to other cylinders, 90psi sounds about right but I don't know specs.

While your at it might as well do a leakdown check as well. Again compare all the cylinders.

It should be pretty obvious if one has a problem.

Good luck man

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Yea took the carbs off and they all have the same suction and spark plugs were removed and they all have similar compression.

so now I know that the motors not junk I'm moving on to rebuild the carb hoping that fixes the issue. Once that's done it should be ridable.

This bike will cure the riding itch until I can use my credit to buy another bike, then this bike will become a track bike.

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