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Should I just buy the murray carbs and hope it fixes my issue?

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Discussion Starter · #1 ·
I'll keep this as short as possible.
When I bought the bike I could not get it to run or come close to starting.

I rebuilt the carbs. The jets that came with my kit may been larger then the oem jets. I'm planning to buy the murray carbs. I'm worried something else is wrong and just putting a brand new set of carbs on will not fix my issue.

After I check the valves. They were so tight at no point in the stroke was there any space. After setting them it's running allot better but still not able to idle well. Right spark plug was coated in black and the left was white/Grey in color. Both plugs are brand new. Any help is appreciated hopefully I'm not being to confusing. Video link below

 

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Any answer you get will be a guess. Put the oem brass parts back in the carbs for starters. Get Larry’s carb book and do a proper carb rebuild or you can just buy the carbs and take the gamble. There is no guarantee as to the shape of your motor and impossible to even take an educated guess over the internet. As for your poll, I don’t participate in that nonsense.
 

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Each carb has it's own mixture screw but it seemed that you were only making one adjustment. I think that you may have been adjusting the idle speed by the black knob between the carbs?

I would revisit setting the valve gaps, making sure that you are doing it with the piston at top dead center compression stroke.

I agree with Doug, put the old jets back in the carbs Make sure that the big jet is in the brass holder.

To keep replacing parts to solve a problem is expensive and frustrating. Much better to diagnose the problem then only replace what needs replacing.
 

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Discussion Starter · #4 ·
Any answer you get will be a guess. Put the oem brass parts back in the carbs for starters. Get Larry’s carb book and do a proper carb rebuild or you can just buy the carbs and take the gamble. There is no guarantee as to the shape of your motor and impossible to even take an educated guess over the internet. As for your poll, I don’t participate in that nonsense.
I wish it was an option. The original brass was seized in the carbs so badly I marred them up badly getting them out. I have the manual and the carb book and I guess my frustration has me grasping for answers and help. I knew it was a long shot anyone would be able to pin point why is surging so bad. I also apologize for offending you with my poll it was more of a joke then anything.
 

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I wish it was an option. The original brass was seized in the carbs so badly I marred them up badly getting them out. I have the manual and the carb book and I guess my frustration has me grasping for answers and help. I knew it was a long shot anyone would be able to pin point why is surging so bad. I also apologize for offending you with my poll it was more of a joke then anything.
No offense taken, just don’t participate. Since your carbs are messed up, buying Murray’s carbs might be a good option. If the motor turns out to be junk you can always get most of your money back out of them. They seem to hold their value well thanks to Murray’s support and warranty. Your motor doesn’t sound bad on your video. Hard to tell on a video though.
 

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Discussion Starter · #6 ·
Each carb has it's own mixture screw but it seemed that you were only making one adjustment. I think that you may have been adjusting the idle speed by the black knob between the carbs?

I would revisit setting the valve gaps, making sure that you are doing it with the piston at top dead center compression stroke.

I agree with Doug, put the old jets back in the carbs Make sure that the big jet is in the brass holder.

To keep replacing parts to solve a problem is expensive and frustrating. Much better to diagnose the problem then only replace what needs replacing.
I'll take the carbs off tomorrow and take some pics I may have installed the jets wrong I might as well check.

I will double check the valve clearance. I used the TL and TR marks.

Yes I was twisting the idle screw. My fault, the air fuel mixture screws broke off at some point from the previous owner and I replaced them. I believe I set them at 2 or 2.5 turns out. I hooked up my carb sync gauges and obviously had trouble getting the to synce but they were close.
 

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Discussion Starter · #7 ·
No offense taken, just don’t participate. Since your carbs are messed up, buying Murray’s carbs might be a good option. If the motor turns out to be junk you can always get most of your money back out of them. They seem to hold their value well thanks to Murray’s support and warranty. Your motor doesn’t sound bad on your video. Hard to tell on a video though.
Thanks again for the reply. I will do some trouble shooting tomorrow and take pics. If I messed it up won't be the first time. I learn everything the hard way lol.
 

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I will double check the valve clearance. I used the TL and TR marks.
The TL and TR marks line up on both the compression stroke, which you want, and on the exhaust stroke, which you don't want. Are you sure that you were on the compression stroke?
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Throwing expensive parts at a problem is a poor method of fixing anything. Identify the failure first, then replace or upgrade parts.
 

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Discussion Starter · #10 ·
The TL and TR marks line up on both the compression stroke, which you want, and on the exhaust stroke, which you don't want. Are you sure that you were on the compression stroke?
I believe so. The piston was at the highest point before checking the clearance. The more I work on this bike the more I realize how much I don't know.
 

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There is a fair likely hood that you adjusted the valves on the wrong stroke due to the fact you say there was no clearance before the adjustment.

I would check them again and roll the motor over checking the clearances on both strokes.

If you find that on one stroke the gaps are enormous this is where you need to redo the adjustment.

With zero clearance you will have low compression and the possibility of burning valve seats.
 

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Discussion Starter · #12 ·
There is a fair likely hood that you adjusted the valves on the wrong stroke due to the fact you say there was no clearance before the adjustment.

I would check them again and roll the motor over checking the clearances on both strokes.

If you find that on one stroke the gaps are enormous this is where you need to redo the adjustment.

With zero clearance you will have low compression and the possibility of burning valve seats.

ok thank you I will attempt this today when I get off work. I really appreciate it.
 

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1978 CX500 "The Grub", 1983 GL650I "Nimbus"
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Replacing the chain and guides isn't the end of the world. Just a chance to become a better mechanic.
 

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Where are you located? If you put that in your profile we might find someone local to you to help.
 

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Discussion Starter · #17 ·
I live near Chicago Lake county area. Sorry for the delay in responding I had a competition this weekend and have not made it home to start working on the bike.
 

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'84 CX650E that is evolving into a GL500
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Please take a few minutes to add your location and your bike's model and model year to your profile as I asked you to last month (see Forum Settings link in my signature).
 

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Another thought. Carb tuning is a ticky process. Multiple adjustments to twiddle on each carb. Each adjustment affects the others. It is an iterative process.

A critical tool to use is manometer to get things balanced correctly.

Patience is the key. The first time I did the carb tune after a cleaning it took me 3 hours until my frustration forced me to quit and try the next day. The next attempt on the following day I was able to complete the "tune" in 2 additional hours. I was able to achieve a balance between the carbs of 11 inch of H2O. Well within the acceptable tolerance. Be patient.

Remember, the initial 2-2.5 turns is a beginning point.

If I recall correctly,...there is an idle adjustment, fuel mix and air mix (?). Each twiddle impacts all the others. Small steps.

Good Luck.
 

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'84 CX650E that is evolving into a GL500
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In your video are you referring to the idle adjustment (plastic knob that hangs down between the carbs) when you say "air fuel mixture"?
If it is the actual air/fuel screw you are adjusting are you turning both of them (one per carb)?
 
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