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Discussion Starter #1
G'day from Brisbane Australia ??,
Recently purchased a 1980 cx500c twisted twin. First ever bike and will be getting it running to begin with before making any fancy modifications.

Have been using the bike as a hobby/introduction to small engines. Used the motofaction page to diagnose a problem with what i believe is the ignition advancer coils on the stator. The symptoms match being very weak spark on both cylinders. Have replaced the spark plugs already and will try an ignitech to bypass this fault and hopefully rectify the problem.

Did a compression test which produced 950kpa LHS cylinder and 800kpa RHS cylinder (this was only done with a rubber plug seal I held in place during the test and not the proper screw spark plug fitting because my kit had the wrong size)

Clean fuel draining from carbs, so i believe it is getting in to the cylinders.(Definitely plan to go to a mikuni vm34 pod filter setup soon regardless of how the ignitech goes; I hear very good things about Murray's Carbs)

Also inspected valve clearances which didn't show any problems, however due to my inexperience I did make a really good rookie error undoing a head bolt in the process leaking some coolant into the chamber ?. I tightened it back up realising my error after a couple of seconds. A friend gave me some advice after chastising me and ensured i drain all the coolant (including via the cylinder bolts) crank the engine with spark plugs out to expel the coolant (did this 4 times charging the battery in between) used dry wipes to aid this process between each time. Inspected sump in the following days and after a week it was still very clear fresh looking oil. I understand this could be very bad for the bike so any other advice on rectifying/inspecting this would be appreciated however as a novice I will likely need time to purchase tools and or parts.

Have been tidying up some of the wiring by adding insulated terminal ends instead of leccy taped uninsulated ones.

Am waiting to buy a dental type mirror to inspect the cam chain tensioner and am praying it is in good nick ?.

Overall has been very interesring working on the bike and very keen to get it running and "roadworthy" as we say here before moving on to other improvements down the track.

Thanks for all the other forum members who have posted and a massive thanks to the gurus that provide advice and assistance solving everyones problem, you guys are da real mvp.
 

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Welcome to the forum.
You wrote "...I did make a really good rookie error undoing a head bolt in the process leaking some coolant into the chamber ?. I tightened it back up realising my error after a couple of seconds.". How do you know that coolant entered the chamber (I assume that you mean combustion chamber?)? That isn't likely to happen if a single head bolt was loosened for a few seconds and then re-tightened.
 

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You said "because my kit had the wrong size)". Just a comment from my own silly experience. Long ago in a far away galaxy I too thought I did not have the right size adapter in a compression testing kit. Until I realized the right size was the thread on the hose, no adapter needed for that particular application. :eek:
 

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I was wondering the same thing as Mike. And why did he tell you to drain the cooling system before running the starter to clear the cylinder?

Welcome to the forum. Please add your location to your profile and your bike's model and model year (NOT year first registered) to your signature (see Forum Settings link in my signature) so that you don't have to remember to tell us every time and we don't have to keep asking when you forget.

And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike has had 39 years of Previous Owners who may or may not have done the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage. I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel because old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet. If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid).

You are on the right track with getting it working the way it is before planning any modifications. That way you can use it for a while and let the bike tell you what changes are needed to make it do what you want/need it to do better.
 

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Discussion Starter #8
Welcome to the forum.
You wrote "...I did make a really good rookie error undoing a head bolt in the process leaking some coolant into the chamber ?. I tightened it back up realising my error after a couple of seconds.". How do you know that coolant entered the chamber (I assume that you mean combustion chamber?)? That isn't likely to happen if a single head bolt was loosened for a few seconds and then re-tightened.
Yeah i had the spark plugs out at the time so I could see down into the combustion chamber.

I am unsure why my mate told me to drain all fluid, sorry not much help there.
 

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Discussion Starter #10
You said "because my kit had the wrong size)". Just a comment from my own silly experience. Long ago in a far away galaxy I too thought I did not have the right size adapter in a compression testing kit. Until I realized the right size was the thread on the hose, no adapter needed for that particular application.
I also took a while to notice that but unless i made a mistake, it also was the wrong size. Am keen to test again though so will try pay closer attention. However i did compare the spark plug thread and it looked different ?
 

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Discussion Starter #11
Thanks for the welcome,

Will definitely be following this advice. Am looking at the sidewall and cant see dates maybe you can discern what i have?

Steel braided brake lines sound like a good investment!

Already have the oil and oil filters for a change although the PO didnt have a oil inspection cap with a dipstick so i guess i will just fill by measured volume. Still need to buy grease for that aspect of servicing.

Will I be in dire straights using regular water to top up the cooling system?

Apologies for the bike model and location not in my profile (?) I am trying to get my head around the website atm.
 

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You wrote in part "Apologies for the bike model and location not in my profile (?) I am trying to get my head around the website atm.". From some of your previous posts it appears that you are accessing the forum on a mobile device. Others have said that you cannot alter a signature line when on a mobile device, can only be done on a PC.
 

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Did you mean plain water instead of glycol based coolant or plain water instead of distilled water?

If you meant instead of distilled, it depends on what your water supply is like. If it is very hard or has other contaminants you would be better off to invest in some distilled water. I try to change the coolant in mine every 3 years (assuming it hasn't been replaced when I had to drain it while working on the engine before then) and I use tap water (we have a water softener) and I don't think it has done any harm.

If you mean instead of coolant that is not a good idea. It may not get cold enough where you are for freezing water to damage your engine but plain water doesn't cool as well as glycol based coolant either, not to mention that plain water boils at a lower temperature.
I don't know what is recommended there but here in Canada the recommended ratio is 50:50 glycol based coolant and water, which mixture has the optimum range between freezing point and boiling point.
 

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If it's temporary, for testing and such, straight water is fine. Just be sure to use a proper mix when you put it on the road.


R
 

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You wrote in part "Apologies for the bike model and location not in my profile (?) I am trying to get my head around the website atm.". From some of your previous posts it appears that you are accessing the forum on a mobile device. Others have said that you cannot alter a signature line when on a mobile device, can only be done on a PC.
You can also switch to deal top mode on a ph. You will get full access. I rally don't like the mobile mode on ph.
 

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Discussion Starter #18
I am on a mobile device however i changed some setting of how i was opening the webpage and i think it opened it in a pc webpage. I think i have successfully changed my signature(?)
 

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Discussion Starter #19
JC that could be terrific, I will privately message you later to find out details, I dont want to say yes or no without finding out postage costs and other details. Thanks for the help on identifying the tyres.
 

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Discussion Starter #20
Excellent, i will leave it for now and fill it properly when i am ready to run it. Yes i did mean plain water but I wont stick with it now I have been advised otherwise.
 
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