Topic: Overheating?

[78_SaltLick]

Today was really the first day ive ever ridden this bike in some serious heat (serious for oregon that is, it was 93 degrees today) normal temp i ride it in is 60's or below. I has always ran a little rich, i leaned out the air mixture screws which seemed to help a bit, but overall i felt on cooler days that it ran good enough. Riding it today in 90 degree heat it was running like crap within 15 minutes, basically once it got good and warmed up. Cutting out, coughing, jesus christ it was bad, i had to turn around and come home, hoping i would make it. It was directly related to the temps going way up that i know. I got a recent tune up like a month ago, new points and plugs, new uni air filter. 4 into 1 exaust, yes it runs better without the air filter. Yes there is black soot inside the tail pipe.
So i take it this is a sign of it running way too rich, probably because of the 4 into 1 exaust, and i know i need to do something with the carbs, either rejet or do something with the needles and slides or something like that, so my question is why would the hot temperatures make this problem worse? What would the heat have to do with the air/fuel mix and make it run even richer?

[TwoTired]

Warm air expands.  This means that there are less molecules of oxgen in a given volume of air.  With less oxygen, fuel molecules that it pairs off with during combustion need to be reduced, too, or leaned.

It could be that your throttle valve needles (or needle jets) are worn, or in the wrong position for correct mixtures.
Be ready to synchronize your carbs after slide needle fondling.

What altitude are you at?

Cheers,

[78_SaltLick]

Warm air expands.  This means that there are less molecules of oxgen in a given volume of air.  With less oxygen, fuel molecules that it pairs off with during combustion need to be reduced, too, or leaned.

It could be that your throttle valve needles (or needle jets) are worn, or in the wrong position for correct mixtures.
Be ready to synchronize your carbs after slide needle fondling.

What altitude are you at?

Cheers,

I live in portland, Oregon USA. Altitude? Dang im not sure, i do believe i need to dive into the needle jets adjusting, ive been putting it off since it ran good ever since i made the idle/air screw adjustment to lean it out, but well i dont want to not ride it every time it gets over 80 degrees either or ill be sitting all summer...dammit. I wish i had a really good discription of how this procedure is done, before i tear into it so my bike doesnt sit for a month or so while i try to figure out how to do it right. Is this procedure in a manuel somewhere? ive seen some threads on it here, but nothing really that would take me step by step how to do this, including how to take off the carbs if this needs to be as well. How much would a shop generally charge for this and resyncing the carbs?

[TwoTired]

I was able to change needle heights on my 74 Cb550 while they were still on the bike.  The inner two were a bit tricky, but it can be done in a couple of hours, including carb synch.

Got tools?

Have you looked at page 58 of the Honda shop manual?

[78_SaltLick]

I was able to change needle heights on my 74 Cb550 while they were still on the bike.  The inner two were a bit tricky, but it can be done in a couple of hours, including carb synch.

Got tools?

Have you looked at page 58 of the Honda shop manual?

Yes ive got tools, the manual i do have i printed out off of this link, http://www.mctangen.dk/CB500-550_Manual.pdf im glad i printed it out while the link was still valid, its not there anymore. I will look at the manual for this procedure when i get to work, i left it there.....i have more time at work to do things like that then i do at home.....thanks twotired.

[78_SaltLick]

One thing i have also noticed and not sure if this would make a difference. I had my oil changed at a MC shop, that was last year around the end of summer. I have ridden my bike at least once a week since, put at least 600 miles on it since then. My bike has a small oil leak, every time i park it after a few days a quarter size oil spot will be under my bike. You would think after a while, that the oil level would go down, it hasnt it is still up to the full line. After he changed the oil, it was past the full line. I keep waiting for the oil to drop. Guess what i am getting at is could it be possible that he overfilled the oil when he changed it, would too much oil make a bike run like this? , and overheat like this on a hot day? or would having the oil overfilled cause other issues?

[TwoTired]

You don't have an overheating issue unless your engine is getting too hot.  If it is, your oil will be damaged.

I doubt oil level has anything to do with your performance issues.

If the oil level gets too high, the spinning crank can start to pick up the sump oil and slow the engine down.  It's called windage, as the crank makes a little tornado of air around 7000 RPM or so.  If the oil level is close enough, the tornado sucks it into the crankshaft.
It feels like a sudden drag on the bike, like 200 lbs was suddenly added or you just got a 75 MPH headwind.

Cheers,