Topic: Stock exhaust discoloration?

[salukispeed]

Can anyone tell me if it is normal for these automatics to turn the exhaust pipes blue . I do not remember ever seeing one that was not discolored most of the way to the mufflers. I cleaned and polished mine last night until they were mostly silver again but they all were discolored by the time I got to work this morning. 28 miles of 65-70 mph travel. Bike runs and drives great so far. Timing is spot on with a timing light and carbs are clean and synced with in 1/2-3/4 inch, all four pipes are discolored about the same amount.

[raymond10078]

I'd say you're running a little lean.  Is your bike stock - i.e, stock exhaust, stock air filter and housing?

My pipes are not blue at all.

[salukispeed]

Yes everything original including a new honda air cleaner. The pipes were already very discolored and blue when I got it and I have no idesa what the Previous owner  did. None of my other Honda's were known for turning the pipes this blue. I agree that Lean or even retarded timing would be a likely cause. When I did the carbs I set the float levels at the Honda Manual spec. ( 14.5 MM ) if my memory serves me. I will recheck for good fuel flow from the petcock when I get home. Valves set at .002 and .003 in Jetting is factory numbers according to the book too. The bike runs great from idle all the way up to 90+ With little or no hesitation on acceleration once the engine is warmed up normally 2-3 minutes
Thanks

[raymond10078]

Well . . . sorry to say, but the Honda spec for a 77 (and 78) is 12.5 mm.  The 76 float setting is 14.5 mm.

I'd say that your float setting is making you run a little lean.

Still could the timing, too - I assume that you set it statically, and then checked when running with a strobe?

[salukispeed]

Yes set static with .014 point gap then used a strobe to get right on including the advance goes right right between the double lines for 1-4 and 2-3.
 As far as the float dimension I was writing from memory ( good memory but short sometimes ) but the dimension I used is the book setting. I will verify when I get home as I wrote it down when I did it. Thanks again for the info and thoughts. It is nice to bounce ideas off someone else and get all the facts together. It is not that hard to remove the carbs and check the level If I need to.

[grcamna2]

The Ethanol in our present fuels may want you to slightly richen it up a bit...possibly raise the float level toward the carb body 1mm closer to richen her up.I could be wrong, but I think the A's have smaller carbs than the K's & F's which would also feed it a bit less flow for Automatic operation...

[raymond10078]

I can relate.  My memory is excellent, as far as I know.

If I don't remember it, it didn't happen - although my wife may say different . . . .

[raymond10078]

I just remembered (told you I have a good memory) that I did put in needle shims - because our bikes do run lean from the factory.  I'd rather run a little richer than stock, for that reason.  Didn't mess with the main, just raised the needle.

But, my bike had 15k miles on it before I got it, and the pipes are not yet blue.

[salukispeed]

Just checked my numbers and I set the stupid float level's to 14.5 just like the book says for the PD44A carbs then I re read the carb body and I have PD44B which calls for 12.5 just like you said, Looks like I need to re-do them. This may account for some of the pinging I heard coming off the stop lights on the way home now that it is 80 degrees. 42+ MPG this way even traveling 65-70 MPH almost all the way home. Plugs are sure clean now too. funny it sure runs well with no hesitation and good throttle responce. Alcohol blended fuel cant help either.
Thanks Again

[77Pinto]

Mine were blue when I got it.




Bill

[Jerry Rxman Griffin aka MuthaF'er]

Does your bike have the same 4-1 stock exhaust as my 75 750F? My pipes have never blued. Have you done a plug chop and richened up the jets?

[dave the welder]

ok mine are not blue they are gold. its a 77  all stock.   also are these things always cold blodded ?mine is a pain to start cold.yes the choke is opening and closing properly.carbs are clean.valve lash is as good as i can get .points and timing spot on.(dwell meter used to make sure both points are as close to each other as possible.timing both at idle and reved up are correct). once its warmed up   5 min or so it runs fine.on another note after running 70mph for 30 min or so when you come to a stop it intermintently backfires out either muffler .not consistently just randomly

[salukispeed]

The A's use a four into two exhaust without a cross over. so 1-2 go left side and 3-4 go right. . Mine are original and not rusted out but were destroyed from the previous owners.  The tuneup was so far off when I got it that I am not supprised they are  so bad. So I dont know if they will even stay silver even when I get the floats set to 12.5 this weekend. I may even try 11.5 or 12 to fatten it a little bit because of the alcohol blend gas today but I dont want to get too close to the top of the overflow tubes. I will look at the idea of shimming the needles while the carbs are out but not sure. My bike is also a little cold natured but after a couple minutes it is fine.

[salukispeed]

Finally got around to redoing the carbs and set the float levels to 12 1/2 mm. after reassembling the bike and resyncronizing them I am very happy. Not as cold natured and runs great. Little or no hesitation little or no ping even when riding in traffic and 90 degrees even if I leave it in the drive range as a test.
Thanks for the thoughts and help

[77Pinto]

I bought some stuff call Blu-Away and it does a decent job of removing the blue off chrome.



Bill

[salukispeed]

Used blue away some years back and it ws pretty good then I will have to look for it again
Thanks

[stinkfinger]

Remember, the stock settings just give you a baseline to "start" with,
then adjust to your preferences.

Tony