Topic: 4into4 pipes on e bay

[junior]

I see used pipes listed on e-bay have 2 drain holes on 1 and 4 cylinders and 1 on 2 and 3. What's the tech reason for that?

[Ozzybud]

All internal combustion engines developed moisture especially at startup. These holes allow that moisture to drain. I don't start any of my vehicles unless I can ride or drive them untill the exhaust gets plenty hot. I believe most of the honda bikes getting a bad rap for rusty exhaust is due to people doing short rides and starting it often in the garage to "make sure they start"
 The exhaust will quickly rot if this is done as the metal is very thin.

[Don R]

  Ozzybud is correct, when I was younger and dumber, I rotted out the exhaust quickly on my new CB500 by starting it often during winter.
 The end cylinders warm up slower than the center cylinders thus making more condensation on the 1-4 than 2-3 and requiring more drain holes.
 

[Cevan]

I'm looking for an exhaust for my 72 500/4.  Did these come from the factory with the 4 into 4?  Mine came with a rusted 4 into 1 (unknown manufacturer).

[junior]

Being "old" I still remember my brand new 72 cb750k2 and the drain holes at the front of the mufflers shooting little "con trails" out on cold mornings upon start up before riding to work. About 2 years later they were rusty around the holes but still solid. I remember only 1 hole per pipe, but maybe on other years Honda added a second hole? Thanks for the response. Gary

[bryanj]

Cevan, all 500 fours came with 4 into 4 from Honda, most cost effective system on sale is Delkavik( not sure on spelling) as there system looks as original and comes with all the brackets you will need to retro fit

EDIT EBay item 276804043787

[jonda500]

Where is the second drain hole on the 1 and 4 pipe located?
I have only ever seen 1 drain hole in these 4 into 4 pipes and I have 12 of them!
John
(edit - I do mean 3 sets of 4, not 12 sets!)

[newday777]

I see used pipes listed on e-bay have 2 drain holes on 1 and 4 cylinders and 1 on 2 and 3. What's the tech reason for that?

Pictures would be helpful in this as 2 holes on one pipe aren't normal. Stock pipes have 1 drain hole per pipe.
Are these used pipes or new??

[BenelliSEI]

Those holes work. I regularly make sure they are clear on all my bikes. Drill them out, blow them out with WD40, air and make sure you can feel them spitting on start up.

[MauiK3]

+1 on holes open
+1 always get it hot, hot after startup

[ZTatZAU]

Does anyone have any good pix of the stock drain holes on stock pipes?
I'd like to accurately locate and duplicate new drain holes in my undrilled HM300 Busso pipes.
ZT

[MauiK3]

Try this.
This is a set of Yamiya reproduction pipes, both sides the same.

[MauiK3]

It's cut off a bit but it's about 2 3/4" from the weld

[BenelliSEI]

Does anyone have any good pix of the stock drain holes on stock pipes?
I'd like to accurately locate and duplicate new drain holes in my undrilled HM300 Busso pipes.
ZT

Your target should be inside the bottom “seam” and at the lowest point. The Honda hole only goes through the outer muffler portion. The main header pipe extends in above the hole location, but is undrilled.

[ZTatZAU]

^  ^^
Thanks guys!  I appreciate the pic and the info.

In the picture, those holes look to be about 3/16"...  Are they really that large?

[MauiK3]

I will go try some drill bits in them and let you know what fits in.

[newday777]

^  ^^

In the picture, those holes look to be about 3/16"...  Are they really that large?

I don't think so. Probably 1/8" or less.

[ZTatZAU]

Hard to tell for sure from Maui's pic but it looks like, especially on pipe #2, there's a slight outward (downward) dimple in the drain hole location.  Is this intentional for better draining or simply an optical illusion?

If there really is a dimple, it was likely done at the factory before drilling or assembling the muffler.  Has anyone ever tried to duplicate, or intentionally create a downward dimple after drilling?  If so, how so?

At the least, I'd certainly like to remove any edge or ridge on the inside of the muffler, resulting from the drilling, that might act like a dam or levee and prevent or restrict flow... but has anyone deliberately tried to "pry" the edges of the hole down a bit to facilitate draining?

Thanks!  ZT