Topic: Replacing wheels and exhaust pipes for Honda CB750

[kyle750]

Take some pictures of the “rust through” areas. There are drainage holes on the underside where the head pipes connect to the muffler portion…. Keep those open.
Smaller holes, on the underside where they are not visible?

Thank You. I will look for them tomorrow.

[kyle750]

I remember seeing pictures of your bike. The pipes looked pretty good. Did you try cleaning them up?

Thank You Sir!

[Stev-o]

I have no idea why my #2 rusted out so badly. 

This is very common.  At one time on this forum, there was a "#2 club" made up of guys that were in search of a #2 pipe 'cause it was rusted out and needed replacement.

[kyle750]

I have no idea why my #2 rusted out so badly. 

This is very common.  At one time on this forum, there was a "#2 club" made up of guys that were in search of a #2 pipe 'cause it was rusted out and needed replacement.

Does anyone know or are there any popular theories  why the #2 pipe had so many rust problems?

[MauiK3]

Not sure but rust from the inside is usually from not running them until they are hot and dry inside, corrosive liquid settles in the bottom. Have to keep the little weep holes open.

[newday777]

I have no idea why my #2 rusted out so badly. 

This is very common.  At one time on this forum, there was a "#2 club" made up of guys that were in search of a #2 pipe 'cause it was rusted out and needed replacement.

Does anyone know or are there any popular theories  why the #2 pipe had so many rust problems?

Was it dripping battery acid from the vent tube of a wet cell battery?

[kyle750]

Was it dripping battery acid from the vent tube of a wet cell battery?

Impossible for me to tell why this #2 rusted so badly while the other 3 stayed in relatively good condition. Once removed I will not be conducting an autopsy to determine the cause of death.  #2 had a good life, rumbled and roared like a lion, rest in peace!

[kyle750]

341 baffle diffusers

I ordered replacements from Yamiya and they will be arriving with the new #2 pipe. A quick update on shipping from the USA.  The consolidated shipment (very large) of Honda parts from FEDEX arrived in Thailand quickly but it is being held in Thailand Customs awaiting clearance.  Most packages are cleared quickly in only a few hours but Customs randomly selects packages for inspection.  All the documentation and actual costs are correct so hopefully it will clear and get delivered soon.

Delays are inevitable - No Worries - No Hurry

[kyle750]

Finished cleaning the #3 and #4 header pipes. I have a problem with chrome flaking off the #1 header pipe that I am looking at now. Also the chrome on the oil filter cover is flaking off and looks terrible.   Not exactly sure how to proceed with this.  I will take  photos and post later. 

[HondaMan]

The biggest problem Honda cited about the #2 pipe has to do with the drain hole on the bottom clogging up with chain-lube thrown-off goo. In my [old] shop we made it a point to wipe the bottom of the #2 pipe on every 750 (4-piper) that came through, and poke a broken-off cotton swab up into the hole to clear it. Some had 2 holes, too, about 1/2" (1 cm?) apart. I think this was why/how my own OEM pipes went over 80k miles before that spot finally cracked open. I put on a new #2 then (1980) and rode it until 2 more split at the rear diffusers in 1996 or so, and finally bought a set.

[kyle750]

The biggest problem Honda cited about the #2 pipe has to do with the drain hole on the bottom clogging up with chain-lube thrown-off goo. In my [old] shop we made it a point to wipe the bottom of the #2 pipe on every 750 (4-piper) that came through, and poke a broken-off cotton swab up into the hole to clear it. Some had 2 holes, too, about 1/2" (1 cm?) apart. I think this was why/how my own OEM pipes went over 80k miles before that spot finally cracked open. I put on a new #2 then (1980) and rode it until 2 more split at the rear diffusers in 1996 or so, and finally bought a set.

Thanks for the excellent explanation.  I'm looking for the drain hole now through the thick forest of rust

[kyle750]

Oil Filter Cover

I'm not sure what is going on here? Flaking chrome plate over aluminum??  I did not have the time to work on the bike today but I'm thinking just wait until the next oil change and then take a small circular brass wire brush connected to a drill to both sides of the oil cover to remove all the flaking??? Then what?

Did Honda CB750s come with chrome plated oil filter covers or maybe this was a peculiar JDM thing?

[kyle750]

 . . .  or I could just buy this  . . . but my goal is not a show bike - running well and looking better is the objective. IMO this is too shiney and  would look out of place with the rest of the engine.

 A direct quote from the seller.  I appreciate someone who takes pride in his work!

Sorry aluminum polishers. Our polished covers are better than yours.
These covers are absolutely polished to perfection. Awesome!
Includes the Dyno, Clutch, Transmission & Valve Covers.
Attention restoration folks! You might not want these covers, because they are better than original Honda covers.

[newday777]

Oil Filter Cover

I'm not sure what is going on here? Flaking chrome plate over aluminum??  I did not have the time to work on the bike today but I'm thinking about taking a small brass wire brush and knock off the flaking??? Then what?

From your pictures, I don't think that is flaking chrome on the oil cover. Does it look like chrome? Do you have other engine covers that are chrome on the bike?
Stock the filter covers are painted like the cases, cylinder barrels and the head.
Most of us use Duplicolor DE1615 high heat engine paint on our engines.

[kyle750]

Most of us use Duplicolor DE1615 high heat engine paint on our engines.

Thanks mate.  I agree that refinishing and repainting would be the way to go! I am quessing that bead blasting would be the best way to get back to bare metal.

I saw this listing on ebay:

https://www.ebay.com/itm/166992379689

I also like the seller's tag at the bottom on the item description:

Pay for it ONCE, love it FOREVER : )

[BenelliSEI]

Clean and paint yours. It will look just as good. You can do it anytime. You’ll just lose a few once’s of oil that are in the filter. Put everything back when done, and add a bit of oil.

When you remove the filter, look closely. When you pull the filter off the centre mounting bolt, there should be a washer between the filter and the spring under it. It will stick to the underside of the filter, and often gets thrown out by mistake…..

[kyle750]

Clean and paint yours. It will look just as good.

It does look like an easy job

[BenelliSEI]

Clean and paint yours. It will look just as good.

It does look like an easy job.


When you remove the filter, look closely. When you pull the filter off the centre mounting bolt, there should be a washer between the filter and the spring under it. It will stick to the underside of the filter, and often gets thrown out by mistake…

[MauiK3]

The filter housing can be buffed up and not look too bad, no real need to go full polished, it won't hold up in your environment.
Be careful not to over tighten when installing, a common problem.
Use a socket on the filter bolt, not an open end wrench. Keep the hex from rounding off!

[newday777]

The filter housing can be buffed up and not look too bad, no real need to go full polished, it won't hold up in your environment.
Be careful not to over tighten when installing, a common problem.
Use a socket on the filter bolt, not an open end wrench. Keep the hex from rounding off!

Use a 6 point socket!

[kyle750]

Continuing with the inspection and cleaning of the chrome on the exhaust pipes.  All the header pipes are in good shape except the #1 which has some flaking and bubbling up of the chrome. Not sure how to proceed here?

I will go ahead and refinish and paint the oil filter cover. Many Thanks for the advice!

I imagine I should try to clean the rust off the exhaust header pipe flanges clamps (which BTW I think look super cool).  I'm not sure I can get steel wool in the very tight space - maybe just wrap some steel wool around a thin stick??

[kyle750]

#1 vs #2

OEM Honda heat shield has been ordered and new #2 pipe ordered from Yamiya

[BenelliSEI]

The best way to clean the finned clamps is when they are off the bike. Do it when you replace that pipe…..

[newday777]

I clean the finned clamps up on the bench grinder wire wheel. It doesn't harm the chrome unless the chrome if flaking off already. If it is flaking off, replace the clamp.

[newday777]

Continuing with the inspection and cleaning of the chrome on the exhaust pipes.  All the header pipes are in good shape except the #1 which has some flaking and bubbling up of the chrome. Not sure how to proceed here?

I will go ahead and refinish and paint the oil filter cover. Many Thanks for the advice!

I imagine I should try to clean the rust off the exhaust header pipe flanges clamps (which BTW I think look super cool).  I'm not sure I can get steel wool in the very tight space - maybe just wrap some steel wool around a thin stick??

Replace the #1 pipe. Unless you have a chrome shop local that will rechrome it.