Rebuild

[KarlM]

I am thinking of having my 71 Cb750 rebuilt. (Top end). It has just 8k miles and is all original.  It runs perfect but is weeping very very small amount of oil between head and cylinder.  I think the valves could use a cleaning and seats re done while it's apart.  The bike was last registered in 1980 before I bought it 2 years ago and spent that time in a basement. It's a beautiful bike and I actually want to use it more next season.  Can someone recommend a real good mechanic.  I live in PA but  will trailer of ship on the east coast.
Thanks

[TOOLS1]

8,000 miles, that engines is not even broken in yet. Also cleaning of valves, and seats is not something that is actually done on an engine. You oil seeping is actually the seals (which are referred to as nickels because they are about the size, and shape of a nickle) under the cam towers that seal the holes over the head bolts. The only hard part about fixing this is removing the engine to be able to remove the valve cover. I could do this whole procedure in a day, and I am sure you could do it. A shop will probably charge you $600-800 to do it. However a top end rebuild is going to be $2,500 +.... thrown away.
TOOLS

[KarlM]

Thanks.  I have a backfire on #4 cylinder on down shifting. I thought maybe the valve had a deposit and wasn't seating perfectly and thus the backfire.  I know 8k miles is Nothing but it sat for 33 years.  I am just guessing that's why I am asking.   I have rebuilt twins but never a honda.

Thanks

Sent from my iPad

On Dec 6, 2014, at 4:06 PM, "TOOLS1 [via Honda CB750'S]" <[hidden email]> wrote:

8,000 miles, that engines is not even broken in yet. Also cleaning of valves, and seats is not something that is actually done on an engine. You oil seeping is actually the seals (which are referred to as nickels because they are about the size, and shape of a nickle) under the cam towers that seal the holes over the head bolts. The only hard part about fixing this is removing the engine to be able to remove the valve cover. I could do this whole procedure in a day, and I am sure you could do it. A shop will probably charge you $600-800 to do it. However a top end rebuild is going to be $2,500 +.... thrown away.
TOOLS

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rebuild-tp4054678p4054680.html

To unsubscribe from Rebuild, click here.
NAML

[KarlM]

I believe the leak is the head gasket and could be a reason for the backfire. No?

Sent from my iPad

On Dec 6, 2014, at 4:06 PM, "TOOLS1 [via Honda CB750'S]" <[hidden email]> wrote:

8,000 miles, that engines is not even broken in yet. Also cleaning of valves, and seats is not something that is actually done on an engine. You oil seeping is actually the seals (which are referred to as nickels because they are about the size, and shape of a nickle) under the cam towers that seal the holes over the head bolts. The only hard part about fixing this is removing the engine to be able to remove the valve cover. I could do this whole procedure in a day, and I am sure you could do it. A shop will probably charge you $600-800 to do it. However a top end rebuild is going to be $2,500 +.... thrown away.
TOOLS

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rebuild-tp4054678p4054680.html

To unsubscribe from Rebuild, click here.
NAML

[TOOLS1]

That leak between the head fins, and cylinder fins is very common on these engines, and is the seals between the cam tower and the head. Also a leaking head gasket would not make an engine backfire. You most likely have a dried out carb boot causing a vacuum leak, which will cause a backfire.
TOOLS

[shinyribs]

Nothing for me to add here. Tools is spot on.

[KarlM]

Thanks.  I will get some new boots and not worry about the leak.  It's really a non issue. 

One swipe with a paper towel between fins.

I appreciate your input.

Sent from my iPhone

On Dec 6, 2014, at 5:23 PM, TOOLS1 [via Honda CB750'S] <[hidden email]> wrote:

That leak between the head fins, and cylinder fins is very common on these engines, and is the seals between the cam tower and the head. Also a leaking head gasket would not make an engine backfire. You most likely have a dried out carb boot causing a vacuum leak, which will cause a backfire.
TOOLS

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rebuild-tp4054678p4054686.html

To unsubscribe from Rebuild, click here.
NAML

[KarlM]

Thanks again TOOLS1.  I have purchased parts from a few suppliers.  Do you have a preference?

I see carb boots at various prices and wonder why such a difference.

Thanks

Sent from my iPad

On Dec 6, 2014, at 5:23 PM, "TOOLS1 [via Honda CB750'S]" <[hidden email]> wrote:

That leak between the head fins, and cylinder fins is very common on these engines, and is the seals between the cam tower and the head. Also a leaking head gasket would not make an engine backfire. You most likely have a dried out carb boot causing a vacuum leak, which will cause a backfire.
TOOLS

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rebuild-tp4054678p4054686.html

To unsubscribe from Rebuild, click here.
NAML

[TOOLS1]

I would recommend vintagecb750.com I get most of my parts from them, and Cycle-X
TOOLS

[KarlM]

Thanks again !!!

Karl

Sent from my iPhone

On Dec 7, 2014, at 11:16 AM, TOOLS1 [via Honda CB750'S] <[hidden email]> wrote:

I would recommend vintagecb750.com I get most of my parts from them, and Cycle-X
TOOLS

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rebuild-tp4054678p4054702.html

To unsubscribe from Rebuild, click here.
NAML

[Rockwork]

I've been ordering a lot of replacement parts over the past 18 months, and in addition to vintagecb750.com have been very satisfied with:
cb750supply.com (seems to closely parallel vintagecb750.com)
4into1.com

However, after my aftermarket clutch cable braking just coming out of the Shenandoah Mountains I've been looking more for OEM parts and willing to pay the higher price. A descent source beside eBay has been:
Babbitsonline at hondapartshouse.com

Regarding the boots, TOOLS gave priceless advice to boil them in wintergreen oil, which made my originals supple again and completely cured my vacuum leak.

[KarlM]

Thanks Rockwork.

Sent from my iPad

On Dec 7, 2014, at 2:58 PM, "Rockwork [via Honda CB750'S]" <[hidden email]> wrote:

I've been ordering a lot of replacement parts over the past 18 months, and in addition to vintagecb750.com have been very satisfied with:
cb750supply.com (seems to closely parallel vintagecb750.com)
4into1.com

However, after my aftermarket clutch cable braking just coming out of the Shenandoah Mountains I've been looking more for OEM parts and willing to pay the higher price. A descent source beside eBay has been:
Babbitsonline at hondapartshouse.com

Regarding the boots, TOOLS gave priceless advice to boil them in wintergreen oil, which made my originals supple again and completely cured my vacuum leak.

---

If you reply to this email, your message will be added to the discussion below:

http://honda-cb750-s.456789.n3.nabble.com/Rebuild-tp4054678p4054708.html

To unsubscribe from Rebuild, click here.
NAML