engine rebuild

[fathacarl]

What's you best guess on the cost to completely rebuild a 750-4?
I may wind up doing this but it looks quite expensive.
Cycle X seems a little spendy to me, what do you think?
                                           Thanks
                                               Carl

[Piute]

 
yourself or shop ?complete(new carbs?) is a whole lot ,back to stock ? or competition ?good luck.
                                                http://www.satanicmechanic.org/bigbore.shtml

[fathacarl]

I'll do it myself.  All Stock.  
It just doesn't seem worth it compared to what it would cost to by used motor in running condition.
Just curious.

[TOOLS1]

Rings, and a valve job are about the only thing these engines ever need. And that is after several thousand miles. Rings, and gaskets would be around $150.00, and valves depend on the shop that does them.
TOOLS

[Lucky 1]

Except one thing -if you buy a used motor you still do not know what you have.
If you or another person rebuilds it then you know exactly what you have.

Why do all the work to rebuild the motorcycle and in the end have the nagging question in your head.....
Are the cam chain rubber rollers 33 years old and about to crumble?

[Re-run]

Too bad there is no set cost. I wish there were. It all depends on the work you intend to do. Is it mainly top end or are you doing some bottom end as well?
If top end only, I would budget for $1000. This would include most items and some extra work such as boring. If doing some bottom end, double that cost.
Which incidentally, is the cost of a basic motor from cyclex.
Again, this assumes having to replace most parts with no major damage to repair. If you get stock parts from honda, good chance things will cost even more.
When I do my engine, I will either do a cyclex motor, or do a bare check on my bottom end and put the money into the top in the form of a hotter cam and some porting. I have a once over set of pistons I won from cyclex in my basement that I will also bore for. I will probably reuse my rods and just shot peen them if possible for added strength. I am not going to swallow the cost for new rods if I can at all help it. To me, rods are the most overpriced item in a low power engine. If I were going to really open things up, then some falicon rods would be on my list.

TL:DR $1000 for top end, $2000 for both to cover unforeseen issues.

[Piute]

    When I say stock I'm referring to stock engine spec's 1st off,exh.,air,yes then jet witch will be an on going thing and we get good at it but as it comes along,easyer each time
  stronger and more advanced in technology(money allows)update all ignition stuff,eng.still stock but there  goes 300 or more easy .

[LukeM]

Definitely cheaper to do it yourself.  When my DOHC motor threw its long cam chain, I decided to have a local mechanic work it.  He was a Harley guy, but did do some work on metric bikes/motors.  To pull the motor and tear it all the way down to see what needed replacing, we were up to about $500.  All the parts that we decided to replace (those that needed it and those that were to be done "as long as we've got it apart") were close to $800.  This was rings, main bearings, 2 intake and 2 exhaust valves, long and short cam chains, full gasket set, several seals, and some other stuff.  This was with a friend's 40% discount at the Honda dealer for about half this stuff, and Rice Paddy MC for the used stuff.  I think putting it all back together would have been another $500 or so.

So you see, even with me helping, the labor would have been about a grand USD, and parts close to another grand.  

These engines are not hard to work on. The FSM is just about spot on for working on these guys. You might need a factory tool or two, but sometimes a workaround is possible. There's a bunch of guys on this forum who've done the work you're talking about, and are willing to help as best they can.  You might try a search on the forum for "engine rebuild" at the homepage in the upper right corner.

I wish you good luck, and happy rebuilding.
Luke M

[ATX77]

I am actually having my 77 rebuilt as we speak, so far, with Honda parts, used, and new gaskets, rings, pistons, and complete rebuild its running about 2300.large, but my love for this beauty is much more than that cost. Check out the book "My cb750 book" by mark paris on LULU.com its a pricey book, but well worth the knowledge I just don't have that much time to rebuild myself. Bucly

[Piute]

   Thats what this sight and others are here for So Your Not BY YOURSELF

http://www.amazon.com/CB750-book-Putting-Them-Back/dp/B003NTKQTA 
Available from these sellers......2 new from $149.94

   I paid 250.00 for my bike that just needed tune up stuff,runnlng great with-out 150 dollar book,paid 35 for my F.S.M..
            MAY-be it's for the guy that has every-thing.Sorry

[shinyribs]

Here are rough prices I'm looking at.

New rod and main bearings-      $200

New piston w'rings & pins           150

Cylinders bored                         200

Cam and springs(performance)      250

Paper gasket set                       100

Oil seal kit                                  35

HD cam chain                              30

HD studs                                    80

----------------------------------------
                                            $1,045

New clutch                                  100
----------------------------------------
                                            $1,145 just in parts.

 This assuming your head is good. Mine is,so I haven't priced new valves and guides.

If you need new cam followers they are available new at roughly $55-65 each. You can usually pick up a ''good used set'' off ebay for $40-75 depending on who's selling/pricing them.

IIRC,a new set of primary chains,if needed,will run about $80

They're not cheap! Good thing they are super reliable!

[Lucky 1]

I had cycle-X rebuild my CB750 engine and I am glad i did it.
It did cost but they specialize in those engines and know all the
ins and outs and have all the right equipment and machining services and parts.

Remember you need to round up all the parts(good ones).
You need machining services by a shop that knows motorcycles.
The cases need to be cleaned spotless when re assembling the engine.
You need the special tools to measure the bore and the pistons too.