1978 CB750F - Metric Mayhem

[Rocan]

Re: 1978 CB750F

I've decided to fight temptation on the 836cc, and I'm sticking with stock. Basically the main reason is that I want it to be as reliable as possible. It doesn't make much sense to put a big bore kit in my bike, because I don't want to upgrade the entire engine. It would be nice, but I just can't afford all that high performance stuff. It should probably be completely built for racing, or completely built stock. Not mixed... I'd rather not take the risk, and play it safe.

you can build a reliable street motor.

836, mild cam that only increases lift/not much overlap, maybe a mild port job. throw in a new cam chain and tensioner and your done.

should gain you a couple hp over stock, sound meaner, and still be just as reliable (if not more since you would be going through the motor) as stock.

 

[scroggins5000]

Re: 1978 CB750F

Price is a factor too. I'm saving up for my wedding in January, and I need to keep as much cash in my pocket as possible. ;D Another reason I'm gonna go stock, and not invest in parts that don't need replacing to upgrade the entire motor. Like new cams, cam chain etc.

I should also mention the other stuff we found out <i>needs</i> to be fixed on the motor:

The head gasket seal was warped slightly, and will be machined down. This was probably the only major flaw with the head, and is an easy fix for the shop. The cylinder walls are in pretty good shape. A couple of the spark plug holes need to be re-threaded, because like half of the threads are missing. It looks like there was some moisture build up in the engine that caused this. It probably also caused the pitting in the valves (and the pistons), so the valves need to be replaced. The valve guides need to be replaced too. One was worn down pretty bad. I am also going to replace the valve springs, and retainers as a preventative measure.

 

[tWistedWheelz]

Re: 1978 CB750F

Sounds like the 836 kit won't be that expensive then, have you priced the stock parts? They are just as high as the 836 kits when you add it all up! The kit would solve some of your problems with new pistons, piston walls, gaskets...ect.! Find some titanium valves/springs and you will have a very strong and reliable motor, not to mention the cool factor that the 836 upgrade brings to the racer table! With the 836, some good carbs/intake/exhaust! you could really have some power! I have heard people claiming 65HP from them. The site I sent you has a 4 into 2 into 1 exhaust for the 750 that has the best flow of any pipe on the market for the 750's and is said to work even better on the 836! I would really consider getting the 836 if I were you, check the prices and see if it don't make more sence to upgrade to the 836! You could always run the stock cam and change it later!

 

[scroggins5000]

Re: 1978 CB750F

Sounds like the 836 kit won't be that expensive then, have you priced the stock parts? They are just as high as the 836 kits when you add it all up! The kit would solve some of your problems with new pistons, piston walls, gaskets...ect.! Find some titanium valves/springs and you will have a very strong and reliable motor, not to mention the cool factor that the 836 upgrade brings to the racer table! With the 836, some good carbs/intake/exhaust! you could really have some power! I have heard people claiming 65HP from them. The site I sent you has a 4 into 2 into 1 exhaust for the 750 that has the best flow of any pipe on the market for the 750's and is said to work even better on the 836! I would really consider getting the 836 if I were you, check the prices and see if it don't make more sence to upgrade to the 836! You could always run the stock cam and change it later!

Directly from honda I can get the .5 OS pistons, rings, pins, and clips for $457.56, and I've already got a head gasket. The 836 kit from dynoman (which I think is the only correct kit available for the F2/F3: http://dynoman.net/bikepages/F2/pistons.html ) is $599.95. I know there is one at cycle xchange that is pretty much exactly the same as the wiseco kit and will fit the F2/F3, but I'm certain that it won't give the right compression. It will work better for earlier F models, that are compatible with the K heads. Just look at the photos and the difference in the dome height.
I've already got a Yoshimura <i>style</i> 4 into 1 exhaust from Carpy. Black of course. It's sick. Plus I'm not going for power, I'm going for reliability... and looks

I'M STICKING WITH THE 750, NO 836! LALALA! CANT HEAR YOU!! Hahaha

 

[scroggins5000]

Re: 1978 CB750F

My friend Aaron who is helping me work on the bike decided he wants to start an LLC for working on bikes called "Metric Mayhem". Being a graphic designer, I made a logo for him (and some other artwork), and I've decided I want to use the logo to make some new custom badges to go on the tank. I'm going to try and get them 3D printed in plastic (I may have them done in stainless steel, but it may be too expensive for me). This guy I went to school with said he would help me with converting the art into 3D files for printing. I still need to work on getting the sizing correct, but here's the flat artwork. I wanted them to look similar in shape to the stock Honda super sport badges. I haven't seen anyone do this yet, but I think it will work out well.

 

[tWistedWheelz]

Re: 1978 CB750F (METRIC MAYHEM)

love the logo man, looks great, nice details in there.

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

Thanks!

I think I am going to use a material called Alumide, which is a plastic that has aluminum powder mixed in it for added strength and durability. It will be produced by a process called selective laser sintering.

Here's a video of how the process works:

[youtube=425,350]<object width="640" height="385"><param name="movie" value="http://www.youtube.com/v/gLxve3ZOmvc&hl=en_US&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/gLxve3ZOmvc&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="640" height="385"></embed></object>[/youtube]


I finished more detailed specs of the badges, and sent it to my friend Wes to be converted into a 3D file for printing. Here is the revised art.

 

[gribbs]

Re: 1978 CB750F (METRIC MAYHEM)

Looks like a handfull, but your doin well so far! Just wondering - what does your rear-set set-up consist of?

 

[tWistedWheelz]

Re: 1978 CB750F (METRIC MAYHEM)

I suggest eliminating the mounting post and having a 2mm raised lip around the back. Then use 3M emblem tape to mount on any surface. The lip will conceal the tape!

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

Looks like a handfull, but your doin well so far! Just wondering - what does your rear-set set-up consist of?

I purchased a set of Raask rear sets from Omar's rear sets. Here's the link: http://www.rearsets.info/ I think they were about $300. Some of the pictures in the gallery don't match to what's correct for a certain model year. It's best to call or email them.

Oh, and the set I have doesn't have the swing arm bolt go through it like the original sets. They go around the swing arm bolt, so I had to shorten it, and have it re-threaded.

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

I suggest eliminating the mounting post and having a 2mm raised lip around the back. Then use 3M emblem tape to mount on any surface. The lip will conceal the tape!

That's a pretty good idea. I may end up doing that, because then they can fit on any tank.

Depending on how these turn out, I actually might do some more custom badge designs. That site allows you to upload your design, and whoever wants it, can order them directly from the site. You can even choose your own materials.

 

[InkOverdoseD]

Re: 1978 CB750F (METRIC MAYHEM)

Scrogg, dude just read this whole thread and my girl is about to kill me avoiding her on a weeekend...hehehehehe...

I'm a NewB, no mechanical skills but been learning alot from you and "tweakin"...thx for the detailed posts..it helps me learn kid...

My biggest mistake might be that I got into the cafe craze 4 weeks ago without knowing what I was getting into and bought two 750SS cause I learned "of the internet" that they were the optimun cafe bikes to have.....but the more I read up on it the more intimidating it becomes...but I'm sick in the head cause I like challenges....hahaha...but I know I'll be happy once I get it done....

Keep up the good work kid...

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

Scrogg, dude just read this whole thread and my girl is about to kill me avoiding her on a weeekend...hehehehehe...

I'm a NewB, no mechanical skills but been learning alot from you and "tweakin"...thx for the detailed posts..it helps me learn kid...

My biggest mistake might be that I got into the cafe craze 4 weeks ago without knowing what I was getting into and bought two 750SS cause I learned "of the internet" that they were the optimun cafe bikes to have.....but the more I read up on it the more intimidating it becomes...but I'm sick in the head cause I like challenges....hahaha...but I know I'll be happy once I get it done....

Keep up the good work kid...

It's cool. I consider myself a newb too. Maybe once this bike is done, I will feel differently. Plus I'm getting a lot of help from my friend Aaron (the bike is in his hands now), and my Dad's machine shop. I have the vision though, and I am learning a whole lot.

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

Here is the 3D rendering of my custom tank badges. I thought it came out bad ass. It's going to be revised slightly so that the text isn't as tall as the wing logo. I can't wait to get this printed. Also, the posts on the back have been removed, and it is recessed 2mm. This way we can use this design for other tanks in the future with 3M emblem tape. Thanks for the suggestion Twisted.


3D Rendering:

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

Here is the updated revised version:


Back and front view:

 

[tWistedWheelz]

Re: 1978 CB750F (METRIC MAYHEM)

That is going to be great! I love it! Glad I could help in some way, that is why I am on DTT, to exchange ideas and knowledge. I offer what I can because I have learned so much from so many on here!
Cheers!

 

[scroggins5000]

Re: 1978 CB750F

I've decided to fight temptation on the 836cc, and I'm sticking with stock. Basically the main reason is that I want it to be as reliable as possible. It doesn't make much sense to put a big bore kit in my bike, because I don't want to upgrade the entire engine. It would be nice, but I just can't afford all that high performance stuff. It should probably be completely built for racing, or completely built stock. Not mixed... I'd rather not take the risk, and play it safe.

Well this is becoming a wash... Every place I call, or try to order pistons and rings from, doesn't have them. I was hoping to find one place that just had at least 4 of each, but now I'll take whatever I can find. I have found some pistons here and there, but I have only found two ring sets. Both on ebay. If I can't find two more sets, I am going to have to just go with the big bore kit form Dynoman.

 

[scroggins5000]

Re: 1978 CB750F

Well this is becoming a wash... Every place I call, or try to order pistons and rings from, doesn't have them. I was hoping to find one place that just had at least 4 of each, but now I'll take whatever I can find. I have found some pistons here and there, but I have only found two ring sets. Both on ebay. If I can't find two more sets, I am going to have to just go with the big bore kit form Dynoman.

Just two more ring sets! Anyone have any? Here's the part no. 13011-410-601

 

[scroggins5000]

Re: 1978 CB750F (METRIC MAYHEM)

Well, I gave up on finding STD pistons and rings. I just went ahead and ordered the 836 piston kit for the F2 from Dynoman. Once these come in, we can finally finish rebuilding the motor. The shop already has the new valve guides I ordered (from Dynoman) and the new valves (from cyclexchange.net). I'm tired of looking and waiting, especially since it's spring. I've got the itch to ride.

Two of the spark plug holes in the motor have new threads in them now, because they were halfway gone.

Next I need to find a new gear for the transmission. One of them had some teeth snapped off. I think it's the first gear, but I can't remember right now. I guess the PO(s) of this bike gave it some hell on the street.

 

[thompsonmx100]

Re: 1978 CB750F (METRIC MAYHEM)

I just saw a set of oversized pistons from cycle exchange for the f2 on ebay.