Author Topic: 1975 CB750 Build! "Kona" - Sold and gone. (Read 69502 times)

Tews19 · « **Reply #100 on:** July 26, 2014, 07:39:02 AM »

Nope. I read if I recall from bwaller or Ape that it was somewhat overkill on the 550. I may be lucky to gain a few HP with this build with the minimal work I did.

calj737 · « **Reply #101 on:** July 26, 2014, 07:58:41 AM »

Sorry for the hijack...

Just a big bore kit? No Stage 3 or big cam? If not, then yup, stock is good. But if... MRieck told me I'd be very smart to install them with the work on my 500. I got APE studs and ARP nuts.

Ravie · « **Reply #102 on:** July 26, 2014, 09:16:45 AM »

No problem!

Is there any HP difference to go multiple oversizes up if you did nothing else to the engine?

calj737 · « **Reply #103 on:** July 26, 2014, 11:05:37 AM »

Yes, but not the full benefit without improving the induction and valve train. In essence, it becomes somewhat fruitless. A large combustion chamber needs more air and fuel mixed into it to provide the best result. Otherwise you're starving the chamber, so no point really.

Whether you change carbs or cam, or even valve sizes, it's always advantageous to port and polish the intakes, head and exhaust ports. It provides the best flow of air and smoothes the turbulence. Think of it as the foundation upon which you can build larger combustion events.

Ravie · « **Reply #104 on:** July 26, 2014, 11:25:11 AM »

That's pretty much what I was thinking. Are there any examples of the best places to "help" head flow around? Maybe some pictures or videos?

calj737 · « **Reply #105 on:** July 26, 2014, 11:40:06 AM »

Here's some pictures from the best guy around, Mike Rieck. This is my 500 head he did a Stage 3 job on. Intakes and exhausts, plus manifolds pictured:

SOHC4 Cafe Racer Fan · « **Reply #106 on:** July 26, 2014, 03:12:11 PM »

Quote from: calj737 on July 26, 2014, 11:40:06 AM

Here's some pictures from the best guy around, Mike Rieck. This is my 500 head he did a Stage 3 job on. Intakes and exhausts, plus manifolds pictured:

Magnificent. I think even MR would tell you that it's not solely about widening the ports but getting optimal shape. That's where there is an art to porting to optimize flow.

Tews19 · « **Reply #107 on:** July 26, 2014, 03:36:06 PM »

Quote from: calj737 on July 26, 2014, 07:58:41 AM

Sorry for the hijack...

Just a big bore kit? No Stage 3 or big cam? If not, then yup, stock is good. But if... MRieck told me I'd be very smart to install them with the work on my 500. I got APE studs and ARP nuts.

650 cam and I think stage 2 head work. ...

Ravie · « **Reply #108 on:** July 26, 2014, 08:02:01 PM »

Hey guys. I had a bunch of little things I wanted to talk about so I just went ahead and made a video for you.

https://www.youtube.com/watch?v=R-ti1IDkVZg

Tews19 · « **Reply #109 on:** July 27, 2014, 06:10:13 AM »

Ravie we just got home. The 360 tank is funky on my 750. I'd say it doesn't work on a 750.

Ravie · « **Reply #110 on:** July 27, 2014, 06:40:46 AM »

^ Cool Tews. Thanks. I'll go ahead with the CX tank.

Ravie · « **Reply #111 on:** July 27, 2014, 02:17:37 PM »

I haven't seen any replies to my vid here yet, so I'm guessing you haven't yet seen my mess...but it was BAD. Spent nearly half the day today cleaning the garage. Trying to clean the built up tar and oil and guck from the inside of my chain guard. Both are just as bad as one another...i've got it soaking and every 20 minutes I go scrub some more...

I went scratching up the rear light bar with rough grade steel wool hoping I could score it enough for paint...but it kept getting shinier...haha So I kept going with successive grades and now it's shiny! I guess the bike will have some shiny parts after all... But not many, darnit! This ain't no show queen!

I've been really thinking hard about my plans going forward. When I still had a full time job I was planning to get the frame blasted and powdercoated and stuff, but now that I'm looking at it with fresh eyes I'm thinking of other options. It's not in terrible shape. I could likely clean up some rusty spots and hit it with either Rustoleum or POR-15.

I may make another video before too long with more thoughts and questions. I'm hoping a few of you will give me your opinions on some of the things from the vid a few posts above ^

edwardmorris · « **Reply #112 on:** July 27, 2014, 03:07:28 PM »

I saw the vid but I can't recall all the questions. I do know you were wondering about ultrasonically cleaning the carbs, I can tell you it works well if you have one, I had a loaner so I did mine that way, came out nice

http://forums.sohc4.net/index.php?topic=126735.msg1542350#msg1542350.

Ravie · « **Reply #113 on:** July 27, 2014, 03:55:07 PM »

I saw a cool write-up on cleaning them using a home-made soda-blaster, too. I bought the hose for it... you essentially use a small clear hose and cut a slit and put your air hose in it and tape it on and it creates a venturi that will suck baking soda right out of the box. I need to get a new belt for my compressor tomorrow and then plan to try it.

I've got a thing of carb cleaner I plan to dip them in, as well. If I can't buy parts I can at least clean what i've got so it's ready for re-assembly.

One of the questions I had was about the coils. I've got two TEC coils (and TEC points...should I clean the contacts and try to use them?) and I'm curious if I should see if one works and how I might about testing them. I know that can be difficult to do.

mrbreeze · « **Reply #114 on:** July 27, 2014, 05:18:05 PM »

I use an old chevy points distributor for checking coils. That......a battery charger (or a charged car battery), and a vise. Just wire it up the way the way you would in the car using which ever coil you want to test.

edwardmorris · « **Reply #115 on:** July 27, 2014, 05:24:25 PM »

Soda blasting is good for the carb bodies, but you may still need to US clean the jets and such to get the gunk (if any) out of the small passages. As for the carb dip, I was advised to stay away from it if you don't want to lose the factory iridescent finish on the bodies.

Ravie · « **Reply #116 on:** July 27, 2014, 06:49:52 PM »

Too late! haha. So far it looks like all I'm going to need are bowl gaskets and fuel share-pipe o-rings(just came up with that name myself.). The first two I have taken apart were OK. Floats look good, etc. I finally figured out where the ID stamp is. 657B's. 105/40 jets. 2.0 on the inlet.

Ravie · « **Reply #117 on:** August 01, 2014, 07:53:37 AM »

Prepped and sprayed the frame and swingarm yesterday. Several coats of spray bomb rustoleum flat black and hot sun to help cure it.

836 big bore the plan, as it will actually cost less. That'll be neat. I have some experience porting aluminum heads so ill do some light work in the head.

Obligatory pics.

Sent from my HTC One V using Tapatalk

calj737 · « **Reply #118 on:** August 01, 2014, 09:18:24 AM »

if you can rig up some type of oven or hot box to help cure the paint, it will improve its durability.

Ravie · « **Reply #119 on:** August 01, 2014, 11:56:00 AM »

I suppose I could set it up and put a heater on high below it for a couple hours...

edwardmorris · « **Reply #120 on:** August 01, 2014, 12:32:25 PM »

Grepper's attempt

http://forums.sohc4.net/index.php?topic=130303.0

Ravie · « **Reply #121 on:** August 01, 2014, 01:02:29 PM »

I could see cooking the small stuff but the frame? I'd need a whole refrigerator box...

Ravie · « **Reply #122 on:** August 01, 2014, 02:13:56 PM »

I'm certain I should google this first, but, Is it possible to install new wires in the stock TEC coils?

calj737 · « **Reply #123 on:** August 01, 2014, 03:18:02 PM »

Replace the spark plug wires? Yes, it can be done. Gotta drill out the originals. Many simply use a splice kit to create new ends.

Ravie · « **Reply #124 on:** August 01, 2014, 03:25:32 PM »

I guess my second question is: The two coils I have are obviously originals. Which means if they even still work it'd be a miracle. Are there replacements that don't cost an arm and a leg? I shall google.

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Author Topic: 1975 CB750 Build! "Kona" - Sold and gone. (Read 69502 times)