Topic: 1978 CB750 - Re-born a 836cc Wiseco JMR Ported Hot Rod

[SOHC4 Cafe Racer Fan]

Do you have any plans to have the stator rewound? I assume you have all new electrical parts coming in and just haven't gotten to that part of the build yet. I also do not know what sort of power it out put you want. Just kind of curious with your alternator/stator plans as you put this all back together.


Sent from my iPhone using Tapatalk

Ruckus2115,

Why would he need to consider having the stator rewound?  This is a part that VERY RARELY has issues.  Charging is anemic on CBSOHC4s compared to modern bikes, but the stator is NOT a common source of failure.  The usual culprit of a defective charging system is a short in the 40-year-old wiring. 

Here. Eric has no plans to run EFI or taxing electronic accessories that I am aware of, so the stock charging system should suffice.  IF he wanted to augment the charging system, he could go with an Anders-build 32 AMP upgrade, but that is overkill for his needs.

[Ruckus2115]

I was really just curious if he had any plans for that area of the rebuild. Wasn't suggesting that he needs to. And from my research I have gathered that yes these are pretty bullet proof stators. Was really just wondering what else he planned to do with the rebuild. Wasn't a loaded question or anything. Genuine curiosity that's it.


Sent from my iPhone using Tapatalk

[Ericcb750]

Thanks for the info on the stator...So Far I have already picked up the wiring for an entirely new harness... i have an M-unit v.2 as the brain, new Ricks Reg/rec, Dyna Coils, dyna ignition, All New Moto-gadget 3 button momentary switches, New H4 headlight, LED tail light , and 4 spankin new Moto-gadget pin turn signals,  Also, My buddy Don helped me out by selling me a KOSO speedo/tach combo that i have mounted up to the front end in my garage at the moment...

I had Devin (at Cognito) drill and tap a couple bolt holes into the lower side of the top triple so I could mount a few different types of gauges.....

I may have bitten off more than I can chew with this as I've never wired a bike but I will take my time and have help from the pro's when needed.....I also picked up a full motogadget wiring kit to go along with it.

I've never put this much into a bike before ($ or time) so it is definitely initimidating but i know in the end it's going to be the EXACT BIKE That i wanted...... Always appreciate info/advice and a lot of the guys here have been awesome...

Don has been amazing, Cal helped me out with some wiring diagrams for literally the exact wiring job i'm doing....

[SOHC4 Cafe Racer Fan]

I was really just curious if he had any plans for that area of the rebuild. Wasn't suggesting that he needs to. And from my research I have gathered that yes these are pretty bullet proof stators. Was really just wondering what else he planned to do with the rebuild. Wasn't a loaded question or anything. Genuine curiosity that's it.


Sent from my iPhone using Tapatalk

Ruckus,

Hey. I wasn't trying to bite your head off or anything.  I had a charging issue on my first 750 and (and a proclaimed 750 guru) had me change the stator.  A few bucks later (on ebay) and lots of time lost, I still had the problem with a newer stator.  It turned out to be a short in the harness.  From years of other similar stories, it is almost always the wiring.  I've never heard of the stator crapping out, other than with severe crash/rash going through the side cover and into the stator.

The long and short of it is to check the charging system and make sure it is functioning within spec.  With a from scratch wiring harness, reproduction, or the old one, if there's a charging issue, FIRST check the wiring connections before re-wiring or replacing a stator.  Or, if you are going to convert to EFI, you will definitely need a charging system upgrade.

[Don R]

 I finally rode the K2 I bought with the K1 Wiseco? big bore engine, this thing is a beast. W0W!. I'd love to slap on a ported head and cam. 

[Ericcb750]

Hey Don R, That's awesome to hear!! I've only ever rode a stock 18K mile 78 cb750 and even that thing boogies pretty well!! so I am very excited to ride a real fresh hopped up version with the ported 836... this thing is going to scream and hopefully be pretty reliable.

[SOHC4 Cafe Racer Fan]

My K8 with a Wiseco 836, ported head and cam was no joke. 

[PeWe]

Hey Don R, That's awesome to hear!! I've only ever rode a stock 18K mile 78 cb750 and even that thing boogies pretty well!! so I am very excited to ride a real fresh hopped up version with the ported 836... this thing is going to scream and hopefully be pretty reliable.

A CB750 like your project is a good and reliable touring machine!  Strong power that handles 2 persons with luggage bags and more really well. My bike had no problems twisting the throttle at around 150kmh to pass cars on Autobahn as well as highways in Italy, France and Spain. Cruise most of the day in 150-180kmh, sometimes even more.

Cam I used back in the touring days, meas when I timed it:  IN 257* 22/55, EX 260* 56/24 @0.04"lift   Lift@0 lash: 0.361"/0.361" (9.18mm)
Timing differed a  degree or 2 when I timed it several times. I looked for equal LC. Duration could be 2-3 * less too when tighten 0 lash better or use of tighter cam holders with rocker shafts.
You guys living in USA have a huge area to go by bike!

[MRieck]

Hey Don R, That's awesome to hear!! I've only ever rode a stock 18K mile 78 cb750 and even that thing boogies pretty well!! so I am very excited to ride a real fresh hopped up version with the ported 836... this thing is going to scream and hopefully be pretty reliable.

You ride up here Eric and I'll take 1000cc CB out. You can try it too.

[BLAC]

Hey Don R, That's awesome to hear!! I've only ever rode a stock 18K mile 78 cb750 and even that thing boogies pretty well!! so I am very excited to ride a real fresh hopped up version with the ported 836... this thing is going to scream and hopefully be pretty reliable.

You ride up here Eric and I'll take 1000cc CB out. You can try it too.

Ride up there, Eric!   

[Ruckus2115]

How's the build going? I am doing a similar 836 kit and was wondering if you have installed the Super Rods? What's your opinion on those?

I'm trying to see if I should spring for new rods or get my stock rods polished and balanced..


Sent from my iPhone using Tapatalk

[Ericcb750]

Hey Fellas, hope everyone is doing well. I have been slacking real bad on the build...been trying to get in as much riding as possible.

Ruckus2115, The Super Rods are EXTREMELY well made pieces...I was looking at having the stock rods shot peened/polished but the small ends had a little bit of galling on them so i ended up saying "F" it and doing the Super Rods, they're absolutely beautiful, have nice heavy duty bolts and nuts and brass bushings in the small end. I ended up getting brand new bearing shells for the rods and the crank so this motor is litreally going to be a brand new Monster version of what honda produced back in 78.

I'll get back on the band wagon with updates and the build , now that all my cases and everything were vapor blasted by Nils (THE MAN by the way) , i'm ready to rock and roll.

I'll get crankin and post up my progress, first is to get that stubborn kick start back in and new bearings on the mainshaft and countershaft..... Thanks for all the support

[Ericcb750]

Can't believe how the time has flown...This build is getting done this winter. I'll post up the step by step, gotta dig into a huge box full of Freshly vapor blasted parts from Nils and start building!!! I know it's been a while, will get this thread going again.

[PeWe]

Repairing, modifying a CB750 is a never ending story :-) You might change your mind about the build and change some with help of all other builds going on here!!
I have a K6 that need some repairs (leaking fork due to scratched tube).
I started a K2 build since I had a K2 case I could fill with leftover parts from my K6 and knew a K2 frame with registration i could buy. This will be a close stock with no engine mods.

What to do with my 836 cylinder, 900cc cylinder + old ported head with std valves + some cams + K6 transmission, clutch,  VM29 carbs I have? + 2 extra tank sets.
I need to find 2 cheap engines I can use...... This is a very addictive hobby thanks to this forum and all helpful resources with many years of experiences.

[Ericcb750]

I hear that , I have gathered a lot of CB parts over the past couple years. I do however also have a 100% bone stock 1978 CB750F Super Sport that I'm doing with my dad, and that is staying 100% Bone stock...I Even was lucky enough to track down an OEM Muffler (Black tip) that is in amazing shape... I'm so excited for that one too to have a completely original one.

[PeWe]

That F bike can be worth some in the future when a lot of F bikes have been chopped to bobbers and what they are called in a way not possible to go back.

[Jerry Rxman Griffin aka MuthaF'er]

FYI JamesW (??) has, what he says, is a rechromed 77/78 F exhaust he wants to sell. Texted me but I delete all texting after done with. For me THIS is a preferred way to communicate within SOHC4. Except for doing pictures which are MUCH easier for me to text.

[Ericcb750]

yeah I'm so excited as I've gathered almost everything I need for it. all HONDA OEM stuff, The biggest hurdle I'm having is figuring out what to do with the pistons/rings. the motor has super low mileage and is not frozen but I would like to at least re-hone the cylinders while I'm in there....Haven't been able to find OEM rings for the 410 pistons and don't know if I can re-use the originals.....

took me 1.5 years to find that muffler.... they are not easy to come by.

[NobleHops]

Holy smokes, I disappear for 3 months and you guys run amok. :-)

I am so overdue to post an update, things have been hopping and I have tons to fill you in on as usual.

Eric, thank you for the good words, and you too Don and Cal and Bryan the others, it's an honor to work with you guys.

N.

[SOHC4 Cafe Racer Fan]

Holy smokes, I disappear for 3 months and you guys run amok. :-)

I am so overdue to post an update, things have been hopping and I have tons to fill you in on as usual.

Eric, thank you for the good words, and you too Don and Cal and Bryan the others, it's an honor to work with you guys.

N.

Nils,

Are. you going to IMS Long Beach this weekend?