Topic: New Member Question - Camshaft Source and Selection for Hot 836 Kit

[RRRToolSolutions]

Guys, hello. New to CB750's, not new to Hondas or CB500's or CB550's. I'm starting a build on a 1973 750 and have always liked the performance given by a high school buddy's 836. 30 years later and I'd like to reproduce that bike. Low bars, 4 into 1 Kerker, Wiseco 836cc, and hot camshaft.

I've bought the bike, found that Wiseco still makes the piston kit, but I don't see a camshaft and Kerker doesn't list the old 4 into 1 and I don't like MAC. Do I have some choices?

Thanks,
Gordon

[Sam Green Racing]

Welcome to the forum Gordon.

You can get the 836 Wiseco piston kit along with a Cometic head gasket to suite from Megacycle Camshafts.

They also do a special cam to go with this kit and also uprated valve springs.

The full kit comes complete with a T shirt

Regards Sam.

[scunny]

I need a place that sells the shirt and gives motor freebees

[Sam Green Racing]

Don't we all.   

[Jerry Rxman Griffin aka MuthaF'er]

By all means go with HP springs if you're boring and camming. My stock redline was 8500 and it will now do 10K. The HP springs will help those valves close at high rpms rather than float &/or break. I put a new Kerker on my 75 CB750F this past winter. Expect to spend $500 + but it's available. Was working with Bike Bandit at first. Took over 1 month for the first to arrive. Apparently they do not stock, just order from kerker as needed. It arrived with a bent collector from shipping. For $500 + I sent it back and reordered. The replacement took even longer and when it arrived it had peeling chrome. Sent it back and reordered, they cancelled due to length of time to get it, reordered, etc. Told them to piss off and ordered from MAWOnline. Got it in a month or so and it looks sweet on the bike. 
Jerry 

[Sam Green Racing]

Jerry, is your bike a 836 or 736?

Sam.

[scondon]

       Wiseco just bumped the cost of the 836 kit to $524 MSRP, up $100 from previous year. Low online price is now around $399, check Ebay for stores that have kits left over from last year and you may be able to score a set at last years low price.

      Megacycle sells their cams at around $280 per for the cb750 and I have actually found them cheaper when not bought direct from them.     dynoman.net  is a good online source for cb750 performance stuff and has everything on your list except the low bars. Low bars can be bought just about anywhere.

      Supertrapp bought Kerker and, you're right, they don't list the old style system that slips over the exhaust spigot on earlier heads. All you need to do is remove the spigots and install studs, or use a 75-76 750F,77-78 750K head which already have the studs. $600 MSRP for a new exhaust or look on ebay for a used system that will fit your spigots.

Cam choices new are Web Cams or Megacycle

Piston kits new: Wiseco and ?(I know there's got to be someone else making piston kits)

Exhaust choices new: Supertrapp/Kerker (and nothing else cause you know you really want one

[RRRToolSolutions]

Thanks guys. I pick it up on Saturday and will start the tear-down process. I've been restoring and collecting for several years now, but I've just recently decided to do an early 70's 750 Honda. I've got several Kawasaki triples done and am just a little bored with them.

Again I appreciate the information and will be hanging out here for sure.

Best Regards,
Gordon

[Jerry Rxman Griffin aka MuthaF'er]

Jerry, is your bike a 836 or 736?

Sam.

I have a Yoshi 810, etc in it.

Jerry

[Sam Green Racing]

Jerry, have you any idea what sort of BHP it's turning out ?

Sam.

[Big Jay]

http://cbrzone.com/pistons.html
http://cbrzone.com/cams.html

Hope this helps.

[Jerry Rxman Griffin aka MuthaF'er]

Jerry, have you any idea what sort of BHP it's turning out ?

Sam.

Sam,
I'm not sure of the hp my 810 is doing. More than before but it ran really great stock. It was running good enough for me to jump on a 900 Kaw. How does never enough sound ? My story is I broke a valve in '76 (Kaw story) and pieced it back together not really knowing what I was doing. Told myself that if I ever went into it, it would be put back together better. That was my first attempt. I did a little research and picked up the 810, Daytona Cam and S & W springs from Yosh. Put in Manley stock size stainless intakes. Stock carbs. Its held up well for the most part. It survived my first attempt luckily. I got back into it to do a better job and fix a couple mistakes such as routing the cam chain around the tensioner improperly (noisy!). Decided to put new rings in while it was down and used 1 piece ring instead of a 3 piece. Wasn't happy with that! Due to various circumstances (money & wife issues-imagine that!) plus it was pretty much shot, it sat in the garage until I got rid of the wife. Then I had some money so it was time to break it down. Same configuration just better. Had the usual carb and electrical issues to deal with. I've been playing with it for over 10 years again and it gets a little better each year. Think my carbs are mostly tuned in now. I'm at 7000 ft running 110s. Had straight header (no muffler) with these 110s also. Might be a little lean with the Kerker. I have some 120's but no 115's to try. It's my second bike now so I'm in no hurry. I do have an excuse to get into it again. The infamous leaky head gasket/wet pants/stretched cylinder studs. So, guess what, it won't go back together the same this time either. May stick with the 810 but I have a big valve head I acquired and it will need some big CR carbs I'm sure. I'd love to take it down one last time then put in on the dyno to get it tuned in. Do you have any HP figures on your bike? Yours has CR in front of it. That adds some HP doesn't it???

[RRRToolSolutions]

Jay, all - thanks for the replies. I'll use this thread for reference as I start buying parts.

Three questions -
1) Does the Wiseco 836cc kit allow for later rebuilds or is this the absolute maximum bore and cylinder replacement required on the next bore/hone? I ask because I don't see oversizes listed.

2) Is there another overbore kit out there of less cc that will offer rebuilds and still do a good job with bumping compression and moderate displacement increases while using higher lift cams?

3) How do the stock carbs work with these motors? I know jetting with the K&N's I'll use along with the Kerker will be mandantory, but what about the carb's sizes? Those on the Kawasaki H2's had to be changed with porting improvements.

I'm not after a fast bike, just one muscled-up. I've got several triples, a ZRX, and a Nomad for touring. I want this 750 for it's sound and memories.

Thanks again - Here's my 1972 500 -
Gordon

[MRieck]

 #1- Yes...maximum bore unless you find an old 915 kit or possibly order custom from Arias. #2- no  #3- Yes...they work OK with jetting changes. I'd recommend K&N's tytoo.

[Sam Green Racing]

Jerry, if you are cotemplating pulling it down, and Gordon, if you have not started, you both might want to consider the main job when tuning a motor, the cylinder head.

No amount of pistons, cams, super dooper ignitions, carbs and exhausts will allow these  motors to do their job without the head being flowed.

A set of 2mm larger inlet valves and the head flowed may seem like a lot of expence, but when it comes down to it you'll wonder why you didn't do it in the first place.

If you decide to go down this path, have a word with Mike Rieck about having it done.



Jerry, the reason I asked about the power, I am about to have an 836 race motor built and no one on the forum has dynoed one of these motors apart from Mike who gets 92bhp but it is from 910cc. Also you said it went up to 10k and I wondered if it still made power at these revs.

Sean (scondon) has been running one of these motors with a head by Mike but has yet to put it on the dyno.

Your question about the CR, sorry to disapoint you, it's a stock motor

If you search 836 power at the top of this page you will find a couple of pics of it in a similar thread to this one.

Sam.

[Jerry Rxman Griffin aka MuthaF'er]

Sam,
I have a couple projects planned. First a 836 or 900 (if I can find a good kit) with lots of goodies especially a good excellent head and carbs. This will take some time and will probably run into next year. There will be some serious case splitting on this one. I want to do it right. Mike and I have touched based briefly. This will be my stronger engine. Once this is done I'll tear into my 810. May not split the cases unless I decide to do the crank on it too and replace primary chains plus go with stronger rods. Probably leave it 810 but fix it up some. I have a new head (not as pretty as Mike's!) with 33.5 stainless intakes and mild porting that needs a matching set of carbs. Does Mike give a volume discount? Cylinder studs to keep my Levi's clean and keep the compression in the cylinders is needed. Funny, but, my Honda leaks and my Harley doesn't?! 
 
" A set of 2mm larger inlet valves and the head flowed may seem like a lot of expence, but when it comes down to it you'll wonder why you didn't do it in the first place" 
- EXACTLY and damn well worth every penny!!!! My 2 excuses were money (lack of) and inexperience. I can overcome both of those issue these days in my older age.

As far as power at revs goes, I generally don't take the time to watch my tach to shift. I shift by sound and feel. In the split second it takes to check the tach I could over rev and blow that SOB up again. It revs fast! It probably starts tapering off at about 9500 but will go farther. The Yoshimura Daytona race cam really starts pulling strong at 7000 then hold on because it'll get there fast. The HP springs are a must (see reference to blow that SOB up again - EXPENSIVE) and allow these revs.

If your engine isn't top secret I think you should start a journal with parts & prices, where you got your parts, procedures, etc.

We need to start a PayPal fund for Scondon to defray the expense of dynoing. I know he could use some fine tuning while it's on there. That would be the finishing touch. Plus he could show what has been done and the definite results. I had it done on my Fat Boy a few months ago when I had cams installed. It was mapped with a race tuner during the dyno run. Very helpful. I've taken it from 58hp stock to 84hp. That SOB was pulling real strong today!

Jerry

[Sam Green Racing]

Jerry, just spotted your post, but I am about to leave work for home, it's 7.30 am here, been a long night.
I'll take up back with you on Monday night when I'm next in work (not on line at home).
You realy don't want to know what's been spent on this new motor, but as long as you are sitting down I will tell you Monday.

Sam.

[78CB750F1]

The Kerker 4:1 is available from Dynoman for $475:

http://www.dynoman.net/bikepages/sohc/header.html

[MRieck]

Jerry, have you any idea what sort of BHP it's turning out ?

Sam.

Put in Manley stock size stainless intakes. .

Jerry
  Any problems with the tips on those valves. The Manley CB valves I've used needed lash caps as the tips weren't stellite.

[Jerry Rxman Griffin aka MuthaF'er]

Jerry, have you any idea what sort of BHP it's turning out ?

Sam.

Put in Manley stock size stainless intakes. .

Jerry
  Any problems with the tips on those valves. The Manley CB valves I've used needed lash caps as the tips weren't stellite.

Mike,

Best I can say is I hope not. The valves have taken quite a bit of abuse for over 20K miles. It doesn't get a lot of miles these days. Thats something I'll definitely look at next time it's down. I'm glad you mentioned the issue.
Jerry

[Big Jay]

Jerry, have you any idea what sort of BHP it's turning out ?

Sam.

Put in Manley stock size stainless intakes. .

Jerry
  Any problems with the tips on those valves. The Manley CB valves I've used needed lash caps as the tips weren't stellite.

Right. Those Manleys used to mushroom the tips like mad.

Jay