Topic: How can I make a bunch of torque?

[shinyribs]

I have a '76 CB750 F. It runs great and I really have very little to complain about ,power wise.However,wheelie-ing on my bike involves a fair amount of clutch abuse i.e.-rev her up and dump the clutch

I have never been inside one of these motors and know very little about the high performance lingo or parts that are available.

What can I do to help build torque to the point where I can just stab the bike and get it to wheelie?Or is that doable on a decently streetable CB? I used to have an older 600 XR that could wheelie on command and am slightly disappointed that my old one lunger makes my I-4 seem weak in the bottom end department. I am not looking for 2nd or 3rd gear wheelies,rolling 1st gear wheelies or 15-20 mph is what I am looking for.

I am happy with the gearing of the bike now ( 18/48-5,000 rpm @ 70 mph) so heavy gearing is not what I am looking for since I do run the freeway alot.

Any and all ideas,opinions,point of view...etc. please! Thanks!

[BLUE71TURBO]

 You run on the freeway, 5,000 rpm at only 70 mph ?      Geared way to low.      As for killer torque, a stroker crank is in order....$$$$$ !! Plus a bigger bore, higher compression, head work, and a better camshaft.  Alot of $$$$$  just to do wheelies.

[shinyribs]

You really think I'm geared too low? According to my FSM 18/48 is my stock gearing. The bike seems to do well with it and get great fuel mileage,I think. I average about 43 mpg and have gotten a best of 51 mpg.

Is there any such thing as a ''bottom end cam'' or do I really need to throw the gauntlet at it?

Thanks for your input!

[lucky]

Just get a back sprocket twice as large and you can do wheelies all day long.

When you dump a 500 lb. bike, expect some serious damage.

[754]

 Put Webers on it, then you will get low and midrange grunt that you will like..

[Retro Rocket]

There is a different technique to wheelie a 750/4 compared to an XR, for a start the XR is way lighter and comes up way smoother due to its longer swingarm and power to weight ratio, the best way to wheelie a 750 is to bounce the bike whilst working the throttle, the 750 is a hard bike to keep up because it has a very high balance point due to its relatively short swingarm, i used to do it a lot in my younger days but being older and wiser i wouldn't do it on a 40 year old bike at all, the XR's excel at it and would be a far better choice....

[mrbreeze]

Well Lucky don't sound very lucky! These bikes aren't really the best set up for wheel stands but it can be done with some effort. I don't even attempt on my stock displacement scoot runnin' a nice 42 tooth rear (better for the highway) but if I went back to a stock 48 with an 836 kit..........game on. I used to pull wheel stands at the drop of a hat on my Kawis (74 900Z1 & 77 1000LTD). Had more ponies in those bikes but still diggin' the 750 Honda!!! Be hella careful though.......there's a time & place for everything

[bear]

I have a '76 CB750 F. It runs great and I really have very little to complain about ,power wise.However,wheelie-ing on my bike involves a fair amount of clutch abuse i.e.-rev her up and dump the clutch

I have never been inside one of these motors and know very little about the high performance lingo or parts that are available.

What can I do to help build torque to the point where I can just stab the bike and get it to wheelie?

Any and all ideas,opinions,point of view...etc. please! Thanks!

Try one of these.

Cheers,
Brian

[Sam Green Racing]

Kart wheelies comes to mind.

Sam.

[voxonda]

I have a '76 CB750 F. It runs great and I really have very little to complain about ,power wise.However,wheelie-ing on my bike involves a fair amount of clutch abuse i.e.-rev her up and dump the clutch

I have never been inside one of these motors and know very little about the high performance lingo or parts that are available.

What can I do to help build torque to the point where I can just stab the bike and get it to wheelie?

Any and all ideas,opinions,point of view...etc. please! Thanks!

Try one of these.

Cheers,
Brian

Interesting bunch of steel you got lying around, Brian.

Cheers mate, hope all is going for ya!

Rob

[bear]

I have a '76 CB750 F. It runs great and I really have very little to complain about ,power wise.However,wheelie-ing on my bike involves a fair amount of clutch abuse i.e.-rev her up and dump the clutch

I have never been inside one of these motors and know very little about the high performance lingo or parts that are available.

What can I do to help build torque to the point where I can just stab the bike and get it to wheelie?

Any and all ideas,opinions,point of view...etc. please! Thanks!

Try one of these.

Cheers,
Brian

Interesting bunch of steel you got lying around, Brian.

Cheers mate, hope all is going for ya!

Rob

G'day Rob.

I'm pleased to see the big orange beasty going so well for you.

One thing I'm not short of is a 900 crank or two.

I'll be heading home in three weeks thank God!

Cheers,
Brian

[shinyribs]

I need ideas people, where does this thread belong or should it just be removed.

It could be moved to the humor forum but that would be an insult to some of the material there.

Help.

Remove it ,erase it,nuke it...I dont care.I thought I was posting in the area to gain high performance information. Apparently not,and apparently it is a joke to get a CB750 on the bike tire. Perhaps I should just get another bike.Sorry for the mis-post.

Nonetheless,I am interested in your mention of Webers 754.Any info on that would be appreciated.

Also on the pic of the cranks. I'm not sure what those are.Like I said,i am new to these bikes and know very little about the particulars of them. Let alone spotting parts by eye. Thanks for the reply. I will see if I can investigate stroker cranks (? is that what it was?) and get some more info on them.       Thanks for the help.

[Really?]

It would be much easier if you started your own threads in your sub-forum Sam.  I feel spoiled!

[bear]

on the pic of the cranks. I'm not sure what those are.Like I said,i am new to these bikes and know very little about the particulars of them. Let alone spotting parts by eye. Thanks for the reply. I will see if I can investigate stroker cranks (? is that what it was?) and get some more info on them.       Thanks for the help.

Yes the pic is a few of the Honda DOHC 900 cranks that I use, all varying weights.
These cranks give you an extra 6mm and provide a very good torque curve.
There is quite a bit of work putting on of these motors together though.
Check out the link.

Cheers,
Brian

http://www.satanicmechanic.org/bigbore.shtml

By the by, these motors are forty years old.
If you start mono-ing  your bike on a regular basis you will break it.

[shinyribs]

Thank you bear.Much appreciated!

What is Bol d'or?

I see where it mentions shorter rods or a raised cylinder foot. Which is better? I would think shorter rods would help reduce rotating mass,but does rod angle become to severe for extended rpms?

So I'm guessing there is no easy way to get torque? You gotta stroke it?

How do you go about reversing the crank?Custom engine covers?

A big bore kit I am ok with,but stroking is getting to the point of where I am wondering if I would not be better off the spend my money elsewhere.Like a turbo. But I hate the thought of all the fuel system upgrade needed for a turbo...ugh .

[754]

 Read what I just posted over in the cam question. The Webers and probably Dellortos give very crisp responce and have huge squirters in them..

[PeWe]

Higher compression and correct cam. 836 kit with 10.5 will end up in wheelies on 1:st and 2.nd gear without fiddling with the clutch, just twist right handle

Worked on mine with RC836 and Action Fours SS-1 cam (ported head too). Later pistons had lower compression. Soon compression back in engine and most likely a DP295 cam for more of everything.

[Doctor_D]

Higher compression and correct cam. 836 kit with 10.5 will end up in wheelies on 1:st and 2.nd gear without fiddling with the clutch, just twist right handle

My 836 makes 17 lb/ft more than stock (56 lb/ft vs 39 lb/ft).  No clue why you'd need to loft the front end, but it's too easy to do on my bike - and something it takes work to avoid.

Price tag wasn't bad at all; you can build one correctly for about $7k. That includes lightening the crank, Carrillo rods, pistons, camshaft, all new bearings, heavy duty primary and cam chains, slipper cam chain tensioner, cro-moly crank and cylinder studs, backcutting transmission gears, heavy duty clutch kit, porting the head and getting new valvegear, MLS gaskets, RS34's, Dyna 2000, lots of little odds and ends, all the other related machine work, and a decent exhaust. Way cheaper than a Manx or a Goldstar motor.

A 915 kit would even do you one better.

[PeWe]

..... That includes lightening the crank, Carrillo rods, pistons, camshaft, all new bearings, heavy duty primary and cam chains, slipper cam chain tensioner, cro-moly crank and cylinder studs, backcutting transmission gears, heavy duty clutch kit, porting the head and getting new valvegear, MLS gaskets, RS34's, Dyna 2000, lots of little odds and ends, all the other related machine work, and a decent exhaust. Way cheaper than a Manx or a Goldstar motor.

A 915 kit would even do you one better.

Perfect wish list for Santa
I hope he exists when I had a nice list with better rods (Cycle Exchange's). List now way shorter due to the final cost. My repair will contain minimum parts for the engine when the bike need so much else when not used since 1990. New and probably better 836 pistons bought and home.  http://www.ebay.com/itm/NEW-69-78-HONDA-CB-750-CB750-COMPLETE-CYLINDER-PISTON-KIT-836CC-BIG-BORE-KIT-/370602211821?pt=Motorcycles_Parts_Accessories&vxp=mtr&hash=item56499cf9ed

I compared the rings and pistons with my old Action Fours that use CB350 TWIN +1mm piston rings (65mm. These can be fitted on new pistons too
Next will be internal chains and tensioners, DP295 cam, thinner head gasket (MLS), exhaust valves and APE Cyl studs. Later on an ignition like PAMCO, maybe compl set with coils.

[754]

 You can get a basic healthy increase without headwork or rods.
 RC used to sell the 30-30 SUPER SAVER Claimed 30 % power increase and 30% decrease in fuel consumption. (IMO your results could vary)
 Kit had; 10:1 cast 836cc pistons, RC240 cam (exchange), 4-1 black exhaust.
 RC developed this kit to provide you with most effiecient motor possible. Bysustantially increasing the volumetric efficiency, we are able to give you a kit that will make more HP and produce more midrange torque. Permits use if hi-speed gearing without losing low-end or midrange performance.
   I agree mostly with the above.. i am not saying that you will szee an increase below 2000 rpm, there are trade-offs to increasing power in other areas. ( if I dont mention it, it willget brought up..)
 The above is really good bang for the buck, dont skimp on compression, and add a good valve job, and lighten the alternator.
 FWIW on a rolling start, my buddies early ducati Monster was not pulling away on my tired 836, thought the torquey twim would have got a big jump on mew at lower rpms.

[shinyribs]

Thanks for all of the information. I am learning alot the past few days here. I'm slowly learning the lingo...very slowly.
I am still hearing from others that what I want to do is not going to ever happen,but PeWe, your set up sounds just like what I am looking for. My bike will wheelie now,so I know it doable,I'd just like to do it without clutch abuse...maybe I should get a 'matic?!LOL I dont have thousands to spend on this bike. What is realistic to obtain with just an 836 kit and the correct cam? Are improved valve springs a must or will the stockers hold up? I have been building drag v8's for a long time so I understand some of the basics,but everywhere i see spring for sale they simply list them as heavy duty. I am used to selecting springs based on open and closed pressures and maximum lift allowed. it is irritating to not have actual info,just a nice sounding name

Thanks again for the replies. Keep them coming ,please!

[754]

 If you want to do this getting a real clutch is the LEAST of your worries.... and a must..

[Retro Rocket]

Higher compression and correct cam. 836 kit with 10.5 will end up in wheelies on 1:st and 2.nd gear without fiddling with the clutch, just twist right handle

My 836 makes 17 lb/ft more than stock (56 lb/ft vs 39 lb/ft).  No clue why you'd need to loft the front end, but it's too easy to do on my bike - and something it takes work to avoid.

Price tag wasn't bad at all; you can build one correctly for about $7k. That includes lightening the crank, Carrillo rods, pistons, camshaft, all new bearings, heavy duty primary and cam chains, slipper cam chain tensioner, cro-moly crank and cylinder studs, backcutting transmission gears, heavy duty clutch kit, porting the head and getting new valvegear, MLS gaskets, RS34's, Dyna 2000, lots of little odds and ends, all the other related machine work, and a decent exhaust. Way cheaper than a Manx or a Goldstar motor.

A 915 kit would even do you one better.

Wow Dave, you just described my engine down to a T, add some performance coatings and 71mm pistons and thats it....

[fang]

Higher compression and correct cam. 836 kit with 10.5 will end up in wheelies on 1:st and 2.nd gear without fiddling with the clutch, just twist right handle

My 836 makes 17 lb/ft more than stock (56 lb/ft vs 39 lb/ft).  No clue why you'd need to loft the front end, but it's too easy to do on my bike - and something it takes work to avoid.

Price tag wasn't bad at all; you can build one correctly for about $7k. That includes lightening the crank, Carrillo rods, pistons, camshaft, all new bearings, heavy duty primary and cam chains, slipper cam chain tensioner, cro-moly crank and cylinder studs, backcutting transmission gears, heavy duty clutch kit, porting the head and getting new valvegear, MLS gaskets, RS34's, Dyna 2000, lots of little odds and ends, all the other related machine work, and a decent exhaust. Way cheaper than a Manx or a Goldstar motor.

A 915 kit would even do you one better.

Wow Dave, you just described my engine down to a T, add some performance coatings and 71mm pistons and thats it....

+1  lol. ...but mine cost more than $7k...

[Doctor_D]

Wow Dave, you just described my engine down to a T, add some performance coatings and 71mm pistons and thats it....

Like most, I cant' wait to see your numbers.  Should be a monster.

FWIW, I did the full suite of dry-film, thermal barrier, and oil release coatings, and some shot-peening and cryo treating as well.