Lets make some more horsepower...

[shinyribs]

I know it can be done,but I've never been inside one of these engines before.So,what are the options for pumping up the power on a SOHC?Ive seen the ads for the big bore kits at 836cc.But I've heard tell of 1,000cc + kits,too.Even stroker cranks.Does anyone have any experience on this matter?Does anyone know of any particular high performance components,or where to find them?I'm talking cams,rods,pistons,ignitions...etc.Any advice very much appreciated!Especially if you have used a particular part yourself,that would be great to hear about the gains seen.Thanks!

[TOOLS1]

For cams. Go to WEB Cams. A google search should bring them up. For The really big bore stuff, you will need to find some vintage RC Engineering components. They pop up on ebay every now, and then. However when, you get over 850cc, you are really talking serious money, and loss of reliability. Your really into race only then.
If, you really want to make some HP. Call Red at Cycle one, or talk to the people at Cycle X.
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[shinyribs]

I found a lot of parts by googling,but was curious if anyone had personal experience with particular parts.I know what you mean about big money,a lot of these parts cost the same as the stuff I use in the big block!Im afraid about reliability looking at the bigger stuff,too.A big nasty 1,000cc CB with a wicked cam would definitely sneak up on some vintage Jap bikes scoffers

[TOOLS1]

A Cycle X 850 with a cam will do the same thing.
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[Piute]

http://cbrzone.com/sohc.html

The big dog engine kit. 1000cc performance engine kit.

This kit includes a 10.5:1 c.r. 1000cc forged big bore piston kit with sleeves. H370 billet cam, performance valve spring kit, titanium retainers, adjustable cam sprockets, Carrillo billet H beam rods, and heavy duty cylinder studs. Complete match components at a kit price.

#SSRH1000 $2373.05  

[Piute]

 Good read from S.O.H.C.4......but you(Chromeribs) no these thing due to your Olds

     Bracket racing is consistency racing. You can be inconsistent with 10, 100, or 1,000 horsepower.  The biggest single variation in racing a quarter mile track comes in the first 60 feet. How quickly you cover the quarter mile is dependent on how quickly you cover the first 60 feet. Samauto hasn't yet been able to consistently cover the first 60 feet. When there are differences in the first 60 feet, the differences increase by the end of the quarter mile. If you are slower to 60' by a tenth of a second than you were in a previous run, you will run slower in the quarter mile elapsed time by over twice that amount. When Sam's bike launches off of the starting line, it currently has under 10 horsepower and under 20 ft/lbs of torque. You're launching a 450 lb bike plus what the rider weighs.
     Everyone can see the dyno plots that have been posted.  Getting 100 horses from this 836 cc bike won't happen. We've posted that there is a 10-12 horsepower loss due to the torque converter. Even with a clutch, it would be in the lower 90 horse range. Launching this bike at 3,000 rpm where the torque is small would nearly stall a clutch bike! The only thing that more horsepower gives a drag racing motorcycle is the increase in miles per hour as measured at the finish line. The elapsed time is controlled by the torque of the motor and what rpm you launch the bike at.
     The quicker the overall elapsed time, the quicker you have launched the bike. If you have more power, but can't grip the track with it, you will run slower, but with a great top end mph, assuming that it eventually hooks up. Elapsed time for the quarter mile is affected more by the first 60' than anywhere else on the track. If you can get consistency in the first 60', you can be consistent in the quarter mile elapsed time. Yes, there are exceptions for other higher powered bikes, but not here. There are traction limits between tires and pavement. Sam's bike doesn't have any problems with that. It currently doesn't repeat well in the first 60'.  This is what must be corrected if the bike has any hopes of being a contender to win any race.
     Low horsepower launches are very sensitive to variations. Does the front tire move sideways at all when you initially start? Did you push off with one foot when you launched? It doesn't take much to vary your 60' times by a tenth of a second. That variation will cost you a race most of the time. To have an ATM, you need a bike that varies by .05 seconds in ET (or less) at the end of the quarter mile race. That amount of variation needs your 60' times to repeat within a couple of hundredths of a second.
     How do we get the 60' times to repeat better? More power at the rpm that we launch. Our consistency will improve up to the point where the traction between the tire and the pavement start to vary. High horsepower bikes need more tire to get the traction that they need at launch without variations. (aka spinning the tire) Differences in track temperature affect the amount of grip that a tire can have. The more power that you make, the greater the variables line up against your ability to repeat.
     Ok, too little power is bad; too much horsepower is also bad. You want to be making enough power to consistently travel the first 60' with minimal variations. With temperature of the air and track affecting the bike's performance, you want to not be near the edge of the performance window. Hondamatics can make enough power to be consistent at launch. You can get enough tire grip to hold what power you make. 80 horses at 9 grand won't be a traction problem at 3 grand with a street tire. My drag Hondamatic uses a small slick to get traction on a 100 horse Hondamatic that launches at 6 grand. I'd spin a street tire like the one that Sam uses. We build the combination to work together.
     We're getting 2.3 second 60' times (best) with Samauto. With more power in the 3-4 grand portion of the powerband, it can easily get into the 1.9 second range. I've run stock motored Hondamatics to 2.0 second 60' times. Yes, the stock motors are making more power at the launch rpm than Sam's bike makes.(with either set of carbs) This is a function of how the motor combination was put together. Until the air fuel ratio is shown to be consistent with either set of carbs, the jury is still out for some. Since we are not doing much of anything to change the idle circuit in either set of carbs, I am jumping to the conclusion that we won't find another 3-5 horses at 3 grand with our current setups.  
     What can help? Among other things - Gearing. Increase the numeric final drive ratio will have the motor revving quicker into the range where there is the power necessary for consistency. (you spend less time in the low power/high variation area) This has been done, but not yet tested. We're taking small steps in the right direction. If anyone else has Quarter Jr. software, you can plug in the information about this build and see the theoretical results. I've had excellent correlation between the software and what I actually run. My software is very old (Dos based). I'm in process of getting the Windows version.
     Everybody who races has goals. Road racers want quicker lap times. Drag racers also want quicker quarter mile times. Bill has an 11 second goal. Sam wants to win a few races. It's all good. Goals make us work harder to achieve them.  Getting the most out of any motorcycle combination is what the "high performance and racing forum" is all about

[Peterwh]

Shiny, I have similar thoughts for my 78 that is my riding bike while I rebuild my 74 - got the engine in the powder coated frame yesterday by the way and now have an engine and frame combo in the vertical position.  On the 78 I'm thinking about leaving everything stock but getting as much extra power into the engine as reasonable expense will allow.  Like you, I think that could be an impressive combination.  I've been looking at the cycle x big bore kits but I don't know much about cam requirements and I've read that to get the best out of the big bore kit you need a modified cam.  I'm also wondering if there's much advantage in changing the carbs.

[shinyribs]

Peter,i saw some carbs for sale that come with a bunch of extra jets.8 sizes up and down for about$750.I dont know how much extra cfm is left in the stockers.When do you need to up the cfm of your carbs?Anyone know.Will they handle 900+ cc's  or is 836 about the limit?My biggest fear on a cam swap is losing drivable power.I know on v8's too big a cam will murder slwo speed performance.Thats what i want to avoid.I wish i could find somewhere that had dyno charts showing the gains related to particular pieces.
  Piute,$2400 for a strong running 1000cc CB"750" would be worth it for me.It's hard to beat a matched kit like that for price and reliability/compatibility.Thanks for the linkTheres no way you can buy a GSXR 1100 or 1300 for anywhere near what you could build a big 750 for.I know there are still a lot of differences,but it'd be worth it to me.My biggest obstacle,besides money,is finding a competent machinist.My engine guy said he doesn't do bikes

[TOOLS1]

Send your parts to Red at Cycle one. He does all the machine work himself.
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[Peterwh]

Most of what I can see on the cycle one website is frames.  What am I missing?

[shinyribs]

TOOLS1 wrote

Send your parts to Red at Cycle one. He does all the machine work himself.
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Awesome.Good to know.Thank you kind sir

[shinyribs]

My bike has,as far as im concerned,crazy top end power.It really has little power below 3000.Plenty for cruising,but any decent car would out run it from a 15mph roll.From 3-6000rpm power is more than expected.From 6000 on up it amazes me how fast it builds speed and rpm.I would be willing to sacrifice top end power in exchange for more power down low.Say 3-6000 where you really need it more.Thats all im looking for at this point.

[Daddyman]

Change one of your sprockets, I prefer the rear because smaller sprockets on the front are hard on chains.  Go up like 3-4 teeth on the rear.

[TOOLS1]

A Lot. Just call Red, and Kate, and if they don't have it. They will get it.
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[TOOLS1]

Like Daddyman said, change your sprocket, or swap in a cam from an automatic. They are ground to make power lower in the rpm range.
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[shinyribs]

The auto cam sounds like a better option for me.Im already turning 5000 rpm at 70 mph.I hate to increase that any more.Is an auto cam something you can buy new,or do i just find a good used one?How does the midrange and top end compare to a manual vs auto?

[TOOLS1]

I do not know about a new one, but WEB Cam could grind one, for, you. Or, you could get a good used one. Since the matics used a torque converter that engaged at a lower RPM then a clutch would be engaged at Honda designed it to have more torque across the power band.
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[MarkPBG]

I hear you! I'd like to have around 100HP on mine….crankshaft HP is ok, but RWHP is better. LOL
I guess my old crotch rocket spoiled me…11.4 quarters were fun! (bike could supposedly do 10.9, but not with my fat ass on it! lol)

[Peterwh]

Thanks.  I swapped emails with Kate today.

[TOOLS1]

I hope, you did not mention me. She might charge, you double.
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