My '59 Enfield /Indian 750cc Chief High Compression Build

[TheBaron]

I've been crewing racing motors from 3 to 3000+ cubic inches over the last 50+ years, and here is a rule of thumb that always seem to play out when "endurance racing".

2 rwhp per cubic inch for air-cooled pushrod engines is about the upper limit for real world reliability when racing (WFO) really hard for more than a few seconds at a time...

As you go above this, you break a lot of parts and you break them often....

Work out all your issues at 90hp, then tip-toe up from there...

Best Luck to us all,
Robert

[RansomT]

I don't know what the drivetrain losses are on a bike compared to a car but even 10% would equate to 152 crank HP. 

Sumner

7% gets you in the ball park.

[Sumner]

I don't know what the drivetrain losses are on a bike compared to a car but even 10% would equate to 152 crank HP. 

Sumner

7% gets you in the ball park.

Thanks.  So is that through the primary drive, transmission gears and the final drive or just the final drive to the wheel?  I guess it would be determined how the engine was dynoed.  Can they dyno an engine anyway other than off the output shaft to the chain drive or at the rear wheel?

Sum

[RansomT]

The bikes that have internal transmission (German, Japanese, etc..) get their power reading off of the output shaft.  If you take the factory reading multiple by 0.93, it gets you close to the reading at the wheel on a Dyno using SAE correction.  I'm not sure how the Harley's and such fair compared to known engine readings.  Most of the Harley's I've tuned have been highly modified ones, so I don't have a comparison to go by.

[Sumner]

The bikes that have internal transmission (German, Japanese, etc..) get their power reading off of the output shaft.  If you take the factory reading multiple by 0.93, it gets you close to the reading at the wheel on a Dyno using SAE correction.  I'm not sure how the Harley's and such fair compared to known engine readings.  Most of the Harley's I've tuned have been highly modified ones, so I don't have a comparison to go by.

Thanks, good info,

Sum

[Scottie J]

7% is an accurate drive train power loss for the Enfield bikes.  Tom at Ace Performance thinks that based on his formulas, baseline flow tests and the spreadsheet in post #199 we can achieve 125hp @ 6000 RPMs.  Now I've been doing all the preliminary figures going off of the factory redline of 6000 RPMs.  My motor is going to not only have a supercharger  but a custom 1-off valve train, and to the best of out knowledge, the best performing heads an Enfield twin has ever seen.  Now take into consideration that guys who actually have raced these Enfiled twins that were "highly modified" were reportedly spinning their engines around the 7500 RPM mark.  Now we all know that EVERY engine has a limit but I think this motor is going to be be 1 very serious contender for the PBF class.

Scottie J

[Scottie J]

I had the wonderful opportunity to meet with Stainless1 and John (not sure if you're a member here or not  ) tonight.  We got to chat for a good hour and I was able to get a lot of my "little" questions answered.  It was very cool and rewarding being able to sit down with a couple of Salt Vets and hear some of the stories and experiences they had to offer.  They were also kind enough to leave a photo album of Stainless1's streamliner, which I am very excited to look over tomorrow.     Even though I'm still very early into my build, I was getting so excited and hyped up just talking about running on the Salt, or any speed event for that matter.  Good times.   

Scottie J

[Seldom Seen Slim]

I'll guess that the "John" you met, in conjunction with Stainless, is more commonly known as "Johnboy" or, in Freud's parlance, "Johnbuoy".  He's a regular member here -- "Speed Limit 1000".  He doesn't shave his face very often.

[Scottie J]

You're right Seldom, John is in fact "Speed Limit 1000".  I met with him again yesterday for a short time.  He's going to be helping me out with some odd and end machine work, like the 7/8" nut for my solid strut that I built, he machined down into a jam nut, and now the strut has perfect adjustability.     He is also going to help me machine new chain adjuster plates that go onto the end of the swing arm.  The ones that are on there are made of pot metal (Freaking garbage crap.  I hate pot metal) and one is already broke in half.  The one I gave to Speed Limit 1000 turned out was ready to fall apart as well.  Slowly buttoning up the tiny stuff.  As soon as I can get a car or 2 sold sold out of the car collection I should be able to go shopping for all the good stuff!  Then I can start making some real progress on this bike.  It doesn't help I have a BIG time project at work right now, a '07 Forester with the entire left rear corner off of the car now.  I've been working on it for a week and just now got all of the bad metal off.  NOW I get to pull in the '06 parts car and gut that pig, cut off the entire corner, start cutting spot welds in all the right places and put it back together again.  I'm guessing another 2-3 weeks before it's finished, job security.     By that time, Tony should be back in town and I can get a couple cars posted for sale, and hopefully finish up the '56 Bel Air Custom we are getting ready to drop a 620hp 572ci Chevy crate motor in.       

Scottie J

[SPARKY]

Work out all your issues at 90hp, then tip-toe up from there...

Best Luck to us all,
Robert

 

[Scottie J]

Geesh!  Started researching connecting rods again and came across www.rrconnectingrods.com.  It sounded familiar so I jumped back on here, dug all the way back to like page 8 of this thread, and sure enough, R&R is the company that Briz recommended a while back.  I think I'll be giving them a call tomorrow as I'm starting to NOT appreciate Hitchcock's.com very much.  I'm starting to realize that a lot of the stuff they sell they claim to be their own designs and such, but in reality other people have designed the stuff, and then they get it from them and mark it up 20% above retail pricing from the original manufacturer.  Perfect example:  Hitchcock's sells a performance belt drive kit.  They offer the standard 25mm belt 4 disc clutch kit for 580 GBP.  OK Fine.  Then after looking into things, I realize that they are actually selling the Bob Newby belt drive kit, and Bob is getting hosed by Hitchcock's on the deal.  So I send Bob an email personally to see what he has to offer me directly (I'd rather do business with the "small business" guy anyways) and he sends me the following offers;

"The std road kit is £440 The 30mm belt and 4 plate clutch is the same. The 30mm belt and 5 plate clutch is £450  The 40mm belt and 5 plate clutch is £475  Shipping is £45  Any additional work required for the v drive would be extra depending on your requirements."

Guess who I'm ordering a 40mm Belt 5 Disc belt drive thru?     As for the forged conrods, after conversion rates, they will cost $515 thru Hitchcock's, so hopefully R&R can give me a better deal than that.  Or at least about the same price for a much stronger steel rod.

Speaking of which, maybe you guys can put some input on this.....  I understand the differences and pros & cons of using different types of metals for conrods, titanium is lightest and strong but fatigues and needs to be replaced regularly, aluminum is light but not as strong and cannot handle high HP or RPMs, steel is super strong but also heavier which creates more weight on the rotating mass.  From my semi-educated decision making, I've come to the conclusion that a steel "H-Beam" is going to be best for my application.  It is very strong first and foremost, and secondly the additional weight shouldn't have that big of an effect with the blower installed.  Am I correct in thinking this?

Scottie J

[Briz]

I dont think Hitchcocks make anything. As you say, they are just middlemen.
R&R charged us $550 for a pair of custom alloy rods.
Steel were going to be more & take longer.
Alloy rods are fine; after all top-fuel dragsters use them. They do have a shorter service life than steel in extreme conditions....like top fuel... because they fatigue quicker. But for what you're doing, no worries.
Tell R&R what you are doing and take their advise. They'll know better than anyone.

[Scottie J]

Were those rods you got from them for this crazy custom motor job you're doing now or a different bike?  That motor you're building now is freaking wild!

Scottie J

[Briz]

Yep, thats the one!

[Scottie J]

I have a question for all the Brit Bike racers out there......

Is anyone familiar with Rex Caunt Racing?  It was suggested by another Enfield racer (a road racer on the Enfield forum) that I get my ignition system from them.  They offer a crank fire system that sounds like it has an electronic advance curve, not sure though.  They are supposed to be calling me this week to discuss the details of my bike and the ignition.  I was just curious if anyone has dealt with them, and what was your experience with their product/s and customer service?  Thanks!

http://www.rexcauntracing.com/pages/misc_products.html

I'm looking at the second product on this page, the Racing 4-stroke, 36deg Crank Twin Battery System.

Scottie J