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

[Nortonist 592]

Excellent!  Thanks for the tips and advice! 

Scottie

Like I told you Scottie, there are a lot of knowledgeable people here.  They may not always tell you what you want to hear but they will tell you what you need to know.

[Scottie J]

Excellent!  Thanks for the tips and advice!

Scottie

Like I told you Scottie, there are a lot of knowledgeable people here.  They may not always tell you what you want to hear but they will tell you what you need to know.

That's exactly why I joined this forum, to fill in the gaps of the unknown!

Scottie

[thefrenchowl]

Koncretekid:
Lots of engine calculators on the net.  This one suggests maximum RPM.  It basically just divides 24,000 (or 30000 for highest performance parts) by your stroke length in inches to get piston speed.  It suggests that with a nodular iron crank, high performance rods and forged pistons, you should limit your pistons speeds to 4000 fpm.
http://thefirstgensite.com/code/maxrpm.htm

Wonder if the calcs on that site ONLY relate to the cars talked about herein...

If not, my engine should have exploded everytime I used it, street or race use, in the last 30 years... It suggest max 4600rpm, I have restricted meself to max 5500rpm on the salt... Used a lot more on the road in flashes.

Scottie, it's fine to read up to a point, but don't overdo it...

Patrick

[Sumner]

Koncretekid:
Lots of engine calculators on the net.  This one suggests maximum RPM.  It basically just divides 24,000 (or 30000 for highest performance parts) by your stroke length in inches to get piston speed.  It suggests that with a nodular iron crank, high performance rods and forged pistons, you should limit your pistons speeds to 4000 fpm.
http://thefirstgensite.com/code/maxrpm.htm

Wonder if the calcs on that site ONLY relate to the cars talked about herein...

If not, my engine should have exploded everytime I used it, street or race use, in the last 30 years... It suggest max 4600rpm, I have restricted meself to max 5500rpm on the salt... Used a lot more on the road in flashes.

Scottie, it's fine to read up to a point, but don't overdo it...

Patrick

Are you confusing rpm and fpm?  If I plug his 90 mm (3.54 inch) stroke into the calculator and it gives 5900 rpm for stock, 6900 for the "forged or nodular iron crankshaft, shot peened connecting rods, forged pistons" and 8500 for the " forged crankshaft, high strength alloy rods, high strength alloy pistons".

Of course I agree that the formula is open to quite a bit of interpretation on parts used and such.  The Atlas 2900 I recently bought for the lakester is rev limited in the stock truck to 6000 and according to the calculator with stock parts the rev limit should be about 5250 with the 4 inch stroke and 7500 for the best parts yet I'm aware of some that are running the engine over 10,000 but that is at the drag strip not land speed racing.  I plan on about 7500 for my build,

Sum

[thefrenchowl]

Hi Sumner,

No!!! my stroke, H-D 900 KHK, is 4"9/16...

With std gear on the street it's OK for 6000rpm... so about 4500fpm for std cast pistons. They don't blow...

Mind you, the cast iron crank did suffer a bit last August  so changing it for a forged steel one soon!!!

Patrick

[Sumner]

Hi Sumner,

No!!! my stroke, H-D 900 KHK, is 4"9/16...

With std gear on the street it's OK for 6000rpm... so about 4500fpm for std cast pistons. They don't blow...

Mind you, the cast iron crank did suffer a bit last August  so changing it for a forged steel one soon!!!

Patrick

Ok sorry about that, didn't know you were talking about your bike's stroke but his.  Enjoy the new crank,

Sum

[Scottie J]

Any suggestions for clear coat, waxes or specialty coatings for getting slippery?

Scottie

[sabat]

Any suggestions for clear coat, waxes or specialty coatings for getting slippery?

Scottie

I think you've got a lot to do before worrying about wax!! 

[Scottie J]

Any suggestions for clear coat, waxes or specialty coatings for getting slippery?

Scottie

I think you've got a lot to do before worrying about wax!! 

I can't get anything done until after the holidays.  I'm just trying make conversion.   

Scottie

[Scottie J]

I finally got my rule book last week right before Christmas.  After having a look thru the different rules and different class records, I have a slight change of heart on the build.  One problem I was able to diagnose with common sense was that I'm going to have a hard time kicking my bike over with a full LSR fairing covering my kick starter.  Second thing I noticed was in the record book after realizing maybe I shouldn't put a fairing on the bike right away.  Looking at the book, the record for 750cc M-PBF is only 129.953mph and hasn't been touched in quite a few years.  I am very confident that I can make that record my bitch.  I think going this route is not only going to save me a few thousand dollars off the initial build, but I think 130mph should be easily obtainable with how I plan on building this motor.  From what I can find from pictures, it looks like most guys in the "M" class are building their bikes to lay as flat as possible across the top of the bike, keeping the foot pegs within a legal distance ahead of the rear axle and clip on bars mounted really low on the forks? 

Scottie

[thefrenchowl]

Hi, Happy end of year to you all...

Scottie, I thought you were looking at an NA record...

M-PBF is a supercharged record.

The M-PF record is at 138 and a bit.

Patrick

[SPARKY]

S J
Welcome to the rule book--you will have a big advantage of us Sr. types---you should be able to remember the classes better

but I bet you will have to write them down and spell them out just like us---lol 

Read the whole book several times and the bike classes that you are thinking about dozens of times---this will serve you well before its over other wise you may not be the first guy that shows up to run on one record only to find you didn't build your bike so that it meets the rules for that class.

[Scottie J]

Hi, Happy end of year to you all...

Scottie, I thought you were looking at an NA record...

M-PBF is a supercharged record.

The M-PF record is at 138 and a bit.

Patrick

I was when I thought my bike qualified as vintage, but it is in fact a classic and therefor I can build how I originally wanted to with EFI and a turbo.

Scottie

[panic]

It may still qualify as vintage if you can make a strong argument that no significant (and positive = conferring an advantage) changes were made to the engine between pre-1956 (last automatically legal date) and your actual date of manufacture. This is going to look like a legal brief, with exhibits, affidavits etc.
I'd be looking at part numbers, engineering comments, casting dates, and road tests made during the period. Statements from the authors are preferred over references to their work, etc. A 1959 factory parts manual which contains notations such as "Cylinder head, left..... 1952-*" may prove useful.
Why try to make vintage?
Because the engines in OHV pushrod are far more evolved, and have more recent race development.

[Scottie J]

There was a change over in '55 so that's not possible.