best flathead cam?

[Colt sr]

Not to muddy the waters but does the OP want to pull start the engine? I've read on here some cams without easy-start can be a pita.

This might influence a casual mini bike rider...

Not too hard to pull start any stock class or slapper cam engines. Just make sure you blow in the fuel cap. Once you get to modified cams that's when the good ol electric starter becomes your best friend.

 

["J'-remy]

If following stock class rules, the easy spin is mandated as part of the cam grind.

there is no easy spin on a flathead cam or rules that mandate it+ I don't think the op is following any ruleset just modifying a motor

 

[95 shaw]

there is no easy spin on a flathead cam or rules that mandate it+ I don't think the op is following any ruleset just modifying a motor

701.27 Flywheel: ARC Billet Flywheel part #6620 will be the only flywheel allowed. Non adjustable, with minimum weight of 4 lbs. Any flywheel key or no key is permitted. Flywheel key slot and crank key slot must not be altered and must remain in stock location. The old Briggs Part #555657 is no longer legal.

701.28 Set up degree wheel, pointer, dial indicator, and prepare to profile cam. (See photo E.) Zero degree wheel. with positive stop method.

CAM PROFILE

EXHAUST

INTAKE

0.05

38-33 BBDC

0.05

7 BTDC-0 TDC

0.1

21-16 BBDC

0.1

10-17 ATDC

0.15

2 BBDC-3 ABDC

0.15

29-36 ATDC

0.2

21-31 ABDC

0.2

55-64 ATDC

max.

233"

max.

.233"

0.2

76-65 BTDC

0.2

43-33 BBDC

0.15

48-40 BTDC

0.15

13-6 BBDC

0.1

28-21 BTDC

0.1

6-13 ABDC

0.05

10-4 BTDC

0.05

23-31 ABDC

E-Z Start

45-60 ABDC

E-Z Lift

.013" minimum

E-Z Lift

.019" maximum.

E-Z Duration

30 degree minimum at

.001" drop






From 2021 ikf rules.

Pg 207


https://www.google.com/url?sa=t&sou...IQFnoECBAQAQ&usg=AOvVaw2krSwQirnvVdKdHkHI7R1o

Follow on question post 12 asks about flathead stock heavy.

 

[XXX#40]

701.27 Flywheel: ARC Billet Flywheel part #6620 will be the only flywheel allowed. Non adjustable, with minimum weight of 4 lbs. Any flywheel key or no key is permitted. Flywheel key slot and crank key slot must not be altered and must remain in stock location. The old Briggs Part #555657 is no longer legal.

701.28 Set up degree wheel, pointer, dial indicator, and prepare to profile cam. (See photo E.) Zero degree wheel. with positive stop method.

CAM PROFILE

EXHAUST

INTAKE

0.05

38-33 BBDC

0.05

7 BTDC-0 TDC

0.1

21-16 BBDC

0.1

10-17 ATDC

0.15

2 BBDC-3 ABDC

0.15

29-36 ATDC

0.2

21-31 ABDC

0.2

55-64 ATDC

max.

233"

max.

.233"

0.2

76-65 BTDC

0.2

43-33 BBDC

0.15

48-40 BTDC

0.15

13-6 BBDC

0.1

28-21 BTDC

0.1

6-13 ABDC

0.05

10-4 BTDC

0.05

23-31 ABDC

E-Z Start

45-60 ABDC

E-Z Lift

.013" minimum

E-Z Lift

.019" maximum.

E-Z Duration

30 degree minimum at

.001" drop






From 2021 ikf rules.

Pg 207


https://www.google.com/url?sa=t&sou...IQFnoECBAQAQ&usg=AOvVaw2krSwQirnvVdKdHkHI7R1o

Follow on question post 12 asks about flathead stock heavy.

Yeah easy spin had to be there even in WKA.

 

[XXX#40]

Not to muddy the waters but does the OP want to pull start the engine? I've read on here some cams without easy-start can be a pita.

This might influence a casual mini bike rider...

Watched many guys start limited with a pull start.
I wouldn't but people did.

 

[XXX#40]

Cam, carb and header will all need matched to get the most out of that range.
Almost a stock Cam with a really good plate carb the flows more fuel, and a good header for lower RPMs

 

[flattop1]

Watched many guys start limited with a pull start.
I wouldn't but people did.

For sure .
You had to want too in order to do it .
No Limp wrist allowed .

 

[Colt sr]

For sure .
You had to want too in order to do it .
No Limp wrist allowed .

It wasn't my wrist that had the issue. It was my shoulder... lol

 

[flattop1]

My fore arm.

 

[95 shaw]

I started ours with the cup type starter still mounted on engine.

Problem was track guys thought they could start it for me.

Never turned out good.

 

[flattop1]

Someone's always getting slapped by a recoil assembly. Never stand behind the person starting it .

 

[Colt sr]

The best is when the starter doesn't want to come off when the engine is started and you always have that guy that either gets hurt trying to take it off or leaves it on. Next thing you know you have a starter on the track. Lol