Cam, rockers and valve train

K

Kylekoch012186

New Member
#1
#1
Hi everyone. I love all of the info I have gotten from this site so far. But with all the reading I have done I am still somewhat baffled on a few things. Before i start with the questions. however, I want to let you know what I want and what I'm doing. I have a brand new HF-6.5c engine with maybe 5 minutes of burn time on it. This engine will be going on an older model box frame go-kart. I want to beef it up some before I run it though because; one, I like speed and two, I have read posts on other forums where people have blown the engine and blamed it on a bad valve train. Now for the questions:

1) Would replacing the stock cam with a CL1 cam be beneficial in anyway?As to the longevity or performance of the engine? I don't want to go crazy with this motor, just want it to run great and sound good too. (More on this below)

2) I have read about the 1-1.3 ratio rockers and was wondering if i should get a set? Would they work with the stock or CL1 cam with no hassles?

3) I am already planning on replacing the stock springs with 26lb springs since every forum you goto recommends it. Especially since I will be going billet on the rod and fly-wheel (yup after those are in... buh-bye governor :p). What other recommendations do you guys have for the valve train to increase longevity and slight performance boost?

Back to the cam question, if the only difference between stock and the CL1 is the hardened contact surface, what would you recommend for a cam for this motor build? (please give links! I plan to be buying from NR-Racing). I would like to have the motor revving about 6500-7000 after all the work is done.

MANY thanks for reading this and double thanks to those who provide input.

Kyle
 
minidragbike

minidragbike

Supporting Speed Nut!
#2
#2
The CL1 is not a harden cam
You can only run a max of #22 pounds of spring pressure on it, or a stock cam. Running with #26 pound springs will flatten out the cam.

The 1.3 rockers will work better with #26 pound springs. but you can't with those cams and your valves will float with the #18 pound springs and the CL1 cam.

So the best setup would be a stock cam and 1.3 rockers and #18 pound springs, or CL1 cam and #18 pound springs.

After all of this, it's best to get aftermarket stainless steel valves. With the matching locks and retainers. Making your motor rev pass the factory 3600 RPM will cause more wear, no matter what you do.
 
novaracer

novaracer

New Member
#3
#3
minidragbike said:
The CL1 is not a harden cam
You can only run a max of #22 pounds of spring pressure on it, or a stock cam. Running with #26 pound springs will flatten out the cam.

The 1.3 rockers will work better with #26 pound springs. but you can't with those cams and your valves will float with the #18 pound springs and the CL1 cam.

So the best setup would be a stock cam and 1.3 rockers and #18 pound springs, or CL1 cam and #18 pound springs.

After all of this, it's best to get aftermarket stainless steel valves. With the matching locks and retainers. Making your motor rev pass the factory 3600 RPM will cause more wear, no matter what you do.
Click to expand...
STOCK CAM 1.3 ROCKERS AND 18LB SPRINGS coil bind or hell my spring coils were touching at max lift when i tried it. and arc racing sells a flame hardened cl1 for 55bucks:thumbsup: the hardened cl1 and 1.3 with 26lb springs would work but then you need retainers and locks so you dont drop a valve.
 
K

Kylekoch012186

New Member
#4
#4
Well then with that said... what would be a good beginner cam for a little extra umph without having to modify too heavily. Like i said this is not going to be a radical engine. My budget for this motor is going to be around 300-350. had I have thought about it I would have just bought a race ready engine but thats moot now. Besides I like the challenge of doing it myself so I understand what is goin on later :p !!
 
K

Kylekoch012186

New Member
#5
#5
Oh and one more thing... Minidragbike... your awesome videos on youtube are what led me here. Thanks for posting those vids!! How did the dual carb turn out??
 
T

tlizard2

Member
#6
#6
How about this: Instead of going with rockers and CL1 cam, go with the 18lbs rev kit from NR, advance ignition key (or make your own), stock rockers, header, and flat top piston. Then rejet the carb and add a filter. This will make a noticeable difference in power and give you 6200-6500rpm. Also you could find a machine shop near you and see if they will shave the head for you. It's pretty easy so should not cost much. Have them take it down to the first cooling fin which is about .055". You could also radius the ports for better flow.
 
jprice

jprice

OldMiniBikes.com
#7
#7
me and my buddy are using for the time being, 1.3 rockers stock cam,18 pound springs ,runs very well , you will need to get new quide plates or just dremel yours out a little longer,runs strong! easy cheap upgrade..
thank MDB
 
B

briggs_boy

Banned
#8
#8
you should try the cl1mod2 this cam has the same lift but TONS more duration it is heat treated so it can take the high spring pressures.

that cam with ratio rockers, chromoly push rods, and billet rod makes good reliable power.

also Charles they do have a hardened cl1 cam. they are 45.00


i have them in stock also along with everything else i listed.


let me know if i can be of any help to you.


- david
DLR engines
 
minidragbike

minidragbike

Supporting Speed Nut!
#9
#9
briggs_boy said:
you should try the cl1mod2 this cam has the same lift but TONS more duration it is heat treated so it can take the high spring pressures.

that cam with ratio rockers, chromoly push rods, and billet rod makes good reliable power.

also Charles they do have a hardened cl1 cam. they are 45.00


i have them in stock also along with everything else i listed.


let me know if i can be of any help to you.


- david
DLR engines
Click to expand...
That's cool
How much spring pressure can the harden cam handle?
 
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