Will this cam work?

X

Xtreme_karts

New Member
#1
#1
Hi there,

I have just purchased a few different parts from affordable gokarts but im not sure if this cam would be ok on a stock carb....

affordablegokarts: Cam, Custom Ground .265" Lift, Modified

As the duration is longer on the intake

The engine seem very sluggish and underpowered and im thinking it might be the cam spec of engine as follows....


Every other fan blade cut off (for less drag)

8degree advanced timing

Spark plug indexed to exhaust

Spark plug gap adjusted to 1.15mm

18lb valve springs (gap adjusted to 0.5mm inlet 0.7mm exhaust)

0.10inch thick head gasket

Flat top pistons

.265" lift cam (236 duration on intake/exhaust)

Long billet rod 3.313 (.10inch longer)

14cc cylinder head with ported intake/exhaust

custom exhaust

Honda aluminium flywheel.


What do you guys think...
 
Oldschool

Oldschool

New Member
#3
#3
Might be running lean does it start well?

What else was done?
Stock carb and ehaust?


More cam does not help unless you do something to allow it to exhaust spent gasses more easily and draw more fresh charge in accordingly.

Sort of like trying to eat when your constipated
 
C

C9H13NO3

Active Member
#4
#4
Oldschool said:
Might be running lean does it start well?

Sort of like trying to eat when your constipated
Click to expand...
That is a really good example. Xtreme, as you increase the lift you will need a bigger carb, so what you need to do is either jet your stock carb accordingly or have it bored out, or buy a bigger carb like a Mikuni, Tillotson, or GX390 carb.
 
X

Xtreme_karts

New Member
#5
#5
Its running very lean and is difficult to start uless the choke is on and full throttle.

Do you think its worth getting a 80, 90 jet or sticking the old gx200 cam back?

It has a custom exhaust but i dont think it very flowing, it has the 70 standard jet at the moment.

I did try the mikuni vm26 but had all sort of issues and couldnt get it tuned very well (Very sluggish) even with the 125 jet and 12.5 pilot.
 
K

Kylekoch012186

New Member
#6
#6
Xtreme: Get these parts here and you will see a HUGE difference in how the motor runs. These made my engine go from timid to a monster!

Mikuni 22mm Carb kit from www.affardablegokarts.com. Get the kit that has the Carb, Filter and Pulse fitting.

Mikuni Fuel Pump (Also be sure to get fuel hose)

Any open header besides stock exhaust. Stock exhaust is absolutely horrible!!!

I am short on time now but I can get you links later.

I have a vid of mine after adding that stuff and its here: http://www.oldminibikes.com/forum/honda-clone-engines/39260-my-6-5hf-clone-update.html
 
Last edited:
X

Xtreme_karts

New Member
#7
#7
Hi

I already have the mikuni with the pulse pump and manifold, but couldnt get it to run well atall, so gave up on that idea.

Do you think the cam would be suitable or should i ditch it with the clone gx200 carb (with amybe a bigger jet in?)

Regards
Xtreme_karts
 
E

Eradicator

New Member
#9
#9
If you are using the stock jet, it is way too lean. Start with a #35 jet and go from there. If you have removed the stock air box (I'm assuming you did) and removed the stock muffler the motor will run very lean. The jets are cheap, around $4 for drilled and $6 for Honda jets. Where I live, it gets to over 100* so I have even raced my kart with a 42 jet.
 
Oldschool

Oldschool

New Member
#10
#10
C9H13NO3 said:
That is a really good example. Xtreme, as you increase the lift you will need a bigger carb, so what you need to do is either jet your stock carb accordingly or have it bored out, or buy a bigger carb like a Mikuni, Tillotson, or GX390 carb.
Click to expand...
Not that much lift on the 265 but a header and air filter would realy help it take a big gulp.
Its all quite reasonable but the longer durration on the intake probably takes a little bite out of the bottom end. No getting around that....
Small carbs respond well to modest lift with more durration more than high lift and short durration. They make up for the small size at mid range and higher RPM. Thats my take however others may have a difference of opinion.

Tom did a great piece on running a ball hone on stock carb to bring out a little more flow potential end on Kartttrax.
Worth watching.
I would like to try this on a 5/8 tilley and see if I can come closer to .675
I don't want a big carb for a machine that needs to idle and make some low end power but you can shoot yourself in the foot with too much cam.

I don't have all the answeres
 
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