6.5hp motor

[nixta]

Hello my fellow brothers of epic gokart builders..
I've removed the govener and made a straight pipe for the exhaust system would taking 1 or 2 thou off the head give me more power or kill the motor oh and fitted a pulse pump lol

 

[OzFab]

Waaaait a minute... 6.5cc motor? Are you sure?

 

[nixta]

Sorry my bad I ment 6.5hp

 

[OzFab]

Thread title edited...

Now, you've fitted a pulse pump why? Does the kart have a remote fuel tank?

Do you realise how minute 1-2 thou is? You can remove more than that with a rough emery paper; to make any noticable difference, you need to start at ~20 thou

I've removed the govener and made a straight pipe for the exhaust system

Did you also fit a hi flow air filter? Without it, a straight pipe is all but useless...

 

[nixta]

Yes hi flow filter is fitted pulse pump was fitted to increase fuel into motor but it back fired had to close fuel on off bout a 1/4 turn

 

[nixta]

Cheers fabro man umm ....What are the advantages of advancing or retarding the motor and is there a better spark plug and or better gap I should use

 

[mckutzy]

How about some pics of current setup.

 

[firemanjim]

If the fuel tank is on the engine, get rid of the pump. If your still able to feed the carb by gravity, get rid of the pump. It's only going to hurt your performance......

 

[nixta]

6.5hp clone

cheers um re. the lash caps would putting one on the intake side were there isnt one would this damage my motor

 

[Poboy kartman]

cheers um re. the lash caps would putting one on the intake side were there isnt one would this damage my motor

Try it and see.....

Why are you using a valve lash cap?.......It possibly could....if it hit the piston.....if you clay to check clearance....no.....

It actually shouldn't do anything. .... (now that I think about it) other than very slightly alter cam timing. ...and cause you to readjust valve lash. .....

 

[rmm727]

cheers um re. the lash caps would putting one on the intake side were there isnt one would this damage my motor

You need an exhaust retainer to run a lash cap on the intake valve. You usually need a shim to regain the spring pressure lost from the exhaust retainer. There is a height difference between the intake retainer and the exhaust retainer.

 

[Poboy kartman]

You need an exhaust retainer to run a lash cap on the intake valve. You usually need a shim to regain the spring pressure lost from the exhaust retainer. There is a height difference between the intake retainer and the exhaust retainer.

Wait....WHAT......WHY???????? I'm not questioning you. ....but can you explain? ???

Why exactly do you need an exhaust retainer????? For one........

 

[itsid]

If I understand that correctly the intake spring retainer is .. uhm.. narrower where the bore is for the valve stem.
So it will not allow a lash cap to fit "in"..

the exhaust spring retainer has a wider recess that does allow a lash cap.

The question I'd have is.. why is there a height difference *shrugs*

'sid

 

[rmm727]

The lash cap with exhaust retainer IMO is a more stable arrangement. Less likely to knock the retainer off at higher rpm's. The lash cap also serves to take wear off the tip of the valve, lessening the chance of the tip mushrooming. Not sure why the height difference but NR racing provides a shim to make up the difference if you go this route.

 

[Poboy kartman]

Ahhhhh......it's all becoming clear now......the intake won't accept the cap......the exhaust retainer has a deeper cup......hence the need for the shim on the intake valve. .....

 

[OzFab]

Cheers fabro man umm ....What are the advantages of advancing or retarding the motor

Are you referring to spark timing or valve timing?

Realistically, there are no advantages to altering stock valve timing; if you wish to do that, get a performance cam...

As for spark timing, there's a huge advantage to advancing this; the closer to TDC the fuel ignites, the more compression occurs, meaning, you get a bigger bang; the downside is it's only an advantage up to a certain RPM, at which point, you get pre-ignition (aka detonation or pinging)

is there a better spark plug and or better gap I should use

Yes, there are a few performance plugs on the market; also, a slightly larger gap can be benificial (40-45 thou)...