196 cc engine mods

[Poboy kartman]

You need to read your spark plug. It'll tell you which way to go with your jets. I think you may be running rich...

Your intake and exhaust may not be balanced as well....(more intake than the exhaust can handle will make it run worse....)

Post some pics of your exhaust and a few more details of exactly what you did.

 

[leesiel]

Thank you for your explanation! I removed the autolite racing plug and went with regular plug and that helped alot. When I get home today I'll read plug again. I also ported and polished my exhaust header as it was not a perfect match for my engine.( didn't make a difference at first)

 

[leesiel]

You need to read your spark plug. It'll tell you which way to go with your jets. I think you may be running rich...

Your intake and exhaust may not be balanced as well....(more intake than the exhaust can handle will make it run worse....)

Post some pics of your exhaust and a few more details of exactly what you did.

1 removed governor
2 fuel pump
3 exhaust header & air filter
4 e tube
5 36&37 jets
6 smaller diameter cooling fan
7 autolite racing plug ( did not like )

Tested jets and e tube combinations by running it and checking plug also by gps speed .
Best so far is 37 jet & stock e tube with standard spark plug . (That one by seat of pants and gps...it was dark will read plug when I get home.)
Still have 8 ° key to install

 

[bob58o]

Did you read the recent thread about fuel pumps, fuel return to tank, needle valve seat size?

---------- Post added at 03:47 PM ---------- Previous post was at 03:45 PM ----------

http://www.diygokarts.com/vb/showthread.php?t=32714

I was just pointed here. It might help you too. Maybe not, but worth a read.

 

[Poboy kartman]

Well...we're kinda back to the cam again when you start talking 8° of advance...it may or may not help...but that's a LOT of advance for a stock cam....IMHO.

A 4° key might help. At any rate ... I think a cam would really wake that thing up.

 

[leesiel]

Did you read the recent thread about fuel pumps, fuel return to tank, needle valve seat size?

---------- Post added at 03:47 PM ---------- Previous post was at 03:45 PM
I was just pointed here. It might help you too. Maybe not, but worth a read.

Didn't develop problems until I installed the hop up kit. But I'll admit that that doesn't necessarily mean anything.

 

[leesiel]

Also I installed the pieces in the order that they appear but not all at once
Here's pics of plug ...Not a good pic I know but it does show that it's fouled out...might I add with it reading as such I posted my highest mph to date 39 mph on one gps 40 on another .. sooooo it stands to reason I get the fuel mix right I should get a mph or 2 right?
Very interested in the cam and rod upgrade but am also in need of tires and rims and taller tires will also increase top end a little. I know it seems like top end is all I'm worried about but my launches in dirt or on asphalt are solid and quick( I race against a predator 212 same mods as mine and a single seat kart with a predator 420 no mods ; I have a c.c, they have t.c.) and we are all hovering between 38_42 mph(predator 420) .

 

[Poboy kartman]

Holy moly....yeah that could not be a more CLASSIC example of a plug that shows an engine is running rich!!!!!!

Back off those larger jets....and....GET A CAM.... you'll be like: "WHY DIDN'T I DO THIS BEFORE? "

 

[leesiel]

Then my next engine upgrade will cam ,rod ,and springs. Any particular cams I should look at?
I'll start shopping early. Gonna be a while . (UnLess I pick up extra work)
Can I get a higher revving cam now leave off rod and springs and use the stock springs as a "limiter/govenor" for the time being till I can get said parts?

Thanx for your time and help everyone.

 

[Poboy kartman]

Unfortunately, even if I found a cam for you...I couldn't link it!!!

But...if I'm not mistaken, that engine is a TRUE clone, and a Honda cam should work.

I'm fairly confident someone will be along shortly with a recommendation....

But just to give you a general idea of what and why:

Basically, a combustion engine is an air pump....OK...So your mods call for more air in and more air out, right?

Now , what a performance cam does is the same thing one of two ways: it either opens the valve MORE....(giving the engine a chance to take a bigger gulp quickly) ....or it keeps the valve open. longer: (letting it take a long deep breath) ...but MAINLY, a combination of the two...sooooo....anyway, you can see how a performance cam would help maximize your modifications....

But meanwhile, Hawl yes, youse running richer than Donald Trump!

 

[leesiel]

Kinda off topic got theses for FREE today.
Gonna strip blue one for all usable parts, red one gonna put it right immediately ( the motor on it is not included) small black one with the Briggs & Stratton motor on giving to a buddy so he will have one and the large black one will become a project .

 

[landuse]

Kinda off topic got theses for FREE today.
Gonna strip blue one for all usable parts, red one gonna put it right immediately ( the motor on it is not included) small black one with the Briggs & Stratton motor on giving to a buddy so he will have one and the large black one will become a project .

Score!!!!!!!!!!!!!!!!!

 

[leesiel]

I know right? Stoked about the Murray.....

 

[bob58o]

Then my next engine upgrade will cam ,rod ,and springs. Any particular cams I should look at?
I'll start shopping early. Gonna be a while . (UnLess I pick up extra work)
Can I get a higher revving cam now leave off rod and springs and use the stock springs as a "limiter/govenor" for the time being till I can get said parts?

Thanx for your time and help everyone.

Looking through a thread on Bob's....
I found a quote from Tim at Isky - Small Engine Cams.

The intake valve has an opening point and a closing point.
The exhaust valve has an opening point and a closing point.
The INTAKE CLOSING POINT is the most critical valve timing point because it determines the powerband of your engine.
The intake closing point can be changed by:
1- adding or subtracting duration
2- changing the lobe separation angle
3- advancing or retarding the camshaft
4- changing the valve lash

Earlier intake closing = more POTENTIAL bottom end power
Later intake closing = more POTENTIAL top end power
More lift = more POTENTIAL power at any rpm
Less lift = less POTENTIAL power at any rpm

I use the word potential because every combination is different and anything can be taken too far.

---------- Post added at 10:20 AM ---------- Previous post was at 10:07 AM ----------

This seems to be a popular option.
http://www.dynocams.com/item/mod2/cl-mod/
SPECS
Engine: 196cc OHV Clone, 212cc Hemi Predator
Recommended Class: Builder's Prepared
Target (MAX) RPM: 7000+
Spring Pressure (In / Ex): 18 lbs
Valve Lash (In/Ex): .003"
Ignition Timining: 32 Deg BTDC

PROFILE
Intake
Exhaust
Open: 46.3 BTDC 83.0 BBDC
Close: 82.7 ABDC 44.0 ATDC
Lift: .2245" .231"
C/L: 108.5 ATDC 110.0 BTDC
DUR @ 50: 245.7 Deg 245.5 Deg

Look into CS MOD, CL MOD, Black Mamba..... Dyno Cams, SmallEngineCams.....

 

[Poboy kartman]

I actually do know a little bit about cams....when I was planning my 399 ci...Windsor stroker , I contacted Comp Cams and gave them all the info, the tech recommended the exact same grind I had determined would be best!

And no...I didn't mention in any way shape or form ...any particular grind I had in mind!

 

[bob58o]

I actually do know a little bit about cams....when I was planning my 399 ci...Windsor stroker , I contacted Comp Cams and gave them all the info, the tech recommended the exact same grind I had determined would be best!

And no...I didn't mention in any way shape or form ...any particular grind I had in mind!

When great minds think alike.... (makes for less interesting conversations)!

You can try calling all these places. The Guy from SmallEngineCams is a one man show, so hard to get on the horn. I spoke to a guy a Dyno Cams very easily.

 

[ezcome-ezgo]

Did you find the kind of grind you had in mind?

 

[bob58o]

Can I get a higher revving cam now leave off rod and springs and use the stock springs as a "limiter/govenor" for the time being till I can get said parts?

Thanx for your time and help everyone.

I think it depends on the shape of the lobes on the Cam. At first it make sense that this would work, but I fear the recommended springs are required even at lower RPMs to operate the valves correctly. Just guessing here, I'd call the manufacturer on that.

 

[leesiel]

If I'm correct the poundage on the springs is due to expected rpms of the motor....heavier springs, higher rpms....lighter springs less rpms.
So I wouldn't think that would change due to lift or duration. But I'm here cause I DON'T know it all sooooooo. Someone correct me if I'm wrong.

 

[bob58o]

If I'm correct the poundage on the springs is due to expected rpms of the motor....heavier springs, higher rpms....lighter springs less rpms.
So I wouldn't think that would change due to lift or duration. But I'm here cause I DON'T know it all sooooooo. Someone correct me if I'm wrong.

Again I'd check with someone with more experience, perhaps the manufacturer. Makes sense that It should work, but even some LOW RPM, Torque Cams (5500-6000 RPM target) require stiffer springs.

If it were me, I'd wait to install the Cam and recommended springs until I got a billet Connecting Rod.

The reason.... The increased lift or duration is because of the shape of the lobe. I fear that the valves MAY not close properly, even if you stay around 5500RPM because of the reshaping of the lobes on the cam. It may be too tall, or the slope or curves on the lobe don't allow the stock (10.8lb ) springs to close the valves properly.

AGAIN, NOT SURE. JUST MY CONCERN.

It will probably work, but hard to tell at what RPM valve float will occur. It may happen sooner that the 5200-5600 RPM Valve Float that occurs with Sock Cam and Stock Springs