Tune your engine without busting your budget

[DMCdesign]

After doing many research on how to tune the engine to full potential, here are some of the tips I have compiled from the following sites- affordable go karts and ehow.com

Governor- while many people feel removing the governor is a surefire way to increase performance, but the governor does a lot more than that. Not only it controls the RPM, but it also controls the throttle to keep it steady. If it bogs down, it opens up the throttle and if its over revving, it will relax the throttle. Tweaking will also help which will not only allow higher peak RPM, but also keep the RPM uniform.

Valve springs- after the increase in performance, the stock valve springs will not be able to handle the load and will float- which we all don't want. Getting stiffer valve springs is a fairly inexpensive performance investment.

Flywheel- in some engines, especially clones, the flywheel tends to detonate at higher RPMs. needless to say, It is similar to a bomb going off. If you haven't got the buck to switch to an ultra light aluminium flywheel, Bionically Optimise it! This trick is used by BMW for its diesel engines which consists of cutting off the "body fat" from stock parts to make it lighter (ex-remove the fan). Not only you get a lighter flywheel, you have practically paid no money for it! Bonza!(however this is not recommended if you do not have the appropriate balancing machinery to check balance of the flywheel- which is more dangerous than a stock flywheel detonating)

Polishing and Porting- this classic tuning method consists of grinding out factory imperfections from the head which allows smoother circulation of fuel, air and exhaust. this increases performance and efficiency.

Free Flowing Exhaust/ Intake- take time to study the stock muffler on these engines and you will discover that the stock muffler restricts airflow, which often bogs down the engine while the stock intake does the same too. installing free flow machinery on both sides will contribue to performance increase.

Spark plugs- hot rodders have used "indexing" the spark plugs near to the exhaust valve which helps the engine to get rid of exhaust gases much faster. there is another tip that is used on spark plugs is to increase the gap between the electrodes to burn the fuel air mixture much more properly and efficiently

Check gaskets and other fixtures- always check for gaskets near important engine parts and trim them if they are blocking the path. every little bit counts here.

Carbs- lastly, the carb has to be tuned for getting more performance out of your engine, adjusting fuel air mix and trying bigger jets is a surefire way to increase performance.

I have tried to keep the information as accurate as possible, any suggestions are welcome to correct the above article.

Regards
DMCdesign

 

[jamyers]

IMHO, cutting on a flywheel is a BAD idea, unless you have the means to re-balance it - which costs $ and defeats the low-budget purpose.

On some things, spending money up front saves money in the long run - assuming you get what you pay for.

 

[Doc Sprocket]

A couple points here, from the peanut gallery-

1) Never- but NEVER manually alter a flywheel. Only a competent machinist with ALL the right equipment to do this job fully and properly, should get anywhere near your flywheel with a cutting instrument. That's just BEGGING for shrapnel.

2) IF your engine is still governed, stiffer valvesprings really will not do much at all for you unless your stockers are shot.

3) On a kart or minibike, the "equalizing" effects of the governor are pretty much pointless. It's not often you'd be driving at part-throttle and relying on the governor to keep a mid-range RPM.

 

[DMCdesign]

since so much argument on the flywheel, I am going to experiment with one off from a non working engine. I have my own questions-
#if a flywheel is balanced, it should run without vibes or shaking, right?
#"balance" in a flywheel means equal weight in equal angles, right?

 

[jamyers]

...
#if a flywheel is balanced, it should run without vibes or shaking, right?
#"balance" in a flywheel means equal weight in equal angles, right?

Yes.

Not necessarily, it depends on the engine. Many flywheels are also part of the overall counterbalance for the crankshaft/piston/rod assembly. For example, old Buick V8's were externally balanced - meaning that they used both the flywheel and harmonic damper as part of the dynamic engine balancing, and those parts were unique to each engine. Ch*vy engines on the other hand were internally balanced and you could interchange flywheels and dampers at random. I don't know about Briggs or Clone engines, but I'd be VERY leery of one that had been cut or hammered on.

 

[DMCdesign]

I don't have a clone or any industrial engine. I have the good old 145 cc 9 hp scooter engine. Recollecting what I have read and heard, these engines are pretty mod friendly-
# 145 cc
# Keihin carb
# TRICS-throttle regulated ignition control system
if these heavy flywheels are polished (and/or) precision cut along with exact angles, I may have a lighter flywheel........

 

[DMCdesign]

I saw some videos on flywheel balancing and found out that testing them on an axle with precision bearings can show whether the flywheel is balanced or not. I dont want a fancy design on my flywheel to balance it, just plotting the metal to be cut in concentric circle and cutting it along. What you think? this is what mine looks like-

 

[mckutzy]

They do drill and cut to balance flywheels and rotating assemblies for various spinning machines and devices. Electric motors and turbochargers are good examples I have personal experience with.
If the mass is not spinning it is call static balancing, which is what your describing. If a flywheel is used on a shaft to check balance, the shaft must be true in its form to act accordingly for the wheel.

I think that unless you have a dynamic balance machine you can only truly tell if it is balanced and that by when you are reducing its mass.
This will tell in all forms where true balance is.

 

[DMCdesign]

If I attach a motor to it and spin the assembly. On high speeds you can know if the flywheel is balanced by checking for vibes and shakes

 

[mckutzy]

here is a link on some info about this.
http://www.balance.net.cn/phe.htm


You will need AFIK some balance software, sensors and strobe to find this.

 

[DMCdesign]

this is exactly what I meant. static balance is low cost and shows where the balance is actually needed to be enforced.

 

[mckutzy]

On that plane yes, but that is why they need to do a dynamic balance to show the other forces that will make it explode by balancing them out.

Basically said Its kinda a black art. There's a type of experience that is hard to describe simply. The link above kinda explains what im saying.

If you dont know much about balancing, it is not the thing you want to mess with on your own without expert advise and demonstration.

 

[DMCdesign]

aluminium flywheels are quite expensive. Are there used ones too?

 

[tundrabeagle3]

I agree

 

[mckutzy]

All this is why those flywheels are expensive. The engineering, machining, all the finish work ect.

 

[jamyers]

A lighter flywheel lets the engine rev faster - it doesn't add power in any way. It also makes for an engine that won't idle down as far as it used to.

You may or may not affect the total, overall engines DYNAMIC balancing with a lightened flywheel, it depends on the specific engine design. The DYNAMIC engine balancing is what MUST stay within specs or the engine WILL tear itself apart.

Unless you've got a SERIOUS lightweight racing kart, there are MUCH more cost-effective mods you can do to your engine than screwing around with the flywheel.

 

[jandj]

Does anyone else hear an Ambulance in the distance while reading this thread? Yeah, aluminum flywheels cost a bit...but they're
less than the bill the Rescue Squad will send you if you end up with shrapnal in your back.

 

[Doc Sprocket]

Oh- Is that what that sound was?...

 

[mr.matt]

I think the idea of this thread was a good one, although I also agree about no altering of the flywheel. But the overall idea is a good one with some potential, perhaps in need of some changes

 

[mckutzy]

I'm kinda glad that most of these motors have a cover that will somewhat contain or at least redirect the blast, potentially into the motor. So that saves shrapnel danger, then again there is the boiling hot oil and gasoline to contend with. Naa prob, it's all good..