Max Rev Limit?

[danielflo216]

I have upgraded almost everything in my engine apart from the crank, flywheel, rockers and other bits and pieces. I put 36lb valve springs in with a .265” lift cam which I realise now in the case of the valve springs was probably overkill, but my main concern is when revving it those rockers will snap. I was wondering how likely that would be and if I am in any extra danger because of the heavy springs. No cracks on the flywheel inside or out but I am still concerned for it as I bought a very cheap clone engine (the 196 eBay special ) and those parts have been known to be cast very poorly, especially the flywheels. I live rurally so my engine is currently not on a go kart, every few days I just start it up and once its warmed up I give it a few revs to make sure it’s healthy. I’ve never taken it past 3k even though i’ve got a billet rod, I’m just anxious I’ll blow something up or send a chunk of the flywheel into the stratosphere. Regardless, do you think my build is safe for me to rev past 6, 7? Maybe to 8? If not what is a safe RPM until I get some rockers and a flywheel? Thanks in advance.

Cheers,
Dan

 

[Master Hack]

Flywheel is the biggest concern. Go too fast and you might get a flywheel chunk enama!

 

[Hellion]

What engine you got there, newbie?

Don't ever rev it or redline it off of a kart or not connected to anything. A chain, axle and wheels is a safeguard because it acts as mechanical drag.

Oddly these cheap industrial engines are fragile in the big picture; they were designed from the get-go to trundle along below 4,000 revs or less, powering small implements.

 

[Master Hack]

What he said!
And don’t even think about 6-7or 8k rpm

 

[danielflo216]

What engine you got there, newbie?

Don't ever rev it or redline it off of a kart or not connected to anything. A chain, axle and wheels is a safeguard because it acts as mechanical drag.

Oddly these cheap industrial engines are fragile in the big picture; they were designed from the get-go to trundle along below 4,000 revs or less, powering small implements.

Just a cheap 196cc clone engine. The ripoffs of the GX200s. Thanks for the advice! So those rockers aren’t much of a concern atm?

 

[Master Hack]

Probably the least of your concerns….

 

[Hellion]

It doesn't need to be started up every few days and revved to make sure it is healthy. You need to put it on some kind of vehicle asap and see what it will do. Doesn't matter how much it will rev on its own...unless you just like to make noise.

It can always rev higher on a test stand than it will connected to a drivetrain and that's probably the saddest thing of all.

You definitely need to invest in a billet flywheel. That and a billet connecting rod are the two main prerequisites for a speed build, then go for valves, etc.

These cheap clone engines do indeed have weak flywheels--seems the magnet goes first since it is bonded to the flywheel. Once it goes, the flywheel becomes dangerously unbalanced at that moment and you might have two rapid catastrophes, instead of just losing the magnet.

 

[Master Hack]

These cheap clone engines do indeed have weak flywheels--seems the magnet goes first since it is bonded to the flywheel. Once it goes, the flywheel becomes dangerously unbalanced at that moment and you might have two rapid catastrophes, instead of just losing the magnet.

Thats a very eloquint was of saying you could die, or best case, just get seriously hurt.
Never underestimate the (lack of) quality in anything made by the fine craftsmen on the other side of the pacific. (not all countries on the other side included)

hope l wasn’t too vague?….

 

[danielflo216]

Yeah definitely. Would you say investing in a billet flywheel is much better than a PVL Aluminum one. Some are nearly half the price of the billet ones and I wonder if the PVL is good for the price or just another cheap alternative.

It doesn't need to be started up every few days and revved to make sure it is healthy. You need to put it on some kind of vehicle asap and see what it will do. Doesn't matter how much it will rev on its own...unless you just like to make noise.

It can always rev higher on a test stand than it will connected to a drivetrain and that's probably the saddest thing of all.

You definitely need to invest in a billet flywheel. That and a billet connecting rod are the two main prerequisites for a speed build, then go for valves, etc.

These cheap clone engines do indeed have weak flywheels--seems the magnet goes first since it is bonded to the flywheel. Once it goes, the flywheel becomes dangerously unbalanced at that moment and you might have two rapid catastrophes, instead of just losing the magnet.

 

[Denny]

Why do you want to rev it to the moon anyway? Torque moves mountains not rpm.

 

[Master Hack]

Denny’s right! Not only is he smart he’s the resident pharmacist! See him for your innoculation.

"Torque Is How Far You Move the Wall" Is a Pretty Bad Explanation of Horsepower vs. Torque

Debunking a gearhead cliche, and better understanding the difference between horsepower and torque.

www.roadandtrack.com

 

[BrownStainRacing]

Yeah definitely. Would you say investing in a billet flywheel is much better than a PVL Aluminum one. Some are nearly half the price of the billet ones and I wonder if the PVL is good for the price or just another cheap alternative.

I don't call "tested at 17,000 rpm" a cheap alternative. They have been around for a long time.

The 1 on my mini bike is over 5 yrs old, and I know it's been on more different builds then most will ever see.

It's a lil bit heavier then a billet, but I find it more balanced at different rpm's then some finned billets, on certain builds. These engines are no where near BALANCED,
ARC billets are a fine quality flywheel, I jus perfer the PVL.

Racing Cams and Parts | PVL Flywheel, Clone, Honda GX160/200 | DC-PVL-FW | DynoCams

PVL is known for their quality flywheels. This flywheel gives the racer a high quality option with a great price. Made from die cast aluminum, the PVL flywheel is dynamically balanced and tested by PVL at 17,000RPM. | DC-PVL-FW

www.dynocams.com

 

[Hellion]

Let's just say speed rated parts then, shall we?

Billet, PVL, anything with a rating or a proven reputation.

 

[Master Hack]

Funny how 90% of my ugly vibrations went away when the craponese flywheel went away.

 

[Hellion]

You mean the stock flywheel?

 

[Master Hack]

No, l bought a craponese electric start conversion kit, when l was young and inexperienced. That flywheel was chiseled out of stone.