2011 6.5 HF Clones, "SAFE" RPM range? (there is no safe range other than stock)

[Clyde]

OK.
So this site has great mandates (and info) on NOT removing the governors to exceed the factory governed speed of 3600rpm (spec 3600 +/- 150 rpm per manual).

The first thing a kid usually hears when even mentioning wanting to own a mini-bike is that it is dangerous and to "forget about it".

So, nanny lectures aside ... who really knows the safe un-governed (or partially governed) RPM's that these HF 6.5 clones will take?
Who actually MEASURES?

I have seen failure analysis done on reciprocating aircraft engines, I know the concepts of piston speed and piston acceleration with these 54mm bore engines (and that stress loads on parts roughly increase 4 fold per each 1000 rpm increase), I have seen the anecdotal pictures of trashed (grenade engines) BUT what is the safe limit that you all think these engines can handle in RPM's STOCK (no parts replacements no load) from measured experience?

The reason I revive this issue is that #1) I don't see many tachometers being used on the engines that are exhibited as "grenades".
#2) I see the "tradition" of making the flywheel and the connecting rod w/extended oil slinger, more robust with aftermarket parts as an anecdotal precaution.#3) I see broken pieces but damn few measuring tools.

SO has anybody actually ran these motors at over 3600 spec RPMS and quantified the results by measurement? Somebody has to have actual factual quantified experience (racers?, re-builders?, shop equipment sales?)

Summation: max 3750 RPM's OK by factory spec with proper oil and proper oil level @ recommended operating temps.

What's the first KNOWN weak link in the power-train components when over-revving >3750RPMs?

(oh...PS... I did use the Search feature, lots of stories, few actual/factual numbers or measurements)

 

[Miniwood]

Lol. I get it now vette66. I was wondering why you were so touchy.

OK.
So this site has great mandates (and info) on NOT removing the governors to exceed the factory governed speed of 3600rpm (spec 3600 +/- 150 rpm per manual).

The first thing a kid usually hears when even mentioning wanting a mini-bike is that it is dangerous and to "forget about it".
So, nanny lectures aside ... who really knows the safe un-governed (or partially governed) RPM's that these HF 6.5 clones will take?
Who actually MEASURES?

I have seen failure analysis done on reciprocating aircraft engines, I know the concepts of piston speed and piston acceleration with these 54mm bore engines, I have seen the anecdotal pictures of trashed (grenade engines) BUT what is the safe limit that you all think these engines can handle in RPM's STOCK (no parts replacements no load) from measured experience?

The reason I revive this issue is that #1) I don't see many tachometers being used on the engines that are exhibited as "grenades".
#2) I see the "tradition" of making the flywheel and the connecting rod w/extended oil slinger, more robust with aftermarket parts as an anecdotal precaution.#3) I see broken pieces but damn few measuring tools.

SO has anybody actually ran these motors at over 3600 spec RPMS and quantified the results by measurement? Somebody has to have actual factual quantified experience (racers?, re-builders?, shop equipment sales?)

Summation: max 3750 RPM's OK by factory spec with proper oil and proper oil level @ recommended operating temps.

What's the first KNOWN weak link in the power-train components when over-revving >3750RPMs?

(oh...PS... I did use the Search feature, lots of stories, few actual numbers or measurements)

 

[Clyde]

miniwood: perhaps I should explain the need for the knowledge?

I am not 13 years old. I have a few years experience with "engines & motors".
I use these 6.5HF clones on a work minibike (good for surveying) AND a lot of other work equipment (boats too).
Their size to retro-fit on my old equipment frames is perfect in the power-to-weight dept. Their price is miraculously cheap.

I could use peak 4200-4500 rpms for direct drive to prop on some of my applications.
YOU FOLKS probably have the BEST experience with these particular motors on the whole fricken' internet and I would like to know what the actual experience is.
I know that it is "touchy" knowledge. I also know you guys have some of the best knowledge of why a certain RPM range will, or will not, work "safely".
I am not asking to "remove a governor", I want to know actual measured experience with over-revving (which can be done by adding extra springs?).

 

[mmisterbungl]

So, nanny lectures aside ... who really knows the safe un-governed (or partially governed) RPM's that these HF 6.5 clones will take?


I am not asking to "remove a governor",

:shrug::shrug:

 

[balljoint]

miniwood: perhaps I should explain the need for the knowledge?

I am not 13 years old. I have a few years experience with "engines & motors".
I use these 6.5HF clones on a work minibike (good for surveying) AND a lot of other work equipment (boats too).
Their size to retro-fit on my old equipment frames is perfect in the power-to-weight dept. Their price is miraculously cheap.

I could use peak 4200-4500 rpms for direct drive to prop on some of my applications.
YOU FOLKS probably have the BEST experience with these particular motors on the whole fricken' internet and I would like to know what the actual experience is.
I know that it is "touchy" knowledge. I also know you guys have some of the best knowledge of why a certain RPM range will, or will not, work "safely".
I am not asking to "remove a governor", I want to know actual measured experience with over-revving (which can be done by adding extra springs?).

Go buy one,and try it out,there cheap for a reason,what will fail is the flywheel may gernade,the rod may gernade ,or the valves will float ,you can buy one for around $100.00 or less with a coupon.for your application at 4200-4500 it will probably work ok,you can always beef -up the parts if need be .

 

[Clyde]

Go buy one,and try it out,there cheap for a reason,what will fail is the flywheel may gernade,the rod may gernade ,or the valves will float ,you can buy one for around $100.00 or less with a coupon.for your application at 4200-4500 it will probably work ok,you can always beef -up the parts if need be .

I have 3 now.
I took the time to actually "measure" some parameters.
One 2011 version HF 6.5 clone will not 'govern' (or rev limit if you prefer) itself per factory spec (measured with an impulse digital tach) . It revs a wobbly 3650+ RPM but pulls back sharply to cruise max 3400 rpm. The nuts holding the throttle assembly cables are crappy , bind, and slightly misaligned on the stamped metal, I also suspect the governor spring to be pretty darn weak and cheaply made (I'll quantify spring tension later).

IF I spend money and labor to set this motor up to run in factory RPM spec, I simply what to know why ...or how much further I can go stock (with reasonable and logical numbers that forewarn me of a possible CATO outcome).
I'm pulling a 5hp Briggs I/C and replacing it with a 6.5Clone on a prop drive boat strictly for the increase in rpms on my stock 7X5 ss. Money, money.

When it comes to actual numbers ---I guess you-alls' guess, is as good as any guess. Thus "Who actually MEASURES?":shrug:

mmisterbungl: I like that tag line "truth has no agenda". Appropriate.

 

[vette66_00]

Lol. I get it now vette66. I was wondering why you were so touchy.

It's nothing personal just get tired of the never ending questions like this.


Clyde I dont think you quite understand when it is said we do not talk about removing the Gov here WE DONT TALK about anything pertaining to this adventure. Including what the failure point of some random test that Olajoe has on a flywheel.

Each China motor is built by a different person on a different day with a different amount of materials of whatever combination. Its too hard to tell each flywheels failure point, there are no real guide lines to how much of this or that metal is included in the production of these flywheel, aside from that the casting procedures are inconsistent.

So when you say no nanny lectures we are simply at best trying to educate people.

So I say no talking about this subject and you do not comply with that statement. Do it again and you will take a vacation from the site for a couple days.
How about that for a nanny lecture ?

 

[creia]

I believe that Clyde brings up a very interesting (and legitimate) question. I think that extending the same question to "other" small engines (B & S, Tec, etc.) could prove to be interesting as well. While the common perception is that these HF engines are generally inferior-quality as opposed to other engines (and they very well may be, at least in some regards) would they hold up to over-revving above the factory-governed RPM just as good as a stock B& S, Tec, would etc.?:shrug: Is it at all possible that due to the fact that they are 1) Chinese made, and 2) Sell for a very low price contribute to the (possibly bias, exaggerated, and unwarranted) perception that they would not hold up to over-reving as good as non HF engines?
FWIW, I am in no way asking about, encouraging, or believe in removing or tampering with a governor at any time! My inquiry and point is purely hypothetical and fodder for discussion.

 

[supernova]

I believe that Clyde brings up a very interesting (and legitimate) question. I think that extending the same question to "other" small engines (B & S, Tec, etc.) could prove to be interesting as well. While the common perception is that these HF engines are generally inferior-quality as opposed to other engines (and they very well may be, at least in some regards) would they hold up to over-revving above the factory-governed RPM just as good as a stock B& S, Tec, would etc.?:shrug: Is it at all possible that due to the fact that they are 1) Chinese made, and 2) Sell for a very low price contribute to the (possibly bias, exaggerated, and unwarranted) perception that they would not hold up to over-reving as good as non HF engines?
FWIW, I am in no way asking about, encouraging, or believe in removing or tampering with a governor at any time! My inquiry and point is purely hypothetical and fodder for discussion.

Ain't but one way to find out.:doah: Just don't publish your findings here.......

 

[vette66_00]

I got it and understand. This goes for any engine. I personally have had several B&S grenade on me, generally rods but one flywheel but this was long ago.

I am just one person on this board I control the DB and the Honda/Clone area (most visited by newbies) and I over see the rest. The Clone seems to be the one that this failure happens to the most, this is the reason for the constant harping on not doing these mods on a clone without the proper equipment installed. And also the reason we do not talk about it and post the link to the pics and what not.

 

[Mr.Blue]

I am not 13 years old. I have a few years experience with "engines & motors".
I use these 6.5HF clones on a work minibike (good for surveying) AND a lot of other work equipment (boats too).

from what I've seen on here, the main failure points on clones are rod/pin-flywheel and the block when putting put lots more hp/rpm's. I don't know how much and what level experience you have with any car/truck engines as fair as performance but here's an example h beam rods for a honda h22 engine go for around $400 (for 4 of them) and a lightened flywheel go for around $250, my point why take a chance by skipping on 150$ (rod/flywheel) worth of parts for a clone when asking a engine to work above spec? if not for safety then for reliability

no disrespect intended but i don't understand the point asking a engine to work above what it was designed to do with stock parts when you could replace them in under 1 hr inside nice and warm for such little money

end rant

 

[Miniwood]

You don't understand. I just got back from being banned for a similar question. I could care less about your question or anything else!

miniwood: perhaps I should explain the need for the knowledge?

I am not 13 years old. I have a few years experience with "engines & motors".
I use these 6.5HF clones on a work minibike (good for surveying) AND a lot of other work equipment (boats too).
Their size to retro-fit on my old equipment frames is perfect in the power-to-weight dept. Their price is miraculously cheap.

I could use peak 4200-4500 rpms for direct drive to prop on some of my applications.
YOU FOLKS probably have the BEST experience with these particular motors on the whole fricken' internet and I would like to know what the actual experience is.
I know that it is "touchy" knowledge. I also know you guys have some of the best knowledge of why a certain RPM range will, or will not, work "safely".
I am not asking to "remove a governor", I want to know actual measured experience with over-revving (which can be done by adding extra springs?).

 

[Clyde]

It's nothing personal just get tired of the never ending questions like this.
Clyde I dont think you quite understand when it is said we do not talk about removing the Gov here WE DONT TALK about anything pertaining to this adventure. Including what the failure point of some random test that Olajoe has on a flywheel.
Each China motor is built by a different person on a different day with a different amount of materials of whatever combination. Its too hard to tell each flywheels failure point, there are no real guide lines to how much of this or that metal is included in the production of these flywheel, aside from that the casting procedures are inconsistent.
So when you say no nanny lectures we are simply at best trying to educate people.
So I say no talking about this subject and you do not comply with that statement. Do it again and you will take a vacation from the site for a couple days. How about that for a nanny lecture ?

The "WE DONT TALK about anything pertaining to this adventure." seems to be a firm new addition to this forbidden topic , and I sure don't want to have myself (or others) banned for asking an intelligent question about an engine. Sorry , didn't see the ANYTHING part of the stipulation posted prior to this warning.

Thank you for trying your best to "educate people" by censoring the subject of engine RPMs. Keeping folks like me ignorant for my own good is a surely a worthy "adventure".
I do need to get "my mind right" boss.:thumbsup:
I henceforth encourage all here to respect the authority of the boss mods and refrain from asking forbidden questions on the topic of anything to do with engine RPMs.

What we got here, is a failure to communicate .....

 

[vette66_00]

I see you just read what you want and did not get the point. I explained why we dont talk about it, but I guess you just want to not get it.

Ungoverned RPM's on stock Clone parts equal failure. What part of that dont you get? Why push the limit off stock RPM's? Why take such offense to this?

 

[metal man]

the answer is 3600 +- 150 . i have to wonder why in the hell people when they bitch all day how crapy shit from china is even think of pulling the safety . i was looking over the crank and side plate i just got off a clone , and my first thought after yes this will work for what i need was ,WHAT A PILE OF SHIT !!!!!!!!!!!!!!!! cheap casting, piss poor machining , blue coloring, on the metal from when it was ground to size . my worst and i do mean worst briggs crank dont look like that . hell the rotten one i tossed from my 61 looked better then that . and thats after is had sat under water for some long time .
this how fast idea has the same intelligence as ok a bouncing betty gos off at 7.2 lbs , how close can i get to that is 7.1 safe ?

i do see what your looking at, as what is known fail points and such . buy looking at what the motor is made from , at best weak junk .dont push ya luck .
call arc and ask them the safe range of there wheel and go from there much safer and cheaper

 

[supernova]

Clyde, you said you needed to operate between 4200 and 4600 revs. My two clones operate at that and more with a cheater spring, but only for short runs and I'm risking much IMO given what I know about the manufacturing of them. I would not trust one for pulling long duty cycles at anything past 3600 and even at that the hours they would see would wear em out. That is the reason you see Honda and Robin Subaru on the best equipment, briggs intecs are used as well but to a lessor degree in construction related fields. There is a reason for that, reliability and long engine life. I trust my clone to get me down the block and back but wouldn't venture into the wilderness with it. I admit that I abuse mine and rev to 5000RPMs on top speed runs, it's only a matter of time till I find it's weakness I would think. I keep it stock and can return it under warranty so that's what I do, I've said before that were I to build a performance engine I'd start with a briggs intec or animal and but the billet stuff for it. That's my personal preference though, I've seen some high revving bad ass clones!:thumbsup:

 

[Clyde]

For those that have dared to speak so freely on this verboten subject … let me definitively say that I consider your responses to be no more than unsubstantiated opinion and thus I will not now (nor ever) hold you liable for any fricken' suggestion you all may make.

I consider all responses naught more than possible b*llshit, unfounded theory, or mere hypothetical speculation: and thus not worth the money I paid ya for your suggestions (which is zero $$ to be exact).

For instance: if you suggest I strap a small nuclear reactor to the mini-bike to get more revs, and that same said minibike flies into outer space with me on it; and then I get my family jewels irradiated , severe brain freeze, and subsequently captured and probed by alien UFO's ... I hold you 100% non-responsible in any fiduciary duty (or practicality) in any way, shape, or form for your ideas.

I do hereby fully and positively grant you release from any effects on me due to your "free speech".

I take 100% full responsibility for any and all actions I may (or may not) take in regards to my inquiry... thus I waiver in full … signed Clyde.

It is a shame free speech, free thought, and free ideas have such a price.

Now, special thanks to those who dared to speak the "forbidden knowledge."
I hear, I think, but I can not freely respond any further.
I must OBEY or be banned.

Without Freedom of Thought, there can be no such thing as Wisdom; and no such thing as public Liberty, without Freedom of Speech.
BENJAMIN FRANKLIN, The New England Courant, Jul. 9, 1722

 

[Strigoi]

call arc and ask them the safe range of there wheel and go from there much safer and cheaper

i believe their flywheels are safe up to 10,000rpm.

It is a shame free speech, free thought, and free ideas have such a price.

it's a privately owned board. if you don't like the rules or aren't able to abide by them, then GTFO.

that's all there is to it. go start your own board if you don't like how this one is run.

 

[jesse8931]

i believe their flywheels are safe up to 10,000rpm.




it's a privately owned board. if you don't like the rules or aren't able to abide by them, then GTFO.

that's all there is to it. go start your own board if you don't like how this one is run.

Well put, I visit a board that does not allow any talk about modifying a certain gun I own and people get mad all the time but if they dont like it they can go else were.

 

[supernova]

I thought my response was geared specifically toward your question and was honest and sincere. You have lost your mind behind the deal it would seem and might need to go elsewhere for your questions. The mods have discretion to do as they see fit and like it or not that's the way it is. You are not unlike me in that you defend your actions fervently, although I don't always understand why some threads get quashed it is not my call so I leave it alone. Were I a mod I would likely make different calls on many things but I'll never be a mod with my temperment so it's irrelevant what I'd do. I would however not allow you to argue as you have and be defiant as you have IMO. So our mod had to put you in your place, we all have one and it's just below the his in the pecking order. Get past it or move on. So much for trying to give you an honest answer that pertained to your question directly. It seems we do have here is a failure to communicate as it appears that you have closed your mind.:doah: