Engine Whistle

[luk3x3]

Okay so me and my brother were out riding in the mud/playing kind of hard.

and when i was on my way back, the quad quit on me twice, just like stopped, locked in gear, and i had to wait like 5-10 minutes before it was even loose enough to kick it over. and the last time before i made it to my yard, there was a loud whistle coming from the engine, which has got me confused.

because theres still good compression, i dont have any leaks, and it kicks over just fine.

anyone got any ideas?

 

[wwholden]

Turbo blown? 151515

 

[slickerthanyou]

Four point seize, Not letting it warm up enough?

 

[gb blaster]

Does that say because u still have good compression it doesnt have leaks... that not true from what i know about air leak you can have compression an still have one right? u need comppression to start the bike an you can start a bike with an air leak.

.... An u said you were playing hard where you playing long to?? was the bike overheating beacuse you said that it took 10-15 mintues for it to crak back over that could have gave it enough time to cool down an when it got to hot again it stoped?

 

[luk3x3]

Does that say because u still have good compression it doesnt have leaks... that not true from what i know about air leak you can have compression an still have one right? u need comppression to start the bike an you can start a bike with an air leak.

.... An u said you were playing hard where you playing long to?? was the bike overheating beacuse you said that it took 10-15 mintues for it to crak back over that could have gave it enough time to cool down an when it got to hot again it stoped?

Thats what i was thinking, i mightve over heated it, i just wanted some other opinions, and yes i did blow the turbo on it, so now were going to a supercharger....YOLO.

ahah. anyways, were going to pop off a few peices today and check it out

 

[gb blaster]

You can super charge a blaster?

 

[borednstreched]

^i doubt it....lol WAY more money than it would ever be worth in terms of performance. plus what would spin the charger?

 

[gb blaster]

Thats what i was wondering thats a pully system an yeah i was think that was some seriorse bread to spend on an atv an i just didnt see that hooking up at all

 

[Triplecrown421]

^i doubt it....lol WAY more money than it would ever be worth in terms of performance. plus what would spin the charger?

run a pully off the flywheel with a right angle bend for the carb

 

[Triplecrown421]

now r u sure is was a "whistle" sound or a high pitch "ringing" almost like a very high pitch scratching sound. cuz if thats what u hurd it could be cyl and piston not getting along. sounds like you over heated the old girl

 

[sporty982000]

The atv is over heating, you are vapor locking it up. If anything you scored the piston / rings and cylinder wall.

So, beyond adoubt you have some damage.

Not sure how you did your compression check !! to determine you had good compression.

What I mean, you have to let it warm up. install the compression tester, open throttle all the way up, hold full open and kick it 1 time, write the number down, do this 3 times.make sure your fuel is shut off.

no more, no less.

throw out the low and high number and thats your compression number.


if you do it more, you will need to drain the float bowl. cuz the more you kick, the more fuel you are adding into the cylinder, this gives you a false reading.

I recently heard that each time the temperature goes up 10 degrees on two cycles, it is recommended to change the jet. to avoid issues.

Sometimes, a whistling sound can also be a air leak, like a blown gasket, but most often a blown gasket happen due to blowing it up.

You could also check your reeds, make sure one is not cracked or broken.

 

[slickerthanyou]

The atv is over heating, you are vapor locking it up. If anything you scored the piston / rings and cylinder wall.

So, beyond adoubt you have some damage.

Not sure how you did your compression check !! to determine you had good compression.
What I mean, you have to let it warm up. install the compression tester, open throttle all the way up, hold full open and kick it 1 time, write the number down, do this 3 times.make sure your fuel is shut off.

no more, no less.

throw out the low and high number and thats your compression number.

if you do it more, you will need to drain the float bowl. cuz the more you kick, the more fuel you are adding into the cylinder, this gives you a false reading.

You are wrong! You will never get actual compression if you only kick it once and you have to hold the throttle wide open and kick till the needle on the gauge stops going up. Ya do that three times and get the average. Doesn't really matter if it's warmed up or not.

 

[Blaaster]

/\ . /\ . /\ . /\ . /\ . Seconded.

 

[sporty982000]

I am right, way right. saying im wrong. wow.

So many people do it wrong, I think they think they are right.

I learned how to do compression checks from a 30 year plus mechanic, who helped build proffesional dragster for a famous racer. not to mention, from a local motorcycle shop. who sponsored me, when I drag raced motorcycles.

It's also the same way I been checking it for 20 years.

Not to mention more than a few service manuals over the years, say pretty much the same thing.

And it does matter if its warmed up or not. Thats in about every service manual and rebuild I have ever read and been taught.

Reason why, heat exspands and contacts soem, including the piston rings. if you do it cold. you get a higher reading, a false reading. that not the compression you will have after its warmed up and the condition in which you will be riding. you want the compression, that its going to be likely at, when you riding it.

I have seen so many people do that wrong, do it cold ! got a higher reading, and thought they were good, warmed up, the reading was low ! and it needed a top end rebuild. the differance was more than 25psi !, between those readings from a cold read and a warm reading !

The only thing I coudl be wrong on, is the 1 kick. as I deal more with 4 strokes than 2 strokes. and perhaps its not building as like a 4 stroke does.

 

[Blaaster]

Compression, is compression, wether it is a 2 stroke or 4 stroke, its the same, you need more than one kick, especially with a 4 stroke as they compress every fourth stroke.

You kick until the compression stops rising, and it has been that way for over 50 years that I have been wrenching.

I have been struggling to understand how you go about vapor locking up a motor as well, please enlighten me.

It is a term that I am unfamiliar with.

 

[luk3x3]

BOYS! JESAUCE! STOP IT!

the engine is being rebuilt for safe measures, and there is no need to fight about this.

and before i sent it to my friend, she held 68lbs on the leak down tester for 1.3 hours.

compression was set at 70 psi when i did it.

 

[sporty982000]

Vapor lock, is when fuel can vaporize due to being heated by the engine. it is often hard to start after this happens.

Most common problems of this are from improper fuel mixture. running lean, a clogged air filter or dirty air filter. restricting air flow.

That little hose on top of the gas cap, well thats there to prevent pressure build up, which can cause vapor lock also.

I dont know how old you are, im 40 and I learned about all of this stuff when I was around 12, 13 years old.

And compression is not suppose to keep building, when doing a compression test, atleast not very much, thats why you toss out the low and high number. cuz its likely wrong.

The onyl way if you are still building compression, is if you are letting fuel into the cylinder and its building pressure because of it.

And anyone of a mechanic knows, aluminuim exspands and contracts with heat. thats why you dont do readings cold, they are not right or accurate.

Frankly, Im a bit surprised, that you did not say you were sorry, cuz, if you took the time to look at manuals, they tell you how to do a compression check.

But this is not about you are me, I want to make sure the person who posted, gets the right information.

And some manual reading and searches on yahoo or google, is pretty much gonna say the same thing, that I did.

Since in the more modern world, better fuel pumps prevent this and electronic fuel pumps.

Still somewhat common in 2 strokes, see it in weed eaters, 2 cycle chain saws.

A decompression lever on atvs, It came on two of the 4 atvs, I currently own. While not intented for vaopr lock, im sure it was in mind of it also. So it was nto so hard to try and pull start the darn engine, if it didnt start right away, with compression building up.

 

[sporty982000]

BOYS! JESAUCE! STOP IT!

the engine is being rebuilt for safe measures, and there is no need to fight about this.

and before i sent it to my friend, she held 68lbs on the leak down tester for 1.3 hours.

compression was set at 70 psi when i did it.

B)8-|

Keep us posted. No worries.

Did you check the compression ? or just said, the debate was to much and will just take it off and head 4 the shop !!
But do feel bad the drama, distracted from helping you.

 

[Blaner]

I dont know how old you are, im 40 and I learned about all of this stuff when I was around 12, 13 years old.

he is old enough to your father and my grandfather, so no bashing the old father Aussie here please.

 

[Blaaster]

I dont know how old you are, im 40 and I learned about all of this stuff when I was around 12, 13 years old.

With 17 years in the Technical and Further Education Automotive Department, I feel that I am qualified to advise you to forget what you learnt at the tender age of 12, and start reading all over again.