Engine Whistle
- Thread starter luk3x3
- Start date
Blaner
Your Friendly South African Ambassador
Lets get back to your problem.
Sounds like you have seized it, quite possibly from overheating, or from riding it with a slightly lean mix, causing mild detonation.
Compression can still be good after a seize caused by both of the above, but I fear the piston and rings may have been damaged.
The whistle could be caused by the rings fighting with aluminium that has been deposited on the bore surface.
Pull the pipe off and get a look at the piston up the exhaust port.
Whilst you have the pipe off do a leak down test, which you should 2 or 3 times a season. It should be pressurised at the carb boot and should hold 7 psi for 10 minutes.
Please list your mods so that someone can steer you in the right direction as to your jetting.
I feel that he has pressurised at the spark plug hole.
Gee I would hate to be the oil seals!
Listen bro we are about the same age, u can keep doing it ur way if u prefer however it is wrong. I have tested my motor cold and hot only aboua 5psi difference. Doesnt matter if it 2 or 4 stroke. Your way is the same just performed differently. Must discuss this when im not on my phone.
I just wanted to add that ive compressioned check my bike 3 times ive done it how blaster tought me all my numbers were about perfectly 130 125-130 once hot twice cold so idk how ur way works but it doesnt differ 25 psi if it does i think you may be doing it wrong...
Not my words!
The first hit on google returned this info..
1.Screw in the compression tester in to the cylinder – always worth having adapters/convertors for your compression gauge to allow for different sized spark plugs etc…
2.Open the throttle fully, otherwise your figures will be out
3.Hit the start button or use the kickstart to turn the engine over for around 5 seconds or until the needle on the engine compression tester is at it’s maximum reading.
4.Take the reading and remember to add 5% if you did this with the engine cold.
5.Refer to your service manual for the recommended compression results
6.Typical values will be around 110 – 190 psi depending upon the engine size – generally the higher the compression your cylinder produces then the better (although too high of course will lead to blowing gaskets or cracking cylinders).
…...........................................................................................................................................................
(Warm up the engine to allow the metal parts to expand and seal properly, and make sure to hold the throttle wide open (full throttle) during the compression test.)
1. Remove all the spark plugs and ground the plug wires or disconnect the ignition coil. Many of the manufacturers have some grounded posts to attach the plug wires to, if not use a set of alligator clips from the tip (metal) of the plug to a Good ground. Try to keep the spark plugs away from the spark plug holes in the head. Examine the plugs carefully for signs of a problems.
2. Screw the compression gauge into the plug hole and grab a pen a paper to write down the values of each cylinder.
3. You'll need to hold the throttle in the wide open position (full throttle) while doing the compression test.
(Tip: On a waverunner or ATV you can ziptie or tape the throttle lever to the handlebar (at full throttle) if you are by yourself to make it easier.)
Now press in and HOLD the starter button until the needle on the compression gauge stops rising, usually 5-10 seconds and try to note how many compression strokes it took to climb to the max value. You will notice that each compression stroke made the needle jump and increased the compression reading until it peaks out, and that's the compression value for that cylinder. The faster the compression climbs to the peak the better seal you have, and you should mentally note if any of the cylinders tended to take more strokes than the others to obtain the peak compression. Tip: Worn rings and cylinder walls tend to increase the number of strokes to achieve your maximum compression reading (Compression for that cylinder).
(Tip: You must release the pressure in the compression gauge after each reading by pressing the relief valve on the gauge to reset the needle.
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How to Compression Test a 2 Stroke or 4 Stroke Dirt Bike's Engine
yeah sorry, was typing a little fast last night, also had a few in me 
i meant 6-8
and since everyone is battling it out about compression and what not, im going to go clean the frame and finish removing my front breaks.
oh and building a bracket for my supercharger.
i meant 6-8
and since everyone is battling it out about compression and what not, im going to go clean the frame and finish removing my front breaks.
oh and building a bracket for my supercharger.
yeah sorry, was typing a little fast last night, also had a few in me
i meant 6-8
and since everyone is battling it out about compression and what not, im going to go clean the frame and finish removing my front breaks.
oh and building a bracket for my supercharger.
Please post some pics and dimensions, I am toying with fitting one as well.
Blaaster, that info you posted is about the same as what I was trying to say. The zip tie to the throttle, thats something I left out.
My 1989 yamaha moto 4, that just re built the top end.
here is what I got cold and warm for compression readings.
low-80
mid was 85
high was 90
warm-
low was 90
mid was 97
high was 103.
I said it could very as much as 25psi, but does not have to.
Now I'm at
warm
low 125
mid 128
high 132
All I had to do, was have it rehoned and new rings, the previous owner had it rebuilt .020 over, but did not break it in right and the rings did not seat.
My schooling was automotive class in high school, and in college and 1 year at giesons motorcycle shop. Not to mention what I learned from other mechanics.
Just cuz there is differances in technique, is not call to say my ways are wrong, when they are close enough to what you are saying.
The biggest issue I have seen on this forum, is people are leak down testing happy. likely cuz, it was a known issue for the blaster, but most of those seals are good for 5 to 7 years. For the average rider, unless you out riding hard and racing it.
Just like the porting and polishing info, unless I missed it. but 1/2 the posts fail to mention you need to rejet the carb, when you do this.
But I came here to learn more about the blaster and common issues with it, not point out the common mistakes on posts here on the forum from members.
I seen a post the other day, someone pushign rebuilds every 20 to 30 hours of riding, Wow. ya know, unless you got that thing so ripped up, its onyl lasting that long. But engines last way longer than that.
You made a mistake in your post and went after me, then you post info, thats basically what i was saying all along. So, the only point you made was mine. Stop looking like, your toes are getting stepped on, and lets focus on helping people. my info was right. You just wanted it conveyed by you and your way.
And it would have been much more proffesional to shoot me a pm and say, u think my info i shared was not right and do a much more better way of explaining why, versus slamming me on the forum. Only mucks up trying to help someone.
My 1989 yamaha moto 4, that just re built the top end.
here is what I got cold and warm for compression readings.
low-80
mid was 85
high was 90
warm-
low was 90
mid was 97
high was 103.
I said it could very as much as 25psi, but does not have to.
Now I'm at
warm
low 125
mid 128
high 132
All I had to do, was have it rehoned and new rings, the previous owner had it rebuilt .020 over, but did not break it in right and the rings did not seat.
My schooling was automotive class in high school, and in college and 1 year at giesons motorcycle shop. Not to mention what I learned from other mechanics.
Just cuz there is differances in technique, is not call to say my ways are wrong, when they are close enough to what you are saying.
The biggest issue I have seen on this forum, is people are leak down testing happy. likely cuz, it was a known issue for the blaster, but most of those seals are good for 5 to 7 years. For the average rider, unless you out riding hard and racing it.
Just like the porting and polishing info, unless I missed it. but 1/2 the posts fail to mention you need to rejet the carb, when you do this.
But I came here to learn more about the blaster and common issues with it, not point out the common mistakes on posts here on the forum from members.
I seen a post the other day, someone pushign rebuilds every 20 to 30 hours of riding, Wow. ya know, unless you got that thing so ripped up, its onyl lasting that long. But engines last way longer than that.
You made a mistake in your post and went after me, then you post info, thats basically what i was saying all along. So, the only point you made was mine. Stop looking like, your toes are getting stepped on, and lets focus on helping people. my info was right. You just wanted it conveyed by you and your way.
And it would have been much more proffesional to shoot me a pm and say, u think my info i shared was not right and do a much more better way of explaining why, versus slamming me on the forum. Only mucks up trying to help someone.
You said one year at collage of automotive school. I belive old man blaster said SEVENTEEN I haven't even been alive that long!
Relax-Not trying to bash you, just stating what I know about Blasters! Because I have done it! I apologize if I offended you! You can confer with anyone on here, and they will tell you the same, hold throttle open, kick till needle stops (usually 3-6 kicks), Warm or cold. - Maybe we all are doing it wrong *shrugs* :-/
I don't consider 3 total kick and using the middle number a correct compression reading that is all. Not when I can kick a fourth/fifth time and the needle goes higher!
If you dissasemble any part of the top end for any reason and do not perform a leak test or a vaccum test either works ok, you run the risk of frying the top end and/or decreasing longevity of that piston/rings.
I agree, any changes in air/exhaust flow requires a jetting check/change!
I address this already!
Probably the racers, Rebuild no break in just busting balls, rebuild after every race or two!
Normal engine wear last much longer I agree!
HUH? :-/
Ya I don't help people at all! Bro lets have a beer or two and take a step back- chilax!
I saw a Buffalo twice, I blinked!
Gees Slick, 6 quotes in one post and not one from me.
What have I done, for you to miss me out.
Gees Slick, 6 quotes in one post and not one from me.
What have I done, for you to miss me out.
I shoot a bufflo once..
No B.S. on a hunting trip u know the size bullet you need for that sh*t the guide service like makes special bullets. MY uncle took me when i turned 18 i dont even like hunting but it was fun
No B.S. on a hunting trip u know the size bullet you need for that sh*t the guide service like makes special bullets. MY uncle took me when i turned 18 i dont even like hunting but it was fun
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