how would a piston get jammed?

[ahcongie]

any1 know y will piston jam ?

i am new to bike sorry to trouble u guys~~

[SK I]

Mainly due to overheat. The piston is too hot, melts and gets stuck. I think it usually happens to 2 stroke bikes becos 2 stroke pistons need to work a lot harder and moves faster...

That's why it requires 2T. The 2T will mix with petrol which burns in the engine. The 2T doesn't burn...it serves to lubricate the pistons to prevent it from jamming due to to overheating and melting.

Correct me if I'm wrong

[DM]

the piston would never melt. it just expands so much to the extent that it gets stuck.

[SK I]

Originally posted by enfant@March 04, 2007 02:35 am

the piston would never melt. it just expands so much to the extent that it gets stuck.

Yes it will!

Well...not totally melt into a pile of metal lah...

just melt at the corners and gets "welded" to the chamber walls...

 

How I know? My first vespa years back got it's piston jammed lor... riding 100+ all the way on the first lane (too young, too reckless)

[stsoh]

why piston seize or burnt a hole bcoz of wrong heat range spark plug use.

first use only manufacturer recommended spark plug n try to read more on about spark plug.

don't trust any mech, check n make sure he install manufacturer recommended spark plug.

if not sure wat is the plug code, find it out.

[operator]

Its simple. Due to overheat.. It expands and gets jammed with the piston wall.

 

Ways to prevent:

1) Use good 2T for 2 stroke engine

2) Ensure sufficient 4T for 4 stroke engine

3) Ensure enough coolant for those bikes with radiators

4) Don't always ride in the red zone for the rpm.

 

One thing to note is that when it comes to engine, rpm is the factor to consider and not so much on the speed.

 

Spark plug doesn't really attribute to piston jam. Selecting the correct spark plug would ensure that the plug doesn't touch the piston crown which might damage the plug itself.

[redbeacon]

One more: Mechanic carelessness.

 

This is attributed to whomever that tunes the 2T intake incorrectly, resulting in too little 2T flow,...

 

Or one that simply left the 2T pipe disconnected from the carburetor, meaning the engine isn't getting any 2T when it's running.

 

(Just a little FYI to the threadstarter -- most mechanics are always careful when fixing motorcycles)

[retro]

Originally posted by redbeacon@March 05, 2007 02:44 am

One more: Mechanic carelessness.

 

This is attributed to whomever that tunes the 2T intake incorrectly, resulting in too little 2T flow,...

 

Or one that simply left the 2T pipe disconnected from the carburetor, meaning the engine isn't getting any 2T when it's running.

 

(Just a little FYI to the threadstarter -- most mechanics are always careful when fixing motorcycles)

and also to add on to this... too much 2t also no good.. too smoky... and you will have those 2t deposits on your number plate....

[OhMiGosh]

at first i thought he own a pistol or either that his "pistol" jammed.. lol ok jokes aside. hmmmm for 2stroke bikes always change ur piston ring too when it gets too loose.. damaged piston ring will jammed up the piston too.

[handal]

any sign dat indicates the piston ring being loose?

or can we see it with out naked eye?

how to know?

[operator]

Originally posted by hanatek@March 23, 2007 07:35 am

any sign dat indicates the piston ring being loose?

or can we see it with out naked eye?

how to know?

4 stroke bike would probably have some white smoke at the pipe. Due to engine oil seeping into combustion chamber.

[handal]

how abt a 2 stroke bike?

same or juz hear the sound?

sori i'm kinda new haha

[DM]

for 2-strokes, there will be a loss in power

[operator]

Originally posted by enfant@March 23, 2007 10:44 pm

for 2-strokes, there will be a loss in power

One of my fren jammed his 2 stroke bike b4. B4 it happened, he said nothing seem amiss, no power loss at all, but then suddenly piston jammed in the middle of expressway. Luckily for him, never buang. Don't compromise in 2T. Buy good ones..

[Shark]

The head topic spells 'Pistol'. I was wondering what it was... Hahaha... No offence...

[futsal123]

Originally posted by Shark@March 26, 2007 11:52 pm

The head topic spells 'Pistol'. I was wondering what it was... Hahaha... No offence...

hahahaha...pistol will jam also. I was wondering why someone ask such a thing.

[redbeacon]

My friend suffered 2 incidents of his bike's piston jamming up. The first one was attributed to constant high revving riding -- he was a speed devil. Two months later after an engine overhaul, it happened again.

 

Talk about being blissful...Wow.

[handal]

sad sia lol..

maybe he keep revving after the overhaul..

he nv sayang his bike sia haha..

[B20]

Originally posted by hanatek@March 23, 2007 07:35 am

any sign dat indicates the piston ring being loose?

or can we see it with out naked eye?

how to know?

u canot see if ur piston ring is loose... coz piston in inside ur block...

but u surely can hear it... it will be very obvious... the sound is very loud n noisy..

 

and it apply 2 all bikes... regardless of 2 or 4 stroke

[B20]

Originally posted by futsal123@March 27, 2007 12:05 am

hahahaha...pistol will jam also. I was wondering why someone ask such a thing.

eh... maybe the pple really wanna ask how would pistol jam eh... hahaa...

maybe is no feeling or maybe is double feeling lo... for mi i juz shout IA IA!!!!!

 

hahaa....

[Strong Eagle]

Originally posted by al3ex@March 30, 2007 01:32 am

eh... maybe the pple really wanna ask how would pistol jam eh... hahaa...

maybe is no feeling or maybe is double feeling lo... for mi i juz shout IA IA!!!!!

 

hahaa....

A pistol jam could only occur with a semi automatic pistol, rifle, or shotgun. I own a couple of each (still in the US since Singapore says they are a no no).

 

You get two kinds of jams. The first kind is when the slide fails to put the bullet all the way into the chamber. This kind can make you real nervous because you have a live bullet jammed into the gun and maybe or maybe not the firing pin is real close to the primer. Use great caution in removing the jam as the bullet could blow up in your face.

 

The second jam is when the mechanism does not fully eject the spent cartridge. Not so bad. You just have a brass casing jammed into the works that you have to get free.

 

As for PISTON jam, almost always caused by overheating. Cooling fins and radiators are mostly designed for an average heat output. Especially for an air cooled bike running at max power for extended periods means that there is not enough cooling for the power output. The piston expands, further compressing the compression ring until it catches on something in the cylinder wall.

 

This is one good reason not to over oil your 2T bike. Oil does burn, contrary to another poster but if you have too much oil it leaves extremely hard carbon deposits which can cause the ring to catch and jam.

[handal]

there u have it..

haha..

a dude stepped up enlightened us with both pistoL and pistoN jams..

lol..

thx for that

[MrLester]

Just something to take note of.

 

When you change your piston do ask your mech to check your block as well.

As for my case, I was very "sway"

 

1st piston changed

" piston badly scratched when I bought my bike from shop. "

 

2nd piston changed

"mech did not check my carb main fuel jet, suppose to be size 152, but mine was 142 or so only. therefore oil went in much lesser, piston jammed again."

 

3rd piston,

"block already scratched, did a block polished or don't know whatever ****. but too bad still gone. can't be save."

 

4th

Changed block , piston , checked the carb jet, check 2T pump etc. Did a good running in. Now still using it safe and fine.

 

Experience with piston jamming, VERY DANGEROUS.

When I ride at low speed no such problem, but when speed reaches like 120km/h it suddenly just switched my bike off and the next thing, tyres are locked, bike starts to swivel and sway. Hard to control.

 

I countered the problem by clutching in and releasing the clutch, - something like push starting your bike concept.

 

There I urge riders out there. When you go for full servicing of your bike, look and see for yourself, if the piston is scratched, CHANGE IT ! - It almost cost me my life.

 

=)

[YEN96]

Wah ..wat biie u ride ?

 

Just something to take note of.

 

When you change your piston do ask your mech to check your block as well.

As for my case, I was very "sway"

 

1st piston changed

" piston badly scratched when I bought my bike from shop. "

 

2nd piston changed

"mech did not check my carb main fuel jet, suppose to be size 152, but mine was 142 or so only. therefore oil went in much lesser, piston jammed again."

 

3rd piston,

"block already scratched, did a block polished or don't know whatever ****. but too bad still gone. can't be save."

 

4th

Changed block , piston , checked the carb jet, check 2T pump etc. Did a good running in. Now still using it safe and fine.

 

Experience with piston jamming, VERY DANGEROUS.

When I ride at low speed no such problem, but when speed reaches like 120km/h it suddenly just switched my bike off and the next thing, tyres are locked, bike starts to swivel and sway. Hard to control.

 

I countered the problem by clutching in and releasing the clutch, - something like push starting your bike concept.

 

There I urge riders out there. When you go for full servicing of your bike, look and see for yourself, if the piston is scratched, CHANGE IT ! - It almost cost me my life.

 

=)

[CivicR]

My friend suffered 2 incidents of his bike's piston jamming up. The first one was attributed to constant high revving riding -- he was a speed devil. Two months later after an engine overhaul, it happened again.

 

Talk about being blissful...Wow.

 

I personnally encounter piston jam three time on my SP, first time was maybe due to wear & tear, second time maintain 160km/h for over an hour and bang, heng was already back in Singapore. Third time no so lucky half way thru back from Kulai at 180km/h then bang engine give out burn smell and white smoke follows. Heng got kind bro who toll me out with his S4 (Blackheart) while one of the bro act as barrier to protect me (Enotosol). Those were the good time we had. The reason was lack of 2T mixture !!