adjusting the valves while on the bench instead of putting it all togheter and wreste across the frame to mesure the gap : AWSOME IDEA you just save me a lot of trouble THANKS!!!
Hi Daniel, Sounds like you need a new head gasket. You can't ever reuse an old one. When the head is off make sure there are no nicks or scrapes in the mating surfaces by where it's leaking. If there is, use a little YAMABOND (grey) on the nicks with a new headgasket, and it should seal it without buying new cylinder/head. If it has no nicks and still leaks you could have a warped head or Cyl., then one or both must be replaced. Good Luck
I think the book says it's supposed to get a piston every 25 hrs. or so, but no one does that, I'd say one a year for all if you do monthly oil changes. The valves are supposed to be checked after breakin and every 20 hrs. but they usually stay in spec. for much longer. Thanks, Oaky
just to let you know when you check your valve spacing make sure you do it while the head is in the bike with your cam chain still on!!! When you check it with the head off it may throw off your readings.
@averageman67 the two other side valves are air and middle valve is gas so it keeps the gas vaper in the middle so the spark lights it smoother cause a little more power
@Emiley415 Well once the timing marks are lined up, that's TDC, that cam doesn't move wheather there's a chain connected or not. I can't see how it can make any difference tension or not.
@averageman67 the intake valves are smaller, also 2 exaust valves can realease the gas in the chamber just fine, however the more flowing in and easier is why there is 3 intake valves plus they eat away at the valve seats alot less.
@averageman67. The air/fuel mix has to be sucked in by a pressure difference between the motor and atmosphere caused by the piston going down. Once its combusted its pushed out by the piston. Its easer to push it out then suck it in. Thats why it has three inlet valves. Even in the most 4 valve or 2 valve heads inlet valves are bigger than the exhaust valves to compensate for this.
@xxKX125xx Hello, The exhaust cam has a decompression release built into it, I'd check that first, maybe a broken spring, if you take the cover off the head you'll see it on the front cam on left side, good place to start...let me know
Great mechanic! Ex wife comment was hilarious hahaha but if there is sand in the boot past the airfilter what needs to be done? I just bought a 2006 yz250f and changed the air filter as soon as I bought it and there was some sand on the other side. Not very mechanically inclined but what should I do?
@whowanger Do I think you can pull it off? I have no idea. This took me about 4-5 hrs., but that's me. Your time may differ. Just make sure to torque all bolts during assembly if you do it yourself.
Excellent video, have a question for you, do you know in between how many lbs should be a good wr450f motor?? I'm having a hard time with mine right now and I can't find out what it is!! Thanks
@averageman67 the 5th valve is a intake valve the reson for it i guess is more area for the air to come in it may only be 5 square milimeters more area but that could make a difference
I have been looking far and wide and reading plenty of things about top end break in procedures and I have heard to never use synthetic to break in and engine. It is to slick and prevents the new rings from properly sealing against the cylinder wall. This is how it should go 1-2 hours on petroleum oil, change it, then 4-5 hours on petroleum oil, change it, then you can run your synthetic
Let me know Dan what you find, I'll help you through it. Before you go ahead. Get/read your manual and it should tell you all you need to know to get all parts needed to be removed to replace that head gasket. Cam(s) postion/crank timing critical, know how to make that the same as when you took it apart...and you're all set
Hey- after how many hours of riding should I look at replacing my piston rings on my 07 YZ250F? Also do you have any experiences with a K&N air filter on this model? I bought the bike with a K&N and was told to bin it immediately as it sucks in sand so am running a foam filter now. Thanks for the videos.
@oaky132x The tension from the timing chain equals out the cam or something like that I forgot how the guy at JE pistons explained it but that’s the way he said to do it. He said you can check it with it off the bike but your measurements may be slightly off.
40$ is real good...most SHOPS get 70-80$ if not more...glad i been doin this shit myself since i was 15....startin with 2 strokes obv. i could rebuild a 2 stroke top end blindfolded and drunk.
Hello, could get me some questions? I have questions regarding the size of the piston to put in place of the other, I would have to remove it and measure the cylinder diameter? after I know the size of that in the next exchange will be 0:01 mm bigger? Thank you!
What "some metal particles" is kind of an opinion question, it' not that bad (probably gears) if they are few. If they are a lot, it could be a problem. Change oil/filter often and you should be OK.
@averageman67 its a extra intake vavle made for better throttle response aslo guy who took the video did it make a diffenernt the high compreession thùanks
@oaky132x That is true but it also changes when you torque down the head and have the cam chain on, not by much but by a little. not saying you are doing it wrong. Just saying if you are super picky and want the exact readings do it when its in the bike.
hey i got a ?. i just bought a 01 yz250f and the guy that i bought it from said its been sitting for 2 years . i cant get it to start, i got it ti start a few times but it dies right after, what do youthink the prob is? ive changed the plug, do you think its the carb?
Downside of a high comp piston is you take an already highly stressed and high maintenance engine and make it more stressed and even more high maintenance, as in a race team with probably run 2-3 motos on a NEW engine then literally throw it away.
@Emiley415 Again, you're wrong. This is not a pushrod engine, it's a shim and bucket head. It makes no difference if it's on the engine or on the moon. Head being torqued down to cylinder makes no difference, having timing chain on makes no difference. Emiley415, are you a female? I ask because you remind me of my ex-wife. You have no idea what you're talking about, but still want to correct me. If you aren't a female, you must be an MMI student. I've worked with MMI students, 80% were idiots.
adjusting the valves while on the bench instead of putting it all togheter and wreste across the frame to mesure the gap : AWSOME IDEA you just save me a lot of trouble THANKS!!!
thanks for the advice i've started tearing the bike down, i've got to the valve cover so far and ran out of time. btw i love your vids
Hi Daniel, Sounds like you need a new head gasket. You can't ever reuse an old one. When the head is off make sure there are no nicks or scrapes in the mating surfaces by where it's leaking. If there is, use a little YAMABOND (grey) on the nicks with a new headgasket, and it should seal it without buying new cylinder/head. If it has no nicks and still leaks you could have a warped head or Cyl., then one or both must be replaced. Good Luck
I think the book says it's supposed to get a piston every 25 hrs. or so, but no one does that, I'd say one a year for all if you do monthly oil changes. The valves are supposed to be checked after breakin and every 20 hrs. but they usually stay in spec. for much longer. Thanks, Oaky
just to let you know when you check your valve spacing make sure you do it while the head is in the bike with your cam chain still on!!! When you check it with the head off it may throw off your readings.
@averageman67 the two other side valves are air and middle valve is gas so it keeps the gas vaper in the middle so the spark lights it smoother cause a little more power
@Emiley415 Well once the timing marks are lined up, that's TDC, that cam doesn't move wheather there's a chain connected or not. I can't see how it can make any difference tension or not.
@averageman67 the intake valves are smaller, also 2 exaust valves can realease the gas in the chamber just fine, however the more flowing in and easier is why there is 3 intake valves plus they eat away at the valve seats alot less.
@397Dillon If it's a slip on muffler yes. I would guess their header pipe is exactly the same size as the OEM one.
@averageman67. The air/fuel mix has to be sucked in by a pressure difference between the motor and atmosphere caused by the piston going down. Once its combusted its pushed out by the piston. Its easer to push it out then suck it in. Thats why it has three inlet valves. Even in the most 4 valve or 2 valve heads inlet valves are bigger than the exhaust valves to compensate for this.
@xxKX125xx Hello, The exhaust cam has a decompression release built into it, I'd check that first, maybe a broken spring, if you take the cover off the head you'll see it on the front cam on left side, good place to start...let me know
Great mechanic! Ex wife comment was hilarious hahaha but if there is sand in the boot past the airfilter what needs to be done? I just bought a 2006 yz250f and changed the air filter as soon as I bought it and there was some sand on the other side. Not very mechanically inclined but what should I do?
Yes Probably needs carb clean and tank rinse/fresh fuel, Where are you?
@whowanger Do I think you can pull it off? I have no idea. This took me about 4-5 hrs., but that's me. Your time may differ. Just make sure to torque all bolts during assembly if you do it yourself.
Excellent video, have a question for you, do you know in between how many lbs should be a good wr450f motor?? I'm having a hard time with mine right now and I can't find out what it is!! Thanks
@averageman67 the 5th valve is a intake valve the reson for it i guess is more area for the air to come in it may only be 5 square milimeters more area but that could make a difference
I have been looking far and wide and reading plenty of things about top end break in procedures and I have heard to never use synthetic to break in and engine. It is to slick and prevents the new rings from properly sealing against the cylinder wall. This is how it should go 1-2 hours on petroleum oil, change it, then 4-5 hours on petroleum oil, change it, then you can run your synthetic
quick question,since the case shares oil with the gears and top end,is it pretty normal to see some metal particles in the oil filter??
Let me know Dan what you find, I'll help you through it. Before you go ahead. Get/read your manual and it should tell you all you need to know to get all parts needed to be removed to replace that head gasket. Cam(s) postion/crank timing critical, know how to make that the same as when you took it apart...and you're all set
Not much to be done but clean boot and have a beer
Hey- after how many hours of riding should I look at replacing my piston rings on my 07 YZ250F? Also do you have any experiences with a K&N air filter on this model? I bought the bike with a K&N and was told to bin it immediately as it sucks in sand so am running a foam filter now. Thanks for the videos.
@oaky132x The tension from the timing chain equals out the cam or something like that I forgot how the guy at JE pistons explained it but that’s the way he said to do it. He said you can check it with it off the bike but your measurements may be slightly off.
What do you mean you are asking for trouble when you install a high compression piston in? What are the down sides to it? please respond
do you have to adjust your valves after you do your top end?
40$ is real good...most SHOPS get 70-80$ if not more...glad i been doin this shit myself since i was 15....startin with 2 strokes obv. i could rebuild a 2 stroke top end blindfolded and drunk.
Hello, could get me some questions? I have questions regarding the size of the piston to put in place of the other, I would have to remove it and measure the cylinder diameter? after I know the size of that in the next exchange will be 0:01 mm bigger? Thank you!
@averageman67 Im guessing its an extra intake valve because in cares the intake side has bigger valves than the exhaust
Every 3-5 hrs of riding, Screen in frame should be checked as your manual says....
What "some metal particles" is kind of an opinion question, it' not that bad (probably gears) if they are few. If they are a lot, it could be a problem. Change oil/filter often and you should be OK.
@averageman67 where are 3 intake valves and 2 exhaust valves idk why theres 5 but there is
tighter than Mother Superior herself
what chain you got on there? is that a pro taper?
@averageman67 its a extra intake vavle made for better throttle response aslo guy who took the video did it make a diffenernt the high compreession thùanks
@oaky132x That is true but it also changes when you torque down the head and have the cam chain on, not by much but by a little. not saying you are doing it wrong. Just saying if you are super picky and want the exact readings do it when its in the bike.
@averageman67 its a extra intake vavle made for better throttle response
A 13.5.1 compression piston is standered from 08 to 2013 so it's safe
I just got a 2002 yz250f and I was wonder who much I should change the oil. I do not race.
sence u was putting the higher compresion piston in what else did u do.
@marthaalicia15 check the carb see if there is anything in it try draing the gas after that and putting new gas in it
is the pro circuit piston any better than a wiseco?
i just rebuilt my 02 yz 250f it still has small metal flakes in the oil filter though is that okay or do i need to rip it apart again
what what cause an oil leak at the corner of the head gasket on an rmz 250? its doesnt loose any anti freeze just weeps oil
hey i got a ?.
i just bought a 01 yz250f
and the guy that i bought it from said its been sitting for 2 years .
i cant get it to start, i got it ti start a few times but it dies right after,
what do youthink the prob is? ive changed the plug, do you think its the carb?
I get 40 per hr., whatever hrs plus parts....I got no complaints
Downside of a high comp piston is you take an already highly stressed and high maintenance engine and make it more stressed and even more high maintenance, as in a race team with probably run 2-3 motos on a NEW engine then literally throw it away.
was that a fmf factort 4.1
@oaky132x what do u think is better amsoil or hond hp4s
what oil do you think is better amsoil or repsol
@averageman67 good question.....
@CRF80TOP55 Correct, I left that out but ball hone used lightly.
whos got best prices on pro circuit build kits
Hi I need to no how to fix time on the same bike you have on this video I think my value are hiring my pisten
@avzeolla You're right. Motors are electric, Engine is correct
6:40 he wanted to say as tight as a nun sooo bad
wheres part 2?
how long dose hi comp piston last?
you use Motul oil
@oaky132x haha thats the funiest coment i have read yet so true thumbs up!
@Emiley415 How? Why?
i jizzed when i saw the piston....
"As tight as .... Brand new" I was thinking something else there :x oopsy
No you use Motul oil
@yz125rider194 I know many who swear by amsoil, never heard anything great about Honda oil.
what you say boyyy?
@gweller66 $200-250.00
scary
@averageman67
@Emiley415 Again, you're wrong. This is not a pushrod engine, it's a shim and bucket head. It makes no difference if it's on the engine or on the moon. Head being torqued down to cylinder makes no difference, having timing chain on makes no difference. Emiley415, are you a female? I ask because you remind me of my ex-wife. You have no idea what you're talking about, but still want to correct me. If you aren't a female, you must be an MMI student. I've worked with MMI students, 80% were idiots.
No you use Motul oil