I own a husqvarna wr 125 and your 2 stroke advice and demonstrations are helpful. I believe my 2 stroke is well maintained and running well, with thanks to you jeff.
Thanks again Jeff for a great video! I would be interested in learning about cylinder ports. What each one does and how their shape, length, and height affect engine character also how exhaust resonance effects the entire engine on 2 strokes.
I have one of these bikes and i was about to cry when u said miles. I was like no way!!! So i looked in the comments and my heart rose againg. Felt scared as crap
Hey jeff... just wondeing how bad blow by is ? Bought my first 300 exc 2015 and ooened her up to confirm the top end was done recently as i was told... its very close to the last piston in your video... very clean sides same.on top but a little lwss blow by... am i good to leave it on for now ? Also now ive opwned it i ordered new copper washers for the head but should i replace the cylinder gaskwt and the head orings ? Cheers
G'day, not sure if you will be able to help me but i have a yz250 2014 model running motul 800 at 50:1 with 40 hours on it from new.. I just recently took apart the top end to have a look and found the cylinder to be in good nick but the piston had 2 score marks deep enough to feel with your finger nail on the exhaust side (top of piston looked like the second you showed with a tad more carbon build up).. I decided to change it using a vertex piston.. my questions are what could of caused the scoring (bike always warmed up for a good 10 minutes), was it completely necessary to change the piston and finally how many hours between changes using the vertex piston in your opinion (ive read from 20 hours - 100) cheers in advanced!
I always run 60:1 in my 2010 250sx and I usually run redline race oil sometimes maxima castor or motul 800. So they're not all designed to mix the same? Saber is small engine formula, weedwackers and blowers? Now I'm cornfused. I thought i was feeding my bike only the most premium two stroke juice.....
i would prolly have a look anyway.. it does not take much slop in those motors to make them go bang.. even just take the barrel off and inspect the bore, feel the movement in the bottom of the piston and of cause the crank
Hi Jeff interesting video...you obviously know your stuff. I wonder if I can pick your brains. I run a 1969 British BSA Bantam 175 2 stroke..had it re-bore 300 miles ago with a nice new +40 piston...our pistons are all made in the far east that's all we can get...but it looked nice...4 thou piston to wall clearance and a 10 thou ring gap after the rebore. But coming home last Sunday after a 50 mile ride the motor nipped up...when I de-clutched at a set of traffic lights...I has opened it up a bit to 50 mph just before for a few miles. On stripping it there is no alloy transfer to the bore...it and the piston just have a very polished area in the area of the exhaust port...the piston having 2 light rubbing marks 1/2 inch wide. The crosshatching has some light up/down scratching marks on the bore as does the piston...I am presuming this is from carbon? I am thinking of using this piston again after dressing the marked area maybe with some very light filing and a light hone of the bore. Love your thoughts on what maybe my problem...I use a modern semi synthetic oil at 33/1 I have an EGT on this engine just for testing....it starts going to high at 50mph...nothing I do with the jetting helps..it being a bit rich across the range at present. The 1960s timing setting for this engine at 16.5degs BTDC...I was thinking about retarding the timing a few degs to counter the effects of modern gas. Love to hear your views Jeff. Nick in the UK.
The marks are from the piston swelling more and quicker than the cylinder. You were seconds away from a hard seizure. I would change to a Castor based oil like Maxima 927 and reduce the engine timing. The large .004" clearance suggest the piston may be of poor quality which is also problematic.
Hey Jeff< I just found your company on the web this last week. I also just picked up a 2017 kTM 300 xc-w six days yesterday. I'm coming off a 2013 KTM 350 exc-f (4-stroke). I have not owned a 2-stroke for 20 years and excited to get on it. I did order this Amsoil saber from you because of the recommendation from your web page. After receiving the oil I noticed its designed for small 2-stroke engines. Would you suggest another oil mixture other then 80:1 on a new bike during the break in. Also any suggestions on jetting? I'm at 800ft elevation.
Cliff, I wouldn't sell and use Saber if it didn't work well. 80:1 is a very heavy mix ratio for that oil. It is designed for 100:1. JD jet kit or a Slavens Mule HV Lectron.
Not necessarily. The problem at those hours is blowby causing a loss of power. The piston can easily go much longer. In cars and boats they go thousands of hours. The rings have a much more wearing contact with the cylinder, more pressure against it. Motocross riders change rings twice as often as pistons.
At 150 hours what about just changing the rings? 80:1 with Amsoil? That is crazy, awesome. You get 150+ hours using that? As posted below, I thought that was for weedwackers and lawnmowers.
....AMSOIL has about 8 or more two stroke oils for many different applications....Dominator/ 2000 is racing rated....some AMSOIL two stroke oils can be ran at 100 to 1 AMSOIL dealer...
holy fuck hours u dumbass it says right in the video and jeff said it twice .......HOURS .....HOURS.....HOURS!!!!!! Just read and find out urself .....ppl are so lazy nowadays they just ask questions when they can easily figure out themselves but are to damn lazy.
i had an 87 kx 500 and had my buddy run green dye or whatever he did it showed no cracks. 2 weeks later the bitch grenaded the piston. when in doubt replace.
can you hear the slapping? you must not do much riding then.. i mean there good for like 200 hrs and then i would want to look inside of them and 200 is alot.. i ride em hard though but that does not mean you can do a whole lot more riding easy
I own a husqvarna wr 125 and your 2 stroke advice and demonstrations are helpful. I believe my 2 stroke is well maintained and running well, with thanks to you jeff.
You're welcome.
Thanks again Jeff for a great video! I would be interested in learning about cylinder ports. What each one does and how their shape, length, and height affect engine character also how exhaust resonance effects the entire engine on 2 strokes.
Can the carbon build up on the top of the piston be slightly gritty?
I have one of these bikes and i was about to cry when u said miles. I was like no way!!! So i looked in the comments and my heart rose againg. Felt scared as crap
Hey jeff... just wondeing how bad blow by is ? Bought my first 300 exc 2015 and ooened her up to confirm the top end was done recently as i was told... its very close to the last piston in your video... very clean sides same.on top but a little lwss blow by... am i good to leave it on for now ? Also now ive opwned it i ordered new copper washers for the head but should i replace the cylinder gaskwt and the head orings ?
Cheers
G'day, not sure if you will be able to help me but i have a yz250 2014 model running motul 800 at 50:1 with 40 hours on it from new.. I just recently took apart the top end to have a look and found the cylinder to be in good nick but the piston had 2 score marks deep enough to feel with your finger nail on the exhaust side (top of piston looked like the second you showed with a tad more carbon build up).. I decided to change it using a vertex piston..
my questions are what could of caused the scoring (bike always warmed up for a good 10 minutes), was it completely necessary to change the piston and finally how many hours between changes using the vertex piston in your opinion (ive read from 20 hours - 100)
cheers in advanced!
I always run 60:1 in my 2010 250sx and I usually run redline race oil sometimes maxima castor or motul 800. So they're not all designed to mix the same? Saber is small engine formula, weedwackers and blowers? Now I'm cornfused. I thought i was feeding my bike only the most premium two stroke juice.....
I use what I sell, Vertex which is O.E.M.
how many hours are on those pistons?
Great explanation! Subscribed
i would prolly have a look anyway.. it does not take much slop in those motors to make them go bang.. even just take the barrel off and inspect the bore, feel the movement in the bottom of the piston and of cause the crank
I got a yz250 and I can't diced between an forged or cast pistons
+G-man-809 kind of a late reply but, forged pistons are the better choice.
Hi Jeff interesting video...you obviously know your stuff.
I wonder if I can pick your brains.
I run a 1969 British BSA Bantam 175 2 stroke..had it re-bore 300 miles ago with a nice new +40 piston...our pistons are all made in the far east that's all we can get...but it looked nice...4 thou piston to wall clearance and a 10 thou ring gap after the rebore.
But coming home last Sunday after a 50 mile ride the motor nipped up...when I de-clutched at a set of traffic lights...I has opened it up a bit to 50 mph just before for a few miles.
On stripping it there is no alloy transfer to the bore...it and the piston just have a very polished area in the area of the exhaust port...the piston having 2 light rubbing marks 1/2 inch wide.
The crosshatching has some light up/down scratching marks on the bore as does the piston...I am presuming this is from carbon?
I am thinking of using this piston again after dressing the marked area maybe with some very light filing and a light hone of the bore.
Love your thoughts on what maybe my problem...I use a modern semi synthetic oil at 33/1
I have an EGT on this engine just for testing....it starts going to high at 50mph...nothing I do with the jetting helps..it being a bit rich across the range at present.
The 1960s timing setting for this engine at 16.5degs BTDC...I was thinking about retarding the timing a few degs to counter the effects of modern gas.
Love to hear your views Jeff.
Nick in the UK.
The marks are from the piston swelling more and quicker than the cylinder. You were seconds away from a hard seizure. I would change to a Castor based oil like Maxima 927 and reduce the engine timing. The large .004" clearance suggest the piston may be of poor quality which is also problematic.
Hey Jeff< I just found your company on the web this last week. I also just picked up a 2017 kTM 300 xc-w six days yesterday. I'm coming off a 2013 KTM 350 exc-f (4-stroke). I have not owned a 2-stroke for 20 years and excited to get on it. I did order this Amsoil saber from you because of the recommendation from your web page. After receiving the oil I noticed its designed for small 2-stroke engines. Would you suggest another oil mixture other then 80:1 on a new bike during the break in. Also any suggestions on jetting? I'm at 800ft elevation.
Cliff, I wouldn't sell and use Saber if it didn't work well. 80:1 is a very heavy mix ratio for that oil. It is designed for 100:1.
JD jet kit or a Slavens Mule HV Lectron.
Ok like the comment! :)
How many hours can a piston go?
Kevpew Approximately 150 hours but they can last longer
Can tht carbon build up cause pinging
Technically yes, but it would have to be extremely thick.
my piston head had no black on the top it was almost 100% clean on the top of the piston when i took the head off
buddylikeguitar u have ur jetting on the money!!!!!!!! thats what it should have on the top 0 CARBON. well not 0 but close to it.
Jeff slavens how can i send you a pic to get your expert opinion
info@slavensracing.com
Not necessarily. The problem at those hours is blowby causing a loss of power. The piston can easily go much longer. In cars and boats they go thousands of hours.
The rings have a much more wearing contact with the cylinder, more pressure against it. Motocross riders change rings twice as often as pistons.
Careful comparing a 2-stroke engine with a factory TBO of 80 hrs with a car or boat that has TBOs of 5,000 hrs.
At 150 hours what about just changing the rings?
80:1 with Amsoil? That is crazy, awesome. You get 150+ hours using that? As posted below, I thought that was for weedwackers and lawnmowers.
....AMSOIL has about 8 or more two stroke oils for many different applications....Dominator/ 2000 is racing rated....some AMSOIL two stroke oils can be ran at 100 to 1 AMSOIL dealer...
There is a HUGE annotation on the video that corrects it to hours.
Do you have an email?
Do you use oem or aftermarket pistons?
150 to 200 miles, or hours?
holy fuck hours u dumbass it says right in the video and jeff said it twice .......HOURS .....HOURS.....HOURS!!!!!! Just read and find out urself .....ppl are so lazy nowadays they just ask questions when they can easily figure out themselves but are to damn lazy.
i had an 87 kx 500 and had my buddy run green dye or whatever he did it showed no cracks. 2 weeks later the bitch grenaded the piston. when in doubt replace.
can you hear the slapping? you must not do much riding then.. i mean there good for like 200 hrs and then i would want to look inside of them and 200 is alot..
i ride em hard though but that does not mean you can do a whole lot more riding easy
hours
I thought the more carbon on the crown the LEANER the jetting.
Sorry, you are incorrect.
@@slaverace1 there's a lot of info out there about crown wash on 2-strokes.....
@@331moto
OK. Enjoy.
Did you really mean 150 miles or 150 hours?? 150 miles is like 3 or 4 rides for me..
Hours.
When the rings are worn out so is the piston.
150 miles, I think you mean hours