Piston wash / plugs

[Warhawk]

instead of using slp high flow air intake get the one from brp. they use them on the 600 race sleds. air comes in on top of instrment cluster behind windshield

can you post a llink to the air intake sysytem behind the windshield as i can't seem to find it. would like to see if it would work on my 2010 summit800

 

[chrispy]

why did you lean out your main? That would explain why your pistons have more carbon build up. you need MORE fuel to control piston cooling and wash. You do NOT want alot of carbon build up on the outer edges of your piston. that can cause excessive heat in your pistons.

I changed the jets cause my plugs were always black and I had to much wash on the pistons. Going to change back and check again. Will check into the air intake thing never heard of that

 

[drewski]

I changed the jets cause my plugs were always black and I had to much wash on the pistons. Going to change back and check again. Will check into the air intake thing never heard of that

how are you checking your wash? are you doing long pulls at different rpms? Carburetion consists of 3 different fuel circuits. pilot, needle and main. It's going to be very dificult to figure out where your jetting should be without performing checks at different rpms (ALL 3 CIRCUITS) This is why I like doing WOT runs whether it's a proper plug chop (indicates jetting instantly) or check wash, which to me isn't as accurate. you need to do research on jetting before you jump in there. It's not ALL about the main jet.

 

[chrispy]

how are you checking your wash? are you doing long pulls at different rpms? Carburetion consists of 3 different fuel circuits. pilot, needle and main. It's going to be very dificult to figure out where your jetting should be without performing checks at different rpms (ALL 3 CIRCUITS) This is why I like doing WOT runs whether it's a proper plug chop (indicates jetting instantly) or check wash, which to me isn't as accurate. you need to do research on jetting before you jump in there. It's not ALL about the main jet.

I use a borescope to check wash. And from what I understand it takes several rides for your wash to change not just one pull

 

[drewski]

I use a borescope to check wash. And from what I understand it takes several rides for your wash to change not just one pull

Thats why I don't like the wash technique.

The thing is with taking it for several rides to check the wash is, your running the engine through ALL the fuel circuits (low rpm/mid rpm/full rpm)But You have only changed the MAIN jet circuit. This is why your getting inconsistent results.

 

[shoppingcart111]

My xp has a bit of a lean spot at mid throttle, which I was told was all xp's. I have my egts base alarm set around 1250 i think and on the trail or holding it at mid throttle too long will start the alarm and goes up from there.

 

[chrispy]

I guess everyone has there own opinion on the matter which is good. Some people say wash others say plugs and others say exhaust temp. Keeps me thinking lol. I'm getting some good info though which is really good.

 

[drewski]

I guess everyone has there own opinion on the matter which is good. Some people say wash others say plugs and others say exhaust temp. Keeps me thinking lol. I'm getting some good info though which is really good.

Jetting is a pain in the @s$ at first. just do some research first and make sure your 100% confident in doing jetting changes before you go ahead. what I personally think what is going on, is what shopping cart said. lean (from factory) on the needle.

 

[retiredpop]

Dime size washed off area is considered to be good. It sounds like you may still be a touch rich.

Sorry, I was confused myself. If you have a spec of wash only it is too lean. Funny how one main jet size could make it go from too much wash to not enough.
The most reliable way to check is to go by the plugs. I think your plugs look good in the picture as far as color. On your picture is that with a wide open run for about a 1/2K and then kill the engine with the kill switch without letting off the throttle and lock the track? That is the way to check the mains. If it is after a normal ride then you don't really know if the mains are lean or not. Piston wash takes a while to establish itself and also depends on type of oil used.

 

[retiredpop]

I guess everyone has there own opinion on the matter which is good. Some people say wash others say plugs and others say exhaust temp. Keeps me thinking lol. I'm getting some good info though which is really good.

Plugs are the best. When they show all carb functions are good then use the other stuff like egt and wash as a reference. Drewski is right about the different carb circuits. If you really want to do it right you have to check at all rpm ranges and then check plugs after each run.

 

[OVERKILL 19]

Somewhere in between these 2 is what i have been reading

funny how the two pics show different wash patteren for perfect piston wash???

 

[chrispy]

funny how the two pics show different wash patteren for perfect piston wash???

That's what I mean about everyone having an opinion. One guy says this then another something else

 

[drewski]

funny how the two pics show different wash patteren for perfect piston wash???

different oils and piston types will show different wash. You can not go off of a picture on the internet without knowing all the variables. OIL, FUEL, PISTONS, etc.

 

[chrispy]

Should I be jetting for the mountains since that's where I do most of my riding. Or jet here and let the dpm make up for it

 

[drewski]

Should I be jetting for the mountains since that's where I do most of my riding. Or jet here and let the dpm make up for it

Jet perfect for low elevations and let the dpm do the work.

 

[Modman]

Should I be jetting for the mountains since that's where I do most of my riding. Or jet here and let the dpm make up for it

OK first off there are way more than 3 fuel circuits than previously mentioned. The airscrew, pilot, needle, tube, carb slide cutaway, and main are the primary circuits, with overlap on many of them.

Secondly, pretty much all oils are low ash TCW3 formulations these days, you'll be hard pressed not to find one that isn't. Years back you couldn't mix the regular oils and the low ash formulations, but nowadays I don't think there is an oil on the shelf that isn't lower sulphur/ash. You need some ash on the piston dome to protect it from direct heat, which is why it is not always a good thing if your oil burns completely away. The white spots are oil deposition from incomplete burn when combustion temps are not as high. They vary from motor to motor because some guys let their sled idle more or do not run in the upper throttle ranges or at WOT for as long as others. They would probably go away if you ran a hotter plug but if they are not causing issues with fouling I would not worry about it. BRP uses a different blend (full synthetic I believe in all the newer sleds - someone please confirm).

Warhawk, your plugs are spot on to all the other 08 XPs I have seen. The center electrode has good colour without showing the white porcelain and the ground electrode has colour right up the bend. Picture perfect.

chrispy - Piston wash should be some dime sized spots at the transfer ports and intake(s) just like the photos. No wash does not mean too lean unless its a grey colour (just my experience). If its dark brown or black it can mean its just getting too much oil and not burning it all off. You need a few more kms on it to really determine the wash, like 500 kms. From my experience, when the dome starts getting grey is really when things are starting to get hot (not that I've ever melted a piston.... ) Read the plugs and use the wash as a general guideline, set your fuel circuits by plug chops as drewski stated.

Jet for your lowest elevation and the coldest temperature that you will be riding. The DPM will lean it out as you go up in elevation or as things get warmer, or both.

 

[Warhawk]

OK first off there are way more than 3 fuel circuits than previously mentioned. The airscrew, pilot, needle, tube, carb slide cutaway, and main are the primary circuits, with overlap on many of them.

Secondly, pretty much all oils are low ash TCW3 formulations these days, you'll be hard pressed not to find one that isn't. Years back you couldn't mix the regular oils and the low ash formulations, but nowadays I don't think there is an oil on the shelf that isn't lower sulphur/ash. You need some ash on the piston dome to protect it from direct heat, which is why it is not always a good thing if your oil burns completely away. The white spots are oil deposition from incomplete burn when combustion temps are not as high. They vary from motor to motor because some guys let their sled idle more or do not run in the upper throttle ranges or at WOT for as long as others. They would probably go away if you ran a hotter plug but if they are not causing issues with fouling I would not worry about it. BRP uses a different blend (full synthetic I believe in all the newer sleds - someone please confirm).

Warhawk, your plugs are spot on to all the other 08 XPs I have seen. The center electrode has good colour without showing the white porcelain and the ground electrode has colour right up the bend. Picture perfect.

chrispy - Piston wash should be some dime sized spots at the transfer ports and intake(s) just like the photos. No wash does not mean too lean unless its a grey colour (just my experience). If its dark brown or black it can mean its just getting too much oil and not burning it all off. You need a few more kms on it to really determine the wash, like 500 kms. From my experience, when the dome starts getting grey is really when things are starting to get hot (not that I've ever melted a piston.... ) Read the plugs and use the wash as a general guideline, set your fuel circuits by plug chops as drewski stated.

Jet for your lowest elevation and the coldest temperature that you will be riding. The DPM will lean it out as you go up in elevation or as things get warmer, or both.

thanks Bart.

i just ran the piss out of it for 3 days and she never blew up LMAO. Like i said back in another post dpm is working properly because if it wasn't she would have been really fat. pics i have from other runs back home (regina) look almost exactly like the ones i posted. i will be checking wash tomrw.
mag side does appear a little more lean than pto. was going to look at cooling system schmatic to see how coolant flows thru 800r engine. my guess is it flows from pto to mag as the reason mag plug is a little lighter.
will confirm this later.

 

[Modman]

thanks Bart.

i just ran the piss out of it for 3 days and she never blew up LMAO. Like i said back in another post dpm is working properly because if it wasn't she would have been really fat. pics i have from other runs back home (regina) look almost exactly like the ones i posted. i will be checking wash tomrw.
mag side does appear a little more lean than pto. was going to look at cooling system schmatic to see how coolant flows thru 800r engine. my guess is it flows from pto to mag as the reason mag plug is a little lighter.
will confirm this later.

I think the coolant flow is lateral through the motor on both sides, from the front of the crankcase to the head and then out to the t-stat doesn't it. might flow a little more on one side vs the other I guess though still.

 

[davelaw1982]

thanks Bart.

i just ran the piss out of it for 3 days and she never blew up LMAO. Like i said back in another post dpm is working properly because if it wasn't she would have been really fat. pics i have from other runs back home (regina) look almost exactly like the ones i posted. i will be checking wash tomrw.
mag side does appear a little more lean than pto. was going to look at cooling system schmatic to see how coolant flows thru 800r engine. my guess is it flows from pto to mag as the reason mag plug is a little lighter.
will confirm this later.

H20 flow is equal on both sides, pump is located central in the crankcase, and central exit point on top of the head of the XP's and bottom of the head on 07 Summits and lower... One thing that I have found with rebuilding mine is trying to get the carbs balanced equally in throttle slide travel. this would/could be cause of slightly lean on one side.

 

[Warhawk]

good point on the carbs. these are TM flat slides and usually don't require syncronization that often as they use a cam style adjuster, but i will check this out.

thanks