Author Topic: Judge my piston pics (Read 8581 times)

Grande huevos · « **on:** July 27, 2015, 12:03:49 AM »

After seeing my buddies top end get rebuilt I decided to pull the head on my own and have a look. I don't have my hrs logged but I'm guessing there is approximately 20 hrs on this piston. Looks like some dirt or sand had made its way through and was sitting on my piston and dome? A little brake clean on a rag and most of it wiped right off. This motor has had nothing but VP 110 ran through it since day one. Anyways I'm Simply looking for peoples opinions on how it looks.

Grande huevos · « **Reply #1 on:** July 27, 2015, 12:08:32 AM »

I'm curious to know what's causing the two marks on the intake side and why the one on the right is brownish color

C-Leigh Racing · « **Reply #2 on:** July 27, 2015, 08:06:39 AM »

Hummmm, K&N air filter I guess ?.
Those two marks, if you push the piston down, you'll notice where those marks were located, they line up with the rear edge of the rear transfer ports & as the upward flow of mixture exits the port, it has a swirl like effect to it from bouncing off the edge of the sleeve & tends to clean that spot on the piston crown. Sometimes you'll see those same type of marks on pistons from the front transfers, but normally a goo % of the time they are at the rear.

If you do use a K&N air filter, remember what you cleaned off that piston, because you only cleaned up maybe half of what has entered the engine. The rest of that dirt/dust has been churning around in the bottom end. Got to go through their first before it can get to the piston crown.
Neil

Grande huevos · « **Reply #3 on:** July 27, 2015, 08:49:55 AM »

Quote from: C-Leigh Racing;56516

Hummmm, K&N air filter I guess ?.
Those two marks, if you push the piston down, you'll notice where those marks were located, they line up with the rear edge of the rear transfer ports & as the upward flow of mixture exits the port, it has a swirl like effect to it from bouncing off the edge of the sleeve & tends to clean that spot on the piston crown. Sometimes you'll see those same type of marks on pistons from the front transfers, but normally a goo % of the time they are at the rear.
If you do use a K&N air filter, remember what you cleaned off that piston, because you only cleaned up maybe half of what has entered the engine. The rest of that dirt/dust has been churning around in the bottom end. Got to go through their first before it can get to the piston crown.
Neil

Yes Neil it is a K&N filter with outer ware, no lid on the airbox. That's crazy that so much stuff still makes its way through, looks like it might be time for Uni foam filter. But Evrything looks fairly normal to you? Fuel appears to be burning properly? I stuck the compression gauge on the other night and I'm a little concerned as it only pumped to 155 psi. This was a big surprise because the last time I rode about 2 weeks ago the motor ran very well and strong just like it did the day I built it. I've never put a Guage on it before so I'm wondering if it's time for a rebuild or if that's just how it's always been.? Im going to check my squish clearance and prob do the uccr test this week so I have little better idea what's going on since I never checked these things when I built it �� Do you think in the first and second picture that the intake side of piston looks little worn?

jimcarrier · « **Reply #4 on:** July 27, 2015, 07:45:57 PM »

#k/n adding hp before it blow:fighting0061:

C-Leigh Racing · « **Reply #5 on:** July 29, 2015, 12:16:38 AM »

The 7th one is telling me a lot.
If you take a T bar & sit it just a hair above the exhaust port roof, lock it down, pull it out & then measure the T bar, you probably gona find around 0.003~4 larger bore than its suppose to be.

You can carefully pry on the intake side of the piston & then look down between the piston & cylinder bore & see the end gap of the top ring to see how wide the gap is. If the gap looks to be around 0.005 to 7 gap, thats not good but not bad enough keeping you from running the engine.
Now around 8 to 0.010 gap, thoses rings would be shot.

Jim, be nice now, its takes a few years for a person to realize just what those K&N filters really do to an engine. I guess you could call it growing pains & I'm no better than anyone else, cause I had to go through them myself.
Neil

dem3500 · « **Reply #6 on:** July 29, 2015, 09:49:37 AM »

K&N flows well but at a really horrible price! Even with a outerwear.

Powerstroken · « **Reply #7 on:** July 29, 2015, 10:16:53 AM »

So should I get rid of my k&n lol

dem3500 · « **Reply #8 on:** July 29, 2015, 10:27:00 AM »

Yes!!! Those things should be illegal! Haha

jimcarrier · « **Reply #9 on:** July 29, 2015, 03:48:39 PM »

i dont understand the thing about beeing nice tho.... only said that k/n filter where crap. but ok....

guess what i got trought some motor before switching to twin foam filter.... now getting back on k/n for the dyno run xd

Jerry Hall · « **Reply #10 on:** July 29, 2015, 05:48:42 PM »

My experience with air filters:

1. A K&N will usually out flow a foam filter of equal size
2. Most guys ruin a K&N the 1st time they clean it.
3. Most guys do not know how to oil a K&N filter or do not know when they have enough oil on it
4. A K&N will usually allow more of the fine dust through than a properly serviced foam filter.
5. A K&N cleans the air better the dirtier it gets if properly oiled.
6. K&N filters are good for a limited number of cleaning and re-oilings and then they need to be thrown away.
7. Foam filters will usually outlast a K&N
8. All foam filters are not equal in their ability to catch the dirt. The two stage filters usually filter better but do not flow as well.
9. Foam filters and K&N filters catch the dirt using two totally different principals.
10. Foam filters catch the dirt on the zillions of tacky surfaces of the small interconnected tunnels that go through the foam.
11. A foam filter will allow dirt to pass through the filter when all of the tacky surfaces have dirt on them and there are not any tack surfaces remaining to catch dirt.
12. A K&N works more like a strainer that allows a given size particle of dirt to pass through the mesh of cotton strings unless the the dirt or dust particle sticks to the oil coated microscopic cotton fuzz that surround the cotton strings that make up the cotton mesh.
12. Going through one talcum powder riding area for 30 seconds can render any filter but a paper filter useless. (the powder blots the oil from a K&N or deposits powder on all of the tacky surfaces in a foam filter, allowing dirt to immediately pass through.
13. Foam filters are easier to clean and oil and get good cleaning action using a wide variety of cleaning methods and foam filter oils.
14. There are some air filter oils other than K&N filter oil that will make the K&Ns filter better but they dramatically reduce the air flow through the filter.

Pumashine · « **Reply #11 on:** July 29, 2015, 07:21:40 PM »

I run a K&N with outerware. I don't ride dirt so they have never been cleaned in 3-5 years. Never had a problem sucking sand on either of the 3 bikes.

fearlessfred · « **Reply #12 on:** July 29, 2015, 11:23:30 PM »

I always wipe the inside of airboot down with white rag and every time I have used KN there will be a brown residue on the rag.

Jerry Hall · « **Reply #13 on:** July 30, 2015, 06:06:00 PM »

Quote from: Pumashine;56583

I run a K&N with outerware. I don't ride dirt so they have never been cleaned in 3-5 years. Never had a problem sucking sand on either of the 3 bikes.

The K&Ns usually catch the sand real well providing they have not been ruined when cleaning/servicing.

Powerstroken · « **Reply #14 on:** July 30, 2015, 07:07:53 PM »

What exactly ruins then when servicing them?