honda ut1 flat top piston help

[chriscouncill3]

has anyone had any experience with this piston I just got one in for my blue greyhound 196cc clone and have searched a lot and the only thing I can find is that I should stagger the rings 120 degrees... ok got it. but the two top rings (the thicker ones) neaither one has a lip like I am used to seeing the shiny ring seems to kinda have angle on the inside my question is how should I install the rings for that piston? also the piston does not have an arrow which I think is supposed to be in the lower part of the engine as in closest to the bottom. I have put the piston in to the best of my knowledge so far and it was a very tight fit but however is 1000x smoother to turn the engine than with the factory piston so once I get this ring thing figured out and my torque wrench comes in i'll be on and put in a review but from what I noticed so far not only should I get the better compression which hopefully gives me a bit better takeoff but with how much smoother it now rotates I would imagine I will notice an extra few RPMs (aka an extra MPH or two). thanks guys

 

[davidlamb78]

have you checked youtube? i know i found something about this on there when i did my greyhound upgrades. i didn't do the 120 degree thing with mine. i think i did mine every 90 degrees, but i can't remember for sure. i don't really know that it matters that much, but i'm not an expert. i thought they moved around a little once installed and used.
as for the beveled edge, i know i saw something about that on the how-to video i watched on youtube. that was the first engine i ever built up with heavy mods, and i researched a lot of youtube videos before i opened it up.
is there any mark at all on the piston to help determine how it sits? i think mine had a dip in it, but i can't remember for sure. that may have been the stock piston i pulled out. it's been a while since i did all that stuff to the motor.

 

[chriscouncill3]

what do you mean by mark on the piston?

and yes but with this piston I cannot find anything

 

[rmm727]

its a little triangle on the top of the piston.

 

[davidlamb78]

There is typically some kind of mark on the piston. The first pic below is a honda piston. I think there is small "bump" or "divot" on it. The second pic is just to show what the poster above was describing, but it is NOT a honda piston.
Is this going in a gx160? I think the pic of the honda piston below is for a gx200, but I don't know if there would be a difference in design other than size or not.

 

[chriscouncill3]

yeah the little raised circle faces down correct? but my real problem is which rings go where non of them seem to have a beveled edge

 

[davidlamb78]

how many rings, 4? The corrugated ring goes between the two smaller (thinner) rings. The bigger ring (thicker ring) should be a compression ring, I think. I think this only fits in one place. I can't remember what I did with mine, but I thought it was similar to this.

 

[youngengines]

Top ring should be chrome looking, second black, and expander is self explanatory. They should have some type of mark on them, that goes up. Looking down on the piston, with the dot/mark down, I put the end of the expander at 12 o'clock, lower oil ring at 2 o'clock, top oil at 8 o'clock, second ring at 7 o'clock, and top at 2 o'clock. That's just me.

 

[chriscouncill3]

young engines thanks that was exactly the answer I was looking for and what I did and good thing too cause I had already put the engine together and test run it now after I get my throttle all figured out I can test ride it and give a review of the ut1 short skirt piston

 

[youngengines]

young engines thanks that was exactly the answer I was looking for and what I did and good thing too cause I had already put the engine together and test run it now after I get my throttle all figured out I can test ride it and give a review of the ut1 short skirt piston

Your welcome, and sorry I was so late posting.. Good luck.

 

[chriscouncill3]

so with the addition of a flat top how do you think I should ajust jetting bigger or smaller or do you think I will have to redo all 3 main, low speed and needle?

 

[chriscouncill3]

so... here are my findings so far the engine runs well as of now (still breaking it in) when I first ran on regular gas it ran poorly right when I started throttling up but idled well and the higher rpms were fine. I ran out of gas so when I got more I decided to try mid grade I figured flat top piston = more compression so go for higher octane well I was right no lag where I had it before.... as of now I know while on reg gas it was running very rich from plug read I have not read plug with mid grade but suspect I will find the same performance so far is = to or < than before but suspect with carb tuning and further breaking in of rings I will get > than before. more to come........ keep guys and keep the rubber side down!!