250R rattle noise

[85Atc350x]

I just did the top end on my 86 250r with a Wiseco standard size piston, I honed it before installing everything. This is the first top end job. It makes a rattle noise when i rev it up. It is definitely coming from the cylinder. I know i installed everything correctly. I used a '90 CR head gasket and today I realized that a 90 cr's bore is 66.40 and a 86 atc is 66mm so i wonder if that has any difference other than the fact that the CR gasket is thinner and raises the compression. Im gonna take off the head and inspect what i can see from there but I have a feeling Im dealing with piston slap and should have just had it bored instead of tryin to preserve originality. If anyone has any other suggestions let me know.

Thanks
Justin

[dads]

Sounds like piston. If it is you will see drag marks on the skirt of the piston. If people would just part with a little cash, have the cylinder checked they would not spend more money and time redoing a simple job. :cry: ;)

[Mr. Richard]

i'm with DADS!!! when you are dealing with thousanths of an inch and the life of an engine ,,MEASURE IT!!!! its cheap insurance!!!!

why take a chance of scattering a engine and spending HUNDERDSSSSS,,,,,,,,,,


:D:D--- :D

[Fuzzy]

I would also agree that it is piston slap. And the best thing to do is tear it back down before it brakes a skirt off the piston and it goes down in the crankcase and becomes bigger trouble.

And guys he said it was his first top-end job. And i know i have learned the hard way. As i am sure a lot of people have. So go easy on him.

[dads]

Well it's not a good way too learn, But almost every one does it. :yup:
I have pulled some good boners tring to cheat a little. and they all ways come back and bite me in the azz.:bash:

[85Atc350x]

Let me clarify this for everyone. I did measure it was at the max of .001 of an inch taper so I was hoping to get away with it. Also this is the first top end for my ATC not for me.

Justin

[Fuzzy]

Oh i get ya. So it was border line. And you thought you could get by with it. Thats understandable.

And on the first set of new rings in it i am surprised you couldnt get by with a hone and a new set of rings. . Sorry for the confushion i misread what you were saying about it being the first top end job.

Well i guess it is worth a new top end gasket set to open it back up and check it out.

[85Atc350x]

Fuzzy,
It was the other guys i was leaning my last post to. They were coming off a little strong. I put new rings and a Wiseco piston. The only reason I took her apart was cause the head gasket started to leak on top of the base gasket already leaking, so I figured it was time to inspect the 16 year old piston and everthing was in good shape from looking. Measuring reveiled some slight taper. It cleaned up nice with the hone and I figured alright im ready to go. I was trying to keep the 250r close to original on my budget and didnt want to bore it. This weekend im gonna re open her up to re-inspect, I hate doing stuff twice. Arrrgh

Justin

[Mr. Richard]

hey man i don't think i was a little strong ,, from your post i see you measured the taper,, what about out of round, and piston to cylinder clearance of the new piston after honing ,,ring end gap also ,,,, these engines will last along time if they are set up right,,, i think a 17 year old bore is past its useful life and rather than breaking a shirt off and ruining your pride and joy its worth the time and effort to do it right ,,,,, the piston is the only thing on an entire machine that in 1/10 of a second can totally ruin an engine and transmission

i also have a 86 250r with the orignal piston and rings , i'm looking for a .010 piston now ,,,it should last 16 more years with a new piston too,,,

[85Atc350x]

Not even you kasey it was someone else that seemed to have a attitude about things. I pulled it apart tonight and i just gonna get it bored 10 over. I tried to make it last at the original bore but its more than likely piston slap so thats that.

Justin

[Mr. Richard]

when you get it bored make sure it read the paper work so YOU know the minimum and maximum bore tolerances. if you talk the talk when you talk to the machine shop they will do a better than run of the mill bore job . i always bore to the minimum then take my time on break in ,,, like i said before thousanths are thousanths,,,,if clearances are .0025 to .0040 why start at .004 cause the machine shop guy says hey thats close enough....

[85Atc350x]

Yeah i hear yeah, i want it bored mininmally. I might take it to where my friend works but I dunno there jerks over there, they dont like 3 wheelers. I hear ya about the thousandths are thousands. I will take 150 hrs to break the thing in rather than bore it more like an a$$.

Justin

[dads]

Originally posted by 85Atc350x
Not even you kasey it was someone else that seemed to have a attitude about things.

:confused: I hope you don't think i have a attitude. All i was doing was stating facts that i see happen too often.

[Dirtsquirt]

Make sure you have the piston you are going to run before you bore! Slight manufacturing differences can lead to the problems you mentioned above and more.

And if the guys don't like 3-wheelers then tell them the jug is from a '86 TRX :)

[Mr. Richard]

justin ,,, i thought my post had more attitude than dads ,,, gotta remember we are old!!! and we have been there and seen lotsa blown engines i would call them HARD FACTS!!! AND dads is right,,, peace,,,,,,,,RM

[dads]

When I have one bored I bring them the cylinder and piston. Then i say I will check their work when i get it back if not at min tolerances they buy the next piston and bore job. :bash:

[markb]

the biggest thing on bore jobs other than a competent operator is their ability to measure the bore accurately. VERY FEW places can do this they must have a bore gage not a set of feeller gages that they shove down between the bore and your new piston. if you don't know what a bore gage looks like (there are different types) go to www.msc.com and search bore gages for pics. this way they can't snow you i know this seems like a bit much but the older guys will agree with me that many people just want your money they don't care about your bike.
the thing with the piston is the stocker was cast and would have a totally different piston to bore clearance than the wisucko. i don't know what the stock heads squish band looks like but with the thinner gasket i would take some solder and chech your squish clearance also.
mark

[dads]

:thumbsup:

[85Atc350x]

Hey guys, thanks for all the tips. Basically I know what i should have done on the first time, but Im one for orginality and not boring/modifying things. All the info is definitely something I will keep in mind. No hard feelings to anyone, I appreciate the info.

Justin

[Caterpillar]

Hey, could some one post the specs on a 85/250R pertaining to a 10 over bore job? I am talking, measurements! Like, what should the stock sleeve diameter measurement be, and what should it be bored to for a 10 over piston.( That would be a oem piston, as Wiseco is NOT the way to go on the liquid colled R ) I want to get mine done right away, and would like to protect myself from some sac who dosn't really care about his work. I just put a new clutch in, minus the update kit, which I could REALLY use a part # for!! (hint, hint) Thx in advance....

:demon:

[markb]

clutch is 06220-hb2-305
the stock bore is 2.5992 to 2.5998 with a 2.601 limit
the manual calls for a .006 piston to bore so mic your new piston on the skirt at 90* to the pin and add. i was surprised they want that much clearance,that must be where hondaslap comes from
mark

[Mr. Richard]

hey ,,, don't bore it to .006,,,,,,,, thats the maximum service limit!!! a fresh bore with a cast honda piston should be .0024 to .0037,,, and if you get a wiseco the paperwork that comes with it will tell you min to max clearance forged pistons expand more than cast so they will require more inital clearance,,,,,

[RichinMO]

I want to put a cast piston in mine when I rebuild it. Is Honda the best/only place to get these? I have seen the replacement Honda part listing, they say "piston, 0.25" and "piston, 0.50" with rings to match, what does that mean? Is that the same as saying they only go .25 and .50 over stock bore whereas Wiseco goes .10, .20, .30 and so on?

[RichinMO]

Whats that update kit for clutch do?

[85Atc350x]

.25 is in mm .10 is inches, i just ordered all my stuff tonite. This time i ordered all OEM stuff no more Wiseco.

Justin

[Mr. Richard]

forged pistons are alot srtonger ,they expand at a more even rate and are more precise,, i have a wiseco in one of my 250r's , i have never had a problem with wiseco, i also have a cast sudco piston in one of the others and it seems to be ok , i think MOST piston related problems are not failures in piston construction and workmanship,, there are alot of other factors mostly human error,,,,,,,,,,,,,

[markb]

as usual a mind is a terrible thing
thanks for catching that kasey,,,,you'd think that if i thought the .006 was too much i would have looked at it again but refering to line #1 i think we have found the problem here.
i put the clutch update in mine and didn't see a huge difference in pull, although other people have. the difference is that it changes the thrust bearing to a roller style.
i've always used wiseco but i think their quality is slipping. the last one i bought had a chinease wrist pin and i've read about other people having quality problems that they won't stand behind. my phone converstions with their tech dept. were very dissapointing
mark:doh:

[Levi]

Originally posted by 85Atc350x
I just did the top end on my 86 250r with a Wiseco standard size piston, I honed it before installing everything. This is the first top end job. It makes a rattle noise when i rev it up. It is definitely coming from the cylinder. I know i installed everything correctly. I used a '90 CR head gasket and today I realized that a 90 cr's bore is 66.40 and a 86 atc is 66mm so i wonder if that has any difference other than the fact that the CR gasket is thinner and raises the compression. Im gonna take off the head and inspect what i can see from there but I have a feeling Im dealing with piston slap and should have just had it bored instead of tryin to preserve originality. If anyone has any other suggestions let me know.

Thanks
Justin

They way you describe your problem, it sounds like detonation. You can actually hear detonation on a 2 stroke, even with loud pipes on. It sounds like someone's dropped a bag of marbles in the engine. Kinda like a big rattley, metallic tinkling noise.

Sounds are tough to describe - especially on a message board.

I describe the sound as being like a bunch of bb's in a coffee can, rattling around.

[85Atc350x]

I dunno Levi. Id like to hope its that, but now I got it all apart again and a new oversize piston on the way. There was marks on the skirts of the piston as if it was dragging up the cylinder on the skirts and also it apears this Wiseco piston created a ridge at the top of the cylinder, like the ridge you get on a 4 stroke engine. I hate to get it bored but at this point I dont want to take it apart a third time.

Justin