Help/advice installing 250R piston (Installing new piston)

[250r'en +TCB]

Got my 310 kit (cylinder and piston)

Any tips or tricks?? What should i lube the piston and cylinder with? @ stroke synthetic???

I can get any pics if you need them to help me!
Thanks, Devin

[ATCWRENCH]

before you install the cylinder and piston go to www.ctracing.com and read their guide lines to correctly prep and install a cylinder and piston. it is pretty detailed and if you have a question you can call them and they will help you out.

[brrcuda]

all of mine slipped right in - just make sure every moving part such as rings, cylinder wall and bearing is coated in good 2 stroke oil. The piston should slip right in without much effort if appropriately sized for cylinder.

I've done 3 of them and all are still operating.

You might want to take the extra step of checking the ring gap since that is an expensive cylinder. Usually that info is in the instructions of piston kit.

[250r'en +TCB]

Can't get the damn cylinder off!!! I sprayed penatrating oil and tapped with a hammer but it won't budge.....

[Billy Golightly]

This is my own advice but I DO NOT coat the cylinder walls or piston with oil. Bearings, OK though. Its easier for the cylinder to glaze on start up if its coated with oil.


You got all 4 nuts off, head stay mounts, exhaust, ect removed? I dont know about the Rs but on my 500 I have to take off the exhaust flange or it hangs up on the frame. check that.

[250r'en +TCB]

It's off the frame Billy, I'm pushing on the case with my legs while pulling the cylinder with my hands........

[ATCWRENCH]

if you have a rubber mallet keep tapping it front to back, side to side, it will come off. it may require a solid but not over powering hit to knock the cylinder loose.

[Billy Golightly]

I hate to use the word "pry" but see if you can fit something inbetween the intake and the case and work it around a little bit. Don't use a hammer unless you have a fiber or non marring surface one.

[DeePa]

put the kicker on and try kicking

mike

[250r'en +TCB]

Got it!!!! Just pryed it by the intake and exhaust, don't worry no damage!!! I'll post pics later! Thanks a ton guys!!!

Now i have to get the piston off.........

[cragster]

Man that is going to be one hell of a bike you got there 250r'en +TCB!!!!!
GiT it RaGGGG!

[250r'en +TCB]

WRONG PISTON!!!!!!!!!! What the hell!!! The guy must have sent me the wrong piston, not even sure it's for a 250R, maybe one with and extended rod. it's cleary differnt from the one in the aution picture!! I e-mailed him about it, he has been straight-forward so far with 99.7% positve feedback.

the piston won't work because it has no space for the connecting rod to rotate! Stock is on the right in these pics BTW
http://i42.photobucket.com/albums/e306/ATCteen/wrongpiston001.jpg
http://i42.photobucket.com/albums/e306/ATCteen/wrongpiston002.jpg
http://i42.photobucket.com/albums/e306/ATCteen/wrongpiston003.jpg
I sent him these pics too, damn what a pain in the arse! This is what blows about buying on the internet.........

[250r'en +TCB]

Actually I just looked at the auction pics, I think it's the same.......

So what's the deal hear guys????? Do I have to get a +5mm rod or what???

[Pete]

thats an 88/89 250R piston.

[250r'en +TCB]

Ok so where does this leave me????? Do have to get an 88 or 89 connecting rod??? They were +5mm correct???

What must I buy to get this machine running????

[KASEY]

looks like your screwed,,, you will have to get a short rod piston,,,, cause a long rod piston won't go all the way to the top of the bore,,,,,,,,,,,

[SYKO]

hey man I havea stroker base spacer you can have if it will help, let me know..

[250r'en +TCB]

looks like your screwed,,, you will have to get a short rod piston,,,, cause a long rod piston won't go all the way to the top of the bore,,,,,,,,,,,
WTF?!?!?! I would need a longer rod so the piston could complete the stroke, right? Did you get those 2 mixed up???

Would a spacer plate be enough??? Or do i need to buy an 88 or 89 rod???
Please somebody tell me what i have to get to make this work!!! Any pics you need I can get........

[Billy Golightly]

You need a piston that same diameter with the wristpin located 5mm lower or whatever the difference is between the short and long rods, if there is such an animal. Alternatively you COULD cut 5mm off the piston skirt and the bottom of the jug but I dont know how well that would work out...

[250r'en +TCB]

You need a piston that same diameter with the wristpin located 5mm lower, if there is such an animal. Alternatively you COULD cut 5mm off the piston skirt and the bottom of the jug but I dont know how well that would work out...
The guy swears on his life this was the piston run in the quad with this kit. the piston is a match to the cylinder for sure...... I'm waiting for him to answer me if it was used on an 88/9 engine.

This piston has defiantly been ran before, so something must work......... Maybe I would have to shave 5mm off the skirt, but that's obviously a last resort...... Hate to have to break out the bench grinder!!! :lol:

[deathman53]

first, what rod do you have, does it say ha5 on it? I use long rod cranks and 86 pistons, I have 5mm spacer plates on my motors. Most of you big bore pistons are 86 pistons(if not all). Esr sellls a spacer plate kit, that includes everything you need. And yes, the head stay mount does work. I believe 87-89 pistons stop at 68mm or 80 over, 86 pistons go to 76mm bores, maybe78mm?

[250r'en +TCB]

Here's what the guy said to me, looks like he knows his stuff thank god lol:

"The window in the piston indicates that it is the long rod, the short rod piston have a half moon at the bottom, thats why i had the oiston positioned with the window showing. if you have a shortrod motor the cheap way would be to grab a crank and rod off ebay i see them for as little as $40.00"

Is this what i'll have to do?

[Pete]

you need the '85/86 version of that piston or an 87+ crank. I'd do the piston over the crank, that way you don't have to split the cases.

[ChrisD]

Well I guess if you wanted to wait another 6 or so months, you could get a good crank for $40. Then have to dig into your bottom end. Why don't you go to wiseco's page to see if they make the same size piston for the short rod motor?

I looked at LA Sleeve's site. They have them from Pro-X and Wiseco.

[Pete]

I haven't seen a 310cc 88/89 piston in a long time, is this a Pro-X cylinder you're installing, and are you sure the bore size is 72-73.5mm?

[deathman53]

I thought the big bores only came in 85/86 pistons.

[Yamahondaman]

Ohh...my ..... God !!!.........

[gasmask]

my question when was the bottom end rebuilt. if you don't know that the go ahead and rebuild it complete. add more compression can cause the rod bearing to end up on top of the piston. ebay: crank bearing, complete gasket kit , complete seal kit under $100.00 a small price to pay for years of riding. since the crank halfs are the same order a 87 to 89 trx crank rod and rebuild the crank... that's what i do. also i coat the cylinder and piston with WD40 when i'm putting it back together...

[gasmask]

my question when was the bottom end rebuilt. if you don't know that the go ahead and rebuild it complete. add more compression can cause the rod bearing to end up on top of the piston. ebay: crank bearing, complete gasket kit , complete seal kit under $100.00 a small price to pay for years of riding. if the crank halfs are the same order a 87 to 89 trx crank rod and rebuild the crank or ebay again. also i coat the cylinder and piston with WD40 when i'm putting it back together...

[250r'en +TCB]

Well I guess if you wanted to wait another 6 or so months, you could get a good crank for $40. Then have to dig into your bottom end. Why don't you go to wiseco's page to see if they make the same size piston for the short rod motor?

I looked at LA Sleeve's site. They have them from Pro-X and Wiseco.
No another 6 months of wating isn't in my schedual:lol: Here's the wiseco page http://www.wiseco.com/PDFs/Catalogs/CB06/HondaATV.pdf This cylinder is on it's 2nd to last bore, so what do I get for a bore size??? I don't see anything that's close to 72mm, if that is what I need.....:rolleyes: There all a few more CC's than stock (262cc max)...... So would i have to send this cylinder in to get a custom piston? That won't be cheap....:cry:

The only brand label on the cylinder is on the left side of the intake, it's an HM with a circle around it. Anybody know this brand?

I've been thinking, why can't I just cut the needed amount off the piston skirt like billy suggested???? The pistons look the same except for the half-moon cresent on the bottom. Can this be done?

[Fox250R]

Could it be a vertex piston?

[250r'en +TCB]

Ok I took a picture of the box the piston came in, but you can't read anything so I'll type it... http://i42.photobucket.com/albums/e306/ATCteen/piston.jpg

(Sticker on top)
20060629
252 W5032P4 TO295 BB

(sticker on bottom)
W5032P4
LA SL HON TRX250/295 72.95m-2874CD


clear: 0.0020(0.051mm)
2874CD CW18
012306/3/t/1545 Replaces: 8001P7295

Ok there's all the info on the piston, I guess it's a 72.95mm bore? Don't see that on wiseco's website. Could I just call them and ask if they have or can make that size for a 1985 250R engine????

[Erics350x]

i wouldnt go grinding on a piston thats asking for trouble down the road.

[Billy Golightly]

You can order the big bore pistons from ESR and I believe Nacs racing. Just because Wiseco doesnt sell it out of their catalog doesnt mean they dont make them :)

[Pete]

the bummer about the 310/330/370 pistons is that they are NOT cheap!

[SYKO]

hey has any one ever used that 440 kit from LA SLEEVE? I was looking at it, and damn if that would be awesome! (didnt meen to rip this thread)

[ChrisD]

You have a piston from LA Sleeve.....

from their site:

Hi-Performance Forged Big Bore Piston


Part Number W5032PS
Fits 1987-1989 Honda TRX-250R
Your Price: $160.00

The ATC piston is part number :

Hi-Performance Forged Big Bore Piston


Part Number W845PS

Fits Vehicles:
1985-1986 Honda ATC-250R
1986 Honda TRX-250R
Your Price: $149.95

For a forged piston:

http://www.lasleeve.cc/index.cfm?product_type=Hi%2DPerformance%20Forged%2 0Big%20Bore%20Piston&product_type_ID=18

You have the 87-89 piston. "S" at the end of the part number denotes the size of the overbore. It is replaced with a number.

They also have cast pistons too:

http://www.lasleeve.cc/index.cfm?product_type=Hi%2DPerformance%20Cast%20B ig%20Bore%20Piston&product_type_ID=17

Good Luck!

[hrc85250r]

just get a rod kit 88/89...its cheaper...

[250r'en +TCB]

Called LA sleeve and I need a W845P4 piston for 149.95 plus shipping, proubly get like 2 or 3 day shipping cause I'm imaptient lol

Thanks agian ChrisD!!! One day I'll have to try and venture out to NY and give you a run for your money on the ice:beer :w00t: Or maybe I'll see you at TF 07???:naughty:

Thanks guys for all your help! I'll post pics when she's installed!

[badasskfx]

you going to be ready for the nh r+r beds?

[250r'en +TCB]

Here's the new piston before I install it. My dad walked up to me and said "So I'm guessing this is gonna up the HP a little huh???......... Just made that assumption when I compared the honda piston to this one and realized it was about 1/4 bigger........" hahahaha I just answered with "good guess....."
http://i42.photobucket.com/albums/e306/ATCteen/pistonnew001.jpg
http://i42.photobucket.com/albums/e306/ATCteen/pistonnew002.jpg
Anyway the guy i bought this from said i can run the OEM honda head, but I'm not sure about the OEM head gasket...... It sticks out in the cylinder about an 1/16 of an inch......... Is that ok????? Should I try and trim it first or is it ok??