300r where to get a piston

[yellowbeard]

hey guys, where do I get piston and rings for a 300r big bore. my piston size is76.44 mm 1984 honda 250r. thanks Joe

[1upfront]

hey guys, where do I get piston and rings for a 300r big bore. my piston size is76.44 mm 1984 honda 250r. thanks Joe

Thats funny I just bought a 76.44mm wiseco piston for my 300r a few weeks ago. Heres a link with the wiseco you'll also need your cylinder decked a few mm's because the deck height is shorter on the wiseco.
http://cgi.ebay.com/ebaymotors/Honda-ATC250-atc250r-Big-Bore-Cylinder-Piston-Kit_W0QQcmdZViewItemQQcategoryZ34284QQihZ003QQitem Z130168490864

[cr480r]

you'll also need your cylinder decked a few mm's because the deck height is shorter on the wiseco.

How much will that alter the port timings? Have you ran it like that yet? The timing would not be changed if the deck was reduced by cutting material from the base...

[SYKO]

it dosnt alter port timing, the pistonis simply matched to the cylinder that way, and port timin is dead on then

[cr480r]

Wrong... If you were to only remove material from the deck it would have the same affect as raising all the ports

[1upfront]

How much will that alter the port timings? Have you ran it like that yet? The timing would not be changed if the deck was reduced by cutting material from the base...

No I have not run it yet but my port guy at Flotek did the deck work aswell as ported the cylinder and he required the whole motor so he could take care of any port timing issues if they arose. I suppose if you were not also planning on getting the cylinder ported it may become an issue but I doubt it being as the piston is identical from the wrist pin down, you would only be shortening your compression stroke by a few mm's every thing else would stay the same. :cool:

[cr480r]

well if a guy wanted to use that piston without changing the porting the material would need to be milled from the base... a couple mm's is a lot of difference

[1upfront]

well if a guy wanted to use that piston without changing the porting the material would need to be milled from the base... a couple mm's is a lot of difference

The guy who sells the pistons at discount cycle parts also offers the cylinder service when you buy the piston but I chose to use Flotek because the owner is one of my racing buddies and I know his work is superb.

[yellowbeard]

hey guys, don't understand about decking the cylinder. since my cylinder has already had a piston in it. will it need decking? one more question, My piston is trashed, but I honed the head and it seems fine ,no grooves, it is slick, can I just order a piston to fit it. 76.44mm I went to the site to order one, but it says nothing about a 76.44mm it has I think 76.00, 76.50 and 77.00 thanks for the info. Joe

[1upfront]

Yeah I know it doesn't say but he has 76.44mm wiseco pistons for them also your cylinder will only need decked if you run a wiseco because from the wrist pin up on the piston the wiseco is a few mm's shorter. You can also get stock ones but the closest size they sell is 76.50mm. Let me know if you want a stock one and I'll post a couple links.

[yellowbeard]

shouldn't my cylinder aready be decked since it had a 76.44 ? and what is decking? thanks Joe

Thanks a link would be great for the 76.50 just in case I have to bore alittle.

[1upfront]

The reason that it's .44mm bigger than stock is just a combination of wear from the .25 over piston ran previous and from honing. Until recently you were not able to get a wiseco for this setup period.
Heres a pick of the lable from my piston box.
http://i39.photobucket.com/albums/e183/lrdunlap/sticker.jpg

[yellowbeard]

1upfront, you have been a great help, have rebuilt stock bikes, but the big bore kit is new to me. Joe

[1upfront]

No problem man also here's a link for gaskets.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=004&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=140133600923&rd=1

[yellowbeard]

I just ordered head gasket, now for piston. got a question with a 76.44mm piston what kind of cc's are we talking about? went to L.A. Sleeve site looking for 76.44 did not see it, so I e-mailed them. thanks Joe

also looked at site that I got the head gasket and e-mailed them.

[yellowbeard]

watched your vid. cool and Merry Christmas

[1upfront]

The piston were talking about is actually for a stock cylinder with a bigbore 300cc sleeve installed. Just go on ebay and go to where they sell the pistons then ask the seller if he still can get the 76.44mm, I only bought mine a few weeks ago so he should still carry them.

[1upfront]

watched your vid. cool and Merry Christmas

Thanks man it will be even faster next season, oh and a Merry Christmas to you too.

[300rman]

you'll also need your cylinder decked a few mm's because the deck height is shorter on the wiseco.
http://cgi.ebay.com/ebaymotors/Honda-ATC250-atc250r-Big-Bore-Cylinder-Piston-Kit_W0QQcmdZViewItemQQcategoryZ34284QQihZ003QQitem Z130168490864

AH HA! i guess cuting my jug WAS the only option for me!