Is this true about wiscon pistions?

[ranger400ex1994]

i am ording my 416 pistion in a few days that i want to be able to run on pump gas so i was either going to go with 11:1 or 10:8. but i have heard that if i would order a wisco 10:8 compression pistion that it would not be the compression that i ordered it would be alot less. is this true? should i looking into JE pistions? i heard that if i would order a 11:1 wisco pistion it would really be 10:8 anytruth to this?

[hondarider2006]

I have never heard that about wisco, but I have heard that JE is better than wisco. I have never used eaither of the products, I am just passing on what I have read;)

[K_Fulk]

I'm pretty sure the problem is the pistons are designed for the xr 400, the xr's use thinner gaskets and the ex gaskets are a little thicker, you can use the thin gaskets or deck your cyliner but then you run into the problem of retarding your cam timing and loosing some power beacuse of that. You could get an adjustable cam sprocket and degree in your cam and fix that problem though.

But more then likely your not going to notice loosing .2 to 1 of your compression.

[hondarider2006]

Originally posted by K_Fulk
I'm pretty sure the problem is the pistons are designed for the xr 400, the xr's use thinner gaskets and the ex gaskets are a little thicker, you can use the thin gaskets or deck your cyliner but then you run into the problem of retarding your cam timing and loosing some power beacuse of that. You could get an adjustable cam sprocket and degree in your cam and fix that problem though.

But more then likely your not going to notice loosing .2 to 1 of your compression.

so wouldn't it just be easier to go with a JE high compression piston?

[K_Fulk]

Yeah but there more expensize. the .2 or .3 compression your going to lose isnt that big of a deal and if your running 11:1 it will make it a little safer to use pump gas.

[cals400ex]

i think there was only $10 difference in the wiseco and je when i ordered my piston. i would get the je myself.

[K_Fulk]

There was about a 50 dollar diffrence when i ordered mine maybe the 13:1 piston isn't madae as much or I got hosed beacuse I didn't do my homework on pricing.

[whatwasthat]

The ratio problems only occur on the 89 and 89.5 mm pistons (435 and 440) all the other piston sizes are fine

[cals400ex]

Originally posted by whatwasthat
The ratio problems only occur on the 89 and 89.5 mm pistons (435 and 440) all the other piston sizes are fine


are you sure about that? i dont see why they would use the xr ratios on just those two pistons.

[whatwasthat]

thats what i was told a while ago..cant remember when or who...take it for what it is

[Dave400ex]

Call up C&D and get the JE 416 piston. Well worth it!

[xc400ex]

Buy a wiseco 11:1 and a JE 11:1 and i garuntee the wiseco will run on 87 while the JE will require 50/50 blend of 93 and race fuel...the wiseco's are off more than .2 or .3

[416mx]

I asked Colby at C&D what the difference was and he told me the JE will last longer , it will have more pull out of the corners and have a true comp ratio. Only $10 more than a wiesco. I bought a 11:1 comp piston and he said 50/50 mix would be fine( race gas and prem):blah: :blah: :blah:

[shamisc]

See the funny thing is, Wiseco and JE are one company now. So I don't really think one will last longer than the other. They say the JE is a tad bid lighter. But who knows? I have the wiseco myself, but it's a 440 and like someone said earlier the ratios are different. I got mine from Mickey D and he has a true 11:1 custom made for him by Wiseco that takes care of the deck height prob. plus it's been lightened and heat treated.:D But, I have run 94 with no detonation. I just run straight 110 now!

[atvmxr]

The problem with a stated compression ratio is that it is based upon a fixed head/cylinder combo, but with varying bores. The compression ratio is base upon the volume at BDC over TDC. When you increase the bore the volume at BDC increases but the volume at TDC remains the same. In other words as you increase the bore then the compression ratio increases. So at .080 over a piston might be 11.1 but at .020 over the compression ratio is only 10.8. These numbers arent exact, just an example. Usually when Wiseco, JE or whoever offers a piston with a certain compression ratio, their claimed compression ratio is based on a specific bore.
2 cents

[shamisc]

Good info !;)

[Colby@C&DRacing]

As I have said many times. Wiseco and JE are owned by the same large financial entity. But they have no productions ties and operate completely independed of each other. The comp ratio question was at one time completely true the wiseco pistons for the 400ex were not correct but wiseco has supposedly fixed the problem. They know offer a differentt part number for the 400ex. I will still alway use a JE or Ross piston in the 400ex before a wiseco.

[300exthumperluv]

You have to be able to spell *Wiseco* before you can order one lol. You went from *wiscon* to *wisco* in your same first post. Anyway, its a quality piston.

[Dave400ex]

It's good that Wiseco supposedly fixed the problem. Lets hope it really is fixed. I can't wait to get my 416 put together.

[400exdad]

Go read this forum. http://www.exriders.com/vbb/showthread.php?s=&threadid=48435
Probably one of the best ones on here. It explains how the compression is calculated and why the lower comps. Mickey D pretty much says the same thing in one of his "Ask Mickey" forums.

[Dunlap]

Originally posted by Colby@C&DRacing
As I have said many times. Wiseco and JE are owned by the same large financial entity. But they have no productions ties and operate completely independed of each other. The comp ratio question was at one time completely true the wiseco pistons for the 400ex were not correct but wiseco has supposedly fixed the problem. They know offer a differentt part number for the 400ex. I will still alway use a JE or Ross piston in the 400ex before a wiseco.

None of the piston are what they say they are comp. ratio wise. As of 2 min. ago there is no Diff. in a xr or ex piston from Wiseco. Both companys run the same Wiseco rings and clips. As far as lasting any longer I have not seen any diff. here. If one motor starts to smoke sooner then the other what diff. would the piston make? The rings are what go first and they are the same.

[Quadzilla]

What about Ross, do you like them? I assume their rings/clips are different (not Wisco)? I also like that they offer a light weight pin (made of different material, but still as strong if not stronger according to them). It lightens the overall piston weight considerably.

[Dunlap]

Have never seen a Ross so I cant say, do they have the same deck as a stocker?

[Quadzilla]

Dunno, but their is a lot of good info on their site. I also spoke with guy in charge of their motorcycle pistons. He came from JE and he said that in a nutshell, they took the JE design and improved it.... He was a great guy to talk to and was WAY over my head techincally. He wanted to talk forever. Check their site or give em a call. From what I hear, they make great (maybe the best?) motorcycle pistons....

http://www.rosspistons.com/moto_stock.php

[dirtmomma]

someone probably already said this but Wiseco sells high dome piston does that make a difference?? I ALSO heard Wiseco is doing them better now, just put a 75.5mm high dome in mine & it's all good!!:D :D

[northeast400]

I just got my wiscon piston for my motor builder. I put it next to my buddys JE piston and there is no difference in size or dome. (I used a micromiter

[Dunlap]

The Ross has the same deck as all the rest of them. The deck is 0.30 + lower then they should be for good squish and that is very important for running cool, building power and keeping detonation problems down. The domes are all about the same.

[cals400ex]

Originally posted by Mickey Dunlap
The Ross has the same deck as all the rest of them. The deck is 0.30 + lower then they should be for good squish and that is very important for running cool, building power and keeping detonation problems down. The domes are all about the same.


is there anything you can do about the squish area? so you are saying that a ross piston is not the stated compression on an ex either, but just the xr? how much off approximately should it be or is it tough to tell?

[pnut420]

Originally posted by Mickey Dunlap
The Ross has the same deck as all the rest of them. The deck is 0.30 + lower then they should be for good squish and that is very important for running cool, building power and keeping detonation problems down. The domes are all about the same.

So the only way to solve that would be to get a custom made piston or do a stroker motor. Would shaving down the head down help it sit a little closer or would is that not a good thing to do, also if you run the cometic gasket it should make it closer to its true compression.

[dirtmomma]

Originally posted by pnut420
So the only way to solve that would be to get a custom made piston or do a stroker motor. Would shaving down the head down help it sit a little closer or would is that not a good thing to do, also if you run the cometic gasket it should make it closer to its true compression.

Ok well I may be sticking my foot in my mouth but we shaved the head on our 2 stroke(don't kow if it's the same as 4) & just had to get a thicker gasket seems to be all good!!

[Dunlap]

Originally posted by pnut420
So the only way to solve that would be to get a custom made piston or do a stroker motor. Would shaving down the head down help it sit a little closer or would is that not a good thing to do, also if you run the cometic gasket it should make it closer to its true compression.

The best way is to make the piston the right way in the first place which I do with my 440 kit. If you you want I will take and have them made for a 416 size. Otherwise take the base gasket off and use one piece 0f the head gasket to get your decks right. If you need to know more on this you can call me.

[wilkin250r]

Originally posted by Mickey Dunlap
The best way is to make the piston the right way in the first place which I do with my 440 kit. If you you want I will take and have them made for a 416 size. Otherwise take the base gasket off and use one piece 0f the head gasket to get your decks right. If you need to know more on this you can call me.


:grr: :mad: :cuss:

Why don't they correct the problem? I'd like your opinion on this.

Are the compression ratios and deck height correct for the XR400? Are we not buying enough pistons for them to bother tooling up the correct deck height and specify the correct compression ratio?

Am I missing something? Isn't the squish area really important? Why are all these manufacturers neglecting this? Is it supply and demand, are we just not demanding enough, or is it really not as important as I have been led to believe?

[pnut420]

Originally posted by wilkin250r
:grr: :mad: :cuss:

Why don't they correct the problem? I'd like your opinion on this.

Are the compression ratios and deck height correct for the XR400? Are we not buying enough pistons for them to bother tooling up the correct deck height and specify the correct compression ratio?

Am I missing something? Isn't the squish area really important? Why are all these manufacturers neglecting this? Is it supply and demand, are we just not demanding enough, or is it really not as important as I have been led to believe?

Im sure its not going to kill the engine cause alot of people have got at least 2 years out of their 416's and 440's, but the more the cylinder thats been filled up the more power you are getting that is what Im concerned about.

Mickey could you have a custom piston made for a 426 bore and at 13:1 compression, if so PM me a rough price on that and I will be giving you a call for sure.

[wilkin250r]

Originally posted by pnut420
Im sure its not going to kill the engine cause alot of people have got at least 2 years out of their 416's and 440's

You're right, I'm sure it won't kill the engine, but what is the point of buying a high-performance piston that doesn't measure up?

[pnut420]

Originally posted by wilkin250r
You're right, I'm sure it won't kill the engine, but what is the point of buying a high-performance piston that doesn't measure up?

True to a certain degree but mine really likes to run on 100 or better as it is so Im happy with it, but I agree you should get what they advertise. Im going to be giving Mickey a call even if it costs $60 more its worth it to me

[wilkin250r]

Originally posted by Mickey Dunlap
The best way is to make the piston the right way in the first place which I do with my 440 kit. If you you want I will take and have them made for a 416 size.

This might not be a bad idea. Custom pistons can be expensive, and almost always have minumum order quantities, but this seems like it has a simple solution. It doesn't seem like it should be too difficult to get the same deck, just move the pin down .030, right?

I know that it usually doesn't make good business sense to partner up with your competition, but possibly between you and C&D Racing, along with maybe a few others, you can order enough quantity of the custom pistons to drive the price down to nearly the same as the regular pistons, if indeed all it requires is moving the pin.

[remlapr]

So let's just generalize that they are off by .4 across the board and you want to run 10.8:1, isn't the solution to just buy a 11.2:1 and it will actually end up being 10.8:1?? Or is that over simplifying it too much?

[wilkin250r]

Originally posted by remlapr
So let's just generalize that they are off by .4 across the board and you want to run 10.8:1, isn't the solution to just buy a 11.2:1 and it will actually end up being 10.8:1?? Or is that over simplifying it too much?

It's a bit of an oversimplification. Yeah, by doing something similar to that, you can come up with a desired compression ratio, but the compression ratio isn't everything. For example, by properly setting up the squish band, it could mean the difference between being able to run pump gas, or needing race gas. It could also make the difference between your engine overheating or not.

There are more things going on inside the cylinder beyond a simple compression ratio.

[pnut420]

Originally posted by wilkin250r
It's a bit of an oversimplification. Yeah, by doing something similar to that, you can come up with a desired compression ratio, but the compression ratio isn't everything. For example, by properly setting up the squish band, it could mean the difference between being able to run pump gas, or needing race gas. It could also make the difference between your engine overheating or not.

There are more things going on inside the cylinder beyond a simple compression ratio.

This thread has been cool to read and make some imput, by getting the right squash it makes sense that it should run cooler, I had a stroker motor in my old truck and it actually ran cooler than the 350 did, plus the less struggling the motor does the less heat that will be their.