JE 13.8:1 Users?

[Honda Jay]

Anyone have them installed and running yet? I am really intereted in the turnout. . . If so, how does she run, and how do you think she'll hold up? Pretty much a pros & cons.

Jay

[lukester720]

Some of the guys on here have them and said they would post results and that was a week or two ago. Mabey it made it so fast that they wrecked and got hurt and can't reply :eek2: I sure hope not at least!

[cooper505]

can you still run 91 gas or do you have to run a higher octane?

[Honda Jay]

Originally posted by cooper505
can you still run 91 gas or do you have to run a higher octane?

Race gas my friend, looking at about 110 and be well off into the "Money is no factor" region of life!

Jay

[onebad450r]

I just finished installing mine, got it up and running but of course the weather is crappy and its dark. I don't have a headlight so I can't take it for a spin.....Hopefully tommorow I can tell you some more.......Some of the CONS are difinately going to be the price of gas, and the longitivity of the one ring on the JE 13.8:1.....PROS is hopefully going to be more power. After all, isn't that what we all are looking for more POWER




I am running the HRC cam, Sparks Pipe and filter with the HRC air box lid, FCR 40 carb and last mods is the 13.8:1 JE piston and a little of my own work on the flow bench while I had the head off....I 'll let you all know how the piston and head work turned out.

[RedRacer44]

Definitely looking at reliability issues with the 13.8:1 piston, especially with just 1 ring is that what I understand? Price of race gas will put a dent in your pocket, I run 110 in my 310R but luckily I got away from it and its just the dune quad. Race Gas here is like $4 to $5 per gallon depending where ya buy it and how ya buy it (55 gallon drum is cheaper). I think i'm just gonna go with a 12:1 hi-comp piston later this summer, hopefully more reliable.

[2004TRX450R]

It only has one ring? That sucks for longevity sake. I wonder why the heck they went and did that. Oh well mine is already on it's way.

[onebad450r]

Its got one compression ring and one oil ring verus the stock piston which had two compression rings and one oil ring. As far as why they did it, I can only guess that one ring has less friction then a two ring design and produces a faster revving engine......Oh yeh for anybody that was wandering, I think that it kicks the same or maybe a little easier with the new piston installed. One compression ring???? or maybe the decompressor????

[onebad450r]

Well I got to take it for a quick rip tonight. Bottum and midrange felt awsome compared to the stock piston. However seems like my jetting is off a little bit now (seems like its fat). My jetting was spot on before the piston and headwork. I am not sure what made the difference in the jetting. The higher compression piston??? (seems to be a conflict in opions) or the port work??? (this where my money is).....Oh well, if not one thing its ten things. I guess I back to the carb for some more jetting, OH WHAT FUN. If anybody has any opinions on what made the difference in the jetting, lets hear it.

[lukester720]

The head is flowing more now and also it could be from the higher octane fuel also. I know when you run alcohol it throws the jetting way off.

[29FTEX]

Running higher octane race gas, you will not need as big of a jet as with regular gas. Try to go down a size. My friend has the HRC 185 main on his 13.8:1 JE, and he said it may be a touch rich. He was going to try a 182 or a 180. He is running 113 octane VP Late Model Plus, Sparks air filter and exhaust, and HRC cam and air box lid.

He described the piston change the same as you, "awesome". That's all he could say at the time. Must be a good thing!:D

[BigThumper33]

Guys, do yourselfs a favor and split a drum or just get a drum for the summer.

I'm only paying like 3.50 a gallon for T114

[shamisc]

Oh damn I'm lucky. MY ********** works for ************* who delivers the Sunoco 112 to all the east coast Nextel Cup races, and unfortunately they can't get all of the fuel out of the tanker, so they have to take it to a burn-off station. Well instead of that, his boss says he can drain the remaining 28 gals of 112 into his own storage tanks. Therefore, 112 is FREE FOR ME!!!:D :cool: :blah:

[Manny55]

How much are these pistons going for. And also if you put one of these on a 450r and then raced another stock 450r which one would have the advantage. Also when i bought my full exhaust system from lrd they said the head pipe it self only gives about a horsepower or 2 but they said it really comes into to play when you do like motor mods. So would this piston be kind of what there talking about. Also do i have to do any other mods if i were to put this mod on.

[29FTEX]

www.sparksracing.com Click on the 450R tab at the top. Click on the engine section. Compression adds hp even on the stock bore. Yes, the 450R with a higher compression will beat a stock 450R. It would really help with a cam, pipe, air filter, correct jetting and fuel, porting, etc. Then you'll have you something. :D

[onebad450r]

Well I got to take it out again tonight and work on the jetting some more. I am down to a 172 main from 185, I just keep thinking that I am getting to lean. Everytime I go down one size it seems like it gets more reponsive, runs crisper and I am more impressed with the power this thing has.I have just about gave up on plug readings with race gas, it burns so clean that it always looks good. It had a slight blurber(stumble) when triing to get back on the gas when coming out of a corner after a hard acceleration. On the topend it has a miss or cuts out, it is hard to notice in 1st , 2nd, and seems a little worse in 3rd gear or higher. It seems to be getting better but if someone has a suggestion or thinks that I am going about this all wrong, give me a shout.....I never had this much trouble getting my TC 440ex jetted right.....Anybody use an Oxygen sensor for jetting? If so how does it work? Good?, Bad?-not worth the $$$$


Almost forgot.....I am at 2800' and the temp. was around low 70s

[Honda Jay]

Thanks a lot for all of the replies!

Maybe when OneBad450R gets done figuring his jetting out we can get some more good news!!! But until then I am still waiting a type of response that will tell a definite answer to how she feels compared to before the install.
Thanks again and hope to get some more

Jay

[lukester720]

You should save yourself some time and call sparks racing and see what jetting they suggest. They should at least be able to put you in the ballpark. I know when using alcohol you need to use larger jets because it runs lean on alcohol. But I have very little experence with other race gasses.

[BigThumper33]

onebad,

That cut out up top sounds like your lean. Adjust your main until you don't get that. The bog, or stumble down low coming out of a corner is your pilot or air/fuel screw. Adjust those for the down low, and your main for up top!!!

The air/fuel screw will really adjust instant throttle response, from there is your pilot for low range, then the needle for your mid range, and the full main for your top end.

[MIA450R]

Question for you guys, what will make more of a difference in power:

Yamaha bumping up to a full 450cc or Honda raising the compression of the stock piston to YFZ-levels?

[2004TRX450R]

I just got my 13:1 today. It has two compression rings on it. where is it you guys are getting the 13.8:1 pistons and how much are you paying for them?

[onebad450r]

I got mine from Sparks $209. Wish it had the 2 compression rings....Still have not got it running quit right yet, maybe today?

[Crowdog]

Originally posted by 2004TRX450R
I just got my 13:1 today.

Where can you get the 13:1 piston?

[sparky450AR]

Originally posted by onebad450r
Well I got to take it out again tonight and work on the jetting some more. I am down to a 172 main from 185, I just keep thinking that I am getting to lean. Everytime I go down one size it seems like it gets more reponsive, runs crisper and I am more impressed with the power this thing has.I have just about gave up on plug readings with race gas, it burns so clean that it always looks good. It had a slight blurber(stumble) when triing to get back on the gas when coming out of a corner after a hard acceleration. On the topend it has a miss or cuts out, it is hard to notice in 1st , 2nd, and seems a little worse in 3rd gear or higher. It seems to be getting better but if someone has a suggestion or thinks that I am going about this all wrong, give me a shout.....I never had this much trouble getting my TC 440ex jetted right.....Anybody use an Oxygen sensor for jetting? If so how does it work? Good?, Bad?-not worth the $$$$


Almost forgot.....I am at 2800' and the temp. was around low 70s

It sounds like your lean, when you say it runs worse and worse as you shift. Looking back jetting my 330, thats how it was with me. I was going leaner instead of richer and it had an awesome lowend, but no top. I went richer and it got better. The head work and piston/race gas will deffinately call for some jetting changes. You say you did some work on the flow bench. If your bike is getting more air now than it was before, you need a bigger jet.

Good luck, i know this stuff is a pain in the ***. About a year ago my dad broke his collar bone in two places while jetting a bike in the middle of a field:huh . Out of all the riding we do, it happens in the middle of a field. The grass was wet, he was power sliding and it stuck, he went flying. :mad: :grr:

[2004TRX450R]

Originally posted by Crowdog
Where can you get the 13:1 piston?

I got my 13:1 at my work. I work at a bike shop. It is from JE.

[Crowdog]

So does the 13:1 have one more ring than the 13:8? Is the stock piston 10.5:1?

What are the advantages/disadvantages of each?

Sparks is supposed to have a piston out in the next few weeks too.

[thomez]

I wonder if the high compression will lose power in the R just like it has been said to do in the YFZ when going up to 13 or above. I'd be looking for 12.5:1 or 13:1 highest, anything above and I think you will lose top end, or at least that is what the YFZ owners have shown to do.

[Crowdog]

Originally posted by thomez
I'd be looking for 12.5:1 or 13:1 highest

I'm with you there. I'd like to keep it under 13:1 too. That's why I am asking.

[onebad450r]

Well I think that thomez hit the nail on the head. After installing the 13.8:1 JE piston I had an awsome midrange and a pretty good bottum, but the top end had much to be desired. It just didn't seem like it was the same engine that wanted more R's. I thought that it was in the jetting, after 4 days of jetting and every posiible combination I gave up on it....... I have only ported a dozen or so atv heads on the flow bench (Super Flow 600) and have always gotten great results in the past. I have ran some of my heads/engines up against some big name engine builder on the flow bench and on the track and I came up with the conclusion that not all engine builders give you the same attention that they give there sponsered riders or the bigger names in racing. OH WELL, The thought that I might of messed up a good thing was still in the back of my head.....to see if it was in my porting or the compression of the piston, last night I tore the engine down, put the stock piston back in and now it screams. It does not have quite as good of a bottum, but the midrange is still awsome and top is super strong. Looks like I just wasted $209. Maybe I'll try something around the 12:1..... I am not triing to bash this piston, its just not what I like for my particular riding style. I was hoping that it was goiing to have the same top end with a great bottum. I guess that you can't have the cake and eat it to.

[thomez]

What is that saying, those that do not learn from the past are doomed to repeat it? LOL

That is just what I have read from the YFZ guys that have went to 13 or above - no top end - and most of them pulled them back out. Looks like the R is the same. Some decent porting and maybe a small jump in compression is all that they have to gain, unless you go to an alternative fuel such as methanol.

If I were you guys I would be looking at 13 max but probably 12.5 or lower is optimal. Good port job, an FCR, and a cam, and you have just about maxed this motor out. At least that is what it seems so far from my reading experience. Same goes for the YFZ.

[2004TRX450R]

I think a lot of this is due to mismatched parts. I know if you run a big cam with a low comp piston you will not get great results. You have to have everything tuned for the same thing. If you have a cam for bottom end and a pipe for top end they will not work well together. The same is probably holding true here. Now that tow people have said it online it is going to be gospel because everyone else will jump on the band wagon. I see that happen time and time again.

There is a lot more to porting a head that flow. You can open a head up and make it flow a ton of air but it won't perform well because the velocity of the air through the port is now to slow. So it doesn't atomize the air/fuel as well and it doesn't fill the cylender as well either.

What kind of fuel is being run with the higher comp pistons? I hope anyone with a 13:1 or more is running race fuel. I'll see how mine runs with the 13:1 hopefully next weekend. I would have had it together today but I can't seem to find my head gasket so I'll order another one and get it together this week.

[onebad450r]

I was running Turbo BLUE "EXTREME", now I am back to good old fashion super

[29FTEX]

Originally posted by onebad450r
Well I think that thomez hit the nail on the head. After installing the 13.8:1 JE piston I had an awsome midrange and a pretty good bottum, but the top end had much to be desired. It just didn't seem like it was the same engine that wanted more R's. I thought that it was in the jetting, after 4 days of jetting and every posiible combination I gave up on it....... I have only ported a dozen or so atv heads on the flow bench (Super Flow 600) and have always gotten great results in the past. I have ran some of my heads/engines up against some big name engine builder on the flow bench and on the track and I came up with the conclusion that not all engine builders give you the same attention that they give there sponsered riders or the bigger names in racing. OH WELL, The thought that I might of messed up a good thing was still in the back of my head.....to see if it was in my porting or the compression of the piston, last night I tore the engine down, put the stock piston back in and now it screams. It does not have quite as good of a bottum, but the midrange is still awsome and top is super strong. Looks like I just wasted $209. Maybe I'll try something around the 12:1..... I am not triing to bash this piston, its just not what I like for my particular riding style. I was hoping that it was goiing to have the same top end with a great bottum. I guess that you can't have the cake and eat it to.


I was wondering about the loss of power with the 13.8:1 piston on top end. What did you measure this by? Racing against someone? Seat of the pants feeling of power loss? I'm just curious. If the higher compression adds so much more bottom/mid range, and the top end is not affected as much, it may be misleading. I would like to know if it is acutally losing power, or just feels that way before I do this to my bike. Any help is appreciated.

[onebad450r]

I don't think that its mismatched parts but then again I don't know everything and I am always learning something new everyday. My setup was a HRC cam, JE 13.8:1 piston, Sparks Pipe/Filter,and FCR 40MM, and some port work...... As far as the top end power loss, It was all seat of the pants and against my YFZ450 and another YFZ450 on the track and dragging to confirm what I thought I was feeling. Me and my brother-in-law kept switching back and forth between the bikes. He felt the same as I did, top end loss. Before you think that I am a YFZ450 rider triing to start a flame with the honda guys. I am a Honda guy, I got the YFZ before the release of the Honda 450R, I felt that I couldn't keep up on my trusty 440ex. I got the first 450r from my local dealer and had money on it last september. I am still running the YFZ and probally will continue with it the rest of the season. Look out next year because I will be riding RED again, after I get it the way I want it..... Just because I didn't like it does not mean that you won't.