Thinking of change

[nmainehunter]

I'm thinking of doing some changes on my 95 FX springer for a good winter project. I have it setup with a Dyna 2000P, 10.1 Wiscos, EV27, 42 Mikuni and a set of Bassani's that I modified with some Supertrapp discs on a stock bore. It runs good and strong but I don't think I have a good balance. I'm thinking it may be the cam - piston combo. I found that the I had different issues after the piston change, particularly with detonation. The EV27 has been in my last couple of bikes which I have no complaints with. I tried the EV46 but didn't really care for it. I found it's range didn't suit my back road riding style well. Opinions....
   

[Deye76]

Opinions are like.......well you know.
If the pistons/bore are healthy, at that compression, I'd have some headwork, throw in a S&S .561, you have a good pipe, use all 5 gears, and run the snot out of it.

[JW113]

Before making any changes, can you better describe what the issue is with your current setup? What you like, what you don't like, and what it is that you are after?

What does "backroad riding style" mean?

-JW

[kd]

 

[nmainehunter]

Thanks, I love my bike. I've been running the 27 cam in my last couple of bikes, I added the pistons a couple of years ago and I'm not so sure it was the best move. I get more spark knock than I ever had. I find I have to downshift or run in forth more than I like.

Backroad riding is simply riding the 45-50 posted limit roads which aren't in very good shape. I generally run them around 60-65 if I can get away with it. I like getting on the pike where I can run her up to 80 where she really runs good.

So what I've been thinking about is dropping down to a 23 or 31 cam but I'm thinking the the pistons will have to come out also.

[Deye76]

Lots of good cams, I suggested the .561 (with some headwork) because it was designed for 10:1 cr., the cam offered in the S&S Hot Set Up. I had that kit in a FXR, ran very well. Not trying to convince you to go that way, just my thinking/experience with it. Hope you find an enjoyable combination.

[nmainehunter]

Deye76, Thanks but I really don't want to go in that direction. I kinda did that with the 46 cam. It's not that it doesn't run good, it's just moves the sweet spot higher up the rev range and out of my comfort zone. I'm trying to get info on the combo of the 23 or 31 cam with the 10.1 pistons. If it will simply be a timing tweek or voes adjustment I will try the 23.

I think the answer is probably in the fact that I can't find any performance info dealing with mild cams and compression bumps.

[RTMike]

The reason you can't find any info on the mild cams and compression is they were designed as a drop in cam.With the competition you have I would do the heads a put a Comp 3030 cam in it.Good smooth power.

[JW113]

Well everyone has their opinions of just about everything, so here is mine.
 

You sound like a mellow dude that just wants to go out for mellow rides and enjoy the bike and scenery. And to a great extent, I'm right there with you. No more hot rod motors for me. I've "switched gears" and now prefer the low/mid rpm high torque kind of power. High HP means High RPM, which more or less translates to lots of cam lobe timing, lots of compression ratio, and heads that flow lots of air. So logically, low RPM torque is just the inverse of all that.

Enough lecture, opinion time. If it we me, I'd pull the pistons and replace them with stock. Boom. Done. Well maybe not done-done, I'd likely pop a EV-13 in as well...

cheers,
JW

[nmainehunter]

JW113, your reading my mind. Just this morn I went and dug the 13 out and made my decision as you suggest. I'll get the 10 to 1's out and put the EV-13 in. I had it in a Bagger and took it out when I sold it. I got looking at the numbers and it's not that far from the EV-27 and it looks like it is just a bit milder which will still have some grunt to pass a truck and also cruise down through town.

[JW113]

I don't think you will regret that plan.



Just my opinion, of course!



cheers,
JW

[hbkeith]

took me a while to adjust the Dyna ignition to get rid of my pinging , play with it first

[Deye76]

Glad you have a plan and hope it works for you. IME compression isn't everything. For me the magic is in the heads. In my 113" TC a few years back I decided to lower the compression, at the same time I had Dorfman do the heads. Gained power, even with a cam that the expert guru at the time, said wouldn't work. Enjoy.

[JW113]

Deye, I agree with you about that, at least with regards to big inch motors. When you have a cam with lots of intake duration, you lose some torque in the lower rpms due to not enough air velocity while the intake is open after BDC to hold the air in the cylinder against the rising piston. Higher compression ratio makes up for that a bit. However, with a big cube motor, you already have a pile of torque at low rpm, so loosing a little due to a healthy cam is kind of in the noise. I tend to think that it's the smaller cube motors that benefit more from higher compression with a hot rod cam, unless we're talking race motors, which I no nothing about other than you build for every last drop of HP you can get...

-JW

[Deye76]

JW, 

I don't consider 10:1 high compression per se, but don't like CCC up around 200psi for a cruiser. Then one needs to be proficient at tuning and may need CR's in the heads et. etc.

[JW113]

Agree, 10:1 is not in the stratosphere, but probably a bit more than that EV-27 wants to see. I'd reckon 9.25 or so would make it happier, which is about what you get by cutting the heads by .050". The Evo D shaped combustion chamber will be a bit more sensitive to C/R (i.e. static cylinder pressure) than the Double-D or other high swirl type chambers. Also, I believe 10:1 pistons with the stock heads mean crowned tops, yes? So even more prone to detonation. But from the sound of it, mainehunter is after nice, easy to care for cruiser motor, and 8.5:1 and a mild cam works perfect for that.

-JW

[nmainehunter]

I put the 10.1's in with the EV-46 cam and I knew real quick that it wasn't what I wanted. I was hoping that the EV-27
would work but it didn't like those pistons. Your right though JW, I'm just looking for something a little more mello. I also believe that where I'm trying to get my engine to, makes tuning it much easier as well as getting a better tune. 

[Finn]

If I recall correctly Andrews informed me few years ago that they recommend:
- 9.2:1 for EV13
- 9.5:1 for EV27

For my earlier Evo with EV13 we used 9.0:1 and the engine was very happy and there was no pinging with Dyna 2000i.

With current Evo - again EV13 - we will be targeting same compression ratio.

[nmainehunter]

Thanks Finn, I loaded her up with the EV-13 and the stock pistons also using the 2000 Dyna ignition. I'm anxious for spring.