High Comp Piston, Big Cams and Dyna Ign???

[RagingMain]

Hey guys, I have a 1300 conv by Sean. We have the ported heads, 12:1 pistons with stage 3 cams. Thing already runs like a raped ape, but I miss the advance I had with my Dyna.
I dont thrash the bike, just use it as my daily driver.

So do you all think it would be safe to put the Dyna back in???:ummm:
Cheers

 

[naughtyG]

As long as you're not running COPs..

 

[RagingMain]

I am running COPs. If it isnt going to hurt anything, might have to go up a grade or two in the octane, but if it is ok then I will try to put on the resistors I was talking about awhile back and see how that works with the COPs.

 

[naughtyG]

It's just that we've had history of Dyna 3000s blowing up due to the higher current COPs take because of their lower resistance. Are you willing to risk your D3k? I'd say you'd be safer going back to original coils with the Dyna.

 

[Birdoprey]

Fargo,

If you are willing to risk one more Dyna, i'd try the COP's and the resistors. It would let us know if it will work or not. No one has tried it. Risking $$$ though. Might also negate some of the benifits of the COP's(spark wise), but would be at least as good as the stockers i'd bet. My favorite part of the COPs is their being small/light/neat&Tidy. Also give the bike a cool, up to date look IMO. If i were not going the route i am(programmable ignition/injection), i'd be trying the dyna and cops(with resistors).

 

[RagingMain]

Fargo,

If you are willing to risk one more Dyna, i'd try the COP's and the resistors. It would let us know if it will work or not. No one has tried it. Risking $$$ though. Might also negate some of the benifits of the COP's(spark wise), but would be at least as good as the stockers i'd bet. My favorite part of the COPs is their being small/light/neat&Tidy. Also give the bike a cool, up to date look IMO. If i were not going the route i am(programmable ignition/injection), i'd be trying the dyna and cops(with resistors).

The dyna right now is under warranty so frying it is not a big deal. Just need to make sure they have more in stock before I try this.
Guess I will try the Dyna with the resistors and COPs, if this works then at least some of those with COPs that want to run an Dyna might have the ability.

But I am not necessarily concerned about the Dyna or the COPs. What I am worried about is the advance curve with all the other high performance stuff on the bike, so Mark you or Sean would be probably the most qualified to answer the original question.
Will running the advance curve with the ported heads, high comp pistons and big cams have any adverse effects on the engine???

 

[one2dmax]

You can run as much advance as the engine will stand without detonation. I don't think they have any 3000's left on hand.

Sean

 

[RagingMain]

You can run as much advance as the engine will stand without detonation. I don't think they have any 3000's left on hand.

Sean

Thanks for the info Sean and you are right. They dont even have any warranty 3000s left plus they dont make that model anymore.
Guess I will just wait for Mark to finish his EFI :biglaugh::biglaugh::biglaugh:
Cheers

 

[rhoke]

Just to let you know, I do have 12:1 and ported heads minus the big cams and COP's I run dyna miniature series coils with d3k and have run most advance but it did have some ping bout 7k rpm under load with pump gas, i run sonoco 116 and track with no problems. Set to curve 2/3 with 91 or better on street with no problems. Sorry, but that dont really help with the COP's thou. Roy

 

[rhoke]

Ok, my question to you or Sean. Do the cams make that much difference with the setup, Hi-comp and porting??

 

[one2dmax]

In my opionion the cams really open up the breathing if the head is ready. Let Fargo tell the story. His numbers didn't change much but I am sure he can feel the difference.

Sean

 

[Birdoprey]

Fargo,

Did you run the dyna(with advance curves over stk) with the stk cams? Did you have stk cams with the higher compression? Adding performance cams normally lowers cyl pressure. If the added advance worked ok with stk cams, then you should be in really good shape adding cams(to the same motor configuration). You can also change your cam #'s(adjustable cam sprockets needed) to bleed off a little more cyl pressure. Usually higher #'s do this and also add hp up top(looses some down low though).

 

[rhoke]

Well, the cams mechanically have not been advanced(adjustable sprockets). If you mean by changing the advance i.e. the dyna 3000 curves yes I went with the highest advance, by thought either 5 or 6. I have compression tested the bike several times with several different testers and come out with +/- 5-10psi at around 200psi or 14:1. <-----Yes that is why I used different brands. I thought it was way to high for 12:1 pistons. I dont know? You say it will drop the cyl pressure do you mean compression? I cant wait for my compressor back from Tom at Cycle one off to see the difference with the even compression and even shifting 1/4 mile. I do plan on the cams just waiting for the funds. thanks Roy

 

[Birdoprey]

200 psi sounds a little low for 12:1. I built a 1277cc Bandit motor with a right at 12:1, cranking psi was 215-220ish IIRC. I've run 235-240psi(which was around 13:1) and was able to run it on pump gas. Had to run higher #'s on the cams as well as run a lower initial ignition advance(200rwhp 1340cc oil cooled Bandit 1200 motor). Of course, the cams will have some say as to the cranking psi, as will the method used to obtain the cranking psi(throttle closed or wide open, all plugs in or removed from cyls, warm or cold motor, valve and seat condition, etc.)
Yes, if you add cams with longer duration your cyl pressure(effective compression) will go down(not by leaps and bounds though). Back in the day, this was the reason for the compression jump on race motors. When they installed bigger cams, which worked well at high rpms, then their compression went down and so did their low end response(some due to the cams, some due to the lower cyl pressuer). There are ALOT of factors involved with it, but thats kinda the jist.
You can adjust the cam #'s with adjustable gears and help get by with pump gas, or help get by with ignition thats advance just a tad too much.

 

[rhoke]

Ok for the compression rating it is just a reference on my compression gauge pictured below. I dont know if 200psi is right or not just say what is showed. You probably know more that I do by tons. I check it throttle closed, cold, plugs out. I dont know how to check to get more accurate. I do know that before adjusting the valves for the first time after rebuild it was down to approx 150psi and it made a huge difference. Advice is more than welcome. I just learn as I go. Thanks Roy

 

[maleko89]

Roy, engine should be up to normal operating temperature when checking compression.

 

[rhoke]

Okay, I will get her nice n warm tom. and check it again. I didnt know that. Thanks, Roy

 

[Birdoprey]

Also you need to open the throttle wide open while cranking the motor over. With CV carbs, it would be preferable to open the slides or just yank the caps off and pull the slides out for the test. The more air that enters the chamber, the more psi you'll have. With the throttle closed and/or the slides closed, it severely restricts the air that should enter the chamber.

 

[Birdoprey]

Ok for the compression rating it is just a reference on my compression gauge pictured below. I dont know if 200psi is right or not just say what is showed. You probably know more that I do by tons. I check it throttle closed, cold, plugs out. I dont know how to check to get more accurate. I do know that before adjusting the valves for the first time after rebuild it was down to approx 150psi and it made a huge difference. Advice is more than welcome. I just learn as I go. Thanks Roy

Please don't take me as arguing. Was'nt doing that in the least. Just stating that from what i've seen, 200psi does not coenside with 12:1 compression. Once you get the motor up to temp, and open the throttle and slides, you may verywell see 210-225ish, which is where i would expect it. Maybe not, but you might be suprised.

 

[RagingMain]

In my opionion the cams really open up the breathing if the head is ready. Let Fargo tell the story. His numbers didn't change much but I am sure he can feel the difference.

Sean

My numbers didnt change cause I dont have the proper jetting yet or at least havent tested since I have put in what I think to be the proper jetting. My numbers were pretty much the same when my engine was very rich with the bigger cams which leads me to believe it will be better/stronger when I get the A/F mix right.

It definately makes the bike stronger. Even my GF said the bike felt stronger when I played the WOT song with her on the back :biglaugh:

I will go get it on the dyno again and see where it is at