HJR dune port domes

[Darthwall]

I want to go back to pump gas just cause as much as I like to ride race gas is to much $ . its a 4mil at 64.50 im at around 800-1100 ft but do go down to the oregon dunes once or twice a year so what domes should I get any help would be great

Edited July 23, 2010 by Darthwall

[hercalmighty]

I'm running a set of 23cc domes Kevin sent me. I'm about sea level and have 160psi with a HJR dune port. I'm running 93 octane and have no problems at all. To be honest, I actually like the 23cc domes on 93 better then the 21cc domes on 110.

[TeamRealtreeHD]

I'm running a set of 23cc domes Kevin sent me. I'm about sea level and have 160psi with a HJR dune port. I'm running 93 octane and have no problems at all. To be honest, I actually like the 23cc domes on 93 better then the 21cc domes on 110.

 

I am running 23's too. However, I am mixing to be safe. I've thought many a time to run pump. Trust me. I know I can. Kevin says be safe though, so that's what I'm doing.

 

I'm not too far from you. I'm getting 160 PSI too. .020" base gasket.

 

Timing plays a a key role here. 23cc domes is border with pump IMO on many setups out there if you run high advanced timing.

 

I wouldn't go above +4 timing with 23cc domes personally on pump. But that's just me. And I know nothing. I'm a safe cat though. I do know that.

Edited July 23, 2010 by TeamRealtreeHD

[hercalmighty]

Tony, your bike runs freaking great man so whatever your doing keep to it.

 

Im actually running +6 timing on my 4mil HJR dune port. I think mine runs pretty good for a stock cylinder bike. I haven't had any issues with my setup and have been riding it for well over a year now.

 

But like Tony said, play it safe and stick to +4 until you can really test it out. If I was building a bike for someone else I would stay to the safe side, but my own bike I'll go a little more.

[Darthwall]

good thing I posted this I was just going to order 21cc domes so I take it at my elevation with a 23 it should put me around 150-155 and at the coast just mix alil 110 in and be good

[hercalmighty]

Yeah, with the mix you should be good at lower elevation.

What size domes do you have now? And what's your cranking compression?

[TeamRealtreeHD]

Tony, your bike runs freaking great man so whatever your doing keep to it.

 

Im actually running +6 timing on my 4mil HJR dune port. I think mine runs pretty good for a stock cylinder bike. I haven't had any issues with my setup and have been riding it for well over a year now.

 

But like Tony said, play it safe and stick to +4 until you can really test it out. If I was building a bike for someone else I would stay to the safe side, but my own bike I'll go a little more.

 

Thanks

 

I tried everything from +4 to +7 on my setup, at 1/2 increments (as best as the human eye can see atleast) and for some reason, it runs best at +4. It seems to go against the science of 4mil cubs as they like fuel and timing. Mine likes fuel, but likes less timing. However, I am also doing something alot of guys don't do with cubs on this site. I hillclimb it up walls. Most guys running cubs run them straight line track or dune.

 

All of this may change after Kevin drag ports the cylinders. I currently have a cleanup. We will see I suppose.

 

Most guys running the hills here are using Powervalved cylinders. So the ball game changes there.

 

One thing still sticks though in this philosophy. Every setup is different, and as you said, better to play it safe than eat a top end or worse because of playing with fire.

 

I think the original poster here would be fine with 23cc domes and no more than +4 timing. I am at 1300 feet ASL. I know I can get away with pump on +4 but have yet to grow the nads to try it.

 

I do know alot of guys running 23cc domes with the same compression numbers running pump.

 

Funny thing about pump gas... you go to a gas pump. They have 1 pump and tube for the station. You press the 92/93 button. How long does it take to actually get 92/93 fuel?

 

I target non-ethanol stations with 3 separate pumps. One for regular, one for mid grade and one for premium. Even though I mix it with race fuel, I know I'm getting 92/93. And not 1-2 gallons of 87 before the premium starts coming out.

 

Just something to think about.

[TeamRealtreeHD]

good thing I posted this I was just going to order 21cc domes so I take it at my elevation with a 23 it should put me around 150-155 and at the coast just mix alil 110 in and be good

 

If it was me, 1-2 gallons of a little race fuel in that 5 gallon mix will have you more than safely covered. I do 2.5 and 2.5... 50/50. I can't stand it. Hurts the wallet. But better be safe than sorry. 23 cc domes with a gallon or 2 of race fuel in the 5 gallon mix will be more than safe.

[Darthwall]

Yeah, with the mix you should be good at lower elevation.

What size domes do you have now? And what's your cranking compression?

 

right now the topend is on a ups truck coming this way so I dont have any #s as to what anything was the head I have has 19cc domes in it now I just dont want to spend that kinda cash and the way it sounds is I would be running like 200 psi with 19s