BBP wrote:
H2B780......thank you !........I have looked at the K2tec pipes a few times, the non cross are about $700 and the cross over type in SS are something like $1800 I beleive........I think I heard they are a mid range street type HP pipe.....that is kind of what I am going for on my bike........Fast By Gast has a new pipe on their website, it is quite a bit fatter and sharper cone angles, also looks shorter than my earlier FBG pipes.........problem is, they are uglier than sin
.........somebody tried them and said they really produced good tourque and were a big improvement of the early ones. My bike comes on about 5500 RPM, it's like you flipped a switch.......pulls strong to around 7000 or more.......must be the pipes
Jorgen......thank you for the education and tuning secrets
That makes a lot of sense.......squish heads=faster combustion, therefore expansion follows sooner; Compensate by Retard Ignition to start sequence later=More Heat to pipes, therefore better and faster pressure wave.......Retard at higher RPM's
Also makes good sense.......Low speed (3000 to 4500 rpm guessing).........advance timing on purpose=early combustion, then expansion completes, weaker pulse wave to pipes which are out of phase at this lower RPM=less pushing of gasses back into cranckase from transfer port.
Very Very interesting
So then, until I get a Zeel installed and set up this summer........with squish heads and my setup.......retard Ignition from 23 degrees to ?.....something like 21 now (guessing)........and yes I know, this all depends on RPM, driving, etc
What do you mean by Parallel ?........Parallel to the piston dome shape such as Wossner is 13 degrees.........is there a benifit to dual squish bands at different angles ?.......I have read that more squish band is used 70% in a hotrod motor......40% to 50% in a street motor
Do you run leaded race gas in that 109 hp bike ?
I have read some of your posts and seen Dyno info......good stuff.....you use spacers on some of your cylinders I beleive to jack them up and increase duration....and cut piston skirt
I hope I am not wearing you out with questions, it is great to understand some of this.....reading Gordon Jennings can be hard to understand to a degree......and most tuners just won't comment (other than the triple guys
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THX Phil
Hi Phil.
If you buy a Zeel, they (Borat) provide a basic ignition set up for H2. Use that as a start. I think that is logic since you do not have raised transfers nor raised exhaust.
That means, you probably do not have much of an torque dip (flat spot) at all. BUT, you may still try, let's say, 27 degrees advance from midrange (3500 rpm) to powerband starts. (guess you're on pipe from 5000 rpm?
You MUST retard a lot before max torque rpm is reached, if not you may damage your motor. To be on the safe side, set the ignition to 23 degrees from the point you are on your pipe. And this is IMPORTANT: DO NOT TRUST YOUR TACH!!!! YOUR TACH MAY TELL YOU 5500 RPM WHEN HITTING POWERBAND, WHILE YOU REALLY HAVE 5000 RPM. I strongly advice you running a dynorun prior to any adjustments, then you see from both hp curve and torque curve what rpm's you have all time.
THEN, you may, based on that dyno sheet, start to play with your zeel. My test cylinders go from 30 to 16-17 degrres, don't remember.
But that does not mean you should do same, not at all. My jollymoto hits a lot harder than your pipes, due to they beeing fatties with a lot of volume, and most important, the last cone is very steep providing a VERY strong returning wave. Good for peak power, but fucks up mid range. VERY noticable on my test cylinders since the transfer duration is quite high. My Higgspeed has a lot less peak power, but 12 hp more hp when pipe hits compared to jolly, and the 12 hp WITHOUT ignition advance. The pipe design really makes the engine characteristic more than anything else.
My 109 rwhp ran pump gas. Today, they give 90 with Higgspeed, stock iginition and stock heads providing 145 psi compression. Still, the mid range when pipe hits is 12 hp better than with Jollymoto, and both at about same rpm as the Jollymoto also have quite tuned length. For fun, I put on the very short Figarolies, they peaked at 10000!!!!!!! 1500 rpm MORE than the jollymoto, about 1800 rpm more than the higgspeed. But with less power than the Higgspeed gave. Well, I learn a lot doing all these tests on my dyno.
And by adding zeel, peak power went from 104 to 109 rwhp. The torque dip also improved, but not in the same league as changing to Higgspeed. Not at all. Higgspeed more or less cured my flat spot issue, but cost some peak power as said.
I have not tried spacers between cyl and crankcase. But I may do that to prevent the piston edge to be 2mm ABOVE transfer floor at BDC. That is bad for flow, as the flow rate hits the maximum mass transport at approximately BDC when ON AN EFFECTIVE PIPE. I do not talk about the rpm prior to that, when the engine acts as a "pump", not as a resonator. So, I belive the scavenging pattern will improve by not having the 2mm piston edge right in the face of flow at BDC. We'll see.
Parallell: Same angle in squish band area at both head and piston.
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I'm used to work with snowmobile engines (3 cyl. casereed) so i've never messed with inlet timing before and belived the 6mm. cutout pistons bike came with was right on the money! 
About inlet flow, look at pics on page 2 and you will se cyl. are milled to angle up carbs so flow should be good, right?
About carbs, i run lectron 44s now which took away the flatspot and tamed the "hit" a little. With the tm38's (snowmob. rack carbs) i used to run before, flatspot was really bad but response was much better over and under flatspot. Never got the jetting right on thoose, now i know why.. I think i will go with them again after i lowerd
Ex.port is 198deg. and main transfer is 127 sub.transfer is 129 but i never degreed inlet at that time.. and now with thoose cylinders sitting on the shelf right now, i calculated the inlet timing on a online software. Even calced the ex.duration at the same time and came up with just over 195deg. Don't know how accurate that program is tho.. Deck hight is 0,6mm btw. And inlet portwidth is 49,5mm. hight from top barrel is 96,5 so it seems like someone dressed it a bit.
even with so big cutout 