Banchetta

They don't do anything.

The very beginning of a dyno run is unaccurate. From the time I hit the throttle and they start reading the dyno, the first 1000 rpms always has that jump up in hp, so I'm assuming that the first 1000 or so rpms might not be accurate. W/ the spacers (seat of the pants feel) will make the shee more tire breaking loose power, w/o them makes the shee smoother. Hard to tell if I liked them, I like smoother power, so I left them out. I have a set if your interested. $10+ shipping.

162-165 mains, 42 pilots

Low compression will cause it to start hard. I seen a shee w/ 85/105psi of compression and would not start unless you pulled it down a road. The guy finally rebuilt it and walla, starts first kick every time. Stock shees run 128psi at sea level.

300-400' I'd go for the sst's. They'll come out of the hole better. By the time the T3's start catching up, you'll be across the finish line. The only time I have a problem w/ dragging is when I start running over 1000'. Thats pretty much when I'm topped out in 6th gear and the high revs are still pullin, but I get them 2-3 quads out the hole w/ my mids.

Final curve when done.

It did seem to crispen the initial hit of the throttle, but created a dip before powerband, so yes, there is a give and take on that....I spend over 8 hours one day on a dyno comparing all these little mods. .5 hp here, 2hp there, another 1 hp there, etc. here were the results from before I went in and after I left. Now this is w/ my setup, since the stroker, I've found different mods can really shine w/ different setups, so that is a really good point Rnbrad. Note: that ported stock cages did absolutely nothing and boost bottle was removed in the 2nd run also..this was w/ the mods listed in my sig..

Like Rnbrad said. You need velocity to run a carb. You have to have a certain amount of air speed to go through your carb in order to pull fuel from the carb bowl. The larger the carb, the less velocity you have which = less efficiency. If you port your cylinders or stroke it, then you'll move more air which will allow you to go to a larger carb and still maintain good velocity. Here is a dyno w/ ported stock carbs and stock carbs. I also did a dyno w/ 34mm carbs and lost 8hp throughout the whole curve w/ over 16 hours of jetting. Before jetting, I lost 12hp.

What he said..... 287563[/snapback] Thats why there legends. 287723[/snapback] Rod is just a post whore.....

You'll lose hp w/ larger carbs unless you get some porting and intake mods done...

Keep them both the same and look at the plug color, if they are different then you might have an air leak or other problem. We need a little more info.

Start off w/ a 185 main and work down from there....I'm running 175's at 50 degrees w/ the stroker. I ran a 162 w/ stock porting on stock crank, so 185 will be safe, most likely you'll be around 175 when your done.

That is from just normal riding? If so, then throw them back in, run it wot in 6th gear for 5-10 seconds, shut it down, coast to a stop, pull the plugs and take another picture and post it...You can't jet your mains w/ normal riding. Mains mostly control wide open throttle (wot). You'll find that the plugs will look TOTALLY different. BTW, go back to B8ES plugs.

What he said.....

I did a dyno a while back w/ no top end differences but the boost bottle actually created a slight dip when you first whack the throttle. so I left them out. Now I have a stroker w/ intakes and a bottle. I'm thinking of blocking the bottle off..

Good question, you got me there.....

Mine must be different, my diverter was only pressed into a tight slot in the cage. The reed cage dropped right into the intake after...

That statement is absolutely correct!! Most people think dips in the powerband can be corrected with jetting. This is not always the case. 286347[/snapback] True,true, I got mine out w/ my stroke w/ a different head shape and higher compression...worked nicely for me...of course, higher compression alone will change port timing. 286588[/snapback] I was aware that port timing can change compression but didn't realize it could be the other way around. Maybe that's what you meant. 286608[/snapback] No, compression will affect port timing. Anything that will affect timing of a split second will affect port timing and pipe-port timing. Higher compression will speed up the combustion resulting in a faster timing. It WILL affect pipe-port timing. Its one of the reasons why higher compression helps the high rev pipes get back that bottom end...There are so many variables w/ timing, that is almost endless. Your talking about a motor thats turning almost 10,000times a minute and pumps air in and out in a split second ( about 150 times per second) so if anyone doubts that compression will not affect the timing, then........... as for jetting out all dips, sometimes its impossible. Due to port timing, you'll have a resonating wave coming back from the pipe to the exhaust port that might go against the air coming into the intake, so it'll interrupt air flow. Depending on rpms the pressure wave from the exhaust will vary on the timing and will cause a dip at certain rpms. When the timing of the exhaust wave and ports are perfect, the pipe wave will help pull the air out of the motor, acting as a turbo, but pulling instead of pushing...

Banchetta, at what rpm do your PT Mids sign off. I've got my ride going and broken in and am getting used to how they sign off a little earlier than my Fatties did, and was wondering what rpms you experience them signing off at. I'm taking my machine next week to the dyno and just wanted to compare with you. 286599[/snapback] She made peak hp at 7800rpms and peaked at 8600 before falling fast. I'd post it, but the site won't let me....

I have the pro design intakes. I just put the intake on the edge of a bench and tapped the guide or "diverter" out...They are only pressed in, but you need a hammer or press to get them out.

That statement is absolutely correct!! Most people think dips in the powerband can be corrected with jetting. This is not always the case. 286347[/snapback] True,true, I got mine out w/ my stroke w/ a different head shape and higher compression...worked nicely for me...of course, higher compression alone will change port timing.

thats a pretty big jump in jet size, Did you try other sizes as well? Did you pin it down to one size being the best?? I bet you have another few more ponies in there if they didn't try other sizes....49 hp isn't bad, but I think you can get more than that w/ jetting.