Dynoport Jetting Help

[ColumbianaBanshee]

Need help figuring out where to start on jetting for Dynoport exhaust. Here are my mods. Stock cylinders with .60 wiseco pro-lite pistons and slightly shaved heads. Previously with .40 OEM pistons and shaved heads had 126 pounds in each cylinder but no longer have compression test avail to check now so we will use the 126 lb rating (shouldn't mean much with jetting). still have stock filter box, but put clamp on foam filter kit and have outerwear lid replacement cover over the stock box (no lid anymore). was running stock exhaust with silencer baffles removed (still had end caps on though) and had it perfectly jetted with stock pilot and needle setting and a 240 main. put on dynoport pipe with remade pro-circuit silencer to match the barker silencer that comes with the dynoport pipe but with slightly better flow (no spark arrester). this gave me an extremely clean idle with both cylinders sounding perfectly in sync, but here is my issue. it feels like sometimes the off idle throttle hesitates a little before it kicks in, mid-range seems flawless, but top end is sometimes bad. the off idle hesitation is consitent, but the full throttle issue is inconsistent. sometimes there is mad power and sometimes if feels flat. I am thinking I need to make needle and main jet adjustments? When I spoke with Dynoport they said a stock Banshee jetting is fine for a stock engine and intake, but with my changes they can't give a suggestion. there is no doubt the pipe is better than what i had stock being that i gained about 3 more quad lengths against my friends suzuki 400 than i had without the dynoports on in a street drag. also top end is actually unexpectedly faster once it gets itself through the carb issues. the pipe was free and since it is better than stock i plan to keep it. plus when at mid throttle the cylinders get in a perfect harmony and sound like a jet engine whining.

[Snopczynski]

Im assuming this is the 2 into 1 pipe from what you said, and not the twin pipes.

 

Sell the fucking pipe, its not jetting, it's how the pipe is made. Its only strong in the midrange, its not a low-mid pipe, and it has no top end pipe either. to make the hesitation go away, you will need more compression, more timing, and your gonna need to drop the exhaust port, and raise the transfers. Even then, it wont carry you like a set of pro circuits, fmf low-mids, or pt mids will. This pipe gives you a handicap, and doesn't give you anything extra over any other low-mid pipe on the market. It's a garbage pipe that wastes everyones time it comes into contact with.

[gonecheenin]

Need help figuring out where to start on jetting for Dynoport exhaust. Here are my mods. Stock cylinders with .60 wiseco pro-lite pistons and slightly shaved heads. Previously with .40 OEM pistons and shaved heads had 126 pounds in each cylinder but no longer have compression test avail to check now so we will use the 126 lb rating (shouldn't mean much with jetting). still have stock filter box, but put clamp on foam filter kit and have outerwear lid replacement cover over the stock box (no lid anymore). was running stock exhaust with silencer baffles removed (still had end caps on though) and had it perfectly jetted with stock pilot and needle setting and a 240 main. put on dynoport pipe with remade pro-circuit silencer to match the barker silencer that comes with the dynoport pipe but with slightly better flow (no spark arrester). this gave me an extremely clean idle with both cylinders sounding perfectly in sync, but here is my issue. it feels like sometimes the off idle throttle hesitates a little before it kicks in, mid-range seems flawless, but top end is sometimes bad. the off idle hesitation is consitent, but the full throttle issue is inconsistent. sometimes there is mad power and sometimes if feels flat. I am thinking I need to make needle and main jet adjustments? When I spoke with Dynoport they said a stock Banshee jetting is fine for a stock engine and intake, but with my changes they can't give a suggestion. there is no doubt the pipe is better than what i had stock being that i gained about 3 more quad lengths against my friends suzuki 400 than i had without the dynoports on in a street drag. also top end is actually unexpectedly faster once it gets itself through the carb issues. the pipe was free and since it is better than stock i plan to keep it. plus when at mid throttle the cylinders get in a perfect harmony and sound like a jet engine whining.

 

 

Dynoport, though producing a fantastic 2 into 1 pipe for trail & technical riding (Yes it will still rev & make great power on the top end. Sure aftermarket twin pipes may rev higher, but the 2 into 1 will out rev a set of stock pipes on the top end while delivering an uncommon extremely linear & smooth power band that pulls straight out of the basement! - think YZF450F with more power & a 4000 RPM higher rev capability), is wrong about their jetting recomendations(at least for my elevation here in Pittsburgh, PA)

 

I installed the dyno port on my 98 Banshee which @ the time was bone stock except for a K&N filter & Pro design adaptor.

 

I read the Dynoport stock jetting suggestions, installed the pipe, & my bike imediately fell on its face. Not only would it barely run with the airbox lid off (It ran fine with the stock pipes & no airbox lid, but it did turn out to be a bit lean even then) it literally would not run past 1/3 throttle until I installed said lid unless I pulled the choke half way out.

 

I then read the jetting tips here;

http://www.dfn.com/benkaren/jetfaq.html

 

And in particular, this portion;

(Add 2 into 1 Pipe & silencer: 4-5 sizes larger on the mains, 0-1 sizes larger on the pilots, adjust airscrews)

 

Going off of that, (& the portion of the above link about the other mods I already had/had made, after the pipe installation, to my bike like.025 shaved head (which btw: means nothing for jetting) V-force 3 reeds, +4 timing, Pro design adaptor & K&N filter, no air box lid at all), I went to 290 jets in the current 70 degree's-ish temperature we had then & it's run really good for me since.

 

Honestly, I still need to do some pilot jetting adjustments, but that hasn't been a huge deal as of yet. I just want to fine tune that area for overall great performance.

Edited September 11, 2009 by gonecheenin

[Snopczynski]

Dynoport, though producing a fantastic 2 into 1 pipe for trail & technical riding (Yes it will still rev & make great power on the top end. Sure aftermarket twin pipes may rev higher, but the 2 into 1 will out rev a set of stock pipes on the top end while delivering an uncommon extremely linear & smooth power band that pulls straight out of the basement! - think YZF450F with more power & a 4000 RPM higher rev capability), is wrong about their jetting recomendations(at least for my elevation here in Pittsburgh, PA)

 

I installed the dyno port on my 98 Banshee which @ the time was bone stock except for a K&N filter & Pro design adaptor.

 

I read the Dynoport stock jetting suggestions, installed the pipe, & my bike imediately fell on its face. Not only would it barely run with the airbox lid off (It ran fine with the stock pipes & no airbox lid, but it did turn out to be a bit lean even then) it literally would not run past 1/3 throttle until I installed said lid unless I pulled the choke half way out.

 

I then read the jetting tips here;

http://www.dfn.com/benkaren/jetfaq.html

 

And in particular, this portion;

(Add 2 into 1 Pipe & silencer: 4-5 sizes larger on the mains, 0-1 sizes larger on the pilots, adjust airscrews)

 

Going off of that, (& the portion of the above link about the other mods I already had/had made, after the pipe installation, to my bike like.025 shaved head (which btw: means nothing for jetting) V-force 3 reeds, +4 timing, Pro design adaptor & K&N filter, no air box lid at all), I went to 290 jets in the current 70 degree's-ish temperature we had then & it's run really good for me since.

 

Honestly, I still need to do some pilot jetting adjustments, but that hasn't been a huge deal as of yet. I just want to fine tune that area for overall great performance.

 

Thats funny, cause the peak rpm of this pipe is lower than that of the stock pipes. As per our dyno results it peaks at 8,600 rpm. Also stated by Rich Daly (owner of Dynoport) that the max rpm range design for the pipe is 8,750rpm. The biggest thing that fools people about this pipe and rpm's is the sound it makes. Thats because its pushing two cylinders worth of power out 1 silencer baffle hole.

 

There is no talking your way around this. I have dyno sheets and endless write ups on this forum about this pipe and the 2 into 1 intake.

 

Twin pipes work at the same rpm range as the 2 into 1 pipe does. Max rpm out of my pro circuits is 8,750 rpm on the dyno. This has nothing to do with the fact of the pipe being a single or duals. You can design pipes to be better low-mid pipes than the 2 into 1 exhaust. Just like Pal turner, FMF, and pro circuit did with their low-mid exhaust options. The 2 into 1 pipe is a pile of worthless shit. Its a midrange pipe (not a low-mid pipe), and not even a good one at that.

[ColumbianaBanshee]

Thats funny, cause the peak rpm of this pipe is lower than that of the stock pipes. As per our dyno results it peaks at 8,600 rpm. Also stated by Rich Daly (owner of Dynoport) that the max rpm range design for the pipe is 8,750rpm. The biggest thing that fools people about this pipe and rpm's is the sound it makes. Thats because its pushing two cylinders worth of power out 1 silencer baffle hole.

 

There is no talking your way around this. I have dyno sheets and endless write ups on this forum about this pipe and the 2 into 1 intake.

 

Twin pipes work at the same rpm range as the 2 into 1 pipe does. Max rpm out of my pro circuits is 8,750 rpm on the dyno. This has nothing to do with the fact of the pipe being a single or duals. You can design pipes to be better low-mid pipes than the 2 into 1 exhaust. Just like Pal turner, FMF, and pro circuit did with their low-mid exhaust options. The 2 into 1 pipe is a pile of worthless shit. Its a midrange pipe (not a low-mid pipe), and not even a good one at that.

 

 

I do understand what you are saying, but still feel that the smoothness of the pipe is beneficial in trail and tight area riding. Just as high performance cars like the Bugatti sport an x-pipe to connect the exhaust gases together so that all cylinders work in sequence to push air through the mufflers, this is the single reason Dynoport does this. Yes you can rev higher with a dual pipe setup but at the loss of efficiency and torque because it takes longer to get back in the powerband (more fuel and throttle input) with duals compared to single pipe. Unless I plan on running nearly full throttle non-stop (to possibly feel the 1 or 2 extra horses), there is no reason to run duals when trail riding. Now for overall top end power (wide open throttle only) a dual setup might be better(example: drag cars exhaust out 8 heads), but just physics and the fact that every high performance car runs some time of ?? into 1 or x-pipe setup shows overall 2into1's should be better. Otherwise my Mustang's Bassani exhaust would have 8 separate head pipes and exhaust pipes sticking out its ass. The reason for Banshee HQ is not to bash anyones setup. We are all Banshee riders. We are here to support each other and help to beat the snot out of the 4-strokes out there regardless of how lame you may think someones setup is. I plan to keep the 2into1's as they were cheap (free) and I have no intention of paying 400-600 for a dual setup for a handful of horses which I won't even feel are there. I did that with my $1500 car exhaust and regret it everyday (until I hammer it in the tunnels around Pittsburgh). 99.9% of the engineers in the world can't be wrong by connecting exhausts together for power and efficiency. Now since you started! Dyno sheets are worthless! Unless run on the same dynamometer, at the same time in the day with the same temp and humidity, you can experience horsepower differences in the reading. I work at a Harley shop and I am an avid tech for our dyno. I've dyno'd bikes that ran worse with pipes and jetting then factory setup because of the time of day the run was made only to have the run done again the next day with a completely different outcome. I have seen differences of 10-15 horses on a weak 100 hp Harley due to humidity. Now unless those dyno charts were done on a newer SAE J1349 machine, which adjusts to these differences (very few of these machines in the world) your dyno readings can be used to wipe and flush down a toilet. Our dyno is only 3 years old and it does not run the new standard. As a matter of fact, neither does Dynoport, Paul Turner or Pro-Circuit because the machines cost so damn much money. I'm not a mechanic but I am a tech geek that has been running a dyno for about 6 months and I know pipes (original post says I built the silencer out of a pro-circuit can that I gutted for airflow match to the 2into1 pipe). I just don't know shit about jetting because most of what I work with is fuel injected and programming a CPU is my niche.

[Snopczynski]

You are missing out on a ton of torque with that 2 into 1 pipe. I did the first dyno run on this thread on a dynojet with a 2 into 1 carb, and a 2 into 1 pipe. The hp and the torque were crippled.

dyno thread

 

Went back to the same dyno about 1 year later, and with the twin pipes and twin carbs on the bike, it made about 6 more hp and about 3 more ft lbs of torque over the prior setup. At 5,500 rpm the twin pipes and carbs were already making 1.5 ft lbs more torque than the single pipe, and single carb.

 

2 stroke motors rely on port timing and expansion chamber design to create the same effects that a cam does in a 4 stroke engine. That single expansion chamber shit completely fucks with the equivelant to overlap in a 2 stroke motor. 2 strokes rely on the vac. effect created from the piston and exhaust to maximize performance. With two different exhaust waves sharing one expansion chamber, this effect is what appears to cripple this process in the banshee motor. Exhaust is drawn back into a 2 stroke motor to scavenge the a/f charge, they didn't get this process perfected when they designed that single pipe. 2 stroke motors are not meant to share the exhaust with a crossover pipe like a 4 stroke motor is. Exhaust chamber length, diameter, and outlet diameter all greatly effects the 2 stroke motors output ability greatly.

 

Everyone who has ridden the bike before and after the move to the dual pipes and dual carbs says the same thing. "It is way more responsive now, and it takse off like a bat out of hell now". Everyone else noticed the low rpm bog it had, because the dynoport pipe is a midrange pipe, not a low-mid pipe.

 

Dual low-mid pipes work better than the dynoport single pipe does. The single carb does accelerate faster, but at the cost of almost 6 hp on the top end. Im not telling you all this based off just dyno graphs and numbers. Seat of the pants, this thing was majorly different as well. Everything we saw on the dyno was backed up by riding the bike as well. That 2 into 1 pipe is all bark and no bite. Everything we have put pro circuits on and compared to other low-mid setups so far has came with the same results. More power, and it was a change across the board. PT mids vs pro circuits, more hp with the pc's right off the bottom, and 5 more hp on the top end. The pt mids even pulled about 150 more rpm than the pc's did, but they couldn't match anywhere close to the same power output.

 

The idea behind my replies is to save you the time of trying to polish a corny terd. It is never gonna do what you think it will do. Switch to a real low-mid pipe, and you will see what your missing out on. To get rid of that bog your gonna need portwork, low tension reeds, compression, and a single carb kit. Even then, you wont match the output across the board of a set of good low-mid dual pipes on the same setup.

[bigborebanshee]

I agree the Dyno port pipe does nothing well.I run The FMF gnarly and by far are the best twin torque pipes,they do not have the over rev of the PC,but much more meat in the mid.Great for east coast trail riding.