Trinity 2-1

[Duneman101]

Originally Posted by fast350

we ride dunes....my dad blew his bike up twice, i blew mine up only once.just could never get em too work for us

IF you were blowing up bikes you shouldn't be blaming that on the carb.....I had that setup for 3 years and all i do is ride on the dunes.....i had the same top end for those three years too.

It is a great hill shooter setup and if you like sand surfing the 2 to 1 is a great thing.....and the trails that i did ride i ripped to shreds.....the best thing about the 2 to 1 setup was keeping it tuned......it wasn't a dragger though by any means but it was arm ripping from the start to the high mids....

[SAVAGE420]

Originally Posted by Duneman101

IF you were blowing up bikes you shouldn't be blaming that on the carb.....I had that setup for 3 years and all i do is ride on the dunes.....i had the same top end for those three years too.

It is a great hill shooter setup and if you like sand surfing the 2 to 1 is a great thing.....and the trails that i did ride i ripped to shreds.....the best thing about the 2 to 1 setup was keeping it tuned......it wasn't a dragger though by any means but it was arm ripping from the start to the high mids....

Ok i know it gives you bottom end power but trinity claims it gives a bit more up top also?...Anyway even if it dosent give me more top end like they claim will my topend "as of now" be effected in a bad way ...like lost top end power? I dont care if i dont get any topend just that i dont want to lose ANY up top.

[Matt Fisher]

I'm going to throw my 2 cents in here, but it's based on general knowledge, as I have not personally used a 2-1 system.

First, the reason you're able to use one carb with 2 cylinders is because the pistons fire 180 degrees off of each other. So while cyl 1 is moving down in the cylinder (forcing the fuel into the cylinder and shutting off that reed valve), cyl 2 is moving up in it's cylinder and drawing fuel into it's crankcase. So in effect, the carb is only feeding one 175cc cylinder at a time. This additional velocity at lower rpms keeps the fuel atomized better and so the engine runs better.

The reason you will often have a power decrease at high rpm's is that at some point in the rpm range, there is so much air/fuel moving into both cylinders that the carb is now feeding a full 350cc motor- it's "seeing" a 350cc signal. At that point in time, if you have a single 34mm carb it's the equivalent of running two 17mm carbs on a 2 carb system (not exactly, as there are other factors to consider). Secondly, from the pictures I've seen, the 2-1 intake manifold doesn't look like it has a very smooth transition from the carb to the reeds, this will limit the total amount of air that can move into the motor. How much- if any -power is lost on the top end depends on a number of factors, including engine modifications, jetting, etc.

The Keihen PJ carbs are poo. The modern PWK's are light years better. I'd think that a single properly jetted 36mm PWK would be a great choice on a healthy general purpose Shee motor, but would be a lousy choice for a full-on drag machine.

Remember, the Banshee has an antiquated carb, intake, port design, and no power valve. Don't expect it to run like a motor that has 20 years innovation and refinement on it.

[Yamaha_Freak]

Originally Posted by Aussie Bloke

. i go into a turn and unless im on the pipe it feels like im riding a lawnmower out of the turn. shee's need power valves something cronic!

that would be a jetting problem your having their

[SAVAGE420]

Originally Posted by Matt Fisher

I'm going to throw my 2 cents in here, but it's based on general knowledge, as I have not personally used a 2-1 system.

First, the reason you're able to use one carb with 2 cylinders is because the pistons fire 180 degrees off of each other. So while cyl 1 is moving down in the cylinder (forcing the fuel into the cylinder and shutting off that reed valve), cyl 2 is moving up in it's cylinder and drawing fuel into it's crankcase. So in effect, the carb is only feeding one 175cc cylinder at a time. This additional velocity at lower rpms keeps the fuel atomized better and so the engine runs better.

The reason you will often have a power decrease at high rpm's is that at some point in the rpm range, there is so much air/fuel moving into both cylinders that the carb is now feeding a full 350cc motor- it's "seeing" a 350cc signal. At that point in time, if you have a single 34mm carb it's the equivalent of running two 17mm carbs on a 2 carb system (not exactly, as there are other factors to consider). Secondly, from the pictures I've seen, the 2-1 intake manifold doesn't look like it has a very smooth transition from the carb to the reeds, this will limit the total amount of air that can move into the motor. How much- if any -power is lost on the top end depends on a number of factors, including engine modifications, jetting, etc.

The Keihen PJ carbs are poo. The modern PWK's are light years better. I'd think that a single properly jetted 36mm PWK would be a great choice on a healthy general purpose Shee motor, but would be a lousy choice for a full-on drag machine.

Remember, the Banshee has an antiquated carb, intake, port design, and no power valve. Don't expect it to run like a motor that has 20 years innovation and refinement on it.

So why are the PJ carbs "POO" compared to PWK carbs...