Exhaust/intake tuning?

[megafandrew]

Hi everyone, I am fairly new to the forums still and fairly new to tuning a quad as well. My question with details is this: I have a 2001 yamaha warrior that has the stock jetting and 8 plates installed in my supertrapp ids2 exhaust. Now about a week ago I recieved my proflow designs air box adaptor plate system with the optional k & N airfilter. I installed this (with stock jetting and 8 plates still ) and the quad seemed to be surging at a constant higher speed or when I wanted heavy acceleration it would cut out. I read my supertrapp manual and it told me that adding a higher flow/larger air filter would require new jetting or I could remove plates from the pipe to allow more fuel. I removed 4 plates from the pipe, and removed the stock airbox lid so the k&n could breath easier, eliminated the surging of power problem, and it has a cool exhaust note as well, a little quieter but still cool. Now is this what most likely caused the surging problem? as I did not notice it before, and secondly Can I install say 5 or 6 plates in the pipe to fiddle with the flow?, or should i stick to the 4 or 8 only, as thats what the manual states, but does not say you can or cannot use 5 or 6 or 7 plates? Please some answers to this second question especially as I have lost a bit of omphh by reducing the plates but it does run better. Thanks, drew

 

[jasonp]

Pretty simple..
More plates = more power because you're reducing the backpressure of the exhaust so the engine doesn't have to work as hard to get the exhaust out. You'll have to jet the carb to compensate for the change as it will require a richer mixture as now you've made you engine more effecent.
Less plates = less power but more low end torque as exhaust gas volecity increases at low rpm but at higher rpm that will cause to much backpressure and the engine will have to work hard to push the exhaust gas from the pipe. Leaner mixture is requred.

 

[megafandrew]

ok thanks, and in my manual, it says that removing plates richens the engine, not sure, so can put in say 6 plates though?

 

[jasonp]

that makes sense.. less plates will require you to jet the carb leaner.. as the engine will run richer because of the change and less exhaust flow.

 

[jasonp]

whats cool about those exhaust systems is you can tune them for performance.. I'd try and run the most disks you can as that will produce more power but you'll have to re jet the carb richer.

 

[megafandrew]

hey jason thanks, im going outside right soon to play around with the # of plates in the pipe, im gonna try six plates and stock jetting and see if it runs good. I actually have a stage 1 and 2 jet kit here so if I need to install it, thats alright. How hard are these jet kits to install and which is the main jet in the carb?

 

[98warrior]

All you have to do to change the main jet is loosen the carb boots and turn the carb until the bowl (bottom) is pointing in your direction. Take the screws out and pull the bowl off and you will see a big brass main jet, nothing to it

 

[megafandrew]

hmmm i might try that if changing the plates to 6 does not work, Thanks chad. I wont have time to jet this weekend but ill do it next weekend, and Ill probally just leave it at 4 plates for the week, it seems to ride well there.