Custom exhaust for gs850, tuneable straight pipe

[blackstag]

thanks for the information

if we know that the air flow is increased in the carbs and we compensate by increasing jets and changing the jet needle, to accomodate for this. theres still a issue is what your saying.

due to the way in which air is delivered, even if i do accomodate for the change, the air flowing over these points will create a larger issue.....

i dont want to waste time or money here. brainpower and thought come free. dynojet kits dont

maybe there is another route.

ive seen plenty of pod setups on gs's so they have to be somewhat effective eh?

[blackstag]

so i have been continuing the research on the exhaust system design and in continuing the wave length tuning read about torque reversion cones.

anybody ever use these before?

ive read about them before but have never had a reason to use them. they make the exhaust gases exiting from the engine make an abrupt change in pipe size that helps the exhaust pulse flow from the engine without interruption.

basically they help with low end torque and help stabalize the entire torque range. something that I will probably have to do.

these are the ones that I am looking to get;

http://www.ebay.com/itm/LA-Choppers-Torque-Cone-for-1-1-2in-1-3-4in-I-D-Exhaust-Pipe-1861-0400-/350614504052?pt=Motorcycles_Parts_Accessories&hash=item51a240c274&vxp=mtr

if i dont use them for the 850 I will definitely use them for my xs650 project.

also, does anyone here have any idea how hot the gases exiting from these engines are? I need the temp of the exiting exhaust gases to accurately size the exhaust system.

if nobody knows, ill get a reading once I get the electronics back up and running but it would be lovely to know.

thanks all

[Steve]

... ive seen plenty of pod setups on gs's so they have to be somewhat effective eh?

Sure, they are "effective", but effective at what???

The thing at which they are MOST effective is making carb removal easier for all the jetting adjustments you need to make when you install them.

so i have been continuing the research on the exhaust system design and in continuing the wave length tuning read about torque reversion cones.

anybody ever use these before?

Nobody that really matters. Just people like Yoshimura, Vance and Hines, Kerker, Jardine, MAC and a few others.

ive read about them before but have never had a reason to use them. they make the exhaust gases exiting from the engine make an abrupt change in pipe size that helps the exhaust pulse flow from the engine without interruption.

basically they help with low end torque and help stabalize the entire torque range. something that I will probably have to do.

You want to do some reading on that topic? Look up information on designing 2-stroke expansion chambers.

... also, does anyone here have any idea how hot the gases exiting from these engines are? I need the temp of the exiting exhaust gases to accurately size the exhaust system.

Not sure what the temps are on a GS engine, but they might be similar to other gasoline-fueled engines, when under full load. I have seen reports of 1700+ degrees, and have personally observed temps over 1700 after the turbo, where temps are several hundred degrees cooler.

If you don't mind taking shortcuts in your design research, just look to see what the "nobodys" mentioned above are using.

.

[blackstag]

Nobody that really matters. Just people like Yoshimura, Vance and Hines, Kerker, Jardine, MAC and a few others.

lol.... is that sarcasm there steve?

and i dont think anyone here is a nobody. i wouldn't be here if you guys were. this is the single greatest community for the gs series of bikes on the net, period.

pods have their place, they also create alot of mayhem. I am attempting to help reduce the negativity towards them by providing some sort of systematic approach to handling them, their affect on the bike and how to overcome the negative affects.

alot of people spend alot of money for "looks" which realistically, is the only reason they are on many bikes. definitely the reason they may end up on mine.

i however dont plan on spending alot of money, well see though

[Agemax]

pods have their place, they also create alot of mayhem. I am attempting to help reduce the negativity towards them by providing some sort of systematic approach to handling them, their affect on the bike and how to overcome the negative affects.

there already is a systematic approach to handling them..........FIT A DYNOJET KIT.

THEY WORK!

[hjfisk]

Some people just have to reinvent the wheel.

[blackstag]

im just trying to understand what is going on is all, dont want to reinvent the wheel. I usually find that I save money when i understand what is happening.

in this case I have realized that sticking with cv carbs are going to cost me at least 100 dollars.

thats before I buy intake boots.

so, is there any reason why I should not run the vm series carbs found on 79 and earlier models?

[Agemax]

im just trying to understand what is going on is all, dont want to reinvent the wheel. I usually find that I save money when i understand what is happening.

in this case I have realized that sticking with cv carbs are going to cost me at least 100 dollars.

thats before I buy intake boots.

so, is there any reason why I should not run the vm series carbs found on 79 and earlier models?

you will STILL need a dynojet kit to get them running correctly. countless people have fitted pods or belmouths and a race pipe believing they are clever enough to set the carbs up to run perfectly............but they all soon give up,admit defeat and go buy a DJ kit.(mainly just to use the needles DJ supply)

[Steve]

lol.... is that sarcasm there steve?

Me?? Sarcasm??

Never.

You asked if anyone had used wave length tuning and torque reversion cones.
I answered, saying that we basically trust those who have already done the work, and gave a few examples of who has already done it.

so, is there any reason why I should not run the vm series carbs found on 79 and earlier models?

The intake ports on the head are smaller on the '79 engines, as well as the boots. You could make an adapter, since you are adapting everything else, too, but that will be up to you.


Step back just a bit and look at the big picture. You are going to be putting a LOT of time and effort into this. Is that all going to be offset by saving the $100 for the Dynojet kit?

.

[blackstag]

realistically, no

in the end 100 bucks isnt going to end my life. ill probably stick with the cv's and get the dynojet kit.

seems like it will save me some time and provide at least a starting point for me.

thanks for the info fellows

[Agemax]

realistically, how far do you plan to go designing your exhaust?
so, you create a prototype according to all your maths and calculations and tuning theories and get it made, bolt it on, and the bike runs like a pile of crap............
then where do you go? chop it up and take a few mm off each header length, or add a few mm in diameter to the headers, or add a few mm to the length of the baffle?
just how much time and effort do you plan to waste before you give up and go buy a ready made exhaust that works, straight out the box, for a few hundred bucks!

[blackstag]

time is never wasted if i have learned something

i dont care to just go out and by an exhaust. I am doing this to learn about exhaust systems, their effect on the bike and what is needed to create a properly tuned exhaust system.

the information that I have learned thus far has given me a great sense of accomplishment. i understand things that I would have never thought a second about before.

i seem to have offended you by doing this. its up to you whether or not you want to continue coming back to read about my endeavors. I am by no means twisting your arm and making you come back.

to answer your question, i will continue to tune the system until I am happy with the results.

[tkent02]

We need pictures.

[Steve]

We need pictures.

And dyno charts.

.

[Agemax]

time is never wasted if i have learned something

i dont care to just go out and by an exhaust. I am doing this to learn about exhaust systems, their effect on the bike and what is needed to create a properly tuned exhaust system.

the information that I have learned thus far has given me a great sense of accomplishment. i understand things that I would have never thought a second about before.

i seem to have offended you by doing this. its up to you whether or not you want to continue coming back to read about my endeavors. I am by no means twisting your arm and making you come back.

to answer your question, i will continue to tune the system until I am happy with the results.

you have not offended me by any means. i will keep coming back to read this thread, i enjoy a good laugh