Just installed big bore kit. Do I need a performance exhaust?

[mrautorock]

I just finished installing a 72cc big bore kit on my Agility 50 4t. My friend who is helping me told me I will need to replace my market exhaust with a performance one or my engine will be damaged. Is this true? I'm kind of strapped for cash so I'm hoping I won't need to spend any additional money. Will "straight piping" or modding the factory exhaust in any way help?
As of now the CDI is derestricted, I installed the new variator bushing and now the big bore kit.

Your help is appreciated!
thanks

[mrautorock]

Anyone? I dont  want to order the exhaust for nothing, im low on cash

[zombie]

The idea of a performance pipe is to accuatly use sound waves to pull the exhaust from the cylinder. the pipe must be "tuned" to the cylinder to get maximum benefit. meaning the size, and shape are critical for it to work as a performance pipe. there is no harm in leaving the factory pipe in place as long as the mount is secure to the cylinder, (no leaks) you can modify the fact. pipe w/ minamal hp. gain so I would leave it alone (keep as spare, sell) You can save up to get the appropiate pipe later. the mods you have done are the biggest improvements you will see. there are other tweaks like rollers, clutch springs ect... that will give small improvements, but you hit the biggies. I would also recomend using the tuned pipe your cylinder manufacturer reccomends because they did all the design work fo a proper set up. However there are sometimes other pipes that have proven to work so search around for word of mouth testomoney. the more on the plus side the better.

[mrautorock]

Thanks for the reply zombie.
Will I be doing any long term harm to my new setup if I just keep the factory exhaust on there?
Also, can you send any link to an exhaust available for the agility 50? I can't seem to find any, they're all for 2 strokes...was hoping to spend no more than $100 or so

[zombie]

hey Mr. ROK There is no harm at all! my post was in thinking yours was 2 stroke. You can run a straight pipe on a 4 stroke, IF you don't mind the noise.there is however a minimum amount of pipe lenght/diameter. I do not know the formula to get the dimensions you need. What i do know is the faster you can get exhaust out, the faster you can pull fuel in. (same principal as the 2 stroke). Have you changed your carb, Jet size, Intake box/filter? With the bigger displacement, you are increasing the amount of "mixed" fuel you can burn. You are now getting into "super tune terrain" I will look around for an appropiate pipe for your app.,and I should say here, you will be talking about SMALL improvements over what you have allready done! Maybe there is someone who can reccomend gearing, clutch, or other drive train improvements that you can add to your "wish list". Sorry for the long post, but if you want swinging Ba""s power, go bigger. I think you are on the right track w/ the jug kit. NO HARM FROM FACT. PIPE.   zombie

[mrautorock]

thanks much man. I am not looking for improved performance, I am very happy with what I have. Just want to see if I'm doing the engine harm with the factory pipe, glad to hear im not! Let me know if you find out anything about the pipe dimensions and I will surely cut it down, dont mind the noise.
thanks again!
vic