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Drilling holes in muffler, speed pulley kit
Posted: Tue Jun 17, 2008 2:28 pm
by madeline17
I'm trying to improve acceleration and end speed on my 1987 Honda Spree. I drilled two holes in the end of the exhaust with a 5/16" bit. It seems to have improved very slightly. I'm wondering, how many holes in too many? I'd like to put a few more in if I could, but I'm not sure if the engine will start bogging down or not.
Also, is it possible to buy a speed pulley kit for a Spree, and if so, where would I look to find one?
Thanks for any help you can give me
Posted: Tue Jun 17, 2008 2:55 pm
by Kenny_McCormic
Your suposed to put the bit inside the muffler and drill 2 of the internal plates.
No such thung as a high speed kit for a spree, you can install a 1/2 inch auto belt to make the gearing higher but your take off will suffer.
Can you be more specific on where to drill?
Posted: Wed Jun 18, 2008 11:53 pm
by johndej
I am trying to help my daughter improve the performance on her 86 Spree, so I just joined today. I've read some comments regarding drilling the muffler, but yours is the first I've seen with a location mentioned. If it isn't too much trouble, could you describe in more detail where to drill. It sounds like you drill through the tailpipe opening. Thanks for your help!
John
Re: Can you be more specific on where to drill?
Posted: Thu Jun 19, 2008 12:53 am
by adark248
johndej wrote:I am trying to help my daughter improve the performance on her 86 Spree, so I just joined today. I've read some comments regarding drilling the muffler, but yours is the first I've seen with a location mentioned. If it isn't too much trouble, could you describe in more detail where to drill. It sounds like you drill through the tailpipe opening. Thanks for your help!
John
The baffles are *inside* the muffler. you don't need to drill holes in the outside of the muffler. someone will come along with a more detailed description than I can give probably.
Posted: Thu Jun 19, 2008 1:18 pm
by Kenny_McCormic
I even have a picture.

Drill 2 restrictions.
Posted: Thu Jun 19, 2008 4:49 pm
by justinnielsen01
hes right about that you need a bit that is just a tick shorter than your exhaust and drill two but i dont think 3 would hurt just a bit louder. nice pics they make posts more intresting
Posted: Thu Jun 19, 2008 5:20 pm
by Kenny_McCormic
Only drill 2 of them, 3=not enough back pressure and decreased performance.
Thanks!
Posted: Thu Jun 19, 2008 5:42 pm
by johndej
Thank you for the information. I will try it. I assume that since 3 holes would be too much, the size of the bit would have to be pretty small. Any advice there? Thanks again.
John
Posted: Fri Aug 22, 2008 3:25 pm
by needfasterthan31
i drilled a hole in my muffler through the tip with a bit qa little smaller than the opening and noticed no performance increase,actually a very slight loss and a noticeable loss of back pressure so its slower going up hills,and its annoying loud sounding.i also notice i need to give it a tad gas when i start it up and the idle takes a bit of gassing the throttle just a tad to get it to to idle even. dont know what these people are talking about on here but i am looking for another stock un-drilled muffler,i would highly recommend not drilling the muffler baffles out.
Posted: Fri Sep 05, 2008 1:34 am
by Towlieee
needfasterthan31 wrote:i drilled a hole in my muffler through the tip with a bit qa little smaller than the opening and noticed no performance increase,actually a very slight loss and a noticeable loss of back pressure so its slower going up hills,and its annoying loud sounding.i also notice i need to give it a tad gas when i start it up and the idle takes a bit of gassing the throttle just a tad to get it to to idle even. dont know what these people are talking about on here but i am looking for another stock un-drilled muffler,i would highly recommend not drilling the muffler baffles out.
You gotta re-jet for it to run right im pretty sure!
New to mopeds my self, but with any other bike, any exhaust or intake modification that increases flow, will require a re-jet for more fuel
Posted: Fri Sep 05, 2008 1:49 am
by darat
i have never rejet on mine and i rode over 2k on it.
Posted: Fri Sep 05, 2008 1:52 am
by Towlieee
darat wrote:i have never rejet on mine and i rode over 2k on it.
oh ok sounds good
I might try that tomorrow on my friends, I wasn't sure if we would have to re-jet so I didn't mess with it yet..
How big do I go on the drill bit size??