Out of curiosity, I took one of my water cooled exhaust pipes out of stock and modified the bend which bolts to the head. I noticed an amazing difference in torque and power with this set up. This pipe, of course, was installed on an air cooled. Bolting at the tail required a different clamp of course, and it looked really good. I have a lot of customers now wanting this set up, and have made 10 kits so far.
These pipes arent cheap on a retail scale, but I pick them up for about 35 Euros a piece complete. The regular exhaust for the air cooled I get for 5 to 10 euros a piece.
I made a new thread about the Kspeed pipes for stand up scooters that use the cateye engines, but now feel I wasted valuealble space and should have posted here.
The Kspeed seemed to help my 36cc (33cc) engine by a bunch, but it doesn't work nearly as well on a 43cc and even less on a 49cc, so I am guessing the pipe needs to be retuned for the larger engine.
Question is: Can adding 1.5"-2" of belly to the fattest part of the Kspeed pipe help improve how it works on the larger 49cc cateye engines?
The engine is fully ported to use reeds now, wider transfer ports, ported about 2mm off the top of the exhaust port, exhaust groove fixed for more compression, etc. But I can't use a decent 15mm carb and i think it is partly due to the pipe restricting the engine.
At this point, a stock 49cc head has impressed me more than all the mod work I have been doing. I even took out the rocket key hoping I was running too much advance for all the mod work, but that didn't help any. Heck, a 43cc modded head has been more impressive then my two 49's have been, stock or modded.
do you gain anything at all from removing just the tailpipe cover with the insulation in it or would you gain nothing but loudness. i dont want to do that unless i can actually get some power from it.
no you will not gain any power from removeing the silencer and it will sound extremely irritating and cuz tons of nasty oil buildup under your rear fairing :P
OK guys, I sat in the shadows, and read every word posted about this exhaust mod(twice)! Then I not so quietly got out the chop saw and let the sparks fly. I only had about an inch of header protruding into expansion chamber (cut it off) and had none of the other garbage in there. I took off an inch of header and was going to add 2" to expansion, but found if I added 3" I could use the same mounting bracket. So I busted out the mig and arc (used both) and once again let the sparks fly. I have the twin tips and was gonna hack em and make a straight stinger, but instead I opened those babys up so its a open shot out the back. Mounted it back on for a tester, and all I have to say about it is HOLY CRAP!! Went from gutless wonder to a screamer!! major power gain off the line, gets up to speed way quicker, and stays in the meat of the power throughout the whole throttle range, major improvement! Its a little louder (not much) cause I opened the tips. but since I have a YZ250 and a YZ450F my neighbors are used to me being a little loud. So thanks to all contributed to this great thread and awesome mod. Now if you'll excuse me I got a rocket to ride!!
Most leave the silencer alone, but there have been a few that made theres stronger so it won't fall off. There is something in the threads about messing with the silencer but it seem like a lot of work. I believe they removed the stinger and put on a stronger one and some real fiber to silence it better. There is more to it than that, but been a while since I read the info.
ok im just giving my oppinion on the stock pipe mod so heres a pic of my pipe vs the stock pipe now as you can tell even if you mod the stock pipe it'll still never be close to this.
nope its the pbu factory race pipe for lucky7 not the one with the tips but the race pipe they dont show pictured. it's supposed to be the same size as the ip2 or have the same volume and the stinger came like that it's like a pee shooter! i got laughed at in another site them saying my pipe was too small untill i showed them a pic of the whole thing!! then they said it was too big. but it's actually i think the same size as my banshee pipe just has smoother cones the banshee cones are steep. hmmm maybe i might try fitting it to my banshee
yes.. cut out out an inch of the header and add 1-2" to the belly, clean out the crap pipe protruding at the welds into the cones and you should be good to go.. a muffler shop should have some scrap belly tubing with the same diameter in the dumpster.
Quote:
Originally Posted by shnishigus
i have on stock pipe and it broke should i do this? also i need some instructions
a muffler shop should have some scrap belly tubing with the same diameter in the dumpster. 
