Phase 4 : Peace PipeI've removed the center stand, so it must be time to try out the Peace Pipe. In phase 2, using the stock carb, I couldn't even get the engine in tune properly with this exhaust. It was fast, but not ridable. For pics, details, and sound clips, check out the link below to it's test in phase 2.
Phase 2 TestTuning with the Peace Pipe turned out to take more work than any other exhaust I've used. That's how it tends to work with more race oriented parts. I initially tried to get a ballpark using the cylinder head temperature gauge. With setups in great tune they generally stick right around 300°F on a full throttle pass for P90. I was maxing out the CHT gauge, which goes to 340°, with any jet that didn't make the engine sputter from running overly rich. I went to reading plugs and ended up with a 105 main, which happened to be the largest jet that didn't make the engine sputter. I moved the needle clip down a slot to the next to richest condition to eliminate high temps and spark knock at part throttle. I was rich when not WOT, but that helped it cool down fast and I'd greatly prefer rich and cool to lean, hot, and experiencing detonation.
Once I got the carburetor in tune, I moved on to tuning the CVT. I'll start by saying this pipe would have liked a later clutch engagement for the best results. There is a little bit of lag getting on the pipe at times. It's not bad, but it could be better. I already have 2,000RPM clutch springs installed, and those are the stiffest springs I have around. I think lightening the stock clutch would work just fine, as I've done that for other scoots with good results. You can see more details about lightening a stock clutch
HERE. I opted to leave the clutch alone, because I haven't done that sort of thing to accommodate any other exhaust so it didn't seem really fair. It also wasn't completely necessary, but ideally the clutch should engage later than it was for the Peace Pipe to do it's best work.
I had been using 6g sliders for tuning the carb, 1 gram lighter than the baseline tune for phase 4. With 6g sliders it accelerated well to start, but then bogged a bit accelerating to higher speeds. This was caused by the torque driver "shifting". As I went over back in phase 1
HERE, the torque driver in a stock scooter has a dual-angle grooves for best street performance. It starts off in the half of the groove that resists change the most to keep revs higher and get a good takeoff. Then it switches over to the other angle once it's up to say 30MPH or so and that part of the groove lets the torque driver open easier to keep RPM lower for cruising. It's a great setup in most cases for a street scooter, but it starts to become a weakness when working with race parts like the Peace Pipe that have a higher and narrower powerband. I feel a straight groove torque driver is much more appropriate for a pipe like this, but I stuck with stock to remain fair and keep consistent MPH results. If this torque driver talk has you a little confused, please go back to
THIS POST for more detail and pics of exactly what I'm referring to.
I tried 5g sliders and then the engine would rev way too high initially, and higher than I wanted at speed as well. It was hitting somewhere over 10,000RPM and breaking up , and then wanting to cruise around 9900RPM or just over. I swapped to a mix of 5g and 6g sliders to equal 5.5g. That's what seemed like the best result to me. Revving a bit high at first, but then settling in around 9,600RPM or so and pulling hard.
I know that's a lot more of an explanation of the tuning than I normally give, but I wanted to give a little insight on the additional challenges you need to be ready for if you decide to go for more aggressive parts/setups. Just to sum up the tune more quickly : 105 main jet, needle clip moved to next to richest position, and 5.5g sliders.
With the carb and CVT in tune, I went for a ride. I did this test ride different than all of the others for this phase. Normally I ride a little shy of 10 miles to a larger nearby town, ride around there a bit, and head back. I get gas at the same station every time, usually 25-27 miles into the trip. After I get gas I can stop worrying about keeping results for fuel economy accurate and I run it harder and get the max speed figures. The Peace Pipe is quite loud, and I really would prefer not to ride it in that town in the middle of the night as I normally do, or earlier for that matter. I ride a lot, and there are quite a few cops on duty there at any time, so I'd rather not push my luck with this pipe echoing off of everything in town. As of now the officers don't pay much attention to me, and I'd like to keep it that way. I stayed out of any larger towns. Since I was not doing the same type of riding, there's no way that any kind of fuel consumption numbers would be accurate either, so I just kinda rode how I wanted to and observed performance. Besides, I don't think you buy a pipe like this looking for the best fuel economy.
I took a 26 mile ride. Sitting upright and WOT kept me cruising at speeds of 55-58MPH most of the time, and as high as 60MPH from time to time. The low end of the average cruising speed was higher than the high end of what any other pipe has done. The high end is pretty much on par with the other pipes with me tucked down on a long stretch of road. That's impressive IMO. It takes a good bit more power to do 60MPH sitting up compared to tucked, because of the additional aerodynamic drag you have to overcome. When I tried to tuck down for more speed, nothing really happened. I got to 60MPH easily, and then it just didn't do anything else. I know it's making enough power to push past what the other pipes have done, and yet it's 1MPH short of the best results I've seen. By the time I was at 60MPH the revs were right around 10,000RPM. I suspect that with the current porting it just doesn't want to rev higher. 190mech says this pipe should be setup for peak around 10,500RPM, and I've seen this exact pipe pull to 11,000RPM or a little beyond on a more aggressively ported cylinder on one of my other big minarelli engines. That engine has a larger 25mm carburetor as well, so perhaps that is also a part of it. Considering that this pipe puts WOT cruising temps at 340+, a larger carb wouldn't be a bad idea for cooling purposes, even though I had no trouble with it due to the heat. I think it actually ran hotter than this with much milder setups before I added the 21mm carb and larger cooling fan.
Since I did a ride in the daylight for a change, you can check out some video instead of just listening to me ramble on about it. ;D
At some point after the ride, I noticed that the clamp used to support the end of the silencer had broken. When I spoke to 190mech about this, he said he had used a clamp off of a cheap Chinese pipe for this particular one. It looked good to me while it lasted, but it didn't hold up too well. Support for the end of the silencer near the outlet is important to keep stress off the stinger and the pipe near it, so I made a replacement out of some aluminum flashing that I had around. Unfortunately, I seem to have forgotten to take a pic of it. Nothing fancy, just a strip of flashing that was tight around the silencer when bolted in place.
I was really disappointed in the lack of speed increase when tucked on the test run. As I said earlier, I felt like there was more than enough power to push speeds higher. I decided to try again with heavier sliders to keep the revs down a little more. I used 6g sliders, instead of the 5.5g used on the last test ride. The pipe has a higher an more narrow power band than most, so I couldn't drop the revs too much or performance really suffered. I made no other changes.
Cruising speeds dropped to 53-56MPH at WOT and sitting up, 2MPH short on average from the lighter sliders. WOT cruising was done around 9,300RPM. When tucked down I saw 64MPH somewhere near 10,000RPM. Once again it felt like the RPM is what held it back more than power output.
When I hit 64MPH, that was only 8 miles or so into my test ride. Just after that I got this odd warble or wawawa type of sound from the exhaust and then it was suddenly VERY loud along with a clank clank clank. The stinger and silencer had broken completely off. I picked it up and rode 10 miles home to avoid going through town. I thought it was loud before, but this certainly made me realize the silencer was doing something.
I think the replacement clamp I made from flashing was just too thin to do it's job. You can see part of it is still bolted on, but the rest ripped right off. I assume whatever distance I rode with the last clamp busted must have stressed the pipe and my clamp just wasn't enough to keep it in place or perhaps it's all my fault. No way to know for sure.
The good thing to know about that situation is that 190mech is working to ensure it doesn't happen again. As I understand it, his new designs now use a bushing in the mount to absorb vibrations. He also only used that Chinese clamp on this pipe, so that's not a problem. Still, after I told him of the failure he was concerned and will be looking into even more changes to farther improve the design. I believe I am the only person really racking up miles on the street using these pipes as this is being written, so he doesn't get a ton of feedback for R&D. Remember, this is one man building these pipes, not a big corporation like Leo Vince that can spare no expense in testing. The funny part of that is that the Leo Vince 100cc pipe comes nowhere near the power output this Peace Pipe is capable of.
I've told you the results from and characteristics of the lighter and heavier sliders, so which would I choose? Lighter. No contest. I find higher cruising speed much more useful than higher max speed. Max speed is more about bragging rights than anything practical. Not too many people want to spend their whole ride tucked down for max speed.
My real opinion is that I'd choose neither. What I'd really suggest is to port the cylinder to better match the pipe's output, probably 192-194 exhaust duration and 132-134 transfer duration. Those are just a guess, but whatever you think will work for 10,500RPM peak. On top of that, I'd add a straight groove torque driver to keep the RPM more constant and remove the need for so much compromise. Lightening the stock clutch or stiffer clutch springs would get it off the line better. Add in a larger carburetor for better cooling, 24-28mm I'd guess, and you should have a pretty stout setup.
That's an awful lot of add-ons for a pipe, I know. That's because I don't really think you should choose this pipe unless you are up for a serious project and spending some time dialing it all in. It's loud and you can't use a center stand, so coupled in with all the other reasons, the Peace Pipe is basically for people that care more about a quick and fast scooter than the best daily rider. If you are one of those people, and you understand the drawbacks I've mentioned... you're gonna have a blast! If you're looking for a pipe purely for race, there's just no other smart choice among the pipes I've tried.
