About the same as my house. The drag bike pipe was one I made up from exhaust tube, flat sheet and the tail/muffler from a TZ250. Works ok but I think I could do better with more measuring and calculations (and time to work it out).
Thanks. Looks good. I am looking for ideas for a straight pipe for my Hondsa CRM25oAR roadbike, but ave not yet decided on the best option.
torqsoft.net/exhaust-design If you have a fancy calculator and plenty of time/patience. http://www.torqsoft.net/index.html
Hi Murdo, Just another dummies question re. your home-made pipe…. I have a CRM250AR engine in a light-weight road frame and I have to come up with a chamber to extract the max. capability out of it so it is not a dog. Due to my remote location, I have limited fab options (I am not a welder) and any fab that goes on is pretty basic, as most job shops don’t want to know about modding bikes (another story). I have access here to a lot of very nice 2nd hand RZ350YPVS parts, including a good selection of used RZ350YPVS chambers / exhausts. The RZ350YPVS has a power valve setup similar to the CRM250AR. I was wondering if it is possible to take a good RZ350YPVS chamber / pipe and adapt this to my CRM250AR engine as a performance option. Would the fact that they engine is a 250 be greatly impacted by this being a 175 (half a 350) pipe? The original AMF-HD 175 / 250 road bikes used the same part number muffler, but I don’t want to use these as I they will likely sap power. Thanks, Ian B.
In my opinion the half 350 pipes should give you good power up to 3/4 revs when it may become a bit restrictive. It may also give good torque at lower revs. Do you still have the pipe from the CRM engine to measure to compare to the RZ pipe?
Yes, I still have the original CRM250AR pipe - motocross pipe. The CRM250AR is a very tractable engine which has more road manners than a real offroader - 6 speed, balance shafts / power valve and AR (fuel recirculation to cut emmisions). If push comes to shove I can of course get a pipe made up by someone like Higgspeed, but I thought I would check what local options might be available. I have seen a couple of articles about derestricting YPVS chambers, but that involves surgery and I have to be careful of the noise Nazis as well. Not sure I really want to go 'all out' anymore (am done with those days), but I would like to use all the 'usuable' power there is to make it a fun bike. Cheers, Ian B.
Awesome setup you have there Murdo! I think I might need to steal that 'double decking' idea for my shed - might even do a few rows so there are aisles so it doubles as a work bench. But then it'd need bracing and rararar....ill never get around to it! Very nice bikes you have there
Feel free to steal the idea Stu, I stole it from the National Motorcycle Museum at Nabiac, NSW. 150mm x 7.5me Gal purlon cost $58. I've got 4 small bike per length. Purlon is 1200mm from floor (go a bit higher if you can, shed is only 2400mm), I used 100mm purlon for the uprights and the bikes have a bracket from handlebar end tek screwed to wall.
