Sectioned Posted March 13, 2017 Report Share Posted March 13, 2017 Hi all, have searched but no joy. Has anyone opened up a wes or sammy mid box and taken pics or measurements? I would quite like to fabricate something similar as I cant afford to buy fancy parts and also enjoy that sort of thing. Or some good info on what exhaust characteristics the ty250 ts enjoys. Have the '74 model but may change barrel and head to the c or d as I've read they had better porting etc. Thanks. Quote Link to comment Share on other sites More sharing options...
b40rt Posted March 13, 2017 Report Share Posted March 13, 2017 5 hours ago, theoldstuff said: Hi all, have searched but no joy. Has anyone opened up a wes or sammy mid box and taken pics or measurements? I would quite like to fabricate something similar as I cant afford to buy fancy parts and also enjoy that sort of thing. Or some good info on what exhaust characteristics the ty250 ts enjoys. Have the '74 model but may change barrel and head to the c or d as I've read they had better porting etc. Thanks. Why not contact Wes in Spain directly ? I'm sure he would be delighted to give all his hard earned information for nothing, it's not like its his lively hood or anything. Quote Link to comment Share on other sites More sharing options...
Sectioned Posted March 13, 2017 Author Report Share Posted March 13, 2017 Wow! I guess I could always open up my original Yammy part and fab something similar from that but that might upset some sensitive types that I'm doing Yamaha out of business too. If I had a livelihood I would just buy one but I am a solo dad so alas money is thin on the ground. Maybe I'll just tape some old coke cans together so as not to infringe on anyone's copyrights. Sorry I asked. I sure will be reluctant to ask anything in the future. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted March 13, 2017 Report Share Posted March 13, 2017 I can say that TY250 TS is sensitive to exhaust backpressure and you can also have fun experimenting with the length of the header pipe (just like any other trials two stroke) You should know what you like before you start experimenting. The standard Yamaha TY250 design works well but is pretty heavy and the end muffler makes a terrible sound Some people prefer the 74 model engine over the later ones, so again it would be good to know what you want Quote Link to comment Share on other sites More sharing options...
Sectioned Posted March 13, 2017 Author Report Share Posted March 13, 2017 Thanks feetupfun, you say its sensitive to back pressure so is that to say there is a fine line to get right or it prefers more back pressure over less? I just want a nice low down torquey bike with a reasonable spread of power. you know want my cake and eat it too. Have been working on weight reduction (as it's free) just to keep me tinkering. So maybe I'll copy (not exactly for the legal eagles) the OEM but out of alloy. Quote Link to comment Share on other sites More sharing options...
Sectioned Posted March 13, 2017 Author Report Share Posted March 13, 2017 I have cut and removed all the baffle in the mid box to make the thing lighter and larger. Haven't welded a stinger on that and no rear silencer either but the bike is super strong from idle lifting the front wheel easily in third on throttle without any other input. I like the pep of the lighter flywheel weight I think. Does run out at higher revs but may be leaning out due to no air filter/box. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted March 13, 2017 Report Share Posted March 13, 2017 Yes a fine line with the backpressure. Too much and it will be RPM limited, too little and it will have less torque than ideal at low RPM. It should go heaps better (for trials) with an end muffler or a stinger compared with having nothing on the end of the main chamber Quote Link to comment Share on other sites More sharing options...
Sectioned Posted March 13, 2017 Author Report Share Posted March 13, 2017 Aha well there is my current problem then. Thank you for clarifying that. Will have to experiment with the current setup before I charge in making new. Upon reflection, I can see why I got the initial response. First post past intro I'm asking for details of a well respected product seemingly so I can copy. I may have come across as trying piracy on for size but really that wasn't my intention at all. Just needed a few hints so I can work out my own version of exhaust. Been absorbing knowledge here for a while and fixed many things on my TY because of that but this was the first thing that came up where I couldn't find much on the subject. 1 Quote Link to comment Share on other sites More sharing options...
kimpybugalugs Posted March 16, 2017 Report Share Posted March 16, 2017 If you are who I think you are, surely there'll be a spare one amongst all the bits? - and get the front brake working first. Apologies if it's not you. Quote Link to comment Share on other sites More sharing options...
kimpybugalugs Posted March 16, 2017 Report Share Posted March 16, 2017 If it is you, then get it running and we'll hit the river bed. Quote Link to comment Share on other sites More sharing options...
Sectioned Posted March 18, 2017 Author Report Share Posted March 18, 2017 Haha kimpybugalugs, yes it's me and front brake is working well now. Cleaned carb, fitted inline filter, reset float level and its running fantastic. Pulls strong all the way through revs. Ty175 airbox fitted with a mutton cloth filter ? and my oe midbox minus baffle with 1" tailpipe. Quote Link to comment Share on other sites More sharing options...
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