jon v8 Posted July 20, 2012 Report Share Posted July 20, 2012 Nice one Darrell......... Hey Cope you know trials bikes have disc brakes and tubeless tyres now! LOL........... Na,my latest bike has drums,tubes and NO rear shocks ! Rigid - its the way forward. Quote Link to comment Share on other sites More sharing options...
pindie Posted July 20, 2012 Report Share Posted July 20, 2012 Seems like we are all agreed on a range between 30-1 and 80-1? Do what you want I say. If it goes bang add more oil, if it smokes like hell reduce oil! Quote Link to comment Share on other sites More sharing options...
madmostin Posted July 20, 2012 Report Share Posted July 20, 2012 Seems like we are all agreed on a range between 30-1 and 80-1? Do what you want I say. If it goes bang add more oil, if it smokes like hell reduce oil! I run an 07 rev on a747 as I used it on tt bikes and I've loads of it about. Recently altered jetting on the bike to get it to run cleaner. Made a huge difference to the running. I use shell vpower and 70cc to 5 litres. With the jetting changed it runs cleaner and silencer is less oiled up. This topic will go on and on. Quote Link to comment Share on other sites More sharing options...
billyt Posted July 21, 2012 Report Share Posted July 21, 2012 007 I guess we will agree to disagree. The oil helps to keep latent heat in the exhaust header which in turn helps with scavenging. Hot rods etc wrap the header pipes in thermal bandages to help keep the heat in them this in turn helps the exhaust cycle scavenge more efficiently. In the end it is all academic as it will not help me keep my feet on the pegs 1 Quote Link to comment Share on other sites More sharing options...
copemech Posted July 21, 2012 Author Report Share Posted July 21, 2012 1908? pOT CALLING THE KETTLE BLACK, dARRELL! Quote Link to comment Share on other sites More sharing options...
copemech Posted July 21, 2012 Author Report Share Posted July 21, 2012 Billy, are you then running oil in your 4T to help things along? I figure a 1% mix of that castor and it would smell like the ass of a princess! Quote Link to comment Share on other sites More sharing options...
copemech Posted July 21, 2012 Author Report Share Posted July 21, 2012 I run an 07 rev on a747 as I used it on tt bikes and I've loads of it about. Recently altered jetting on the bike to get it to run cleaner. Made a huge difference to the running. I use shell vpower and 70cc to 5 litres. With the jetting changed it runs cleaner and silencer is less oiled up. This topic will go on and on. Till you pull your header pipe and try to de grunge it! Quote Link to comment Share on other sites More sharing options...
copemech Posted July 21, 2012 Author Report Share Posted July 21, 2012 007 I guess we will agree to disagree. The oil helps to keep latent heat in the exhaust header which in turn helps with scavenging. Hot rods etc wrap the header pipes in thermal bandages to help keep the heat in them this in turn helps the exhaust cycle scavenge more efficiently. In the end it is all academic as it will not help me keep my feet on the pegs Point being we have little heat in the first place putting about. Wrap one up and let us know just how you fair with that! Quote Link to comment Share on other sites More sharing options...
pindie Posted July 21, 2012 Report Share Posted July 21, 2012 Cleaning your header is general maintenance. Potato in the end and fill with caustic soda and leave overnight. Once back on the bike try and get it hot before your slow riding. Has anyone ever tried pipe wrapping on a trials bike? Quote Link to comment Share on other sites More sharing options...
dgshannon Posted July 22, 2012 Report Share Posted July 22, 2012 pOT CALLING THE KETTLE BLACK, dARRELL! Yep. Just a couple of old farts! Quote Link to comment Share on other sites More sharing options...
jse Posted July 22, 2012 Report Share Posted July 22, 2012 "pOT CALLING THE KETTLE BLACK, dARRELL" Yep. Just a couple of old farts! Now three old farts, but not the one who can't figure how to shut off the Caps Lock............ Jon #3 Quote Link to comment Share on other sites More sharing options...
jse Posted July 22, 2012 Report Share Posted July 22, 2012 Cleaning your header is general maintenance. Potato in the end and fill with caustic soda and leave overnight. Once back on the bike try and get it hot before your slow riding. Has anyone ever tried pipe wrapping on a trials bike? I have a friend who is a Mechanical Engineer and runs a thermo-wrap on the head pipe of his Trials bike. I imagine that other than the frying-lower-leg-skin avoidance feature, the effect is probably minimal at low RPMs/fluctuating pressures in the pipe. Due to the operating conditions of a Trials engine, you also need to worry about rust and the mud stained appearance is usually not so good after a time. On road race, narrow RPM, consistant load engines I think it works well, reducing radiant heat and keeping gas velocity high. Jon Quote Link to comment Share on other sites More sharing options...
billyt Posted July 22, 2012 Report Share Posted July 22, 2012 Now three old farts, but not the one who can't figure how to shut off the Caps Lock............ Jon #3 Make that four old farts and one bucket of diarrhea........ Guess who is carrying the bucket? LOL Quote Link to comment Share on other sites More sharing options...
0007 Posted July 22, 2012 Report Share Posted July 22, 2012 There is a very significant science to what goes on in the head pipe of a 2 stroke engine The exhaust gas temperature at a certain RPM that the manufacturer designed the exhaust to make its best quality or quantity of power is very specific, the return pulse is timed to hit the exhaust port just as the piston is closing the port, there's a couple of reasons but mainly to keep the fuel mix from escaping into the exhaust If we were to wrap the headpipe to increase the temperature in the exhaust what happens is the thinner gasses allow the return plus to move more rapidly, potentially it would return too early and the effect is spoiled Only an engineer and a dyno and a lot of testing equipment would be able to test the benefits of header wrap and even then it would only work over a small RPM range, it sure ain't no "best kept tuning secret" If it were a cheep way to make power, the factory's would be putting double wall pipes on the bikes rather than wasting their time on high tech ignition systems and time consuming porting work, I have only seen wrap used successfully on snowmobiles, but they are unique in that they get snow on the pipe and they really only at a narrow RPM range so it works on them, maybe a 2 stroke race bike could benefit as well Quote Link to comment Share on other sites More sharing options...
billyt Posted July 22, 2012 Report Share Posted July 22, 2012 Ha but there where some doubled wall headers back in the 80's. Quote Link to comment Share on other sites More sharing options...
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