July 22, 201214 yr Ha but there where some doubled wall headers back in the 80's. Quite true. Honda, for instance, used double wall head pipes for many years before that. From what I was told, it served two purposes, to keep the outer chrome from blueing and for looks as the small pipes did not look as good to riders even though they were more effecient. On the 4RT, they just use the small diameter pipe tuned for that particular engine as that's what works even though it looks kinda funny. Jon Step away from the bucket, Billy, and nobody gets hurt............
July 22, 201214 yr Beta technos had double skinned pipes - made them a sod to repair / blow out. Many large capacity 4 stroke road bikes had double skinned pipes - to preserve the chrome. Lagging your exhaust won't make hardly any difference to to the revs it works best at, it will just make it work better at the revs it was desiged for as it preserves pressure wave energy. Trials exhausts are a long long way from optimum power design anyway. I would think making the torque curve appropriate to trials use, reducing noise and keeping the exhaust as compact as possible are the main design aims. Cheers
July 23, 201214 yr I've got heat wrap on my fantic.... Under the seat to help keep the radiant heat off the carb , and air box and to help the plastic sidecovers live a longer life, as except for the spare set of Really Flexible ones Lee Harris hooked me up with a few years ago, They are pretty much Unobtainium with the OE. type mounts ... And yes in race cars we always wrap headers , but for two reasons . 1 is to improve the thermal efficiency and exhaust velocity (we won't get into stepped header and chambered pipe discussions here ) and 2 is to lower the underhood temp. Every little bit helps...
July 23, 201214 yr Modern trials bikes need to be light. Have you felt the weight of a steel manifold on modern trials bike? Then you realise why modern bikes use single wall exhausts.
July 23, 201214 yr I wa always led to believe double skin pipes were to make them more durable and quieter. Two narrow pipe are used by Honda on a lot of engines to improve gas flow (two pipes) at high revs but also help torque (narrow diamter) at low revs. Nowt to do with looks. When looking at lightness etc then you need thin walled pipes out of unobtainium to make them light. Trials headers are designed for torque as there is no real expansion chamber as such to help horsepower. They are certainly not the optimum design.
December 10, 201213 yr Say Cope, Do the answers change if you are trail-riding the bike (not trials,) trying to keep up with the pack on their enduro bikes? More oil then? Or no need? Jeff
December 21, 201213 yr Hello Jeff . If your pushing the revs yes . You may have to alter the settings on the carb too ,It's not just about pre mix ratio ,you have an air ellement in the fuel mix also don't forget.A propper enduro has a racing engine , tuning conditions deal with thermal dynamics differently . Don't go at it and do nothing or you could end up with a silencer fire or siezure . Ted.
December 21, 201213 yr When stating a gallon, most people think 5 litres, isnt it 4.55 litres? Doug 4.54
December 22, 201213 yr Unless you're american then it's 3.785litres Thought everything was bigger and better over there ?
December 22, 201213 yr Hello Jeff . If your pushing the revs yes . You may have to alter the settings on the carb too ,It's not just about pre mix ratio ,you have an air ellement in the fuel mix also don't forget.A propper enduro has a racing engine , tuning conditions deal with thermal dynamics differently . Don't go at it and do nothing or you could end up with a silencer fire or siezure . Ted. Thanks Ted. I think this must be what happened to me - file://localhost/Users/jeffjen/Desktop/Trail-riding%20Meltdown%20-%20Is%20Race%20Gas%20The%20Answer%3F%20-%20Gas%20Gas%20-%20Trials%20Central.webloc So would you guess that I need to go up 2 sizes on the Main jet? Jeff
December 22, 201213 yr "Getting back to the original question, more oil gives more power and less wear, deposits are not an issue, the only potential downside is you spend a bit more on oil. Cheers " Thank you dadof2 It took a long time but someone finaly caught on to what I was hinting to. I asked this question way back at the beginning of the post. I wrote "First a question: What burns hotter a gasoline fire or an out and out oil fire? What would a fire fighter say is the hardest one to fight oil or gas?" The point is oil not only lubricates but also burns hotter and providing more power.............. If I understand your theory correctly, a diesel engine should produce more horsepower than a gasoline engine... hmmm... But what burns faster? Gasoline or oil? I think that also has a great (or even greater) influence on the combustion. Just thinking out loud... Btw, I used to run my '98 Cota 315R at 80:1 (as reccomended by Montesa) with no problems.
December 23, 201213 yr Thought everything was bigger and better over there ? If you use smaller measurements & convert to normal numbers then always sounds more impressive, saying a tank is 3usgal sounds bigger than 2.5imp gal although 10lt sounds even better. Only thing that doesn't sound better is weights & they definitely know all about them
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