matt_urban Posted October 21, 2009 Report Share Posted October 21, 2009 Would retarding my timing make my bike more controlable at low speed ? im finding it a bit lairy when my rist gets tired Quote Link to comment Share on other sites More sharing options...
benbeta23 Posted October 21, 2009 Report Share Posted October 21, 2009 (edited) Has it got a Flywheel Weight fitted. i no my Evo came with one as standard, not sure about the Rev 3's though. or you could lower the gearing which would probably help. Edited October 21, 2009 by GasGasben Quote Link to comment Share on other sites More sharing options...
matt_urban Posted October 21, 2009 Author Report Share Posted October 21, 2009 oh yer the bike is a 99 techno im running 42-11 gearing bike had a 12 on when i got it ? should i be using first gear more for the slow stuff? did a whole comp in second last time before i changed the front cog Quote Link to comment Share on other sites More sharing options...
benbeta23 Posted October 21, 2009 Report Share Posted October 21, 2009 a 12t front sprocket is way way to big, 11 is ok but try changing the front down to a 10t maybe & then see what it feels, or just use 1st gear going through the sections. Quote Link to comment Share on other sites More sharing options...
chewy Posted October 21, 2009 Report Share Posted October 21, 2009 It was a normal thing to retard timing a bit (in the good old days..ha ha) simply by moving the stator plate with rotation of flywheel by a few degrees. However it would be interesting to know how this would affect modern bikes (they still have stator plates with slots!) but do the modern electronic ignition "black boxes" compensate for misadjustment How is engine mapping arrived at? I know I've got a two position switch on my evo and I can feel the difference. Apart from risking overheating by retarding the spark there would be no "mileage" in retarding by adjusting stator position if electronics then "optimise" timing of the spark...... Be interested to know Quote Link to comment Share on other sites More sharing options...
stork955 Posted October 21, 2009 Report Share Posted October 21, 2009 Gday, the electronic ignitions use 2 coils - one makes the power to run the system, and the other smaller one "tells" the ignition to fire. Both of these coils are mounted on the stator plate, so if you move the stator you move the ignition timing. The pickup or trigger coil replaces the points but effectively works the same way and is what the CDI uses to "know" where the engine is. The modern things with 2 maps (sometimes more) vary the actual advance curve the system has built in, so one curve will use slightly less advance than the other. (Technically CDI's cannot "advance" - they actually retard from a maximum point back towards TDC). This is one major variation from points systems in that they actually have a variable timing system. As an example, one curve might give a maximum amount of 20 degrees and another might give 18. Of course its more than just that, but hopefully you get the idea. Retarding the timing will make the Techno more tractable, but go with the lower gearing as mentioned above. I have retarded my 270 a few degrees and it pulls like a tractor but is "soft" which with my riding skills is a definate bonus! Hope this makes sense, Cheers, Stork. Quote Link to comment Share on other sites More sharing options...
subanator Posted October 22, 2009 Report Share Posted October 22, 2009 Would retarding my timing make my bike more controlable at low speed ? im finding it a bit lairy when my rist gets tired In my experience from having a Techno to the REV3 270 which is quite a lot more responsive, where I should have bought a 200 really. To soften the power delivery, it had extra 2 base gaskets fitted (3 in total). This lowers the compression, but does raise the exhaust port. Power is a lot more smoother and controllable at low speed, just requires a bit more throttle for bigger stuff. Leave the timing standard also. Rides a bit like a 250 now really, and have left it like this even now. Quote Link to comment Share on other sites More sharing options...
nzralphy Posted October 22, 2009 Report Share Posted October 22, 2009 I agree with the gearing.....12t on the front is too high. Try a 10 (for a novice) or 11. Yes adjust the timing. I adjusted my 07 Beta 270 a little retarded (like my riding ) and it was brilliant for taking the edge off the power. It didnt change how the bike started though. Fit an Iridium plug to make the bottom revs smooth. Chewy... is that one or two EVOs? 200cc? Quote Link to comment Share on other sites More sharing options...
copemech Posted October 23, 2009 Report Share Posted October 23, 2009 Gday, the electronic ignitions use 2 coils - one makes the power to run the system, and the other smaller one "tells" the ignition to fire. Both of these coils are mounted on the stator plate, so if you move the stator you move the ignition timing. The pickup or trigger coil replaces the points but effectively works the same way and is what the CDI uses to "know" where the engine is. The modern things with 2 maps (sometimes more) vary the actual advance curve the system has built in, so one curve will use slightly less advance than the other. (Technically CDI's cannot "advance" - they actually retard from a maximum point back towards TDC). This is one major variation from points systems in that they actually have a variable timing system. As an example, one curve might give a maximum amount of 20 degrees and another might give 18. Of course its more than just that, but hopefully you get the idea. Retarding the timing will make the Techno more tractable, but go with the lower gearing as mentioned above. I have retarded my 270 a few degrees and it pulls like a tractor but is "soft" which with my riding skills is a definate bonus! Hope this makes sense, Cheers, Stork. Couple of notes, slowing of timing will slow the bike to a point. But my experiments on the Sherco tend to show that a timing reduction on the rotation of the stator plate of more than about 6mm, which roughly translates into as many degrees of angle, had little effect and could induce other poor running. In small changes of less than 2mm on the plate, there was little difference noted. Another note to Stork, on the Leonelli systems.(Sherco) It seems from the info on their website, they are running dual pickup trigger systems with 20-26 degree offset for angular calculation. I do not understand it all! Quote Link to comment Share on other sites More sharing options...
jse Posted October 23, 2009 Report Share Posted October 23, 2009 Another note to Stork, on the Leonelli systems.(Sherco) It seems from the info on their website, they are running dual pickup trigger systems with 20-26 degree offset for angular calculation. I do not understand it all! Copey, Dual pickups, interesting. Most CDI multiple stage systems use a pre-programmed set of "maps" (distinct bell shaped curves of ignition points/RPM in relation to TDC) and they often are essentially the same curve up to a point, say 2000/2500 RPM, where one has a different rate of advance/retard. The CDI uses the same Hall Effect Sensor (the magnetic pickup) to trigger the CDI using either map. In this case, the rider would toggle between the two CDI programs. Dual pickups would seem to indicate a single pre-programmed map (same curve), but one pickup starting the curve 6 degrees (in this case) sooner than the other pickup. Here, the rider would toggle between the two pickups. Jon Quote Link to comment Share on other sites More sharing options...
stork955 Posted October 23, 2009 Report Share Posted October 23, 2009 Another note to Stork, on the Leonelli systems.(Sherco) It seems from the info on their website, they are running dual pickup trigger systems with 20-26 degree offset for angular calculation. I do not understand it all! Gday, some early Yamaha's (TT 350's and some others I think) used 2 triggers in their systems, the one closer to TDC is used when starting so your knee isn't driven into the bars when it kicks back and the other is the "advance" trigger. That is probably what Leonelli are doing. There is no need these days to use two triggers for different advance curves, even without a battery for a constant voltage source to run the electronics. I've never seen a Hall sensor on a dirt bike, they all use reluctors (factory systems at least) apart from the very early systems like the PE and RL suzuki and KDX's etc. They use a simple coil much like the source coil but with a lower output. Hall sensors take up too much space for the timing disc! (And they might not be as resistant to vibration etc as the reluctor). Cheers, Stork Quote Link to comment Share on other sites More sharing options...
jse Posted October 23, 2009 Report Share Posted October 23, 2009 Gday, some early Yamaha's (TT 350's and some others I think) used 2 triggers in their systems, the one closer to TDC is used when starting so your knee isn't driven into the bars when it kicks back and the other is the "advance" trigger. That is probably what Leonelli are doing. There is no need these days to use two triggers for different advance curves, even without a battery for a constant voltage source to run the electronics. I've never seen a Hall sensor on a dirt bike, they all use reluctors (factory systems at least) apart from the very early systems like the PE and RL suzuki and KDX's etc. They use a simple coil much like the source coil but with a lower output. Hall sensors take up too much space for the timing disc! (And they might not be as resistant to vibration etc as the reluctor). Cheers, Stork Stork, You know what? I think you're correct about the reluctors. My MSEE buddies insist they are Hall Effect Sensors, but as I remember, the magnetic pickups in use now have two wires coming out of it, which would mean that they are reluctors, not HES's, which would require three wires as HES's need a current source to operate and reluctors do not. Cool, I get to tell my MSEE buddies they are full of poop and they owe me a beer.... Thanks for the info, seriously, I love learning new stuff. Jon Quote Link to comment Share on other sites More sharing options...
copemech Posted October 24, 2009 Report Share Posted October 24, 2009 Stork,You know what? I think you're correct about the reluctors. My MSEE buddies insist they are Hall Effect Sensors, but as I remember, the magnetic pickups in use now have two wires coming out of it, which would mean that they are reluctors, not HES's, which would require three wires as HES's need a current source to operate and reluctors do not. Cool, I get to tell my MSEE buddies they are full of poop and they owe me a beer.... Thanks for the info, seriously, I love learning new stuff. Jon Here Jon, go figure! 016.D30.INGLES.pdf Quote Link to comment Share on other sites More sharing options...
ham2 Posted October 24, 2009 Report Share Posted October 24, 2009 Hmmm, I see what you're getting at Cope. I've just had my Leonelli stator sorted by MotorplatUK and I reckon it was the trigger at fault (bike was running but not firing at the right time), whether that was a HES or a reluctor I don't know but I know a man that does... Quote Link to comment Share on other sites More sharing options...
stork955 Posted October 24, 2009 Report Share Posted October 24, 2009 Gday, That's the easy way to tell Jon, 3 wires for a Hall sensor. I was thinking this morning that another reason Hall sensors are not common in dirt bikes is because they need a stable supply voltage to run which is not easily obtained in your dirtbike. Unless it has a battery. Of course Honda have worked around that with the Montys, but I hazard a guess that they still use reluctors for triggering. And definately a hall sensor Cope! What was that system from? Cheers, Stork Quote Link to comment Share on other sites More sharing options...
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