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Post by milkman on Oct 28, 2008 3:45:28 GMT -5
More importantly - will teh days of a kickstart only SR be over now EFI is added?
Will it be W650 style with both elec and kick start - or worse, kicker, gone!!!
Surely they have to keep the kickstart
Would be nice to have something like the KX450, kickstart, injected and battery less
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Post by wotavidone on Oct 28, 2008 16:33:13 GMT -5
The new units going on the big bore trail bikes would not be worth fitting in my opinion.
There was an article on them in Dirtbike Trader a while ago. The thing is, the don't run closed loop cause the oxygen sensors aren't robust enough for the dirt, so they depend on mapping, hopefully getting all the preprogrammed inputs right and thereby getting the desired outputs.
In my industry we call this feed forward control. This can't trim the inputs on the fly very well.
Better than earlier versions of EFI and mechanical fuel injection, which were nothing but electric carbies, but not as good as closed loop.
If you have knock sensing and exhaust gas oxygen measurement you have feedback control, the CPU now has the opportunity to measure what's result is occuring and trimming the inputs to get the desired result. Highly desirable.
Much more likely to get good gains from your engine. Sounds simple, eh?
Mick
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Post by milkman on Oct 29, 2008 0:42:09 GMT -5
Ummmm  Keep it single, kickstart and carbed |
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Post by phoebeisis on Oct 29, 2008 10:42:50 GMT -5
wotavidone-
Why wouldn't the sensors be robust enough for the dirt? It isn't the actual dirt/fine dust/sand that is the problem is it? It should be easy enough to filter that out, I would think?
Is it that they can't take the pounding over time? Seems odd if that is the case. Cars hitting bumps at 70 mph take pretty fierce pounding also(maybe not as hard a pounding as a full on trail bike at speed).
What is it exactly that would cause a failure in O2 sensors in a closed loop systems?
Thanks,
Charlie
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Post by wotavidone on Oct 29, 2008 18:33:43 GMT -5
According to this article, the O2 sensors can't take the pounding. I actually found it a little hard to believe, myself. Plenty of bikes, including EFI harleys I believe, run O2 sensors, and I reckon they would vibrate a sensor more than our babies, so I would aim to find a big single with the sensor in the system. If they haven't got 'em yet, they soon will have, I'm sure.
Mick
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Post by strangeling67 on Nov 6, 2008 19:52:18 GMT -5
So to clarify is it cool to run a straight thru pipe if its a decent length (i.e. not just the headpipe) ? Or is there a homemade style baffle that can be added to a straight pipe to give some backpressure ?
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Post by frankyb on Nov 7, 2008 7:47:59 GMT -5
Have seen 1 3/4 harley drag pipe baffles on ebay from time to time. Sort of like a short baffle tube that goes up the end of the pipe and is fixed with a grub screw arrangement. Only seen them, never tried them, so i dont know how effective they would be. Cheers Franky b.
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Post by woodman on Nov 10, 2008 17:06:09 GMT -5
Drag pipe baffles really kill the power, at least on Harleys. A good muffler will give you a much better riding torque curve, such as a Supertrapp
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Post by wotavidone on Nov 10, 2008 17:57:34 GMT -5
Mate of mine just fitted on of those chinese 150cc racing motors into his XR75 honda frame. The muffler that came with it was very basic, as we found when we got to examine the internals after the aluminium rivets melted and it fell apart on the road.
A simple perforated core with fibreglass mat wrapped around it and an outer shell. That was it. Essentially a straight through pipe with holes in it.
Thing is, it really quietens the bike down, but there is no way that I can see that it would add any restriction to the flow. And it seems to covert the bike from "all noise, no go" to a very quick little beasty indeed.
So that is what I would be looking at, a perforated core in a straight through configuration. But as I discussed with my mate, I'd use the stainless steel wool scouring thingies that Carl mentioned.
Mick
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