March 11, 20188 yr Hiya, my 06 4rt has started cutting out at full throttle a few weeks ago. I've changed the tea bag filter and checked the fuel flow output and it's ok. New plug, swapped the throtte body for a known good one. It now struggles to build revs at low end and top end when throttle is opened quickly. Checked resistances at 32 pin Ecu plug. Only iignition coil - primary out of tolerance. Reading 2.2 ohms instead of 2.6 to 3.2 ohms. I have followed as many threads as I can but hope someone can shed some light on this problem. Thanks
March 12, 20188 yr Check the vacuum line that goes from a tap into the intake port on the head to the pressure regulator for cracks / leaks. Don't know if that'll fix your problem, but it's something that's easy to check.
March 12, 20188 yr Hate to say check compression. We have quite a few 4rt`s with way too many hours on the original piston.
March 12, 20188 yr It will be the throttle position sensor in the throttle body. basically as they get worn the throttle sensor will go past 100% and 101% doesn't compute in the ECU so it causes the fault you described. Easy solution is to remove the plastic cover off the side of the throttle body and put a very thin shim under the wide open throttle stop, bringing it back to with in the 0 - 100% limits...much cheaper than buying a new throttle body. I've had this on one of my well used 4rt's and have come across it a few times. Hope it helps, Matt.
March 12, 20188 yr 25 minutes ago, mattv6 said: It will be the throttle position sensor in the throttle body. basically as they get worn the throttle sensor will go past 100% and 101% doesn't compute in the ECU so it causes the fault you described. Easy solution is to remove the plastic cover off the side of the throttle body and put a very thin shim under the wide open throttle stop, bringing it back to with in the 0 - 100% limits...much cheaper than buying a new throttle body. I've had this on one of my well used 4rt's and have come across it a few times. Hope it helps, Matt. yep - done the same. Normal fault with that is only on flat out throttle (big climb etc). If you ride on normal throttle does it run ok or is bottom end lumpy. As you have tried an alternative Throttle body I would be tempted to try swap tank/fuel pump assy. As maybe failing under load. Does it get worse as the bike get warmer? Earth wire at the bottom of the coil can also corrode =- try a fresh extra earth wire from coil to engine bolt. Best of luck
March 12, 20188 yr Author Thanks for all the thoughts fellas. And no I'm hoping not to have to get a new bike Cubby. Plenty of life in this one? . I have checked the earth wire. Runs well when not on full throttle. I have taken apart all the wiring harness connections and will re seat them just in case there's a poor connection. I'll let you all know how I get on.
March 12, 20188 yr Author Right. It's not the earth on the coil. Not the main connections on the wiring loom. Tried the shim of metal on the full throttle stop. Checked the vacuum pipe on the fuel pressure regulator- its not split of blocked. Still misfiring and cutting out at full throttle.?
March 13, 20188 yr Author Doesn't seem to make any difference how warm it is. I checked the valve clearances a few mo the back. I can't understand why that would depend on revs. If it was valve clearances would it not run rough right through the rev range? Starts and ticks over beautifully.
March 13, 20188 yr 1 hour ago, Jeff mc said: Doesn't seem to make any difference how warm it is. I checked the valve clearances a few mo the back. I can't understand why that would depend on revs. If it was valve clearances would it not run rough right through the rev range? Starts and ticks over beautifully. If the valve clearance is supper off then yes the hole range could be rough, however if its just one side or only slightly off you can see it more at one side of the range or the other. Edited March 13, 20188 yr by jonnyc21
March 13, 20188 yr Author Ok. May be worth checking then. I can't see them being that far off but I'll see. I guess it would be more of an issue if the clearance is not enough. That would mean the valves aren't closing fully wouldn't it.
March 13, 20188 yr Author Next stop will have to be swap over of tank and injector assembly to fully rule out the pump struggling under load. Edited March 13, 20188 yr by Jeff mc
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