A friend, it really is it's not me, has completely stripped his 748 engine, and replaced seals etc. He put it all back together but had got something wrong in the gearbox, so he bought a job of 748, 9** heads, block, gearboxes, he put a different gearbox on his original engine (I think). Now back in the bike, it starts but as soon as you move the throttle it stops, moving the throttle really slowly you can just about get it to 3000 revs and then instantly stops. He has checked TPS and says it reading what it should. Any ideas ??
Sounds ECU-ish to me. But I’m a luddite and very little help - hopefully someone will be along to help soon!
So he stripped and rebuild his engine, got it wrong and though, f..CK it, I chuck another engine in it? Or at least a bottom end/gearbox) Have I understood that correctly? Sounds like a recipe for disaster and it doesn't instill confidence when he says the tps is set correct. If we assume he's correct with the tps, are the belts timed up correct. One tooth out and it may well just about start and do what you describe. Perhaps he could tell us what the tps reads when the throttle is completely shut and/or how he's set it? Did he use some kind of diag software to set it, did he read the voltage of the ECU pin or did he just use a resistance reading?
I popped and saw him again, basically the only things he using from "his" engine are the heads. All pipes are recent in the tank, and it ran perfectly the original engine before he decided to take it all apart, so assume the tank part is ok. I've been there when he's run it and it cuts out instantly, no missing or anything, it's like hitting the kill switch. Not sure what readings he has on the TPS, but he says they are what they should be, I assume it is just using resistance with a multimeter as I know he doesn't have a diag. If the crank sensor wasn't correct could that do it? He's used the original casing that has the sensor, do they have to be set up to make sure the distance between the sensor end and the sprocket/ cog are correct, I assume fairly close. I did question his sense when he first said about taking apart a perfectly good engine, hindsight and all that!
