Mech

If it's here it will be in the downloads section.. Over there --->

From your description of the location and the circumstances I'm thinking it's the overrun bearing/sprag that provided engine braking in the front drive pulley.. I think I'd take the belt cover off and have another go and I'd be leaning over getting my head down as near as possible to confirm the direction of the noise. I can't think of any reason it would start after the other work.. but.. Did you by any chance undo the gearbox mounts trying to get the drive shaft out ?

Even if your plugs are the same you need to confirm the pins are in the right place.. It's probably not as easy as just swapping pins in plugs.. They will be different because the two cdi aren't compatible.. That's what they do so they can tell which is which internally.

Whooo.. That's more like it..

I use petroleum jelly, which is pretty much vaseline but industrial. Smother electrical connectors, spark plug caps, leads and boots, battery terminals. It waterproofs things and prevents corrosion, and it never shrinks or hardens or gets leaks. My bikes go underwater. Exposed metal and switches and things I sometimes spray with WD40 or an equivalent.

Here's how to test a suzuki pump.. that one is probably much the same.. To test the fuel pump you lay the fuel hose to the carb into a bottle. Lay it on it's side with the hose laying flat. If the hose is dangling down you won't see the fuel pumping out properly. Then suck hard two or three times on the vacuum hose going to the pump, and then let the vacuum off suddenly. You should see a single slug of fuel come out of the fuel hose. The slug should be full diameter of the hose and about ten mills long. If that works then your pump is ok and will work if it's getting good pulsating vacuum. To test the vacuum you reattach the vacuum hose and start the motor and let it idle. It should pump fuel out of the fuel hose into the bottle at full diameter of the hose and slugs about eight mills long. If that works then the pump is working and it should start and idle at east. Then you need to check the vacuum is still strong enough when the motor is under load. To check that you leave it all as is but sit on the bike, put the brakes on hard, engage first gear and open the throttle until the motor starts straining against the centrifugal clutch. As the motor starts to labour the pump will likely slow down it's delivery of fuel, but it should keep pumping some. If it stops pumping then you have weak vacuum or a malfunctioning pump. The vacuum has to be strong, and pulsating, when it gets to the pump. If the vacuum hose has been swapped with some soft thin walled stuff the pulsations can get lost as they suck the vacuum hose flat and then let it out again. Low vacuum can be caused by low compression, tight valves, or air leaks.

Is the noise from the back end, rather than down by the drive belt area ? Is the noise a clunk, whine, rattle, grinding, squeak banging.... What's it like ? Is it intermittent or the whole time you are backed off ? Does it get louder if you back off from speed or down a big hill, or is it pretty much the same at all speeds and deacceleration loads ?

If the tank is high enough or pressurised enough the fuel could force the valves open and fuel could flow through, but I'd expect the springs holding the valves shut would put quiet a bit of restriction on the flow.. I wouldn't expect it to flow freely. The valves might seat and work better once it's being used though.. Have you tried it, does it pump ? If it doesn't pump properly, or if it doesn't hold pressure, (only the tiny amount of pressure they work at, about a pound or three per inch), then the valves are defective. Try holding the fuel hose coming off it up high and see if the fuel in it runs backwards and back into the tank.. It shouldn't of course.

How fat's your girlfriend's arse ? Photos please...

No trouble. You could also pull all the fuses one at a time and see which circuit the problem is in.. Relays too perhaps.

And yeah the ECM they call it.. I'm not sure that's so easy to swap over though without having to go through a process to get the dash and ecm to recognize one other.. You could try it.. Even if the bike won't start up without the process it might make the flashing go away, or transfer to your buddy's bike..

Might be worth disconnecting the gear position/neutral switch for a test too..

Recheck all your work .. If the driveshaft is in two parts, a front and rear with a sliding join between them, check the two UJ crosses are lined up. Perhaps squirt a bit of oil over them and the sliding joint to see if it shuts it up.. Can you post a video with the sound ?

No don't short the sensor, it has 12 volts going through it.. Well if it's not the sensor, and tuning the back wheels does it I'd have to suspect a chafed and rubbing wire somewhere on an axle or driveshaft... especially since it causes the lights to flicker.. It's sounding like a fairly plain old electrical connection problem somewhere.. Have you tried just wriggling the wiring one bit at a time while watching the dash.. You could check for stored trouble codes in the dash, which also tests and confirms the communication between the dash and the other computers are ok. The various computers are all connected together by two wires and communicate by sending digital messages back and forwards constantly, and if there is a break in the wire they detect it and store a message saying what's wrong.. We can't just test the wires with a gauge or light, we would just see a small amount of power going through but we wouldn't know if the communication was going on or not.. The dash will confirm that's all ok though, or let us know there is an intermittent disconnect.. If the dash isn't showing strange messages though it's unlikely to be that electronic stuff but we should check it. The manual tells you how to get the stored trouble codes out..

Most yamahas have some way of letting the cdi know the starter is operating.. I suspect that is so it retards the timing a little to take the load off the starter.. It's the only explanation I can think of since they don't need it for a manual start, only when the electric start is being used. I don't know about raptors.. But it might have that and it may be inoperative somehow.. wrong cdi or modified wiring.. if it has that system..

Amen to that Brother.. The dealers know what we are all up against with these electronic bits. They are in the same boat, once they have eliminated everything else, the computer is the suspect, but nobody has a machine to test them so we have to try a substitute to confirm it. I used to have a working relationship with the local car wrecker and he used to let me borrow car computers to try. Can't hurt to talk to the bike shop.. they might have some insights if nothing else..

Yeah well at the moment I think our dollar's worth about 64 cents yanky.. I'd be taking the old cdi into the local friendly dealership(if we had one) and asking very nicely if they had anything they could plug it onto to test....

Ok, got a manual.. It looks like the speed sensor could do that all by itself. Disconnect it and try.

Another thought.. If it is a bad earth or power supply then it should get over loaded by other things, like the lights maybe, or the brake light which will be on the ignition circuit.. Do the lights work ? Horn? brake lights ? The fact that turning it backwards causes a change in the pump cycle makes me thing the problem's inside which ever computer controls that.. efi/ecu or body controller. Best to check/eliminate the simple things first though.. fuses, earths, power supply.

Well so far I've tried two different downloads but they keep failing.. it will be my weather dependent internet connection and this cloudy day. I'll keep trying. What you could do next is find and disconnect the speed sensor, which is most likely on the gearbox. If that doesn't stop the flashing then it would be a good idea to check all around the axles and wheels and driveshaft for any touching wires. If it does stop the flashing then it would seem the sensor is triggering some power drain that's enough to make either a bad earth or power supply play up. The sensor itself shouldn't draw power at all I don't think, and definitely not enough to cause the problem. It makes me thing there will be an electronic fault, in the body control computer if it has one or the ecu, or I would have said the dash, but you've already done that one. Do you think your buddy would let you fit your body control computer(might be called something else) to his bike, it just needs plugging in but not mounted. Any other computers too.. Or borrow his computers. I'll keep trying for the 2008 or 2009 thundercat manuals and get back to you..

If it's on a taper I'd do a puller up fairly tight and then hit the end of the puller's bolt with a hammer.. a short sharp crack with an eight ounce hammer.. I wouldn't heat it..

Yikes, I'll have to have a read what's on that bike.. That's good observations though..The symptoms don't mean much without the circumstances that cause them.. so good spotting there.. I'll have a read.

ha.. That's nuts.

Oh yeah, sand and mud definitely prefer different tyres.. I'd go for sand tyres.

Yamaha electrics are diabolical..haha.. Their manuals are just as bad.. I've got a heap of them and in a single year and model they say the same manual does big bear and kodiak, and others says they don't, they wiring diagrams disagree with one other, and in forums with people comparing the bikes to the diagrams it seems there are a heap of differences and everyone seem to have trouble being sure what they have.. I've been trying to sort this problem out and get to the bottom of it for literally years.. The best I can advise is.. buy genuine !!