Linkin's 1999 Yamaha YZF-R6

The bike started first try this evening. Half choke, no throttle, hit the starter and it instantly roared into life. I had the battery on trickle charge all night.

By the time I had got to the servo a few k's away, it stalled. Filled up with 95 premium.

Jumped back the bike and she wouldn't start. About half throttle and it started but would not get above 2,000RPM. And it was hunting, revs pulsating up and down. More throttle and it bogged down. Ease off the throttle slowly and it would eventually stall.

Held it at half throttle and got rolling in 1st, eventually cleared its throat, but would still stall if left to idle. Raised idle speed a little bit. Sat at about 2,500, slowly dropped and stalled. Noticed lumpiness and bogging at 4,000 and below

I *think* it is a combination of air leak in the intake system and clogged pilot jets based on how it behaved. Can't know until I get it apart. Have been told to change the cam chain when doing the valve clearances... but I cannot hear any noise coming from the cam chain.

Carby sync and balance won't hurt either.

 

Right lads, help me out here. I have done some research on the R6 carbs and what people are saying is that the seat for the float needle has an oring around it, and that is what wears out/leaks. The float needle seats are apparently a press-fit on these carbs.

Taken from the manual of the R6, the carbs are MIKUNI CVRD37. However, I believe they messed up. They should be Keihins.

I can get a float needle set no problem, available all over the place. What I can't find is the right seat for them.

I'm also trying to find a carb kit that contains whatever parts I need, and is proving difficult.

Bike shop that this bike has been to said that a second hand set of carbs cleaned up would be better, but what if it has the same problem with the needle and seat? I think I'll stick to repairing what I have.

 

I'll try Wemoto. I think Mikuni being the brand is a misprint in the manual. CVRD37 is definitely a Keihin model

 

I will do that first before anything else.

 

Bike started fine this morning on the way to bunnings. And again when we left bunnings. And again when we left Kootingal. But now it's been sitting for 2 hours and won't start!!!

I have a list of things to check that is getting longer. R/R can die like on the ZXR250 and melt the plug. The stator can burn out, too. Valve clearances is a distinct possibility. The bike also has water in it instead of coolant, and doing/checking the clearances requires dropping the radiator.

Next weekend, I think I'll pull it all off and inspect everything.

 

Checked R/R plug. Looks fine to me. Battery is on the trickle charger.

Have some pics but Imgur is not playing nice right now.

 

Imgur is having issues and I can't upload images at the moment. I have the carbs out and apart. All the jets are soaking in threebond. The carbs looky pretty much pristine. Even the float needle tips feel fine across all 4 carbs.

I bent the float tangs a little to hopefully stop so much fuel getting in. When I took the carbs off the ports, especially #4 had heaps of fuel sitting there. #3 had the valves open so I couldn't tell. 1 and 2 had a little.

I found these on ebay but the price is absoutely ridiculous for some tiny brass parts. Also the standard seats have the Keihin logo and "1.2" on them, not 2.0 compared to the listing.

Motorcycle Spares Warehouse have needles and seats, have emailed them an enquiry.

 

Finally Imgur is behaving.









I have float needles left over from my 3LN1 carb overhaul. I didn't use them because I mainly needed the emulsion tube and needle. They look fairly similar. Wondering if I can get away with using them.