i,ve had 2 or 3 issues in the last year with my 1098 but managed to fix them. now i have a new problem. the bike is running fine but when i return home it cuts out and will not start when the engine is hot. twice in the last 7 days the bike has done this with the dash reading at about 70. when i press the starter button it cuts out straight away not allowing the starter motor to kick in. i have done about 70 miles with a new battery and mosfet reg/rec. the battery is not a lithium and after this problem last week i moved the reg/rec to the right side of the bike, away from the exhaust but the same thing happened again. both times the bike has started once the temperature has dropped to 40. has anyone encountered this problem ?
Here are some checks. From free to expensive. Free / Very Low Cost Checks Poor battery or ground cable connections (loose/corroded terminals) Weak or ageing battery (test voltage under load) ECU mapping / fueling issue (if aftermarket exhaust or ECU installed) Low Cost Fixes Faulty starter relay Engine temperature sensor giving incorrect readings Dirty or partially blocked fuel injectors Fuel vaporisation / heat soak in fuel system Medium Cost Repairs Crankshaft position sensor failing when hot Low fuel pressure (fuel pump or clogged fuel filter) Worn or weak starter motor Higher Cost Repairs Valve clearances too tight when hot (desmo service) Worn starter sprag clutch (requires engine side disassembly)
Warm engine = more compression plus thinner oil = more strain on sprag clutch Try the free stuff in the list first.
i posted in january about the rear cylinderhead being covered in black soot inside, whilst the front cylinderhead was clean inside. a motorcycle mechanic told me that this has occured because of the bike being fired up to many times without it moving,due to me replacing parts last year . is it possible that the black soot could cause the valves to be out and would need re-shimmed.
I’ve read about heat causing thinner oil and thus pressure in the sprag. What are your starter cables like? I invested in Exact Start cables and no issue since in respect of starting.
just removed the cover plate and checked the gaps on the rear cylinderhead. first time i have done this but i am pretty sure that the TDC has been marked correctly according to my service manual, photo attached. rather than try to explain the gaps at the 8 locations i have taken a photo and written the gaps sizes. please note i did move the green dot into the TDC position. so it looks like 3 locations are out of spec. cannot get enough purchase with a 0.05 feeler gauge on the lower ones so i am presuming that they are steel tight and this is the problem when the engine is hot.
Sounds like the valves are tight, but I don’t think it’s the problem you’re looking for. As it’s not engaging the starter. Sounds like a bad earth to me. Is the starter solenoid clicking?
Yeah, sounds like your bike’s just getting too hot and something’s cutting out. Weird stuff like this can happen with sensors or relays, and if it only starts when it cools, I’d poke around the starter circuit and any parts that hate heat.
i will check that, but again i think my issue might be electrical. why would a bad earth only kick in when the bike is hot at 70 on the dash.
Resistance goes up with heat, giving a voltage drop. Try a jump lead from the battery negative to the engine case next time.
ok, i will try that after another 20 mile thrash. side panel off rapid and attach jump lead to engine casing.
I have had a CPS (crank position sensor) fail before, but only when the engine was hot. As soon as it cooled down, it would start up fine as if there was no problem at all.
My 1098SF does exactly the same, 30 - 40 mile ride, stop for fuel then it never starts, wait 10 mins and off you go. Had it serviced last month and Ducati replaced the battery, waiting to see if that was the cause, other than that they suggested sprag clutch…
My SF can do that as well. The 1098 engine was always one of the most reluctant and difficut starters Ducati made. They can all be troublesome when hot. When mine's having a strop it will turn over OK but doesn't want to fire. Until suddenly it does - usually just as you're sweating about how much battery life you've got left. My SF currently has a failed sprag clutch and it won't turn over at all, just whirrs. If I doubleup the battery power it will throw the sprag suffciently to turn over but very sluggishly. If it's cranking at normal speed the sprag is probably OK. I'm converting mine to lithium this year with a Skyrich battery when I get the sprag replaced. I believe there are also tweaks that can be made to the hot-start map in the ECU, but obviously that needs dynotime.
A lithium battery really helped mine with starting I did upgrade the regulator rectifier though for a mosfet one (to be compatible with the lithium battery) With the battery in the tail it helps with reducing weight up so high
