Hi folks I finally scraped the cash together to get this sorted but wondered if anyone new the cause of the problem. It turns out the engine's reached such a high temp that a spark plug has melted and the valve in number two cylinder has burnt out and disappeared through the racefit can! The head has been sent away to be machined and the new valve lapped in. All to the tune of £900.00. I would really like to prevent it happening again!!!!! I've not been running a power commander.... think I will from now on. Any Ideas????
If you burn oil, crap are in the valve and in the piston, and can touch cause valve isn't 100%closed. it can be a cause. Too lean will fuck more than 1 valve i think. Take off some materials in the head and put a 0,55 head gasket and 0,20 base gasket to bump compression !
Id like to see a pic of the head? Guess they blame the can for the fact it did this.? Interesting if so as they never run lean enough to burn a valve! IF you did have a PC it would make more sense, why, simple, I would then say perhaps someone has shared a map that was from a rich bike, that map loaded onto a bike that's already lean would be recipe for a burnt out valve as the bike would now be running VERY lean! BUT you don't have one so that's not the case, your question is a good one, what's caused it to run so lean and hot to melt a valve! All I can say is I would shocked and can not see just a can causing such a problem, IF you end up fitting a PC then when mapping your bike I would pay extra attention on mapping each cyclinder, as the header pipes of the blade don't have individual sample points you would have to make provision for that buy having removable bungs welded in so the dyno guy can sample each one, this is the only way you could tell if one cyclinder is dramatically out compared with the others, mapping each cylinder individually is the best map a bike can get.
Hi Arthur, They didn't blame the can, they just said it might of compounded an already present issue. When I brought the bike it had obvious signs of having been down the road. Cases ground down, tyres blued,cracked battery tray etc etc. Original fairings were gleaming. When this happened I called on the help of some mates who picked me up, stripped the bike replaced the plugs and ran a compression test (I'm repeating what they told me). No compression on number two and slightly low on one of the others. They also told me that the petrol tank wasn't bolted down and the loom was less than tidy. I wasn't surprised but disappointed in the dealer that sold me the bike. Sold as seen is one thing dangerous is another. Anyway at least the valve clearances will be sorted!
Understand, well if lean overall was a problem i.e as a result of unmatched exhaust system Id expect to see general high temps and loss of compression accross all cylinders, if wiring is untidy then they could focus on the injection system and or ECU, sounds like a simple problem could have caused the issue, saying that if a bike ran for some time on its side then anything can happen, maybe ran without oil for a while.
It seems I've spent most of my time putting things right with this one. I trust the boys that have it now, ones a nuclear welder, ones an engineer I go way back with and the bloke doing the work did his apprenticeship with HRC. I've been extremely lucky in the mates department. At least they'll know the engine inside out now.....
Sounds good.. One thing is for sure, Id bet once it's back together they would like to know the cause, IF the problem was not a result of a crash then you would expect to see something wrong with the AFR on the problem cyclinder, IF no problem is seen mixture wise then Id also bet they would scratch their heads to what caused it to fail.
How about a tight valve clearance ,just enough to burn the valve head off , judging by the scrapes on casings it could of been an ex track day tool and then sold on with fresh fairings fitted? Was it an exhaust valve or inlet valve that failed? Any signs of bore wash I wounder on that cylinder? We're any valve clearances on other cylinders tight? Just the other day I pulled an engine down, the gasket had blown out in 2 places ,once the head was off it looked like someone had set about it with a gas axe across the mating surfaces, we eventually traced the cause to oil blowing back up the bore because it had suffered bore wash wear ,the oil vapour then ignited uncontrollably and carried on past the valve thus making the combustion chamber too hot as well as the valve steam, the head eventually detached itself and embedded into the piston
It was due its valve clearance service........... It was an exhaust valve, the boys put an endoscope into the cylinder and said it looked ok but they couldn't be sure until they'd stripped it.
Sounds like it's been an ex-track bike or something tbh. Burning valves out at that mileage is very rare
Cheers madfish. Just received a text, 3 extra exhaust valves have failed a compression test - £37.00 plus VAT per valve and assosciated machining costs which are unknown as yet........ I said just crack on, there's no point putting it back together again otherwise......gonna stand me in a few quid I reckon......
Could get pricey. But youre right, there is no point in doing half a job. Get them all done and have it back on the road soon.
