Blown Engine?

Curious one - thought it had just started running on one cylinder with failed plug/coil, nothing unusual for me, stopped to check and rear cylinder/exhaust header cold but lots of oil on lhs (from starter motor area), TB, top of rear cylinder and, particularly, rear crankcase and exhaust header.

Home courtesy of SOS breakdown recovery (I'm one of their known regulars) and strip down starts tomorrow.

hope its something simple i feel for you cheers bazz

Sad to see another issue! How many miles now mate?

Race miles plus circa 85k road miles but only circa 20k miles on 'new' engine.

if i can help in any way give me a shout

Ta - hoping that it's just failed rear cam cover oil seal filling spark plug shaft and pumping out via lhs drain hole, wind blown onto top, sides and rear of rear cylinder - can't think of any other theoretical cause given evidence but..............

Ho hum.......damaged rhs inlet valve seat, bent plug electrode so there's unwanted metal in the rear cylinder - nothing obviously fallen in from the inlet tract - so it's engine out again and strip down of rear cylinder.

Engine out and off to Paul R tomorrow - far more experienced eye than mine when it comes to engine internals - should use the opportunity to replace front forks and swing arm bearings, I guess.

Oh dude that looks all too familiar to me Hope there isn't too much damage to piston, head and bore.

Know of any good SDRs for sale?

LOL funny you should mention that.... Fingers crossed it hasn't done too much damage m8.

keep us posted mate!!

Not good, was hoping it would be something minor.
Hopefully fixable without too much drama!

Work in progress.........................

Gutted for you. At least the bore survived. Small comfort I know.

As I said in your similar thread, just surprised there was so little mechanical noise, just felt like failed plug/coil pack - bore conclusion preliminary only, based on quick check and need to look below piston, etc.

Sounds like yours was much more gentle though. My engine stopped very quickly and without the slipper clutch I'd have been off as I was in a corner doing 70 and accelerating hard when it went. I think all those revs were what did so much damage on mine tbh.

Anyone know if anywhere, in UK preferably, has black Samco hose kit for SDR in stock? Being quoted 4 weeks delivery by usual sources.

I got one delivered in a day or two, not branded samco but side by side they were identicle.

I wil look up the supplier and let you know.

Shove this into eBay. Pictures show orange hoses but I ordered black and got them in days. Identical to the Samco hoses that came off the bike.

161569265874

Ta - but whilst they looked the same, were they Samco/same quality?

Side by side they looked and felt identical. I'm no expert on silicon hoses of course but I doubt there is any real difference.

Bore is also shot, unfortunately, so looking at +£2.2k in new parts, etc............time to strip down the original engine and check condition of rear cylinder, methinks.

Aye, will strip down and inspect but assuming that it 'survived' the broken plug episode, plan is to put new valves, springs, etc into the 65K miles rear cylinder and stick it on the 20k miles motor - SDR exhaust valves £45 each, inlet valves £145 each apparently....................................

sorry to hear bro

Ta - have contacted Delwest direct.

do all the 990 have titanium valves or only the sdr

Note to self, order ti valves next time I pull apart the engine.

Can't find valve head, though, so assuming blown out of exhaust port.

my word that did do a lot damage ,wheres the spring from , id be checking con rod too for straightness , i feel for u man , cheers bazz

Valve spring.

What do you think caused it?

Valve stem failure probably.

Holy sugar! That quite something!


So what's the plan?

How many miles had those valves done?

Ay caramba, that's pretty bad!
Not usual to let go that way!

Bent con rod so complete strip down underway...............................

Man thats ordinary news. Good luck to you.

Ouch, messy.

Valve spring broke letting valve drop and hit piston would be my guess.

New set of springs all round? Are they the originals?

Yep, afaik they're the originals - engine was bought used.

Any pics..I love a good pic

Pics of what?

thought you may of had some rebuild pics

Not of engine work but rebuild manual shows it as it is.

Another trophy objet d'art for my collection:

'Tis back on the road.

Well done!

Back on side of road again with dead m'cycle - started cutting in and out, one cylinder occasionally two, no smoke, no oil, no mechanical noise - bad plug or coil, methinks, and carry on - five/six miles later, dies and won't turn over on starter motor - battery fine and breakdown truck's battery pack can't crank engine either - thinking starter motor relay..........hopefully.

You must be a patient man to put up with the crap that bike's given you, I'd be so pissed off by now it'd be down the road if it was me (probably why I'm on to my 37th bike at 41 years old!) Hope it's nothing major for ya again

Not sure I understand - gut feeling is that it's a failing starter relay allowing enough power for the lights, horn, etc but not for ignition circuit or starter.

First check will be to bypass the relay and hot wire the starter, I guess.

Could you to put a muti meter on the starter to see if it's getting the correct voltage?

Hope it is something simple but as soon as it's running I would double check everything, seems very bad timing for something to go wrong after a very recent rebuild.

Front cylinder plug.............................



......................looks like front cylinder may have dropped an exhaust valve less than 75 miles after the rear cylinder dropped one - engine is locked up this time though.

Engine out and strip down underway.

Sh*t happens, just gotta get on with it - Guinness and Gitanes help.

Jesus m8 That really is shit luck

Aye, OE engine rebuild will have to be postponed.

Shit! I thought you changed all the valves!

Sure it is not a detonation issue that causes this?!

BTW Gitanes... spew... I was under the impression that only the Legionnaires smoked this stuff
Yellow paper ones?

New valves and springs to 65k miles replacement rear cylinder, 20k miles front cylinder decarboned and valves lapped only.

Electrical glitch was due to a faulty ECU - replaced and no similar issues since.

Both yellow (Mais) and white Gitanes for me - not the same as they used to be, sanitised to suit the Americanised French taste trend and no longer available in UK - worth persevering with though, just like KTMs..........

I thought you weren't meant to lap titanium valves as it removes the coating from valves and seats??

Aye, just the exhaust valves.

Engine out - snapped exhaust valve stem is all I can see at moment - engine strip tomorrow.

With and without embedded valve head:

Holy shit m8. That has to hurt.

Aye, piston twisted and seized in bore and can't remove barrel - will have to cut piston out.

This is not good.

And I take it SDR engines are as rare as rocking horse poo!

Someone has put some bad juju on that bike. Fix that motor and sell that sucker.

I find it odd that it's happened again so soon.

Could this not be down to bad fuelling and the engine running too lean?

A bot of an horror story there.
Maybe an excuse to do the whole thing up properly with new bits and it'll be fine for another 50 thousand miles!

Not sure of logic of that - rear cylinder drops valve, replace with good used head, barrel and rod but new valves, springs, rings, etc - front cylinder then also drops valve, why not do same?

Whoop Whoop let the fun commence

Ho hum - viewtopic.php?f=8&t=26908

This may be the problem...........................



Front lhs inlet valve this time

picture not showing here..

Ditto

Edited

Nope, your link requires you to sign into a google account before viewing..., but then denies you access anyway... so is a waste of time.

I've started using flickr to host photos now as it just works without requiring the viewers to jump through hoops.

Ffs.....................edited again.

yeah picture link works for me now.

has that dropped a valve and smashed the guide?

upgrade to some bronze type guides may help keep it cool. but then again I'm not sure on policy on titanium valves. sure the titanium itself acts as a heat distributor.

please keep us/Me posted? interested in the cause or possible repair

Not sure yet whether valve dropped or collett broke up first but valve stem is now s-shaped and head destroyed at collett seat.