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Shake Rattle and power loss - thankfully no role.


Andrew Harmsworth

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Andrew Harmsworth

Hi, looking for some help of anyone with similar experience.

My 1150RT single spark 40k miles, started to loose top end power a couple of weeks ago, it was no biggy as it really was only when pulling WOT for more than say 10-15 seconds in 5th or 6th, this was accompanied by a sound which I can only describe as gravel rolling around on a tin roof, if I slowed all returned to normal. I wrote it off as fuel starvation/pinking so my thoughts went back to the last service (not that long ago and the problem only notable since then) and wondering if I put in the fuel filter the wrong way or something.

Got the time to look at it this weekend and checked the fuel filter, but it was in correctly. Took some extra time to re-balance the carbs while all the Tupperware was off – nothing conclusive really

On the ride to work this morning and the bike felt smother and somewhat more powerful so tried WOT again. This time there was a step change in power (down) and the bike refused to go any faster, as before I got the gravel noise so I slowed down – not a lot of option really as the problem is back but worse. Now I have a disturbing ticking from the left hand cylinder and the tick over has dropped from circa 1100 to about 850.

The service was a full service so spark plugs, oil, filter, valves adjusted plus valve end float (it was loose) replace air filter for which I have gone from paper one to a washable K&N.

I now suspect some nasty damage! Has anyone had similar symptoms, or advise on this topic?

 

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Morning Andrew Harmsworth

 

Difficult to tell much from this far away but your initial problem sounds like a fuel flow issue.

 

Maybe a slightly leaking in-tank high pressure hose, or a defective fuel filter, or a kinked fuel line, or a plugging pump intake sock, or ?????

 

You really need to run a fuel flow test (you can run a quick fuel flow test from the fuel return hose)

 

The latest problem with lack of idle RPM & noise is kind of troubling IF you ran that engine hard with a very lean condition due to lack of fuel flow (might have burnt a valve or collapsed a piston top ring land)--In any case you REALLY should now run a compression test to see if you have proper engine compression.

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Andrew Harmsworth

Thanks for the prompt reply, I have ordered a compression tester so should be checking Wednesday postal service permitting. I did give the pre filter pipes etc a visual inspection on Saturday, all looked fine but I will do the flow test. Perhaps I have a blocked filter from the supplier.

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Andrew Harmsworth

I don't know if original, squeezed and visually checked, no cracks I have had the bike about 18 months. I am a UK person no ethanol in the fuel which seems to cause less issues with splitting pipes? Flow test (tonight) should show it, from recollection I should get about a ltr per min from the return?

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Andrew Harmsworth

Ok so just disconnected the return fuel pipe and petrol streams out of the return pipe no pump needed or am I testing this wrong?

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Ok so just disconnected the return fuel pipe and petrol streams out of the return pipe no pump needed or am I testing this wrong?

 

Afternoon Andrew Harmsworth

 

You need to plug or pinch off the return line coming from the front then check the fuel flow coming from the rear return line during key on (2 seconds) & (if possible) engine running.

 

You need to see a pencil sized stream. (at least 1 liter per minute)

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Andrew Harmsworth

Thanks, it was a rush to fit everything in last night and stupidly looking at the wrong end of the fuel pipe …. Case of less haste more pace needed.

I did find what I thought was the issue, loose spark plug – I struggle with getting the torque on them with a very snug fit of the socket binding in the spark plug ‘tunnel’ I am assuming it’s got looser since the service to the point of practically firing on one cylinder yesterday.

Picking up on Greiffsters comment I don’t suspect it’s the vent pipes ‘crossed’ as it’s a UK bike with no canister and both vent to the open air anyway.

So running again but still have the lack of top end power , low and lumpy tick over and a ticking noise which sounds to be valve train related. As Dirtrider suggested, possible cause burnt valve piston ring, or possibly (my wallet friendly option) the butterfly on the carb warn. Not diagnosed/or tested last night as I thought I had found the fault with the spark plug and running out of time put it back together hoping it would settle down after a run – it did not 

So the bike is off the road while I wait for the compression tester to arrive and I have some quality time to check the fuel flow and other bits, so my wallets relief last night that it would not be emptied after tightening the spark plug was possibly just temporary – I will report back…

 

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So the bike is off the road while I wait for the compression tester to arrive and I have some quality time to check the fuel flow and other bits, so my wallets relief last night that it would not be emptied after tightening the spark plug was possibly just temporary – I will report back…

 

Morning

 

If you have access to an air compressor, or compressed air you can TELL A GREAT DEAL by bringing piston to TDC on compression-- then, using a cork, or rubber stopper, in the spark plug hole with a hole drilled through the center of the cork. Then simply blow compressed air through the cork center hole.

 

Where the air hisses out of will be your problem. ie, if air comes out the exhaust then you have a burnt exhaust valve(s). If air comes out the throttle body then a leaking intake valve(s). If out the oil fill hole then a piston or ring issue. Just be sure the piston is at TDC COMPRESSION STROKE.

 

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Andrew Harmsworth

Ok compression issue confirmed 70 psi on the right 140 on the left surprisingly not the side I suspected (loose sp) the other. Test fuel flow next before removing the tank.

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Andrew Harmsworth

Ok I got 130 ml of fuel for two pumps turning the ignition on which is Nearer 2 litres per min. Thinking I should test the injector next

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Andrew Harmsworth

Visually tested injectors both pumping our a nice spray in fact it looked a little like the right was passing more than the left

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Andrew Harmsworth

Sit rep, I have now removed the exhaust and preparing for removing the left head. Can anyone help with the attached pictures, I have set the flywheel timing to TDC for the correct cylinder - see first pick, then when checking the cam timing it looks to be about 2-3 deg out on the timing mark, see second pic,

 

Can anyone tell me is this normal?

Flywheel

 

http://i300.photobucket.com/albums/nn24/aharmsworth1/IMG_0396_zpssvw1ghkg.jpg

 

Cam -

http://i300.photobucket.com/albums/nn24/aharmsworth1/IMG_0397_zpsxg737d4y.jpg

 

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Sit rep, I have now removed the exhaust and preparing for removing the left head. Can anyone help with the attached pictures, I have set the flywheel timing to TDC for the correct cylinder - see first pick, then when checking the cam timing it looks to be about 2-3 deg out on the timing mark, see second pic,

 

Can anyone tell me is this normal?

Flywheel

 

 

Morning Andrew

 

That does look to be a little out of time.

 

Do you have the engine pinned at TDC?

 

If you have it pinned then try putting a wrench on the cam sprocket bolt & see if you can gently line the timing arrow up better (if so then you probably just have some cam chain slack due to chain tensioner bleed-down)

 

How does the other side cam gear arrow line up?

 

 

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Andrew Harmsworth

Hi Thanks, I have not striped down the left side yet still working on the right - was hoping not to touch it as compression is good. I have now removed the left head. couple of picks at the end.

 

I think??? its piston rings where i am loosing compression, I have put some paraffin in the top of the head and there was zero leakage, see first photo. its got a fair amount of carbon but I wanted to test before disturbing it all.

 

The cylinder looks scored at the bottom not heavily (can't feel any ridges) but that extra shine at the bottom with the original hone marks now missing.

 

head -

 

http://i300.photobucket.com/albums/nn24/aharmsworth1/IMG_0399_zpsd8bbqqgy.jpg

 

Cylinder -

 

http://i300.photobucket.com/albums/nn24/aharmsworth1/IMG_0400_zpsd2xbuc3h.jpg

 

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Andrew Harmsworth

So I think we have found the compression problem, Pistons supposed to be round without gouges out the side right?

 

 

Top -

 

http://s300.photobucket.com/user/aharmsworth1/media/IMG_0401_zpskxyoxegs.jpg.html

 

Bottom -

 

http://s300.photobucket.com/user/aharmsworth1/media/IMG_0402_zpstvula47p.jpg.html

 

Guessing the piston rings are not supposed to be fused to the piston as well.

 

Edited by Andrew Harmsworth
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Morning Andrew

 

Yes, the piston looks to be junk & upper ring groove looks to be wavy & crushed.

 

Cylinder might be OK & might not be OK. You need to clean it up the measure the taper & out-of-round as well as see if you can remove most of the scoring (personally I would probably not re-use that cylinder so wouldn't waste my time measuring it)

 

I would also de-carbon the cyl head then remove the valves to check the valve seating area for recession damage & warped seats. (just because they don't leak a thick fluid now doesn't mean they are OK)

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Both the cylinder head with the carbon buildup, and the piston look nasty. I assume this is not "normal." What could cause this sort of condition at only 40,000 miles?

Edited by Selden
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I would think the rings got stuck in the compressed position on the one side and caused metal to metal wear on both piston and cylinder wall. Why???????? I can think of a lot of reasons, but not important at this point. Just needs some TLC and a few new parts, or used good ones.

Edited by SAS
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Andrew Harmsworth

Thanks for the help, I ordered £220 of spares yesterday including piston, rings, gaskets, new exhaust studs nuts etc. I am going to try and revive the cylinder as that's another £200 and it looks like the piston has 'smudged' itself over it. hopefully a hone will clean it up I will let you all know. I also have 1 snapped stud to get out the head. Suds and nuts were original and well crusty.

 

I would be greatfull for any thoughts as to route cause. The repair is underway but I am still guessing as to what caused the failure in the first place. I thought it was lean running, but fuel flow and injector seam fine.

 

I have taken the precaution of going back to a standard paper air filter, thought maybe the K&N was higher flow causing lean running but thought the lambada sensor compensated for that?

 

Other than that the damage seemed to be caused by WOT in 5-6 for more than about 5 sec's

 

kind regards

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I can't offer too many thoughts about the root cause but the damage is impressive.

 

Regarding lean running, up to about 50% throttle, the Oilheads normally run at lambda=1 which produces high CHT and the hottest EGT. Any leaner in that region, and the EGT and CHT get cooler, so I don't think general leanness was the issue. Nearer full throttle, your bike ran in open loop with a somewhat richer mixture, 10-12%, lambda=0.9 to keep EGT cooler and prevent detonation. Low fuel pressure or volume could have leaned it back toward lambda=1, increasing EGT, etc. However, when the fuel pressure/volume drops, most of the time, power drops too. I doubt that the K&N changed air volume enough to matter.

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Thanks for the help, I ordered £220 of spares yesterday including piston, rings, gaskets, new exhaust studs nuts etc. I am going to try and revive the cylinder as that's another £200 and it looks like the piston has 'smudged' itself over it. hopefully a hone will clean it up I will let you all know. I also have 1 snapped stud to get out the head. Suds and nuts were original and well crusty.

 

I would be greatfull for any thoughts as to route cause. The repair is underway but I am still guessing as to what caused the failure in the first place. I thought it was lean running, but fuel flow and injector seam fine.

 

I have taken the precaution of going back to a standard paper air filter, thought maybe the K&N was higher flow causing lean running but thought the lambada sensor compensated for that?

 

Other than that the damage seemed to be caused by WOT in 5-6 for more than about 5 sec's

 

kind regards

 

Morning Andrew

 

Can you give us a nice clear photo of the spark plug electrodes on that bad side?

 

Sometimes we can tell what caused that damage by what the spark plug electrodes look like.

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Sure, picture attached -

 

http://s300.photobucket.com/user/aharmsworth1/media/IMG_0403_zpsmgeinupk.jpg.html?sort=3&o=0

 

not overly different to the other side.

 

Morning Andrew

 

Thanks, that does show us something but not what I thought it would.

 

Plug looks fairly normal so it doesn't appear that your problem was caused from detonation. I don't see any alloy from the piston on the plug either. It doesn't look like the spark plug gasket is crushed enough so that can cause the plug to run as hotter range plug but I don't see signs of plug overheating.

 

Something caused the piston crown upper land to crush down on the top ring-- in most cases that is either combustion related or fluid compression related.

 

Did your engine recently digest a slug of water or oil?

 

Is the air box lower chamber full of oil? (check drain on lower left rear of air box)

 

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Andrew Harmsworth

Hats off for looking at a piston ring and pointing at the air box. About 200cc of engine oil came out. So how did it get their is that the compression passing the piston blowing it down the breather?

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Hats off for looking at a piston ring and pointing at the air box. About 200cc of engine oil came out. So how did it get their is that the compression passing the piston blowing it down the breather?

 

Afternoon Andrew

 

200 cc is a lot of oil build up-- But there could have been more as the oil still in the air box causes no problems, it's the oil that got out & possibly into the combustion chamber (as a big slug) that can cause piston damage.

 

A little oil in the air box is normal but a lot can come from oil overfilling of the crankcase, or a lot of blow-by (you probably had that), or dropping the bike on it's side.

 

 

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I'm not a wrench by any means. You may think this a tad odd. BUT

Just last Saturday on public radio Click and Clack the tappet brothers had a call with symptoms just as described. Rattling like marbles, lack of power, high compression engine. They were pretty sure the caller was experiencing pre-detonation due to build up on valves and pistons. There recommendation was to run some water vapor into the carburetor and clean out the deposits. I don't know if that's possible in an injector system. The alternative may be to buy one of those miracle fuel additives.

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Given the large amount of oil that an oilhead carries, under filling seems less risky than over filling. Aside from the need to wait for all the oil to drain from the radiator to get an accurate reading, my rule of thumb is that if I can see air in the sight glass when it's on the center stand, and oil when it's on the side stand, the oil is within acceptable limits.

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Too much oil is also not good because the crankshaft can "hit" it every time it rotates, adding air to the oil, aerating it.

 

I guess the makers of the engine would like you to put as much oil as possible that fits in there, but not as much as it gets aerated. More oil means longer change interval, right?

 

Dan.

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Andrew Harmsworth

Hi all thought I would drop out a thank you and a quick update.

Firstly thanks to all that have helped with the various questions and particular Dirtrider for the expert support.

 

All the parts arrived last week and I have put the bike back together over the weekend, relatively easy with one problem exhaust stud (original) snapped off in the head with the added complexity of after drilling it out for a re-tap the tap snapping off as well.

 

My personal conclusions based on all the good advice I think the cause of piston failure was lean running at the WOT, caused the piston to melt and subsequently blew oil into the air box via the breather causing the ring failure.

What caused the lean running? I not so sure, I have looked to check all elements that could cause it namely –

 

TPS – now reset

K&N air filter, back to stock in-case increase air flow caused lean running

Fuel flow - no fault found good flow

Injectors, cleaned in an ultrasonic cleaner, was quite a lot of dirt in the cleaner after.

Carbon build up, increasing compression, cleaned - impacted cylinder only.

 

I have now retested compression 130 on the impacted pot, a little low which I have put down to new parts needed to bed in, I will re-test next service. And I have also changed oil and filter, Oil was quite thin and sparkly which I will put down to bits of piston and petrol blowing by the doggy piston.

Started on the 2nd press, tick over back up to 1100, re-balanced the cinders but I am feeling a slight buzz through the pegs, nothing too serious putting that down to the compression delta

I am treating the bike carefully for a while so no WOT or >4500 rpm to let the new rigs and piston bed in - checking oil usage daily.

I will report back after the next 1000 miles or so,

 

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All the parts arrived last week and I have put the bike back together over the weekend, relatively easy with one problem exhaust stud (original) snapped off in the head with the added complexity of after drilling it out for a re-tap the tap snapping off as well

 

So, Andrew, how did you get the broken tap out?

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Andrew Harmsworth

Hi Lee,

 

More drilling and a new tap, old tap was very hard and I got through a couple of drill bits before getting enough depth to tap again. One of these little problems that nearly doubled the time taken to do the whole re-assembly.

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Carbide burrs are also good for really hard things like taps. Use a dremel tool and be sure to wear gloves as the tiny slivers you produce are very sharp. Mike

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Never had success drilling through a tap with any drill - cobalt included. I am pleased you have got it sorted though.

 

Ever heard of Boelube? Works great.

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