| Author | Message | ||
     E30dean |
So my 99 x1 with 26k started light smoking during deceleration on my last few rides. After some reading I found out that most likely the valve stem seals need to be replaced. After pulling the motor out and apart, here is what I found on the rear cylinder. I still need to pull the front one.     | ||
| Phelan |
EEK!! | ||
| Puls4521 |
Sorry for your loss, might be a good time for a 1250 kit  | ||
| S1owner |
Well sad day you have lost a good one ! But on the bright side you get to build it how you want and you will know everything about it and it is fresh and new ready for unlimited fun! | ||
| Kalali |
I always knew smoking was bad for you but how bad until now...Good luck. So what caused this much carnage? Running too lean? (Message edited by kalali on May 01, 2014) | ||
| E30dean |
So the front cylinder turned out to be in much better condition than the rear, it had now damage on it at all. The smoking was most likely caused by a bad valve stem seal which in turn brought the damage on to the piston. | ||
| Rocket_in_uk |
So the front cylinder turned out to be in much better condition than the rear, it had now damage on it at all. The smoking was most likely caused by a bad valve stem seal which in turn brought the damage on to the piston. Almost certainly not the case. That looks like it's a case of piston cylinder overheat leading to ring failure with oil going up into the combustion process and burning. Likely cause poor quality cylinder and piston - but they've done well at 26000 mile if original. You could soon clean that up and run it with a good piston, providing the bore isn't damaged beyond a light hone. Decoke, clean, lap valves, stem seals, Cometic gaskets. Rebuild, check timing and fuelling. Rocket in England | ||
| General_ulysses |
The exhaust valve looks like it encountered an overheat condition. The powdery white coloration indicates it got cooked somehow. Lean condition or possibly pre-ignition. Although usually the top of the piston gets hammered when detonation occurs. Just looks like it was run very hot. The hind cylinder gets limited cooling airflow on these bikes. I'm sure that added to the situation. | ||
| Blake |
Interesting. What oil did you run? | ||
| Oldog |
in that every thing is in one piece I would call that a good catch..... bore jug new piston / rings, replace valves and seals, mechanical cleaning, and new seals/gaskets perhaps freshen up both top ends | ||
| E30dean |
So I dropped off the jugs at a machine shop to be inspected and possible honed if the rear one is salvageable. I am planning to order new pistons/rings/gaskets/valve seals. If not then I found a set of used jugs/pistons/rings with 9k miles for $200 in order to avoid any extra tuning. or go with the nhrs 1250 kit which would involve extra tuning and costs more. I can clean the head and valves myself but is it necessary to lap them if im reinstalling them? | ||
| Arizona_buell |
Since new pistons are in order why not just bore it .010 over and move on?? Do them both and replace Valve seals and lap or grind valves and be happy once more... I would like to see a picture of the spark plug from the bad cyl..Please. Mark | ||
| E30dean |
Mark I will get you a pic of it as soon as I get home. I agree with your recommendation, Im probably going to bore it once I get the machine shops call and get bigger pistons/rings. Blake, I did a fresh oil change when I bought the bike and I believe I used Mobil 1 vtwin 20w-50. I rode about 1000 miles till the first time it smoked and stopped and then roughly another 400 miles during which I figured out that it smoked only during engine braking and always pulled in the clutch to avoid the smoking. | ||
| Kalali |
I thought in the X1s the ECM did a skip spark when it detected an overheat condition. What intake/exhaust set up do you have? Are you running stock fuel maps? What was your AFV? I'm just trying to understand what caused this and how it could have been avoided. | ||
| E30dean |
The bike has a forcewinder intake, thunder headers and exhaust(according to previous owner), aftermarket cams(not sure which ones), and I believe a race ecm but I need to double check but I remember the guy said it was tuned at a shop to the intake, exhaust and cams. I talked to the previous owner today and he said he paid $1400 for a full inspection and tuneup(including the engine) a few months before selling to me. | ||
| E30dean |
All right here is the pic of the spark plugs. Unfortunately I got them mixed up so I dont which one is from the front or rear.  | ||
| Blu1hockey |
Oh boy champion spark plugs. I don't even run them in my mower. | ||
| Rocket_in_uk |
What does it cost to bore and buy new piston kit? If it's not so much more I'd be looking to get away from stock cylinder / piston. Even remaining at 1200 I'd still be wanting forged pistons over stock cast, and a higher quality cylinder if you expect long term reliability. It looks to me like you have a Champion plug and an NGK BCPR7E which is an extended nose cone copper core plug common in automotive use and not Buell. I would absolutely use NGK every time. Just the correct ones! I'm fairly confident looking at the exhaust valve, it's oil that is burnt on it. This engine has been burning oil for some miles as evidenced by the ring, bore, cylinder damage, which likely has been on the increase for sometime until the point of failure. Rocket in England | ||
| Lornce |
1. New valve guides. 2. New valves. 3. 1250 cyls and forged pistons. 4. Go riding with confidence that it's all been put to right. | ||
| Rocket_in_uk |
Plugs confirm failure not due to combustion pre ignition or detonation issues. Champion shows signs of leaner hotter burn evidenced by damage in failed cylinder leading to mechanical failure. The main cause of failure here is more about quality of components, high mileage, fatigue, type of sustained (commonality) use. Rocket in England | ||
| Lynrd |
Plug on the right looks lean to me. Plug on the left is on the ragged edge | ||
| Gusm2 |
As Rocket says its a common failure, you should have seen the rear on mine when it went, and I agree that a hone or rebore if required and a set o Wiseco pistons and rings should sort it, or go 1250 if you've got loads of dosh | ||
| General_ulysses |
I agree that it does not look like the result of preignition (otherwise the piston would show signs of hammering and even possibly be destroyed). However, I wouldn't be so sure the cause is due to "quality of components, high mileage, fatigue, type of sustained (commonality) use." It could simply be caused by a sustained lean burn condition possibly combined with poor cooling conditions (stop and go traffic ad infinitum). The lean burn in the rear cylinder may have been caused by lots of things, including: intake manifold seal leak, partially plugged injector, incorrect ECM map, incorrect FI system pressure (due to fuel pump or regulator problems, a common malady on X1's). I'd make darned sure those things were thoroughly addressed before putting it back together and running for any length of time. You can check for lean burn by checking for vacuum leaks (spraying solvent around the manifold seal areas and watching for change in rpm) and monitoring your plugs. Make sure they don't have that overheated/whitish appearance shown in the pics. Make sure the right temp plugs are in there, the timing is right, you're running higher octane gasoline and maybe even installing cylinder head temp sensors. Check your ECM map values and ensure the rear injector is delivering enough fuel at all times. Enrich as necessary to get your plugs to have a nice George Hamilton complexion instead of all Marilyn Manson looking, like it is now. good...  bad...  | ||
| Rocket_in_uk |
But the evidence points to a damaged piston and cylinder with a degree of oil burning in the combustion chamber. The oil burning, looking at the exhaust valve and tract suggests this has gone on for sometime to some degree until finally the mechanical components have failed due to sustained overheating. There is little to no evidence from these pics this is anything upstream of the inlet valve, but as I said in my first post, check timing and fueling - as any good mechanic being thorough would and should do. I would say all of the above is likely the cause of fatigue as the stock cylinder and piston have done exceptionally well to have achieved the mileage they have. I could be wrong, but to me this looks like a classic case of a worn out top end, but yes, absolutely a must to check everything as the General says  Rocket in England | ||
| General_ulysses |
Rocket I agree the piston obviously has been over-temped as evidenced by a partially melted skirt and scorched rings. Which in turn allowed large amounts of oil to blow by afterwards. But the crown of the piston shows no obvious signs of preignition, hammering or melting, which is what happens to pistons when there is detonation, as shown in these pics: http://tinyurl.com/n96tm45 To me it just looks like the overall combustion temperature was persistently very hot - probably from sustained lean burn - which eventually melted the weakest/thinnest part of the aluminum piston first; the skirt and ring grooves. In terms of it being worn out at 26k miles? I would like to think my S1 and Uly will go a lot longer than a mere 26K without experiencing a top end meltdown. A properly maintained and operated 1200cc motorcycle engine should easily go far beyond that mileage without the damage shown above in the pictures. I don't expect a Harley engine to have the longevity of a modern Japanese engine, but it should still go way beyond a piddly 26K without any serious troubles. I've only owned my Uly for a year now and my S1 less than two months. Hopefully my expectations for Harley longevity are in line? I know you're like the Harley/Buell guru, so I hope I don't learn otherwise. | ||
| Smoke |
new valve springs as well, aftermarket .005 or .010 pistons to go along with the bore job and face valves and cut seats. you know that you can do heads and cylinders with the motor installed. make sure the rod bearings are tight and don't knock the piston pins out with a hammer and punch. (bad for rod bearings) low budget repair. have fun. tim | ||
| Rocket_in_uk |
To me it just looks like the overall combustion temperature was persistently very hot - probably from sustained lean burn - which eventually melted the weakest/thinnest part of the aluminum piston first; the skirt and ring grooves. If the combustion temperature was consistently high you can bet your bottom dollar the piston crown would show signs of detonation. The pictures posted here show damage consistent with overheating due to friction. I'm sorry to tell you but the tube frame Buells are not renowned for keeping their cylinders parallel and bore wear and piston slap will cause exactly this type of damage. Wear leads to ring seal failure which allows oil to burn in the combustion area. I suspect this has been going on for sometime in this engine. The owner says in his first post he'd observed smoking during his last few rides. It's more than likely he saw it smoking when it became obvious, and likely it's been burning oil long before it were obvious. And long enough that the continued use whilst in this state lead to the piston and bore damage. Now had this engine been stripped when the smoking was first observed I'd expect the cylinder would show obvious signs of wear and if caught in time the piston and rings might not have shown any signs of significant wear. I'd bet if the bore is cleaned enough to take measurements it will prove not to be parallel nor likely particularly round where piston travel occurs. Rocket in England | ||
| Screamer |
If this piston, valve and spark plug evidence (photos) were presented to our crew the conclusion would likely be extended periods of a too lean mixture, not pre- detonation. | ||
| Rocket_in_uk |
If this piston, valve and spark plug evidence (photos) were presented to our crew the conclusion would likely be extended periods of a too lean mixture, not pre- detonation. If it were detonation the piston crown would show where the excess heat started. Could be nothing more than a few speckles on the crown and some discolouring, typically on the edge of the crown. Worse, the crown would show obvious signs of damage. Neither are present here. Clearly seen in the pic, excess heat occurred at the exhaust valve side of the engine. Heat has 'cleaned' the carbon off the crown. Heat on exhaust side of crown is not commensurate with lean burn caused by poor fueling. Excess heat typically seen on exhaust side of piston is friction / piston overheat related. Cylinder scuffing seen in pics supports such. Another massive clue which dispels detonation is piston side damage. Damage is on skirt area below rings and ring landings, commensurate with cylinder / piston overheating and not detonation. Detonation would see rings and ring landings damaged as heat transferred from crown to piston side. Exhaust valve shows oil burn, over time, which owner verified. Plug shows higher combustion temps than normal. The hotter burnt plug from the exhaust side. You need a better crew! Rocket in England | ||
| Lynrd |
I think "Lean condition" is just obvious by reading the plugs. Then again, plugs COULD be the wrong heat range, as well. In any event - lean condition could be tracked back to leaky intake seals (oh that NEVER happens...  ), aftermarket exhaust without a re-tune, *slightly* failed head gasket, or just a bad map. No matter WHAT the reason - the bike is obviously up for a top end job. 26K miles for a top end rebuild is not awesome, but it is not crazy low either. Pre-EVO engines would get about that...You should get more - my personal expectation for an EVO is to expect to do top end at ~50K. My $.02 on how: good machine shop - go to next overbore, fit forged pistons, decarbonize the heads, deck them flat if needed, reseat the valves. If I am in there, i'll always end up polishing the ports because now is the time. I personally don't like Nikasil just because they cannot be overbored.,,,no comment on anybody's 1250 kit, just my preference. |
