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XT600E Smoking/Low Compression/Oil Consumption.
I'd like to get some troubleshooting advice on my 99 XT600E, last fall it started smoking like crazy on
start up, white smoke, started up about the same as usual which is to say not immediately but always reliably, except of course in spring when it takes a bit more coaxing, power seems to be the same as when I bought it 3 years ago, it's got 60.000 + km on the odo. at about the same time as the smoking appeared it started using oil like gasoline, would use a whole litre in 2 to 3 hours. I've done a compression check it's got 55lbs :-( So I'm wondering, is it time for a top end or could the lack of compression be caused by tight valves ? can that also lead to oil consumption ? I could also use some help with general specs, since my bike is a 99 and XT600's were not imported to north america after 95 I don't have access to the usual manuals. I'm looking for valve adjustment procedure and specs, top end torque values, stuff not to forget relating to gaskets/O rings/seals etc, and any tips or advice would be greatly appreciated. Thanks guys. |
Rings ?
The valves are work checking for sure but it sounds like worn piston rings to me.
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Hi ,just read the specs for the compression and your is way too low.It should be about 156 psi at sea level so yours is way down.You can pour a little oil into the cylinder and recheck the pressure.If it gets better its your rings.
You should be able to download a service manual from the net somewhere. I,m sure someone will post you a link soon. |
XT600 service manual
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Try these! :) http://www.horizonsunlimited.com/hub...download-32180 Dan |
Valves don't burn oil THAT fast... It certainly looks like ring/cylinder..
Of course, check the bike for leaks elsewhere too and especially the head gasket. It should be pretty obvious if you're losing that much. Time to get that engine out, open your manual and get the kettle on !! It's not that big of a job. Rings should cost about £25, gaskets £25.. Have the bore measured up to see if you need oversize rings. If not, get it honed anyway. XT's don't have a nikisil bore as far as I remember. Btw, tight valves woudn't cause you to burn oil although these should be check as a matter of routine anyway. Also an easy job on the XT. |
Thanks everyone, I've tried those pdf files a few times but it keeps freezing my computer, I do have an online pdf manual for an 03 or 04 TT600RE I hope it's good for my 99 XT. it turns out the intake valves were tight so I adjusted those and the exhaust valves to the specs from the TT manual, 0.05 ~ 0.10 mm intake and 0.12 ~ 0.17 mm exhaust. I've gained a bunch of compression but not enough to get the bike running. I was hoping for one more season out of the beast but I guess it's time to pull it apart and dig out the micrometers.
http://i879.photobucket.com/albums/a...18b676x507.jpg http://i879.photobucket.com/albums/a...22b676x507.jpg http://i879.photobucket.com/albums/a...26b676x507.jpg |
With the amount of oil you are loosing I am not surprised that adding some didn't do much to the compression.
Whip that cylinder off, it won't take long :smartass: |
I've pulled the top end and thought I would let everyone take a look, is it just me or should these parts look much worse than this considering the excessive smoke/oil consumption and the low compression ? I know the tight intake valves were part of the cause for low compression, but I was expecting to see something much worse than this, or will I find the answers when I start taking measurments ? any suggestions ?
http://i879.photobucket.com/albums/a...440512x384.jpg http://i879.photobucket.com/albums/a...459512x384.jpg One of the exhaust ports. http://i879.photobucket.com/albums/a...5512x384-1.jpg http://i879.photobucket.com/albums/a...507512x384.jpg http://i879.photobucket.com/albums/a...500512x384.jpg http://i879.photobucket.com/albums/a...533512x384.jpg http://i879.photobucket.com/albums/a...524512x384.jpg |
sidequestions: where does the valvesealings sit? around the "valvepin"?
do you wash/flush the engin internal before dissembling? it looks so clean... maybe dumb questions... but im asking anyways :) |
You think that doesn't look bad ?? lol
Anyway, you can see with all the carbon build up on the valves, plug and piston that it was burning oil.. Lots of buildup. Now you're this far, measure the bore and check it's within spec. You might need to go for oversize rings if it's excessively worn. Also check the valves are seating properly after all that buildup and burning. You may need to lap them in again... You now need to clean the piston, replace the rings, have the bore honed, change your valve seals and put it back together with a new gasket (after cleaning down the mating surfaces) New plug and make sure your valve clearances are spot on.... :scooter: |
Thanks TT, I know the carbon buildup is bad but I guess I was expecting to see broken rings or a chunk missing from one of the valves, this thing was using a litre of oil in a two to three hour ride ! I took some close up detail shots of the rockerarm/cam followers, they look good to an untrained eye. The rings were gummed up pretty bad, the 2nd ring had no movement at all but was fairly easy to remove, I fit the piston back into the cylinder and it seemed a bit loose, I'll have to buy a 4" micrometer to get more accurate measurments, as you can see in the photos the piston has lots of holes for the oil to get through, not sure if the Wiseco has more or less than the oem Yamaha part. checked the side clearance of the conrod big end/crank, slipped a 0.59mm in there but couldn't get an 0.61mm to go, the specs show 0.35 ~ 0.65mm. the specs I have are from a pdf file for a 2004 TT600RE manual, I still gotta check if this thing has a nikasil cylinder cause the manual is saying to replace the cylinder liner if it's out of tolerance. oh yeah and there's no ridge at all at the top of the cylinder :-)
http://i879.photobucket.com/albums/a...543512x384.jpg http://i879.photobucket.com/albums/a...548512x384.jpg http://i879.photobucket.com/albums/a...550512x384.jpg http://i879.photobucket.com/albums/a...551512x384.jpg http://i879.photobucket.com/albums/a...565512x384.jpg http://i879.photobucket.com/albums/a...566512x384.jpg |
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No I didn't flush the engine, but before I removed the cylinder I used a vacuum cleaner as I scraped some of the crud off the piston top just to keep crap from getting in the cases, I just wiped the cylinder with a rag for taking the photo. |
It might be a god idea to change the valve stem seals while youre in there, they are very cheap.
I wouldnt think the cylinderbore and piston would be within spec when you're burning so much oil, but you might be lucky. |
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You don't have to use a grinding hone if it's not but you should use a rubber ball hone to remove any glaze or build up.. http://www.bayarearidersforum.com/fo...7-dsc01221.jpg |
The Xt's have a iron plate, no fancy nikasil for us :nono: :smartass:
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Those valves are definitely going to need lapping in... Probably with two stages..
Good job on the clean up ! |
Awesome pictures really.
Damn that bike will run great when once finished. My bike have 90k km and doesnt use oil (well, maybe 1dl on 3000km, cant really tell for sure) crazy how different the same bikes can be. |
Looking forward to the pics from the rebuild and keeping my fingers crossed the bike starts first time. Just don't do what I did (when I was 15) and put the pistons in the wrong way! doh
Keep the pics and write up coming.:clap: |
Great Photos
Great close up photos there.
I can't believe how dirty the inside of that cylinder was. Once you have your bore measurements I reckon you will have your answer. |
*Touring Ted*
I do have an old can of Clover compound kicking around, course and fine, I'm looking forward to the lapping process and with any luck getting a really good seal, I did the clean solvent seal test where you fill the intake/exhaust ports and check for leaks, in the dirty condition it failed miserably, I think I'll try it again in the clean condition just to see what happens. Jens Eskildsen Yeah it's gonna run awesome ! I'm expecting a bit more of everything, power, torque and a bit quicker throttle response, the Arrow pipe I installed last fall woke it up real nice so after a rebuild it's gonna be sweet :-) I hope you add lots more km to your bike before you have to rebuild. TurboCharger You must have a lot of experiance if you were doing top ends at 15 ! this thing tried starting I could hear it firing but with only 55lbs of compression even a Yamaha won't run. I'll be keeping an eye open for the "forward" arrow on the new slug. gixxer.rob I agree I can't believe the carbon on that one exhaust port I've never seen anything like it, the buildup on the valves resembles something with 300.000km, I think I may have found my answer today when I measured the ring end gaps :-( I'll post a pic and a few specs. Glad your all enjoying the pics. |
what do you use for the cleaning? looks good:)
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I used a wire wheel on the grinder for the valves carefully avoiding the guide/seat areas, smaller wire wheels that fit into a drill for a few tough spots on the combustion chamber, and the usual asortment of brass/steel wire hand brushes, plastic bottle brushes, tooth brushes etc along with varsol/solvent and elbow grease. it also helps to have 90psi air pressure to blow things clean. the carbon can be tough to remove sometimes you have to carefully use scrapers almost like a wood carver does, holding them with both hands so you don't gouge things up. there's nothing like a shiny clean engine going back together :-)
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I measured the ring end gap in the cylinder and was surprised to see the measurment is twice over what the specs are ! I had to use two feeler guages just to get the 1.07mm. I'm wondering if the specs of 0.30mm ~ 0.45mm are correct for my 99 XT600E since they came from a pdi manual for an 03/04 TT600RE. so much for re-using the old piston.
http://i879.photobucket.com/albums/a...66b512x384.jpg |
Same specs for rings for a 1990 xt600e, so they should be right.
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Thanks Jens.
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While looking for a part number I found this hairline crack on the piston skirt, I don't feel so bad now she didn't fire up this spring.
http://i879.photobucket.com/albums/a...839512x384.jpg |
I noticed one of the intake tracts was noticably dirtier than the other.
http://i879.photobucket.com/albums/a...12a512x384.jpg This could be one of the reasons, the rubber is losing it's bond on the flat part of the aluminum intake manifold, I could also feel movement on the round section which leads into the cylinder. http://i879.photobucket.com/albums/a...15a512x384.jpg |
I think the carbs open at different throttle openings so the port which has the closed carb ('till you open it up) has a vacuum created in it, this could be pulling oil down the valve stem.
What are the valves like for play in the guides, if they're worn you're not going to get a better opportunity to replace, or have guide liners fitted(these are supposed to be the bees knees if you believe the blurb!) |
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Ted |
gixxer.rob: That's exactly what's happening, I'll clean it up and seal it with silicone, about a third of the rubber on the round barrel section has come loose and I can feel it's gritty inside.
*Touring Ted*: Absolutely Ted, I'm just glad I didn't get it running or it might have been a really expensive repair ! oothef: The valves do have some play but I don't have the tools to check if there in or out of spec, I'll have to wait and see what the machinists find. thats the first I've heard of "guide liners" I'll look into those. |
I can't say for sure if the condition of these carbs is after 60.000km or less, I was told the bike went in for carb work but the extent of it may have only been to pop the float bowl off.
Cylinder head side of the carbs. http://i879.photobucket.com/albums/a...477512x384.jpg Loads of carbon and cylinder sludge has been splashing into the carbs due to the tight intake valves not sealing, this shot is the diaphragm carb. http://i879.photobucket.com/albums/a...479512x384.jpg Same cylinder side of the carbs but this shot is the throttle valve on the regular carb. http://i879.photobucket.com/albums/a...480512x384.jpg One of reasons to do your own repairs, I was told when I bought the bike in 2008 it had recently gone to a shop for carb work, instead of replacing the float bowl seal they used some kind of glop that hardened like cement and ruined the rubber seal. http://i879.photobucket.com/albums/a...708512x384.jpg http://i879.photobucket.com/albums/a...25a512x384.jpg Top of diaphragm was pretty much spotless. http://i879.photobucket.com/albums/a...742512x384.jpg The underside of the diaphragm is only filtered by a course inline foam filter that works great for keeping the humming birds out, not so much the gritty fine stuff. http://i879.photobucket.com/albums/a...744512x384.jpg http://i879.photobucket.com/albums/a...745512x384.jpg http://i879.photobucket.com/albums/a...746512x384.jpg http://i879.photobucket.com/albums/a...747512x384.jpg Lots of crud found in the regular carb top chamber, I'm sure some of this stuff finds it's way down the throttle valve and into the intake tract. http://i879.photobucket.com/albums/a...764512x384.jpg None of my manuals list this as anything more than a "Diaphragm Set" this is the top spring side, not sure if thats fuel or cleaning solvent. http://i879.photobucket.com/albums/a...06c512x384.jpg And where the diaphragm sits, would really like to know the proper name for this valve. http://i879.photobucket.com/albums/a...08a512x384.jpg And the underside of the diaphragm that pushes on the brass pin. http://i879.photobucket.com/albums/a...12a512x384.jpg |
info please
hi did you get your bore and piston measured? ( i dont know if you could with the split in the piston ) im interested in knowing if this is a bore / piston or valve problem or both thanks steve
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No Steve the piston/bore was never properly measured since I didn't have a 4" micrometer on hand, the piston did move back and forth in the cylinder, the rings were much worse than the piston, they were excessively worn and sticking, since we discovered the piston was cracked the machinist didn't bother taking measurments, he pretty much just looked at it and said "1st over" I'd say it was a combination of the rings and the valves, the valves were tight and later when I did a solvent seal test all four leaked, also the exhaust valve guides are shot.
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Well, I've just found out today that if you the crankcase breather tube is wrongly routed and causing the tube to be kinked the bike will smoke like hell lol
Vando beer |
She's finished and running like a champ ! Thanks to all my fellow XT'ers who helped with this build.
Motorsports Forum. - Top end rebuild |
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