|
|
Post by bultaco on Feb 4, 2012 17:08:32 GMT -8
1999 Yamaha XT600E Top end job.
After 60.000+ Km my trusted 3TB was showing signs of needing a rebuild, the exhaust was emitting hoards of white smoke during start up and the engine was using oil like it was gasoline, one litre for every 2/3hr ride ! 
|
|
|
|
Post by bultaco on Feb 4, 2012 21:31:40 GMT -8
|
|
|
|
Post by bultaco on Feb 6, 2012 17:22:06 GMT -8
Cam and Rockers are in good condition            Keeping Parts Organised \/   Top two rings are stuck.................\/ Submerging piston in solvent freed up the rings revealing the oil/carbon/grime that sticks them to the piston.\/ Closer inspection revealed an almost invisable hairline crack on the piston skirt...........................................\/   
|
|
|
|
Post by bultaco on Feb 6, 2012 17:28:11 GMT -8
Some before and after pics, a lot of grunge collects after 60.000km. Cleaned \/ The two intake valve guides were in good shape but the two exhaust guides needed replacing.  Cleaned \/ Machined Valve Seats & Sandblasted ports. \/   Cleaned \/ Machined Seat & Sandblasted port. \/  Cleaned \/ Machined Seat & Sandblasted port. \/  Cleaned \/ Machined Seat & Sandblasted port. \/  Cleaned \/ Machined Seat & Sandblasted port. \/ Exhaust Ports \/ Sandblasted \/  Sandblasted \/  Sandblasted \/  Sandblasted \/
|
|
|
|
Post by bultaco on Feb 6, 2012 17:57:22 GMT -8
I noticed one of the intake tracts was noticably dirtier \/ than the other. This could be why, the rubber on the intake manifold leading to that tract is losing it's bond allowing unfiltered air to enter, I could also feel movement on the round section which leads into the cylinder, cleaning this with solvent/hot soapy water then blowing with compressed air and letting it dry before applying silicone to seal should solve the problem, or buy new manifolds $$$
|
|
|
|
Post by bultaco on Feb 6, 2012 18:38:23 GMT -8
    A very accurate centerless valve grinder was used on the valves.
Machined Valve. \/     Machined Valve. \/     Machined Valve. \/     Machined Valve. \/ |
|
|
|
Post by bultaco on Feb 12, 2012 22:33:52 GMT -8
I measured the ring end gap in the cylinder and was surprised to see the measurment was twice over what the specs are ! I had to use two feeler guages just to get the 1.07mm. I've been told the specs of 0.30mm ~ 0.45mm are correct for my 99 XT600E, they came from a pdi manual for an 03/04 TT600RE. Measuring ring end gap in +50 rebored cylinder. gap was set by machinist. \/ Comparative examples of 60.000km old shiny bore and the cross hatching of a freshly honed bore \/       New parts include: + 50 Piston & Rings, 2 Exhaust valve guides, 4 Valve seals, Air filter, Oil filter, 2 Circlips for piston pin, Cylinder base gasket, Head gasket, Large "O" ring at cylinder base, 2 Smaller "O" rings at base and top of cylinder, Cam chain tensioner gasket, Float bowl gasket and smaller "O" ring.
Total cost for parts $ 552.94
+ Machining costs $ 354.48
= $ 907.42 Cdn.
Bike runs like a champ !(Update: May 2012. Compression after 1000km since new top end 159lbs)             Valve Clearance (COLD)
Intake: 0.05 ~ 0.10 mm (0.002 ~ 0.004 in)
Exhaust: 0.12 ~ 0.17 mm (0.005 ~ 0.008 in)
|
|
|
|
Post by bultaco on Feb 12, 2012 22:34:34 GMT -8
Doesn't appear carbs have seen much attention in 60.000km.
Cylinder head side of the carbs. \/ 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 (secondary) carb. \/ Same cylinder side of the carbs, this shot is the throttle valve on the primary carb. Carb screws are very tight and come from the factory with thread locking compound, if your screwdriver bits don't fit well now is time to buy one's that do, you can also use hex bits and a ratchet \/   \/ Rubber diaphragm should be soft and pliable with no cracks The underside of the diaphragm draws air through a very course foam filter which fails to keep the fine gritty stuff from entering the chamber..\/     Lots of crud found in the primary carb top chamber, I'm sure some of this stuff finds it's way down the throttle valve and into the intake tract...\/       One of reasons for doing your own repairs, the previous owner sent the bike to a shop for carb work, instead of replacing the float bowl seal some kind of sealant that hardened like cement was used which ruined the rubber seal. \/   None of my manuals list this as anything more than a "Diaphragm Set" I've also been told it's the "coasting enricher" this is the top spring side, not sure if the fluid present is solvent from cleaning or old fuel............\/ And the underside of the diaphragm that pushes on the brass pin. \/ And where the diaphragm sits, the "coasting enricher"...\/             
|
|
|
|
Post by bultaco on Feb 12, 2012 22:35:00 GMT -8
PARTS COMPARISON (1995 ~ 1999)Yamaha stopped exporting the XT600 to North America after 1995 so finding parts for my 1999 is a challenge, in Canada and the U.S. part numbers and the usual service manuals don't exist, hence the parts comparison routine, parts for the 95 model are working fine.             
|
|
|
|
Post by Andrew on Sept 6, 2021 5:20:27 GMT -8
Great work, Thankyou.
|
|
|
|
Post by Guido on Jul 27, 2023 21:24:03 GMT -8
Just here to thank you as I’ll be having to do something similar.
Amazing info!
|
|
