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-   -   XT600 Engine Rebuild (http://www.horizonsunlimited.com/hubb/yamaha-tech/xt600-engine-rebuild-63104)

Phoenix6 7 Mar 2012 21:55

XT600 Engine Rebuild
 
Hello everyone...been lurking around here for a while and I figure it was about time I posted an intro and ask a few questions.

After researching the XT600 I decided I needed to get one. I ended up picking up a 1990 XT600 with 6,000 miles for $800.

Here it is when I bought it...
http://i882.photobucket.com/albums/a...u/f1f25c83.jpg

Enjoyed it...road around town, climbed some local hills but not wanting to take it too far out of town until I get a couple issues resolved.
http://i882.photobucket.com/albums/a...u/8ef378a6.jpg

As it sits today...plastidip painted it/protaper bars and grips/mirrors that are the worst I have ever had. Need the stock ones back, broke one while offroading.
http://i882.photobucket.com/albums/a...u/34e4f43c.jpg

The main reason I am posting is to gather some information on potential engine rebuild ahead of me. After putting about 1,000 miles on it so far I have been noticing a pretty persistent clank,clank,clank coming from what appears to be either the cylinder head or the main bore itself and also occasional white smoke out of the tailpipe. I have done a compression check and got readings between 100-110 psi, leading me to believe maybe the rings could be worn. So I will be pulling the head off pretty soon to check how the bore is looking and also the condition of the head/valves. I also pulled the bolt off of the oil filter cover and had plenty of oil coming out so I am assuming it is getting plenty of oil.

1) When building the XT600 engine have the aftermarket gasket kits been of good quality or is OEM the best route?

2) How difficult is it to check and replace the cam chain if necessary? Is a special tool needed?

3) Should the crank woodruff keys be replaced? And is there one on each side of the crank? Any special tools?

Any other tips for rebuilding the XT engine would be appreciated! bier

G600 8 Mar 2012 14:01

Nice bike...


The engine is noisy by nature, and 6000 miles is not much. Are you sure you have a problem?


Is the bike burning oil?


I have heard about a loose nut on the balance shaft making some noise. Maybe you should take off the right hand engine cover and check all nuts (the one on the balance shaft and the others) first..

Phoenix6 8 Mar 2012 16:25

Thanks for your response!

No the bike doesn't appear to be using any oil. The only real thing leading me to believing there is an issue within the engine itself is the low compression and noise. I have heard that these engine definitely make their own distinct noise but I just get the impression it is more than that. I'll most definitely take a look at the balancer shaft nut and the various other ones.

I am going to try and not cause myself as much pain as possible, such as starting an engine rebuild when not neccessary. So any other info for diagnostics before tearing it apart would be appreciated.

Jens Eskildsen 8 Mar 2012 20:26

Check the valves and other "easy"parts before you dig into the engine :)

Phoenix6 15 Mar 2012 00:56

Do the basics first!!!
 
Quote:

Originally Posted by Jens Eskildsen (Post 370494)
Check the valves and other "easy"parts before you dig into the engine :)

Thanks for the advice Jens:thumbup1:...I am a chronic over thinker...so its good to be reminded of the basics. Went ahead an checked the valves yesterday and one intake valve seemed extremely tight. Both exhaust valves being a little tight as well.

This time it paid off too, previous readings were near 100psi and now are...
http://i882.photobucket.com/albums/a...u/92fe31f9.jpg

Pulled the plug in the process and regapped. Not a pro at reading plugs but it seemed to look good.
http://i882.photobucket.com/albums/a...u/91535412.jpg

Fired it up and sounded way better. Took it for a spin around the block and most of the "clanking" has gone away. Bike seems to even have more power then before. :scooter:

Panzer 18 Mar 2012 11:08

Thats a very nice straight looking bike when I bought my TTR600RE it was only just over 2 year old and I thought it was noisy at the top end until my more experienced brother in law told me they're all like that, they are air cooled when all said and done. I wouldnt worry you seem to have a nice machine there. :)

Walkabout 18 Mar 2012 15:39

I bet you are glad you stayed with getting the basics sorted out before leaping into stripping the engine!
Now the valves are in tolerance it may be that the spark plug colour improves - in your pic it looks too black/sooty at present.
I suggest that you check it again in a few 100 miles and see how it looks, or even invest in a new one and see how that goes on.

Phoenix6 21 Mar 2012 23:25

Thanks for the help...I will most definitely check the plug again and just go ahead and put a new one in too! I am most definitely glad I did the basics first, it was a good lesson learned.

I have also since heard from other guys with big singles and you guys now confirm that these engines do naturally tend to make a bit of noise anyway. Looking forward to putting many road and dirt miles on the XT this spring/summer! Cheers

mowby7359 30 Sep 2012 06:09

tt600
 
Hi, you have probably finished the job, but for info only I think the xt and tt are very close motor wise. The one that I own had a knock at idle and just above, this turned out to be the key in drive gear on the crank for the balancer shaft and it sounds pretty bad first up, stick your ear or ? on the motor to determine the source of the problem. :thumbup1:

Lassesand 30 Dec 2012 13:50

I bought an old TT600 from 1987 a couple of years ago. It sounded real bad and it was the nut on the primary gear that was loose! It had sheared the key almost completely off! I bought a new key and new washers and used locktite as well. After assembly it was OK! I checked the ignition and pulled the flywheel; the timing was one tooth off and one slipper blade was dislocated. Before taking a trip around the world I would check up such things on a TT or XT. My TT used a bit of oil and it was the rings that where worn. I have fitted new rings and valve seals now. The cylinder bore and piston was very good so no rebore was nessesary.

pursang 19 Jun 2013 09:06

If you decide to rebuild your engine this is some of the stuff I ran into when rebuilding my 99, hope it helps.

Motorsports Forum - Top end rebuild

jjrider 19 Jun 2013 22:30

That's a real good and well explained tutorial on upper end engine work Pursang :clap::clap:.

Most of the work and way to do it is good for other brands as well, I saw quite a few parts that appear identical to my Honda XL and a newer Suzuki quad. It would be a good article to tag or bookmark !!! Thanks

G600 24 Jun 2013 01:19

Quote:

Originally Posted by pursang (Post 426577)
If you decide to rebuild your engine this is some of the stuff I ran into when rebuilding my 99, hope it helps.

Motorsports Forum - Top end rebuild

That is ONE GREAT WRITEUP. Wow...:thumbup1::thumbup1:

otr002 24 Jun 2013 13:45

Have a read of this........
The Ténéré Forum • View topic - Balance shaft gorn west i think

And this......
The Ténéré Forum • View topic - Engine rattle whilst cold


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