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[St] 98,398
OK first off I'm unreasonably upset I can't say it honestly made it to
100,000 miles. BUT, it didn't fail catastrophically and we have the
technology to rebuild it. So here's the story.
For a few months I've been chasing an overheating problem on my 2002
Sprint ST. I figured after 90k miles some things are just worn out, so
I tried replacing the thermostat, the radiator cap, and the temp sensor.
All to no avail. When I really ride it hard the temp gauge goes up
and won't come back down until it sits still for a while. It would hold
it's temp if I rode it gently though. Unfortunately that's just not my
style. The last home test I did was to start it from cold, whang the
throttle(technical term there) 3 good times, then shut it off. I
checked the radiator and had a great deal of pressure built up. Bad
sign. I took it into my trusted dealership and they were able to
confirm my suspicions. The head gasket was failing and allowing
compression gases to leak straight into the water jacket.
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0250.jpg
Fortunately the bike never started blowing white smoke, so it wasn't bad
enough to be pulling water in. Since I'm stuborn and not willing to
spring for a new Sprint, we're rebuilding. The pistons had just a
little extra slop in them rotationally so they tore it completely down.
This is actually pretty impressive.
Pistons just after the head was removed:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0236.jpg
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0237.jpg
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0238.jpg
The bores were very nice. You could still see good crosshatching, and
very little vertical marking. Not much carbon build up at the
combustion chambers either.
(due to board limits this story will have to be broken up into multiple
posts. You can only link 4 pictures per post, it seems, so bear with me
please)
And the combustion chambers:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0241.jpg
OK so the original cam chain was pretty tired, but that's to be expected:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0239.jpg
The overall head gasket was pretty tired too. It actually started to
flake and delaminate when the mechanic was lifting the head:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0245.jpg
close up of the main chunk to flake up:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0247.jpg
Since we were already this far, and the pistons had some slight
rotational slop, it was decided to tear the motor completely down.
Besides we were all curious to see how the rest of it has survived me
NOT BAD AT ALL!
The cam lobes were almost brand new looking, and their bearing surfaces
were barely marked:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0240.jpg
This is the oil pan BEFORE it was cleaned up. Those dark spots are the
only 'sludge' to be found in the motor, and they were not deep at all.
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0257.jpg
The crank faired very well too. Again, the bearing surfaces looked VERY
VERY good:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0255.jpg
This is the crank end sprocket for the cam chain, it's showing some wear:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0258.jpg
The pistons after clean up. Really very little marking on them at all.
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0252.jpg
other sides:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0253.jpg
The piston pins looked worn, but you couldn't feel any ridges:
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0254.jpg
And my final set of pictures is of the original clutch basket that was
running all the original plates(which still had good fiber blocks on the
fibers, obvious dimples still on the steels, and no ugly discoloration
of those steels):
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0259.jpg
http://img.photobucket.com/albums/v231/stk0308/Sprint%20motor/IMG_0260.jpg
These marks are just noticeable when running your finger over them. I
never had a clutch problem on this bike. Unfortunately the pics of the
plates didn't turn out nearly as good as I had hoped. I think my
cameras battery was running down near the end.
To fill in the first question on many peoples mind, yes I am having them
rebuild the motor. It's cheaper than buying a new bike, this bike does
everything I need it to do, and I'm 4 months away from being down to
just my mortgage as my only debt. I'd like to experience that just
once, thanks :)
Now the 2nd question. I only used Golden Spectro Semi-synthetic 10w40.
Changed it every 6000 miles. And at every change I used a new oil
filter. Most times a genuwine Triumph one, but others a K&N. I have
done a lot of touring, commuting and backroads sportbike chasing on this
bike, so I've been know to drone for hours on end at 75-80 mph, and
other times I'm running it in the top 1/4 of it's RPM range to boogie
down a twisty road. The bike has done 4 trackdays as well. Overall I'm
very pleased with how the motor looks inside, I just wish it would have
held on just a bit longer to make a true 100k miles unmolested. Then
again, as many of my sportbike buddies have pointed out, over 96k miles
is A LOT OF MILES!
BTW, early estimate from the shop is somewhere between $2700-2750. I
was so excited by the relative little wear in the motor I forgot to ask
if that was all toll with labor or not. It didn't sound like too many
big parts were being replaced, so this could be close to the final
damage. I'm hoping Triumph delivers quickly on the parts so I can find
out before Labor Day weekend....and break it in on the way to eastern
PA, LOL
I hope the picture links work here.
--
Steven "Dirty Dawg" Kohlscheen
AMA Life Member #548538
HSTA Member #9351
2002 Triumph Sprint ST
2001 Yamaha YZ426f
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