I had this coming…my 2011 pre delivery Tenere ran like a top till about 60 k km (all units will be metric!!). At which point I wasn’t able to do a full oil interval of 5 k without adding oil. It wasn’t much at first, maybe .5 L between fill, then eventually around the 75 k mark it needed 1.5 L between intervals. To top it off I was told that the bike puffed blue off throttle.
Out came the compression tester. For reference, factory spec compression: 84-108 PSI. I’m at 1200 m elevation (3500 or so footsies)
Readings were as follows:
Cyl 1/Cyl 2 (no oil): 62/72 PSI
Cyl 1/Cyl 2 (oil added): 72/88 PSI
I didn’t bother with a leak down test…I don’t own a tester.
If you don’t like reading and like looking at pictures…they are here :
Logic would dictate that rings are suspect, with a possibility of valve seals.
To rebuild or ride, or sell…I went back and fourth a few times. It annoys me to have to carry oil on longer trips. A normal motor will use a small amount of oil between changes i.e. from full mark to low mark on the window. But this was more than that.
Many will say that it’s the oil that I used (non synthetic for a break in-motoman style, google it), then amsoil synthetic from there.
Many will say it’s lack of maintenance. I ride my bikes as intended. I don’t baby them, I don’t putter. I ride. Wheelies, hell yes. Pinging off the rev limiter, hell no. I use the entire rev range. And yes, the bike has been ridden off road. Roughly 40% of the k’s were off road.
What if it was a long weekend bike? The boys at Yamaha Japan wanted to knock off early to drink sake…who knows.
Maybe sub par components? The first gen rings and pistons were discontinued. Same goes for the god awful oil fed cc tensioner. Don’t forget the clutch basket.
At any rate, the decision was made to rebuild the motor. No point in taking it in the ass on a trade in (would sir take $5k, then pay full retail for a new 2016 ST), I didn’t want to sell it second hand to some unsuspecting sucker, besides I really like this bike. It’s a keeper.
I budgeted for a $1000 cdn in parts (not including head work/valve work if needed), Without going into the motor, I wasn’t sure what needed changing/rebuilding.
My initial guess was the parts needing changing would be: pistons, rings, gaskets, valve seals, valves, springs, head bolts, possible head work/valve lap, hone and a possible re plate.
I was extremely fortunate to have a good friend of mine overseeing the process. Richard from nearby Red Deer offered to help me tear down the top end, and rebuild it once we figured out what the motor needed. Richard is one of the top motor guys in Alberta, so I was in good hands.
Disclaimer: THIS BLOG POST IS WRITTEN BY A COMPLETE MUPPET!
DO NOT FOLLOW ANY OF THESE STEPS! THIS ARTICLE IS WRITTEN FOR ENTERTAINMENT ONLY! THE ACTUAL WORK WAS DONE BY A PROFESSIONAL!
Do not attempt this on your own! Do not touch your motor, unless absolutely necessary! Spend lots of money at the dealer, as they will do a better job (highly unlikely) Better yet, sell the Yamaha and buy something reliable like a BMW!
Right. The above out of the way, I set to work on dropping the motor. As always, my trusty Yamaha book by my side, I followed the motor removal step by step. Easy enough. Motor came out without too much trouble. Once out, I had to get my neighbor to help me carry the heavy bastard from my bike bench over to my work bench. The thing weights a god damned ton. I’m guessing about 180 lb.
Motor disassembly was straight forward. Again following the book, I took the head off, set my head studs aside (numbered in a card board sheet)
Now being a complete engine newbie (I only go to the valves, and maybe the cct…but that’s it!!) I was worried by the 1/8″ of carbon on the pistons. It looked pretty gross. No matter, I kept keeping on. Next up was the cylinder head, and to have a peek a boo at the pistons and rings.
Notice the fine scratches at the top of the bore. Yep, the Tenere got a case of KTnatis! took some dirt in somewhere along the way. No worries, a hone will clean it up sufficiently. The nickasil was in perfect shape. About 1/4 thou wear. Cylinder was well within spec. Nothing out of sorts
Rings were just ok. Some blow by present, top ring was starting to move (my plating guy said that that’s what caused the scratches on top of the bores) I’m thinking it’s dirt and shit.
Scraper rings look…meh
Other odds and ends…
If you ride off road, clean the rad from time to time. This never affected cooling of the bike.
Head tear down, and clean day.
I dragged all the various bits over to Richards place and we set to work. Now you can tell a lot from a man’s work space. Mine looks like someone lobbed a grenade into my garage, and ran away. Richard’s shop looks nothing like mine.
I wasn’t sure what to expect with the valves, valve faces, head, guides and seals. Once the valves were compressed, springs seats, valve lock thingies set aside and bagged (Richard’s fine work, not mine…) I was tasked to go to town in the wash basin.
We weren’t going to stop at a varsol bath. Bead blasting was up next. I cleaned the head, pistons, and valves. The cylinder head simply had the excess gasket goop removed with a blade, and sent off for honing
Here’s the interesting bit. The pistons had 1/4 thou wear, after 80k of me romping on them. Basically brand new!
Here’s some hard numbers:
Piston clearance (Piston to cylinder)
Cyl #1: 0.5/.75 thou
Cyl #2: 0.5/0.75 thou
Cylinder number. Taper/out of round
Cyl #1: 0.5 thou / 0.5 thou
Cyl #2: 0.5 thou / 0.5 thou
Piston diameter. Factory spec: 3.8569-3.8575 inch
Piston #1: 3.8571
Piston #2: 3.8571
Head, valve seats, and valves were perfect post bead blast. Nothing wrong with any of the parts.
At this point, I was ready to make my parts list:
-2nd gen pistons and rings. Yes I could have reused the old ones, but Yamaha updated the piston and ring design. You cannot get 1st gen rings anymore. Besides, the 2nd gen is lighter, and higher comp. I did check the cam shaft profiles. Identical from 1st to 2nd gen. Proceed!
-All new gaskets..obvs!
-O ring for water pump
-8 new valve seals. They were gone..like dropping a hot dog down a hallway…
Valve guides were perfect
-Two new coolant hoses. One that drops from the rad to the metal cross pipe. One from cross pipe to water pump. Both were looking a bit swollen
-New cam chain. Old one had about half a link of extra wear. Cheap insurance.
So, what the hell went wrong with the motor. Three things:
-Valve seals (see hot dog down hallway)
-Dirt ingestion and/or top ring flex
Right. Back at it. All parts came in. Well packaged by my friend Don from Lodi. I’m hella cheap, shipping was free from http://www.procaliber.com
Don did say that their packing of the gaskets was sub par. Otherwise no issues. Cheapest parts I found. Plus, if you let you basket contents linger for an extra day, they give you an additional 5% off all items. Bonus!!!
Now, for the fun part. Each piston has a total of 5 rings. Two main rings (with lettering), a scraper ring and a ring on either side of the scraper ring.
These were a total PITA. With two sets of hands, four head bolts to line up the head, we managed to cross the scraper ring several times. It’s extremely hard to notice if it’s actually crossed up. If you’re not paying attention, you’ll put it back together, turn it by hand and find out the hard way. At any rate, we finally got it together, one piston at a time
That shit job out of the way it was time to re-assemble the head. Earlier I mentioned a hot dog down a hallway (see valve seal). When the new valve seals went in, you could feel a nice even drag on the valve. Nice! Richard expertly re-assembled the head (compress each valve. Tweezers in hand and using the force, insert both valve retaining clips (with a dab of grease), while backing out valve compression tool) Any one able to do this, is the fucking man in my book! Tricky, very tricky.
Holy shit on a stick…don’t forget that $2 o-ring on the water pump!!!
I cheaped out, and did not order new head bolts. Think about it. The bolts do stretch, that said, you torque them to a given spec, then use the degree tool on top a torque wrench to go to the prescribed degree (270 degree, or whatever the book says). At any rate, the motor is holding together just fine. Joy!!
Before putting the cover back on we spun the motor, to check that everything is copacetic.
We spun the motor by hand, and there was a very faint ping, and noticeable stop to the proceedings…Yay !!!! Valves contacting the piston..
SHIT ON A STICK !!! When we changed the cc, we re-set the motor to TDC on cyl #1 (T mark on bottom of motor!!). If my little mind can grasp the Yamaha manual, the T mark is only for checking the valve clearance. See page 3-5 and on, in manual.
Remember, T mark is TDC on cyl#1. Then you turn it 270 degrees, and you have cyl #2 at TDC. K mark is for disassembly/reassembly.
Problem being, that we had the valve train set to work with the K mark, but the bottom of the motor itself was set to the T mark.
Long story short, if we didn’t check this, the valve would have run into the pistons on the first crank of the starter. Good catch, scratch that…great catch!
Right. Set the bottom to K. As per page 5-16. Pull the cams, make sure your camshaft marks are aligned on the case, and the hole on the intake camshaft, aligns with the mark on the intake cam cap (closest to the chain)
To sum up:
THE T MARK IS FOR CHECKING CLEARANCE ONLY!!
THE K MARK IS FOR PULLING CAMS. This is where the top and bottom are in alignment/not running interference.
Well no it isn’t. I had to drive home, so we high fived each other. Dragged the heavy bastard to the trunk of my car, and I went home. Job done!
I did forget to check valve clearances the day previous. I was reusing all the valves, and shims. So I marked all the shims, and which vales they went back in. I double checked the clearances, and they were all in spec. Joy. Valve cover back on, and now I can call on my buddy Cam M. to help me muscle the motor back in.
This took about 45 minutes with the both of us moving things back and forth. Eventually we lined up the back bottom motor mounts, slid the bolts in, jacked up the mini jack, slid the top rear bolt in, and last but not least, the four main engine bolts. Done!
The rest of it was straight forward. I basically had to put the whole bike back together. Once the motor was in, I had to re-install the swing arm, shaft drive, and rear wheel. Next up was my clean rad, all hoses, clamps, and coolant. I kept the crash bars and skid plate off, until everything was back on, and buttoned up. I refilled the oil to the top mark, and thumbed the starer. Bike fired up on the first or second crank. Joy!! Got the motor up to temp, and got a low oil light to ping on. Da fug? I forgot that the motor lost a bunch of oil out of the head. No matter. Put in an extra half liter and all was good to go.
Interesting side notes and findings on the rebuild.
While rummaging in the bike, I had a look at my ABS pump. What a mess. I had dried mud half way up my abs pump. The oem drains are too small, and don’t get all the filth out. I removed the pump, clean up the muck, and enlarged the two holes. I’ll check it from time to time to make sure it’s clean.
My throttle cables needed replacing. The bottom cable was catching on the throttle body assembly…can’t remember where exactly, and was starting to frey.
I tested my five year old battery at the local battery shop. The bastard lost five CCA over five years!!! I battery tender all my bikes. Maybe that helped. No matter, i’ll be good for a few years more.
I flushed all fluids, except the shaft drive. New clutch and brake fluids, new coolant, and new oil.
All in all, the whole job took about 10-12 hours. 7-8 hours on the motor. Two hours each for tear out, and re-install.
I took the bike for a break in run, as there was a break in the weather. Wow wee…this thing pulls hard. The bike sounds smooth, and all is well in my world. Now, if I could only get my KTM 300 starter mechanism to behave…
Update: I did some compression readings after a 50 k ride. Here’s the findings:
Prior to rebuild (engine cold). dry/oil added
Cyl 1/Cyl 2 (no oil): 62/72 PSI
Cyl 1/Cyl 2 (oil added): 72/88 PSI
Cyl 1 cold/warmed up motor: 60/68 PSI
Cyl 2 cold/warmed up motor: 60/65 PSI
It’s possible that prior to rebuild the comp read higher because of the extra carbon build up :. more squish/compression
Another interesting fact is that I just did valves on a friends tenere, with 35km of light-ish use, comp cold read:
Cyl 1 cold: 55 PSI
Cyl 2 cold: 65 PSI
Yamaha compression test procedure page
How come I cannot come close to the Yamaha numbers listed on two bikes side by side, at the same elevation? At any rate, I’ll check it again at the next oil change and see what it reads then.
Moar updates: this motor has a decompression unit built into the exhaust cam. So how on earth can you measure compression if the decompression pin lets out the pressure in the cylinders every time? It boggles the mind how Yamaha came up with the numbers.
Whatever. The motor has just over 4k km on it now. Running like a top, zero oil used. What goes in comes out. Magic.