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Hey guys, this isnt my first rodeo, but will be my first yamaha engine rebuild. SO I NEED YOU EXPERTISE TO REVIEW THE GAMEPLAN and Thread!(THANKS IN ADVANCE)

I couldnt find anywhere on this forum about a engine rebuild, so I thought we could document it and get assistance here. Its my buddies trackbike and we will be rebuilding due to a recent spun bearing. Yes we could have sourced a used motor, but with the history of failures you guys speak of, i thought it would be best to make sure every piece with within spec.

Gameplan:
1) Tear Down and Inspection of Damage: At this time, we have drained the oil and discovered brass. Engine noise had started and the bike was shut down. No loose in power or damage from the outside. Since we are on a budget, we will mic out the crankshaft and if anything is borderline, we will have a local yama shop to do inspection on the parts to determine if we can reuse them.​
2) Rebuild: It has always been my belief that the lower end build knowledge is where the genius of a mechanic lies. Therefore, we will have our local yama builder mic out and specify the bearing size colors, supply those and put the case halves together. The rest we will do​

Inspections required:
1.) Cylinder head plane​
2.) Valve/Piston damage​
3.) Oil pump and passage containment​
4.)Crank Shaft journal and connecting rod damage/scoring.​
5.) Crank Case bearing damage​
6.) While there, might as well check transmission shafts/gears/drum​


PART NUMBER QTY
Cam Shaft Chain 94591-61118-00 1 $41.14 new
Head Gasket 2C0-11181-00-00 1 $56.91 new
Generator Cover Gasket(reuse if possible)
Clutch Cover Gasket(reuse if possible)
Oil Pan Gasket(reuse if possible)

Oil Pump (inspect and or replace) 1 $25.00used

Piston(inspect and or replace) 2C0-11631-00-00 X $69.85ea new
Connecting Rod(inspect and or replace) 2C0-11650-00-00 X $122.63ea new
Connecting Rod Bearing 2C0-11656-XX-00 8 $12ea new
Crankshaft Journal bearing 2C0-11416-XX-00 10 $10ea new
Crank Shaft(inspect and/or Replace) 2C0-11411-00-00 1 494.75new (300used)

Oil Nozzles(4) Inspect and/or Replace)
Oil Pump Chain(inspect and/or Replace) 94580-25074-00

MISC
Yamabond Gasket Sealer $15
400-600 grit sandpaper or mineral paper $10
Engine Assembly Grease $10

LABOR
Shop Time: 3 hours @ $70 for case assembly and misc inspection


Optional Machine Shop Cost:
1.) Balance Crankshaft: $149.00

Estimated Cost if Crankshaft, connecting rods and piston are good: ~$500
Estimated Cost if Crankshaft and two connecting rods are damaged: ~$950


Please let me know if im missing any parts, inspections, ect
 

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first mistake... using a yamaha "shop" unless they are well versed in assembly.

second mistake... reusing gaskets. Um dont matter the budget... if you dont have gasket money you might as well give up.
 

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Go fast or die slow.
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Get your hands on an YEC crank and connecting rods as they are actually cheaper then buying oem parts. And they are factory selected parts. "Crank is a optimum balanced version and con-rods are matched. "

You can also stick 08 -> newer rods in there, they have a wider bearing surface then the 06-07 and wont get buggered as fast.

Don't forget to replace con-rod bolts and nuts. Onetime use only.

And buy new gaskets for everything! They don't cost that much and saves you the trouble of having a leaking old one.
 

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I've tore apart a little klx 110 motor and I loved every part of working on it. I wish I could grow the balls to take apart my r6 engine to do myself but there is soooooooooo much more crap involved.

Never re use gaskets unless it's like a clutch cover gasket that goes on and off multiple times.. I've reused them like 10 times. We took all the injectors out of a semi once, put a new(used) one in with the old o rings. Put it all back together. Same problem. It was the damn o rings that was the problem. A 5 hour job turned into like a 20 after tear down and rebuild twice. An extra 100$ in gaskets goes a long way.
 

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"The Dude abides .. "
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you don't need to be a "genius" to pick bearing colors.. the number stamped on the crank, and on the cases determine this. If it's an 06-07, you go one color smaller to keep more oil on the crank (they were too big, low oil psi). We still go 1 color smaller on the 08 in fact, just plastigauge to ensure fit.

i can't picture reusing even the better 08 rods if there is a lot of time on them. I throw away each rebuild (1 full season, maybe few races into another). they are not uber strong/big. If you do reuse, as mentioned by another poster above always use new rod bolts/nuts.

The OEM crank is very good, if not damaged from low oil psi or heat. I wouldn't waste any money at all "balancing". These things are darn good from the factory. Even in a expensive superbike build, we use standard OEM cranks right out of the box. I won't even waste $175 micropolishing any more. If there is a question, it's cheaper to just buy another OEM crank. You can get a good one used for $175-275 depending on how many are on Ebay.

i wouldn't waste money planing the head either, unless you had a bad head gasket to begin with.

Power comes with good cam timing numbers, and good mapping, and of course, good/proper assembly.
 

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Anand Dharma
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14 Posts
Hi,

I am new to this forum but I have used your forum for so much of good advice and inputs.

I have 2007 r6 and the bottom end bearing has given up (i opened the clutch side and can feel the crank rods move)

I have a few questions. I hope this doesn't sound lame..

1. When i replace the bottom end bearing, do i replace just the one thats gone or all of the four bottom bearings?
2. I did read that getting 08 bearings is a better bet? (is this true and will it fit?)
3. Dumb question:(from what i see on the net) To replace the bottom end bearings does the whole top end have to come off (cylinders, cams etc) : is there a possibility of putting the engine upside and only releasing/opening the bottom cases?
4. Is it worth upgrading to a 636 setup?

I see the list of parts needed from Caper656. Very useful
 

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Go fast or die slow.
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182 Posts
Hi,

I am new to this forum but I have used your forum for so much of good advice and inputs.

I have 2007 r6 and the bottom end bearing has given up (i opened the clutch side and can feel the crank rods move)

I have a few questions. I hope this doesn't sound lame..

1. When i replace the bottom end bearing, do i replace just the one thats gone or all of the four bottom bearings?
2. I did read that getting 08 bearings is a better bet? (is this true and will it fit?)
3. Dumb question:(from what i see on the net) To replace the bottom end bearings does the whole top end have to come off (cylinders, cams etc) : is there a possibility of putting the engine upside and only releasing/opening the bottom cases?
4. Is it worth upgrading to a 636 setup?

I see the list of parts needed from Caper656. Very useful
1. You replace all four cause you need a new crank and rod.
2. 08 bearings are wider then the 06-07 helping with load distribution. Haven't measured if 13S bearings are compatible with 2C0 rods.
3. Head has to come off to replace the rod on the bearing that has spun. Also easier to replace the rod bolts when they are out of the engine.
4. Requires lots of work. As the block has to be bored, have new nicasil added to the cylinders.

Cost wise on repairing a engine with a busted rod bearing you might be better of just getting another engine.
 

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Anand Dharma
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14 Posts
Hi Locci,
Thank you for your reply.
I live in India, and crating a engine to here would be quite a task (customs etc )
I am thinking I should go the rebuild route.
thank you
anand
 

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Anand Dharma
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14 Posts
Hi,
thanks to the wonderful folks and the information for helping me get started on rebuilding my 2007 r6.
i blew a crankrod end bearing.
i have taken the engine apart which was fairly simple to do.
my questions are as follows.
1. should i replace all crank rods - i know i need to replace all the bearings
2. my crank looks ok - but i see this discolouration (black burn mark) on the crank web where i had the blown bearing
3. my piston ring gaps are within spec (0.25-0.35mm) - should i still get new rings? or new pistons?

Any other inputs would be welcome

Thank you
 

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do you have access to a machine shop?
The crank can be repaired...
definitely need new rods, rod bearings, and rings. You may need new piston pins or at least polish them and make sure they fit well. Suggest 2 sets of rod bolts for each rod. 1 set for mock up assembly and 1 for final. DO NOT REUSE OLD ROD BOLTS!!
Then while you have all the components out... weigh each of the rods, rod bolts, and try to get them equal in weight (grams). Same with the pistons. Clean up any casting flash.
Youll have to check the cases for bearing sizes. Someone does have a pretty involved assembly video of an R6 engine.
 

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Anand Dharma
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14 Posts
Hi,
I do have access to a machine shop (i assume you mean a lathe)

I am ordering the following new as you suggested

1. New rods
2. New bearings (color codes sorted out)
3. Gaskets
4. New crank bolts/nuts
5. Piston pins
6. Piston Rings

Another dumb question:
Is the usage and measurement of the plastigauge on the crank a must (as mentioned in the manual).
From what i understand that seems to be a measurement you take to understand if the clearance of the bearings are off.
And if so only then you replace the bearings using the "Crankshaft number - rod number" etc.. method

Or do we order the bearings based on the calculations of "crankshaft number - rod number" etc

i guess my question is can i skip the plastiguage measurement since i know i have a blown bearing and i have replace them

thank you
 

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yes pretty much what you are saying. You dont need crankcase bolts...just the rod ones.
Also there is a very specific rod bolt torquing sequence. Make sure you have a good wrench.
 
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