C40TLRX crank removal and install procedure

[99yam40]

Seems I have a lower main bearing rumbling and will need to pull the crank this winter on my C40TLRX.
I dropped the lower unit and hooked up a hose to cooling tube, fired it up and the noise is still there, so it is not in lower unit.

Being as I have never removed a crank from one of these 3 cylinder Yamahas that the rods are part of crank assembly, could someone tell me if you are suppose to split the case and then slide the pistons out part way to get to the wrist pins to remove and install pistons from rods or just pull pistons all the way out with the crank assembly?
Service manual does not say anything about this coming apart or going back together.

Seems putting them back in would be a pain if trying to put together as a assembly.

[robert graham]

Wonder if anything else might create that rumbling sound?....it would be a heck of a thing to go to all the time and effort and find out it was something else....maybe our friend Rod has some thoughts on this before ripping into it?...

[TownsendsFJR1300]

Being as I have never removed a crank from one of these 3 cylinder Yamahas that the rods are part of crank assembly, could someone tell me if you are suppose to split the case and then slide the pistons out part way to get to the wrist pins to remove and install pistons from rods or just pull pistons all the way out with the crank assembly?
Service manual does not say anything about this coming apart or going back together.

Seems putting them back in would be a pain if trying to put together as a assembly.

Split the cases and pull the entire assembly out with pistons.

The upper case/lower end of the cylinder, should have a chamfer to it so sliding the pistons back is from the bottom isn't terribly difficult. You shouldn't need a ring compressor (but of course the piston has a piston ring retainer built in to keep the rings from spinning on the piston).

With the crank offset, (for assembly) it'd likely be easier laying the engine(block) on its side then sliding/slipping the pistons into the bores slowly until the last is in..

With all three crank pins being at different degrees/offsets on the crank, you'd be sliding in one piston at a time;
http://www.boats.net/parts/search/Ya...TON/parts.html

Looks like piston #1 then #3, then #2 by the crank offset

[99yam40]

thanks, for that info. Just thought it would be tight getting hands in around the crank and everything else to get them started properly with the alinement pins for rings
just trying to decide when to start tearing it apart.
I did put a wrench on power head bolts to see if the would move and they seem to be OK, so I hope for the easy way through this thing.

This year we all got cold weather early, I was planning on doing this in Jan/Feb but am staring to wonder how long I can push running it during good weather

Motor runs fine just making some noises.

What are the recommendations going this deep into the motor?
My plan was to replace top and bottom bearings and seals but not much else but gaskets. the rings should be Ok going back where they came from and am worried about pulling head and exhaust bolts

Are there crank clips that I need to replace? Seems I read something about that in manual to replace them

Not sure if I will even pull the heads.
It is getting up there is age, so I am not sure I want to put too much into it

[TownsendsFJR1300]

At this point, with what your accessing, there's no need to R&R the head.

I'd do a compression test (or a leak down tester) to at least check ther sealing of the rings. If using the leak down tester, TDC and lock the crank via flywheel so it doesn't spin. The LD tester I have reqires 70-100 PSI in the cylinder and WILL spin an engine over if NOT locked down.

If you decide to re-ring it (low compression/ excess leakage, scored cylinder), the head should come off for a hone/bore.

As long as the compression is within 10-15% of each other, your top end should be fine. I suspect if it runs good now, the top end should be good.

I don't know if Yamaha like a light hone job if re-using the rings. The rings, with the pin that holds them from spinning around the pistons, will make sure they go back in EXACTLY as they came out.

You may have a puller for pulling the upper and lower outside main bearings, a machine should be able to R&R (press) them on.

Hopefully, the center main bearings, lower rod bearings are ok.

That crank WILL press apart but of course you can't get replacement, center crank, main bearings. The re-assembly would be a nightmare. I would think, they do one crank pin at a time and work their way up, keeping everything lined up(thus one replacement crank/rods)

I've replaced the lower, large, ROD bearing on a 2 stroke Yamaha MC engine (I've stripped down to the crank, single cylinder 125cc). (It let loose in the middle of an an AMA motocross race decades ago). It had the press together crank but of course, being a single, it was much easier to line with crank halfs back together within spec's.

Once the powerhead is on the bench, removing the flywheel will probably be the hardest part to remove. Splitting cases, pulling the crank, paying close attention to how the clips go back in shouldn't be difficult.

You could even leave the pistons on the rods, just wrap them well in some fluffy hand towels once out of the block. Should you pull the wrist pins, new circlips should be used(just an extra step you really don't need to do).

[99yam40]

I plan on pulling the flywheel before the power head comes off,
Depends on the weather at the time I guess.

I read a bearing splitter and press are needed to remove the bearings, and then heat the bearings to drop back on to the crank.

Not sure if they can be heated for install if there are seals/shields on one side. Not sure what they are made of
Maybe someone can answer that for me

Wish I had salvaged one of the inductive bearing heaters at the electric shop at the plant years ago when they came in and took everything and put into dumpsters. Combined several shops when they cut personnel and gave us more areas of responsibilities.
And no one replaced bearings in electric motors anymore, just replaced motors. But there were still specialty motors on some of the old large rectifier and transformer equipment we worked on you could not buy anymore.
Usually sent just off to have a shop rework them during the last few years.

I guess my toaster oven would work or just have the machine shop take care of the install too.
Shop towels and bubble wrap and/or cardboard tubes taped in place sounds like
the ticket. I guess I need to find and talk to a shop before deciding on how to do it to see what they require/ want.

Yea to rebuild a crank assembly would need a shop with the proper jigs and knowledge.
Rodbolt has mentioned the shop he uses. Have not check for closer shops around here yet

[rodbolt17]

seeing two things.
1 is the 3cyl c 40 hasn't been imported since about 2002 AND typical reason for bearing failure is corrosion(rust). I would remove the cyl head and ex covers then crack open the halves and remove the crank assy.
Carolina machine and tool in Wilmington NC does my crank rebuilds on the built up type cranks.(Ken McCall)
typically a 3cyl is about 300 dollars for all new bearings.
then a careful inspection of the cylinders with a dial bore indicator and a careful inspection of the pistons with a micrometer can tell you if a simple hone or a bore job is required.
your already there and the labor is mostly done.
it only costs a bit more to do a first class job over a patch.
on reassembly I place the block,cyliner side down, and using a dab of vasoline on the rings to hold them in place simply load the assy taking care not to **** it.
the biggest part of the job is CLEAN IT WELL.
that's where I see most backyardigan failures.
CLEAN IT WELL.
2nd biggest failure is substituting sealants and adhesives.
DONT DO IT.
some years back a back yardigan friend rebuilt a 115 crossflow jonnyrude.
he actually almost did it right.
instead of gel seal he used silly cone.
took about a week to blow the motor,well actually it caught fire and burned.
as the gasoline weakened the silly cone seal it started blowing vaporized fuel between the crankcase halves that resulted in a fire.

[TownsendsFJR1300]

You don't want those bearings tightening up mid install (with the hot to cold heat transfer).

Depending on how tight Yamaha made those tolerances, an attempt at removing the bearing can't hurt.

If it comes off fairly easily, the new one should be the same.

Slightly dremeling out the ID of the old bearing and using it as an installation tool over the new bearing should make things easier if you go that route..

A machine shop can swap those very easily W/O damaging anything.

On a different motorcycle, I had the left main roller crank bearing fail every 32,000 miles. (happened again at 64,000 miles). After a complete engine tear down, the bearing was found, the cage itself, actually was 1/3 GONE.

That bearing was under a pressed on cam chain/balancer gear (about the ame size as yours, very large), pressed VERY close to the main crankshaft with no room for me to screw with it... Shouldn't be $20-$30.00

[99yam40]

Yea cooling off in mid placement means a new bearing again.
Done many of them on all size electric motors, had very few problems
really not a problem normally if you have everything ready and get bearing to proper temperature. need very good heat resistant gloves

[rodbolt17]

15 min or so in a toaster oven set at 200*F is more than sufficient. just make sure you hold the bearing in place so it does not slip back.
my toaster oven in the cave heats bearings as well as drying brass after cleaning.

[99yam40]

Thanks Rodbolt.
I plan on opening it up and checking things out before making final decision.

Just hate to start breaking bolts on head and exhaust before getting the pistons out. But I can see if they want to move with out breaking.

This 1999 motor has had 3 owners as far as I know and I am the latest one, so do not know much history.
I picked it up in 2005 and found it had the main jets drilled out ( took awhile to find that) and I have never seen any water spray out the idle relief holes so something may have been done to that as well.

It has run well after I changed the jets, but always had a slite weering sound since I picked it up , but seems to be getting louder and want to do something about it before it damages something major if it has not all ready.

Plugs have looked good since the jets replacement, so hoping for a few more good years out of it

[99yam40]

Well I pulled the power head off today finally.
Not to bad of a chore.
I am wondering how the lower crank bearing seal housing is removed.
Not sure if a special puller is needed.

Manual lists the housing removal before pulling crank, but it looks like splitting case and then pulling housing would be a better way to go.
Service manual does not say much on the subject, just lists the steps in order

On second look I guess I need to pull the bolt holding seal housing to case and then split the case to make getting housing out easier.
Any input from Rod, Bosco, or anyone else that has done this would be appreciated.

[rodbolt17]

once the seal housing bolts are out you can either knock it out or split the case then remove it.
then have someone hold the block still with the head surface on the bench and pull the crank out carefully.

[TownsendsFJR1300]

Just to add, once the crank, rod and piston assembly is out, (if you don't pull the pistons off), wrap the pistons (and inbetween the piston and rod) with some old hand towels and tape them up.

It helps keep them from knocking about, accidental damage..

Once that seal/bearing holder is away from the crank, you'll have plenty of room to pop it out..

[99yam40]

once the seal housing bolts are out you can either knock it out or split the case then remove it.
then have someone hold the block still with the head surface on the bench and pull the crank out carefully.

Thanks guys I will post a picture of the seal housing.
I did not see a good way to pull it as it sits fairly flush in the case and nothing to grab hold of without risking damaging it, so was thinking I would need a special puller of some kind if I pulled it before splitting the case