Topic: crank journal / shell wear. advice please!

[kajtek]

Ive taken my engine out to address a few issues i was having. stuck camchain tensioner and planning to replace chain and associated (coming up to 30k miles), leaking output shaft and gear shaft, clutch issues, and to check over bits in the bottom end as things were getting whiny/noisy. leaving the top end in place for now, will do that next winter..

so split the cases, and first look is at the crank main bearings. obviously they will get the plastigauge treatment (is this the right range ? http://www.ebay.co.uk/itm/PLASTIGAUGE-Engine-building-Bearings-0-018mm-0-045mm-/370556458053?pt=UK_Measuring_Tools_Levels&hash=item5646e2d445) but i wanted to get opinions on wear on the journals and how the shells look.

first, my office:

http://imageshack.us/photo/my-images/854/sdc13389.jpg/

bearing shells (some photographed twice):

http://imageshack.us/photo/my-images/28/sdc13396h.jpg/
http://imageshack.us/photo/my-images/706/sdc13400n.jpg/
http://imageshack.us/photo/my-images/26/sdc13399x.jpg/
http://imageshack.us/photo/my-images/827/sdc13397.jpg/
http://imageshack.us/photo/my-images/683/sdc13401w.jpg/
http://imageshack.us/photo/my-images/198/sdc13398i.jpg/

crank journals:

http://imageshack.us/photo/my-images/705/sdc13384h.jpg/
http://imageshack.us/photo/my-images/33/sdc13386l.jpg/
http://imageshack.us/photo/my-images/856/sdc13385y.jpg/
http://imageshack.us/photo/my-images/64/sdc13387c.jpg/
http://imageshack.us/photo/my-images/403/sdc13388u.jpg/

ive run my nail accross the journal surfaces, most feel good, on two i can feel a very slight ridge..

the crankcase has BBBCC stamped on it, i guess this refers to the bearings fitted at the factory?

my main concern is if there is any wear that appears abnormal, an issue of any sort, or means that even if plastigauged and showing in spec that should still be replace.

many thanks for any advice

ashley

[Bodi]

Thise look good to me.
The case code describes only the bore sizes, to get shell sizes you need the crank codes as well. These were marked on the crank when new with some kind of amazing marker pencil that survives engine heat and oil well but they may have been washed off over the years.

[grcamna2]

Hi Ashley,
      I recommend checking the entire cam chain/valve train,tensioner guides,etc.; you may want to pull off the head cover and possibly check your camshaft bearings also.
                                            Have a nice Christmas and a good 2012 !

[Ernest T]

It's tough to figure out what shell to buy if you don't know what you have.  I'm in the process of replacing the cases in my 400F and I bought a set of yellow shells.  I'm hoping I can figure out what I need with one known set.  I'm going to replace all my bearings because I'm concerned about moving a set from one case to another.

 Your bearings look pretty good to me.

[kajtek]

thanks for the reassurance, ive ordered some plastigauge, should be with me soon. will have a look for any markings on the crank, havent seen anything yet though..

i will be going through the camchain, camshaft, rockers/lobes etc, im right in saying though that the camshaft has no bearing shells, that it sits directly in the head?

ashley

[Tim2005]

Yes, the 400's cam runs directly in the head. Check the lobes and followers for major wear, replace the chain and tensioner blade, and make sure the horseshoe hinge is free. Looks like a new airfilter element is overdue too...

[Pecantree]

Kajtek:
Here's a picture of my K3 750 crank. This is looking at the counterweight to the left of the primary chain gears.
I had to clean this very well, used lacquer thinner to get everything off. I think the lettering was done with an engraving pen as it seems to be little stipples. This is the rod journals marked "cl-3333", the crank journals are the same but marked "BABBB"
Hope this helps
Steve

[Ernest T]

Thise look good to me.
The case code describes only the bore sizes, to get shell sizes you need the crank codes as well. These were marked on the crank when new with some kind of amazing marker pencil that survives engine heat and oil well but they may have been washed off over the years.

I'm still trying to figure out what you mean. All the bores for the crankshaft in the case weren't the same from the beginning? Do the letters relate to anything?

[Jerry Rxman Griffin aka MuthaF'er]

Each letter corresponds to a crank bore. Most of mine are A's or B's. They could be the same but usually are not. They apparently were measured after the cases were bored and it is their sizing chart letter. Don't worry about what B means or what A relates to! The only thing that is relative is matching up each letter in order with each letter engraved on the crank in order. Find the crank engravings and let us know. They will be very faint. The first 5 are for the crank and the second are for the rods. Once you have both crank sets then we can help you match them to get the original bearing sizes. I only looked at one of your bearing pictures and as far as I'm concerned it's close to new with next to no wear and could be reused. Another point, these letters were hand engraved very lightly and need to be read with a Japanese accent in mind ie think of how a Japanese would write English letters. You may not understand this until you've done it 1 or 2 times and that's ok.

[dave500]

i just had a quick look at some of those pics at random,,they will be fine to re-use,,if your wearing out main bearings you have trouble no matter what the engine!id be happy to re-use those,if its not a race engine or a re-built sustained high rpm engine id just re-use those,be sure to keep them in the original locations,use a felt pen and number them like from left to right 1 U and 1 L as in 1 upper and lower,polish the bearing mounts in the case and the back of the shell,put it all together "germ free"and itll be ok.

[kajtek]

thank you lots for all the further advice, had a quick look and couldnt find any markings although i havent pulled the plugs so couldnt rotate the crank fully, will charge my camera battery and see if a flash brings it out as light in my shed isnt great, hopefully plastigauge will arrive tommorow and i can find out if need to worry about replacing or not, although with further research on the net looking for worn crank bearings, i can see how mine look ok!

also, the camchain mechanism feels... stuck. not sure if i can afford one of the stainless steel ones, need to have a look at the horseshoe and see if i can fix it.

ashley

[Ernest T]

I've got one good horseshoe in my spare and if the one in my original engiine is good I can sell it to you cheap.

[mca2]

thank you lots for all the further advice, had a quick look and couldnt find any markings although i havent pulled the plugs so couldnt rotate the crank fully, will charge my camera battery and see if a flash brings it out as light in my shed isnt great, hopefully plastigauge will arrive tommorow and i can find out if need to worry about replacing or not, although with further research on the net looking for worn crank bearings, i can see how mine look ok!

also, the camchain mechanism feels... stuck. not sure if i can afford one of the stainless steel ones, need to have a look at the horseshoe and see if i can fix it.

ashley

Seems i have a similar problem. I can't find any tracing of markings on the crankshaft lobes. Maybe i should clean them first? Did you have any luck cleaning them and finding markings? Or is a 400 just like a 750k3 where no markings were applied?

[Pecantree]

MCA2: I can't speak to the 400's , haven't worked on one. Yet!
The markings on the 750K3 lobe are VERY faint and any oil or even moisture will hide the marks.
What I've read is the factory may have stopped doing the marks after the K3, I'm opening a 750K6 this afternoon and will see.
Again I'm speaking about the 750, but in the manual there are tables that give you the crank journal range and what letters correspond to them.
If the marks are there it helps to shine a light at a hard angle to the surface.
Good luck!

[mca2]

I've studied every lobe carefully, but no markings whatsoever. When reviewing the shop manuals, the 750 clearly refers the these markings (serial 1015587 and up for "normal" western numbering), the 500 refers to similar stamps on the side of the lobes (but warns you not to use them), yet the 400 states to measure the crankshaft diameter at the journal and con rod bearings, and allows you to use the markings on the crank case and con rods.

So i tried with my mitutoyo micrometer to measure the crankshaft, yet i think i require a blade type (series 122) micrometer to do accurate measurements.

For your information, i friend of mine restored a K7 and the markings were still clearly present:

[kajtek]

just to update, plastigauged big end and crank shells, all ok! the ones furthest from the crank are outside of the assembly standard but within service limits but they will do for now.

managed to unseize my camchain adjuster, all moves nicely now. new camchain on order, the tensioner wear was down to 3.3mm (limit is 3), it will have to wait till summer, but its easy to pop a new one in with the engine on the bike anyway so not a problem.

with regards to the engine markings, i didnt have anything on the lobe surfaces, although each lobehad something written on its edge in yellow pen, will check it when i get home...