Cracks to rh engine case cover at clutch

[rolie]

I’ve been using the great advice on this site since before I started restoring the 1982 250LC I’ve had in boxes for over 25 years. The pandemic has given me the kick I needed to get going so at least it’s done some good. I’m afraid I’m a complete novice, especially when it comes to the oily bits inside engines, so I hope this doesn’t end in tears! This is my first post and I have no doubt you can help.

I started a couple of months ago and lots of bits are now off to get painted, but I have just started looking at the engine. Strip down going OK though some of the bits have proved somewhat more resistant than I’d hoped!

The rh engine cover came off relatively easily. Everything looked good on the outside but I noticed cracks internally on the section of the cover housing the clutch. Hopefully the photographs show them adequately. 

flic.kr/ps/3ViwQ5

It would be good to know what might have caused this and whether the cover can be used, repaired or needs to be replaced. 

You will also notice part of a red ring to the rear of the clutch basket. This obviously isn’t where it should be but I can’t see it in the Haynes guide so I’m not sure what it is and what I should do about it, if anything. Is this part of the problem?

Your thoughts would be much appreciated.

Rolie

[andy748]

Hi Rolie, your photo link isn't working as they are not shared as public? Andy.

[rolie]

Andy

Not an auspicious start! Hopefully they are on now.

Rolie

[dusty350]

2E5C78D6-AC6D-49CE-A3B2-3524AE4B9BDA by Roland Carson, on Flickr

8F63DDFF-7414-43E6-83E2-DFBA59761CF7 by Roland Carson, on Flickr

[dusty350]

Hi
Welcome to the forum.
The red gasket between the clutch basket and the gear is not available as a separate part from Yamaha. It is a gasket that sits between the 2 parts as there is rotational movement between said parts. A forum member was looking into remaking them possibly. The only way to remove it is to split the clutch assembly - if your clutch is ok I would leave it unless it looks like it will break away, but they are pretty tough, and made from a plastic like material.
The cracks may be casting marks. If there is no evidence of damage/leaks, it may well just be the crappy castings that are found on these engines. I've looked at crank cases before now, thinking they were cracked, and just found the cracks to be rough casting.

Dusty

[dusty350]

20170217_123309 by dusty miller, on Flickr

As you can see, a lot of the gaskets deform over time/use.

Dusty

[stusco]

Do you think that is the original casing from your engine? If it has been fitted to a ypvs in the past it could have been cracked by the clutch like mine
www.dropbox.com/s/rr24w4k6mkbkf9k/Photo%2002-10-2014%2C%2013%2030%2020%20%281%29.jpg?dl=0

[avb]

ive vapour blasted a few of these and they all have the same cracks
they hadnt broke through to the other side.perhaps a smesar of chemical metal would stop them getting any bigger

[headcoats]

Just do a clear clutch window and problem solved :-)

[rolie]

Thanks for the responses, and thanks Dusty for the welcome to the forum. Your resto thread is my guidebook!

Stusco, I can’t imagine it was ever on a ypvs but I suppose stranger things have happened. Having pretty much completed the strip-down now, the bike was certainly mistreated much more in its early years than I thought when I bought it in 1990. A lot can happen in 8 years!

It wouldn’t say much for Yamaha’s quality control if they were from the original casting. Am I right in saying that this part of the cover is not under stress at any time and the central nipple casting is well clear of the clutch? If so I wonder why it was there in the first place. The cracks are certainly not hairline and are very rough to the touch with what feels like a bit of displacement. This obviously raised my concern, but the outside is pristine.

I would be happy to leave them and the red gasket alone if they’re not going to result in a catastrophic failure. The clutch was working fine the last time I rode it. The weld in Stusco’s picture is obviously an option or a thin cover disc welded internally, but I suppose that might just add to the stresses. I’m not sure about using a chemical metal filler though. As long as a chunk doesn’t break off inside, if I leave it at least I can check regularly under the plastic cover for any sign of oil from the cracks breaking through.


Rolie

[JonW]

Accident damage is another thought, they cracks appear to be knocks from the outside as they are open on the inside.

[andy748]

Looks to be rough around the water pump casting too, i'm with Jon, probably accident damage, i'd be picking up a decent second hand one? Andy.

[dusty350]

2278D705-2332-465C-B97B-4F4EA6E68088 by Roland Carson, on Flickr

I thought that too at first but the outer casing looks pretty good. Maybe get the cracks ali welded if they are cracks. Sometimes difficult when alloy has been immersed in oil for years, but I've had kickstart castings repaired before with good results

Dusty

[gavink]

Seen cracks like this many times in engines as I’ve dismantled them and IMHO don’t worry if no signs of leaks. They could be caused by the regular heat cycling of the poor quality castings that were used around the time as that part of the casting is not under any loads, the impurities heat quicker and expand quicker than than the alloy causing the fissures to form and what looks like external damage (the outer side probably looks in A1 condition).

[rolie]

Thanks everyone for the comments.

Following Andy’s comment about the area around the water pump I did a bit more of a clean up and removed the drive gears for the water and oil pumps to get a better look. There are what initially appear to be cracks in various locations, including around the kickstart, and the oil pump cable access. On closer inspection, some of these appear to be casting issues as they are proud of the surrounding area on both sides. The vertical face below the the kickstart is like sandpaper! There are undoubtedly some cracks but I would have thought that if accident damage was the cause there would be signs of damage to the outside of the case, and there isn’t. So on balance I think it’s a mix of, questionable initial design, poor materials/casting, and fatigue cracks caused by heat cycles. Happily the alternator side is absolutely A1. It appears this type of cracking is fairly common so unless a cheap, pristine case turns up I think I’ll just get this one blasted and painted and move on. 😊

Rolie

[midlifecrisisrd]

Just get it blasted and coated

Yam castings are rough. They are all like that and fine

Steve

[dusty350]

You think they are rough ? I have a set Of 350r (Brazillian) cases that were so rough I actually dremelled them back before I got them vapour blasted. Never seen such a rough finish on a set of cases

Dusty

[rolie]

Good to know. Thank God Yamaha don’t do aircraft! 🛬🪂🪂

Rolie

[4l04ever]

It looks like Yamaha used the same mould for many years, and the later ones are certainly rougher than the earlier ones as the moulds start to wear.

[JonW]

Ive said it before but its worth saying again, if you buy a new clutch cover (still available cheaply enough in the usa) you should always check the flashing from the mould in the water pump area, chances are it will need cleaning up.

[headcoats]

Dec 29, 2020 18:14:26 GMT 1 dusty350 said:

You think they are rough ? I have a set Of 350r (Brazillian) cases that were so rough I actually dremelled them back before I got them vapour blasted. Never seen such a rough finish on a set of cases

Dusty

I have some of these too and rough as fook

[JonW]

Funny thing is the new ones yam make in Japan for the banshee are not rough at all. Must be the old moulds they sent to Brazil that are rough or the alloy used was rough there, which seems unlikely as they are all still Yams etc.