Thanks petej. That's great news. I hope I'm not pushing my luck here but can I ask your opinion on reusing the piston pin circlips? I've just bent one of the new ones while trying to fit it and am tempted to put the old ones back in.

Circlips do not deteriorate in use, usually only at the hands of man :smile2:
Using an undamaged pin clip will do no harm.
p

I have to add a caveat to pete j's comment - "usually..."

Personally I ALWAYS replace ALL circlips and seals, and usually bearings. Mostly because you feel like an idiot if a dollar part fails and takes out half the engine with it... or just starts to leak and you have to buy another set of gaskets and do it all again. Cheap insurance, speaking as an ex-mechanic and all around lazy guy.

Yes you can often get away with it if needed; "you pays your money -or not - and takes your chances."

If your old piston gudgeon clip is 100% un-damaged then it's safe to use again.

Every manual will tell you to replace it though.
Because they have to take into account that it was damaged on removal.

To be safe, I would recommend that you replace it.

But you don't have to if you can 100% guarantee that you didn't deform, crack or twist it on its way out.

They're made from spring steel. It's strong and fairly forgiving but once you take it past it's stress point , it's junk.

I always replace them in customers bikes because it's not worth the risk as Grant says. And a customer would expect them to be replaced.

Out of the countless engines I've rebuilt for myself and friends, I have never replaced them and ive had zero failures. But I am very careful when I remove them and use the correct tools. Not twisting them out with screw drivers etc.


Re your gasket question. With modern liquid RTV sealants, it is indeed possible to use them instead of the paper or steel gaskets they come with.
The exception here is multi layer compression gaskets such as your head gasket.

Also, some cases or covers require the genuine gasket as it is part of the tolerance and dimension when the motor was designed. Such as cam cover when the cam carrier is built into the cover.

On engine side covers or faceplates, you're usually okay though. But that does depend on the bike !!

I still prefer to use the physical gaskets. They're just cleaner and easier to use. And if you need to wiggle something you know it's not been wiped off in the process.


Last note.

When building an engine it always pays to take your time and not take shortcuts if you have any doubts. They always bite you in your arse.

I spent twenty years learning that the hardway.

Agree with Ted, I wouldnt worry to much about is.


As for gaskets, the really important one are whre they provide clearence, like Ted mentions about the cam on certain bikes.

Sidecover gaskets can be nescessery aswell, it is on my E-start xt600. Startermotor binds up a bit with no gasket, and on the right side you have the oil return valve which can also act up.

Order the gasket and change circlip, its not like you are doing this same job next week..Its something about that feeling when your done that its all in place and new!

Thanks for all the information. I realised I was letting impatience override common sense so have ordered the circlips so I can do the job properly. The minimum order was five so I've got a few spares in case I bend any more during installation.:smiliex:

Minimum order 5 ?? Huh ?? Never heard of that. Use Fowler's if you're in the UK. All fiches online.

Sent from my Moto G (5) using Tapatalk

Piston circlips are nothing to not put new in , even if they look undamaged from removal and they must come from the piston mfg , not a Yamaha oem if using a Wiseco or JE piston.

I don't remember what the gasket under the oil pump is for on this motor either , if I have one I put it in always , if I don't have one it gets left out . The rest of the motor all gets gaskets .

Honda XR series motors have the valve cover gaskets that must be a certain thickness since they set the clearances for the cam and bearings , at least they have actual bearings on the cam rather than just polished aluminum journals .

.

While you're waiting buy a pair of circlip pliers - makes life SO much easier!

I finally reached the stage of putting the oil back in and was hoping to be out on the road this afternoon. Then I saw the steady trickle of oil escaping through the drive shaft oil seal... It's a brand new seal so all I can think is causing it is I might have pushed it in too far.

Can anyone tell me if this is possible?

When I refitted the cover plate I noticed it wasn't flush with the seal but figured it was just there as a safety precaution. I've double checked with the parts diagram and there don't seem to be any missing bits between the bearing and seal.

Pull it out and install a new one. Apply Oiled cling film over the shaft and slide the new seal on straight.

Thanks ~Ted. Am I right in thinking that I wrap the cling film around the thread to stop it damaging the seal as I slide it on?

Indeed. Lots of oil too. Keeping the seal straight is very important. You need a deep socket or something that will fit over the shaft to drive the new seal in. You can't wiggle them on as that is what damages the seal lips.