Full 951 Rebuild - Rusty flywheel, stator and pickup - 1999 GTX

[mikidymac]

Either mark the stator cup or better yet put the bolts back in as they don't need to come out to remove the flywheel. If you get the timing wrong you will have lots of issues.
Buy the correct flywheel puller.

 

[BensGTXFun]

Either mark the stator cup or better yet put the bolts back in as they don't need to come out to remove the flywheel. If you get the timing wrong you will have lots of issues.
Buy the correct flywheel puller.

Will a bolt type wheel puller work? or the ones you borrow from autozone work? I would like to remove the stator cup to wire brush that as well and get all the rust that had built up in between the crevice of the stator cup and flywheel off.

 

[BensGTXFun]

Another Update!

Got the flywheel puller and a 27mm socket to pull the nut off and flywheel...going to attempt that this weekend... I've seen on videos people putting a screwdriver between the flywheel teeth and then trying to remove the nut...kind of hesitant to do that as I don't want to break or bend any of the teeth...was going to remove the exhaust manifold and put a rag in the chamber, seems like the safer way to go.

Looked for other things to clean/inspect/fix while the engine is out and took off the cylinder head. Looks clean on the walls, but a TON of carbon buildup on the pistons. Probably from years of the idiot who sold it to me using the TC30 oil....Saw a interesting video of someone mixing half and half ATF oil with acetone and using a scotchbrite scrubber gently scrubbing the carbon off. Anyone else use this method or something similar?

Attached pics to see the buildup....

 

[1of500]

Flip it over and split the cases. If the crank isn't any good you will save a lot of time

 

[1of500]

Lots of salt deposits in the water jacket

 

[BensGTXFun]

Lots of salt deposits in the water jacket

I did pull the oil from the crankcase "hole" suggested from another thread, didn't look fouled from water or rust.... just old and black. Want to avoid opening any more "chambers" as all these gaskets are really pricey. I figured once I get to opening the crankcase its pretty much a full engine rebuild.....absolutely necessary?

 

[1of500]

No gasket on bottom half just sealant. If any of the bearing are bad on bottom it won't last long and the result will be catastrophic. Meaning new cases crank counterbalance ect. 951 rods have been known to even destroy the carbs if they grenade

 

[BensGTXFun]

No gasket on bottom half just sealant. If any of the bearing are bad on bottom it won't last long and the result will be catastrophic. Meaning new cases crank counterbalance ect. 951 rods have been known to even destroy the carbs if they grenade

Alright. You convinced me. Lol thanks

 

[BensGTXFun]

Side update!

Took apart the Rave blades....I definitely have carbon buildup every where.... flywheel coming up tomorrow and going to crack the lower half.

Before and after RAVE blades:

 

[BensGTXFun]

Lots of salt deposits in the water jacket

So I haven't gotten the flywheel puller in yet to take that off and split the cases yet, but on a side question, what would be the best way to clean that besides a tube cleaner? I saw some guy boiling theirs in water with salt off in a big pot Its mostly fresh water lakes here, but I do intend to go to San Diego and take these to the ocean. I've had experience flushing the engine with the hose hookup with salt off, but that's it.

Thanks!

 

[mikidymac]

Just flush with salt-away after riding in saltwater and spry the engine down with something like Fluid Film.

 

[BensGTXFun]

Update!

Got the flywheel off after almost dying from a broken bolt flinging towards me! Lucky!

Anyways, pretty bad here....any suggestions on not completely replacing the piston and replacing/reboring would be appreciated.

Some things I've noticed....

1) MAG piston and cylinder is in very good condition. PTO piston has damage to it. I don't think it completely done, but I'm not a mechanic....(see pics) I'll attach a better detailed picture in a bit, but the piston does have some grooves on it.

2) Cylinder cover where the PTO piston is has damage too. I think the precious owner had run it next to an area with water and sand. Small punctures to the roof of the cover. (See pics)

3) While waiting for the right flywheel pull tool specifically for this engine, I got impatient and stupid and used a harmonic puller through the 6M metric holes and dented/punctured the crankcase seal....(see pics - three screw dents)

4) Doesn't seem like there is water or rust in the crankcase, and the seals held,, but I did notice some hard sand grains in the oil or something once looking from above on the PTO side. Won't know for sure until I crack the case.....tomorrow....I'm pooped....

Right now I'm most concerned with the damage to the piston, cylinder and top end cover on the PTO side. I couldn't have checked the compression for this before taking apart as the bendix was rust siezed and wouldn't activate the flywheel.

Let me know if I just wasted 2 weeks of my life and made my garage look like a repair garage for nothing or I can clean the cylinders the best that I can with steel wool and bring this beast back to life.

Thanks!

 

[mikidymac]

I hope you were kidding, that piston and cylinder are trashed.

Something let go and that is why the head is damaged. The exhaust side of the piston is missing from detonation from running lean probably dirty carbs/fuel system.

That engine needs a full rebuild with cylinder boring and new oversized pistons, a new crankshaft and rebuilt balancer, new reeds and complete fuel system overhaul.

You should be prepared to spend around $1,200 to get it back on the water.

 

[etemplet]

I don't take rebuilding engines lightly. If they look good, I'll happily do a partial or just fix what is broken. Judging from the external internal condition of this engine, it looks like a pile of crap and I'd for sure split the cases and have a look inside. I think a rebuild would a good decision. Good Luck.

 

[1of500]

I don't normally recommend sbt but I would send them this as a core for a rebuild.

 

[1of500]

Just looked sbt has 4 to 6 weeks lead time they used to be in stock

 

[etemplet]

Skis are getting difficult to come by for sure.

 

[BensGTXFun]

I hope you were kidding, that piston and cylinder are trashed.

Something let go and that is why the head is damaged. The exhaust side of the piston is missing from detonation from running lean probably dirty carbs/fuel system.

That engine needs a full rebuild with cylinder boring and new oversized pistons, a new crankshaft and rebuilt balancer, new reeds and complete fuel system overhaul.

You should be prepared to spend around $1,200 to get it back on

I don't normally recommend sbt but I would send them this as a core for a rebuild.

I hope you were kidding, that piston and cylinder are trashed.

Something let go and that is why the head is damaged. The exhaust side of the piston is missing from detonation from running lean probably dirty carbs/fuel system.

That engine needs a full rebuild with cylinder boring and new oversized pistons, a new crankshaft and rebuilt balancer, new reeds and complete fuel system overhaul.

You should be prepared to spend around $1,200 to get it back on the water.

If the crankshaft is ok, then would it be possible to resleeve the damaged PTO on the upper engine and just replace the piston and rings with the standard size and just hone the cylinder? Again, doesn't look like there was damage in the crankcase, reeds look almost new with nothing missing or worn and I've already replaced the grey fuel lines and will be rebuilding the carbs.....

 

[etemplet]

I just can't see enough of the crank to make me feel 100% comfortable to call it good. You can do a visual on the outbard bearings but you can only feel the inboards and the rod bearings. I'll have to talk to my race bike building buddy about that. He'll probably say just rebuild the crank and you know what you got.

 

[BensGTXFun]

I just can't see enough of the crank to make me feel 100% comfortable to call it good. You can do a visual on the outbard bearings but you can only feel the inboards and the rod bearings. I'll have to talk to my race bike building buddy about that. He'll probably say just rebuild the crank and you know what you got.

Lol alright, it's a B@#%$ to crack apart....sealed pretty well together. I tried putting a washer in that crevice and twisting a 1/2 breaker bar to try and split it, but it's gonna take major muscle to do.... but after I take it apart and can take a better look and hopefully the bearings are ok I'll report back.

Thanks everyone for the info, I'm pretty much mentally prepping myself for dishing out more money on this thing lol

 

[etemplet]

Be gentle and make sure you have all the bolts out. They are sneaky. I find the slots between the casing and insert a strong screwdriver and I twist it gently but firmly a little at a time on each side. The cases will open up.

 

[1of500]

I wouldn't waste the money on a top end just from the look of the piston.

 

[BensGTXFun]

Update!

Split the case and I'm happy. No small metal shards or anything, reeds look like new and are in tact, all bearings turn very freely without noise, and not a drop of rust inside. I guess the seals held pretty well.

The ONLY thing I saw was 2 teeth on the shaft were slightly worn (see pics). Everything else seemed like it's ok.

Now the next steps...going to gently remove all the left over sealant, vinegar and baking soda scrub the rust in the MAG area, power wash the two halves and dry (ok to do this? The outside has a lot of gunk and it's hard to get everything in all the crevices).

Got a new oil seal for the one I punctured...going to install once I get it in and put together everything.

Question, how do I get all the existing oil off the crank? Don't want to use break cleaner as I have read it damages other seals.

Also, if you guys see anything I might have missed that would be appreciated.

 

[BensGTXFun]

Be gentle and make sure you have all the bolts out. They are sneaky. I find the slots between the casing and insert a strong screwdriver and I twist it gently but firmly a little at a time on each side. The cases will open up.

Yup they are sneaky, looked again and forgot one in. Opened easily after that! Thanks

 

[mikidymac]

You need to replace the rear crank seal also.
Clean the crank and cases with gasoline in a well ventilated area and it is flammable/explosive so be careful.

And as we keep saying you really shouldn't reuse the crankshaft but do as you will.