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Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by COXR650L, Dec 16, 2013.
That part was meant more for the OP.
You're supposed to be helping me to find a low-priced used motor, not encouraging a bidding war
LOL dont worry I think a used engine is out of my price range and hell $3700 for Munn is a ton more than I paid for the bike in the first place.
I am getting prices together, but ball park I should be around $800 without too much of a problem as long as the piston/cylinders and heads are reusable.
Generally, with that mileage you'll find: intake valve's seats are slightly worn, guides will be in tolerance, rings will be worn, but the piston ring lands may be out of spec.
The valves are stainless, you can get them ground if the wear is not too bad. May cost you $30. Do them all.
Find a shop with a Neway Seat cutter and have them touch up the seats. May take one hour $80.
Do NOT lap the valves. That will ruin the seat shape and you'll get fast wear. The Neway system leaves the surface rough and it gets peened into the perfect shape when the engine is started.
Chemically clean the pistons then measure them. New rings are a bitch to break in on a chrome bore. Do not hone a chrome bore. I've use only fine scotch brite pads to wipe a little texture on the cylinder. Don't put any oil on the bore when you assemble, just a little on the skirt of the piston. This get the ring break-in started quicker.
Why do you think the shift drum needs replacing?
I don't see why you'll need to split the cases. This plain bearing engine will go many more miles than a roller bearing engine. It needs more oil, but it can tolerate more dirt. If you do split the cases, replace the transmission bearings, esp. the output bearing behind the CS sprocket and the bearing behind the clutch. These go first and aren't expensive.
Buy a full engine gasket kit. Way worth the money.
The grub screw for flywheel removal is M16 with a 2mm thread pitch.
And bolt is a M20 with a 1,5mm thread pitch.
Will add pictures once I get back home, at work now but wanted to correct previous post that was wrong as soon as possible.
Thanks if you have time I would really appreciate to see some pics.
Thanks for the info. That makes me feel better about the potential condition of the heads and pistons. A lack of aftermarket support really makes these items expensive. I will look into finding a machine shop to grid the valves.
If I go this far I feel I may as well split the cases. One thing I want to replace is the oil pressure plunger (as documented by Pydon) as I have occasional timing chain clatter when the bike is hot.
I may leave the crank bearing as is depending on what they look like, I just did not know if that was more reliable than a ball bearing.
I was looking at the shift drum because it is an engine update. However, mostly I will have a fixed budget and will need to prioritize what I replace once I am in there. Thanks for the heads up on the output CS and clutch bearing
Here grub screw can be seen:
Will upload a few more when I get home.
Oil pump pressure relief is out side of the center cases.
Not aware of a shift drum upgrade. There may be an updated part, but that doesn't always mean you need it.
One more thing, pull all the oil jets and clean out the passages. Don't need to split the cases for this.
In my case I found the parts to be cost prohibitive.
400 piston x 2, 400 cylinder x2, cam chains I don't know, valves/heads, crankshaft?.
So I bought a 10k mile engine on Fleabay.
So If you were in my shoes you would not split the case regardless? Is there any down side to checking/replacing the main bearings and addressing other internal issues, other than me having more opportunities to screw something up?
Have you seen 950s that have 125k+ miles on the bottom ends without any attention? I feel like I need to get at least 50k on this rebuild to make it worth my time and money
Just so people know the bike has to be 100% reliable. It will be used in very remote parts of the Western US solo most of the time and hopefully next year (maybe '15, first kid is due in a few weeks) I would really like to do a 2 up trip through baja as a belated honeymoon with my wife.
I am getting a list of 'must do" items and then optional stuff that will depend on the budget once the engine is apart. I will post up what I have along with prices and maybe that will help push me down the right road.
I hear you about main engine parts, they are stupid expensive and in my case or out of the question for the most part.
I am cautiously optimistic the engine will be in decent shape. Most of the miles came from the PO commuting to work as I understand. It has seen its fair share of off-road and long trips no doubt, but I dont think it was abused like some 950 are with the same miles.
DIY grub screw, just cut threads of a M16 bolt and added a slot for a screwdriver:
1.75 Thread gauge is too small but was the biggest I had but its close so must be 2mm thread pitch.
Puller bolt, M20 with fine threads, 1.5mm thread pitch:
I did what you are planing, but took a bit of detour and blew right through the budget badly with some serious mission creep.
A little later I harvested the 950's gears for the installed SD engine;
My advice reading your thread;
An impact wrench and the right sized sockets gets you everywhere you need to go in an engine rebuild, except for the valve stem seals - need a special clamp for them.
Only if the shifting is buttery smooth and no false neutrals then leave the bottom end and don't split the cases.
But it is not so much more effort to do it, especially if you buy a complete gasket kit from Athena. (I used one 2 weeks ago, it is brilliant). I would as a matter of course change; the 3 shift fork rollers, cam chains, any notchy bearings (all are standard size and good bearing shops will have them), and have a good look at the shift drum - from 2005 they upgraded the drum to prevent a fairly rare issue of one of the walls close to 6th gear position breaking.
My experience with my motors is that all the hardwear in the motor is practically bullet proof and very hard wearing. My 950 engine that had been beaten on for 70k km's looked practically pristine inside.
Your oil leak if it is from the base of the rear, is almost assuredly the Pydon effect. If budget doesn't cover a new bottom end then I've seen an engine repaired by using a new gasket with a thin film of gasket sealant on both sides and then torqued to spec and a second time after a few thousand k's.
Good luck, shout if you need help.
Interesting. I'd always heard mixed things about aftermarket gasket kits.
Is this: http://www.athenaparts.com ? I couldn't see the 9x0 listed.
Sorry this was the one I used...
Is that aftermarket or genuine KTM?
Your eBay ad says "OEM-Partnumber: 60030099000 *The OEM-Partnumber is listed for comparison purposes only". This other one on eBay specifically states "athena": http://www.ebay.com/itm/Full-Gasket...-Adventure-Super-Duke-Supermoto-/200851282898
If I look up that OEM part# on a US fiche I get
Description: GASKET SET CPL. 03
Of course US prices on KTM stuff are often way less than elsewhere.
It is not OEM
I held my breath when I purchased it worrying about quality. Once it arrived and checking against the replaced parts I was happy. Little things like the parts of the base gasket that has beads of silicone on it were faithfully reproduced.
It is a very comprehensive kit. It has both 990 and 950 manifold gaskets along with everything that I needed to replace as well as the valve stem seals.
I'd buy it again for the next time.
Kamanya and DirtADV thanks for the help and pics I will read through your rebuild thread.
I am torn now with splitting the case after your advise and what has been posted previously. Bike shifts fine and never a false neutral.......but who knows. Part of me would love to yank the heads, new rings clean up the valves and be done in a weekend. But then I would hate for a problem to pop up 2k later that I could have addressed the first time.
One question I have that has not been clear after reading different rebuild threads is how to remove and then replace the main bearings? Do I need the special KTM tool to get the split bearing in and out or is there a shade tree method? I have a shop press, just trying to figure out if the KTM tool is necessary?
Its your call but if it runs good and shifts good and its just the leaking base gasket that is the problem just lifting the cylinders with piston still in the bore would be cheap.
There are many high mileage bikes that have not reworked the heads or pistons.
You would get away with just 2 gaskets and some sealant pretty much.
I myself is worried about the shift drum since I do have false neutrals between gears every now and then.
The rekluse and not using the clutch might have tortured the gearbox over the last 40 000 kms. But now a stock clutch is back in it and will be only street use for the 950 so Im crossing my fingers that it will hold up.
I just got up from the garage working on winter maintenance, and this year I figured I'd do a leak down test, since I'm at 65k miles, and the bike has been running a bit off for the last couple months (I think it's a clogged pilot jet, actually). Leak down numbers were great, and I don't feel like I could make the bike perform better or be more reliable by tearing it apart when it seems to be fine shape.
I'll be interested to see what your top end looks like with a few more miles than mine, but I do think you should do a leak down test and make absolutely sure your oil leak is from the base gaskets before you take the motor out and start taking it apart. My 2 cents.