Engine rebuild: what to buy and where
 

Okay, so I thought I'll do an engine rebuild this winter. Sucks, I need it NOW.
Yesterday, after a ~2km stretch of ~140km/h it started knocking a lot louder. It had this noise, but not nearly as loud (still isn't as bad as it might sound from what I tell, but I don't want to ride it like this any more).

I haven't opened the engine up yet, but I am looking at various parts options.

So anyway... What to buy?

Piston. I'd like a higher comp one. Between 10:1 and 11:1. Or maybe just got for it and buy an 11,5:1?
Here's two options (looks really good actually)
Wiseco Yamaha YFM600 YFM 600 Grizzly Piston Kit 98mm 3mm 1998 2001 4607M09800 | eBay
Wiseco Piston 96mm Oversize Yamaha 4596M09600 | eBay
I'm not sure of the diameter yet though. Will know that after the disassembly.

Gaskets. What gaskets to buy and from where?
Oil seals. The same as gaskets...
O-rings. I think I can get them at the local hardware store, if they won't be included in the gasket set.

Bearings. Are there any specific ones? I might not need to change them, but still...

Connecting rod. Well I don't know in what condition it is in now, but still, any options?

And so on... Stuff might get done later on, like a stage 1 or 2 cam, but the original one looks very good, so... Will stay for a while.

I might look like a headless chicken, running around without knowing where to run, but heck, I need your help and experience bier

Hi !
I would go for oem head gasket, but try to source one from somewhere other than a main dealer. Mine was £54.00 and i paid it cos i was desperate to get the bike back on the road. Ive since got a couple nos ones off ebay for a lot less to use if and when theyre needed. Cant help you with anything else but good luck with the rebuild and keep us updated


Bill

Since I'll probably need an oversize, won't the OEM gasket be too "small" for the larger piston?

Im guessing it will be yes! Missed that bit of your post. Oops

Since I want to still be able to run regular pump gasoline and I don't want to have a low moto-hour engine, I'll probably stick with the 10:1 comp piston. It's on a "sale" right now, link given in the first post. It's a 98mm piston though...
So, what should I do with the gasket? doh

If you're staying original piston size, go for either genuine or quality pattern.

I've used loads of Athena head gaskets and gasket sets and never had a problem. Never had one come back.

Like many things in life, it's all about the prep work. Those mating surfaces need to be beautifully clean and smooth and most importantly, FLAT !!

If you're going for an oversize (which I think you will end up doing) then you're best off to get an oversize head gasket. I think you're better off with genuine Yam if you're going oversize too. You don't HAVE to go oversize with a head gasket but why wouldn't you !!

To be honest, when it comes to oversize stuff, I always go genuine as you will know it's been properly measured and tested.

I don't know you're level of experience but if you need to go oversize you need to get your barrel honed out (usually 0.25 or 0.50mm bigger) Eg, if you go 0.25mm bigger.

You need an oversize piston 0.25
Oversize rings to fit 0.25
Oversize head gasket 0.25

Same deal if you need to go 0.50mm over.

If you're barrel and piston are totally goosed then you might need a new cylinder sleeve putting in. Then you're back to standard sizes usually.

Hope that helps.

Ted

You need to stick with an XT specific piston whichever size you get. The wrist pins are not always in the center of the piston, many are offset some to prevent tipping and knocking at TDC. The XT600 is centered but I don't think the Grizzly's are.

You said you haven't taken the motor apart, how do you know the cam is good? If it was starved of oil, even for a short period, the cam and its corresponding rocker get wiped out and make a bad knocking/clanking. The other is timing chain slap. Doesn't mean the bore is bad or needs to be redone. Though if it is dug into very far it is nice to just make things new and tight again.

If you wanted to you can just get a new sleeve and drop it in your cylinder, have it bored to stock size and re-use your piston with new rings, it comes out just a little cheaper that way but it is stock compression though. There are way to up it but it involves more machining.

If your looking for a power boost, the hi-comp isn't going to get as much as you'd think with the stock carbs. You'll gain way more usable power with a stock topend but better carb(s) than an improved topend and stock carbs.

Ted,

I'll probably go with an aftermarket gasket set. But I can't find an oversize gasket, unless it's for a 101mm conversion...

I'm rebuilding oldtimer motorcycle engines/gearboxes "for living", so I know everything there, where to get what and at what prices, but the XT's engine is a new to me. So I don't want any screw-ups.

The piston is "dead", read on for more... :)

jjrider,

the piston in the given eBay listing is noted as compatible with XT600/SRX600/etc. so it should be okay. Also, the part number 4607M09800 looks to be the same as the XT600 piston. So it's the same piston, just listed under "Grizzly/Raptor" title. As far as I understand...

I looked at the cam through the valve adjusting covers, haha!
But now the engine is apart and I can say 100% the cam is in very good condition.
Cam and rockers are 98-99% like new. The cam chain has some play in the links, so I might change the chain and sprocket in the same go.

However the piston is "dead" as mentioned before, it has two cracks and the cylinder has some serious scoring. Also the piston ring gaps are way too big.

Another question/asking for opinion:
my con rod bottom bearing is like new, no play what so ever, but the top hole where the piston pin goes in has some slight scoring. The piston pin (old one) has some play in it. Should I change the con rod or wait for the new piston and pin to arrive and check for play with the new pin? Check pictures.

The bike has Raptor 660 carbs, re-jetted and with aftermarket needles, K&N air filter and some Yoshimura carbon fiber exhaust. So little by little I want to make it better, even if the high comp piston gives me just a bit more power/torque bier

My XT's threads are here:

http://www.horizonsunlimited.com/hub...lization-64290

and here

Yamaha XT 600 personalization - ADVrider

Pics:

http://imageshack.com/a/img540/9850/iPqxbh.jpg
http://imageshack.com/a/img674/9048/iTWKuH.jpg
http://imageshack.com/a/img537/829/Muul8f.jpg
http://imageshack.com/a/img540/2607/4w6R0E.jpg
http://imageshack.com/a/img631/7395/Y9dhM2.jpg
http://imageshack.com/a/img746/6683/Nu4vq2.jpg
http://imageshack.com/a/img537/3963/IT4qtH.jpg
http://imageshack.com/a/img674/971/IbEbLJ.jpg

Kedo should have a 98mm gasket for the bigger piston.

I just finished rebuilding my 87 XT600 engine. Don't worry about the headgasket size, the stock gasket will be fine, unless you go crazy on the over-boreing. You sir need a new piston and bore. Take the bore out and send it to a machine shop (Stock bore size is 95mm) and have them mic it. See if you can bore it over to 96mm. You will need to check the crank for up and down play (a little side to side is normal) on the big end, and also mic the small end on the rod. Make sure it's within clearance. I personally went with a 11.5 Wiseco 96mm. Also check the transmission, as these bikes have gear issues. Open up the oil pump and check for scoring marks. Just give it a good once over. I ended up having to replace 1 case roller bearing, which was for the output shaft.

http://i.imgur.com/smWE1kE.png

I'd double check the piston deal, Raptor pistons I know are offset(I have a motor build using both model parts) but the XT's are not. The Grizzly 600 might just be the same as the XT, never had one, but the Raptor part isn't right.

I do have a pile of good oem pistons I don't need.

I wonder how your piston got cracked like that. Pre detonation .

Hi Zergman
others here have been disappointed with the fitment of aftermarket gaskets, not sure if that included the head gasket?

Bob

I got the Vesrah engine kit, the only gasket I didn't like was the paper cylinder base gasket! Didn't fit perfectly.

Thanks Jens, but Kedo has a 99mm gasket. Not sure what I'll do, but maybe I'll go OEM size...?

AnthraxBird, don't make me regret going 10:1 :innocent: I would love a 11.5:1 but I'm not prepared yet for the crank durability and fuel octane questions, yet...

I've ordered the 10:1 98mm 4607M09800 piston, it has to fit.

How the cracks were done I don't know. Maybe due to piston slap - lack of lubrication when the scoring was done, maybe pre-detonation, but there was no pre-detonation except on high rpm in neutral gear, it was shooting sometimes (only sometimes...). Don't know why.

Still wondering if I'll need a new con rod.

Think you may want to look fairly carefully at the lubrication circuit,starting with strainer and pump.
There's a good chance the small end of the rod is excessively worn looking at the plight it all seems to be in.
This was the cause of the clatter on mine when I first got it.
I used a genuine yamaha rod and big end,wossner piston kit,main bearings, the usual gearbox parts and bearings and fitted a used 3aj oil pump,recut the valve seats and that was about it. 20,000 miles on its still fine..the bikes taken me all over Europe and been a great after a bit of a shaky start..

I'd agree with Marcm, the rod end looks to be a little too galled and need honing but would probably be out of spec. Get the 3AJ pump definately, the extra oil those pumps provide goes entirely to the topend, right where these motors need it.

I wouldn't go by looks, mine looked similar, and was only .001" clearance! :)

I need to buy a micrometer for inside diameters... But the con rod end looks bad and also good at the same time: the light scoring is there, but mostly in the middle/maybe right, but on both sides I can see the polishing (honing) marks. First I think I'll wait for the piston kit to arrive and then check the clearance between the new pin and con rod. I'll buy new if in need...

The oil pump: 3AJ is a 600Z Tenere, right? Well, my engine looks to be THAT engine, haha! Is there a code on the oil pump so that I would be certain it's the right one?

Here's the pictures, maybe not very informative, but...:

http://imageshack.com/a/img84/7821/dscn7352y.jpg
http://imageshack.com/a/img831/6761/dscn8350.jpg

Although that doesn't make much difference, but I measured the old piston pin.

In the places it doesn't wear it's exactly 22.000mm. At the con rod it's ~21.985mm, and at both ends (piston wear places) ~21.990mm.

The manual says: 21.991~22.000mm.

The worst would be if it hadvtighter and looser spots , it would cause all the pressure put on smaller areas. I've run a cylinder hone with very fine stones in it to just polish off the high spots(usually galled material).

Your motor should have the good pump, it will have the letters 3AJ cast into it.

Hi I have just bored my 91 600e out from 95mm to 97mm and the standard head gasket was fine. I ported out the head heaps and had cam modified to a stage two yossie grind. I split the two piece steel base gasket down to one layer to lower the barrel and raise the comp. It has lots more low down talk and revs better ! The REV light on the dash even pops up from time to time :mchappy: Your bike looks good :thumbup1: but after fitting an exhaust like that you will need to make a brace to support the seat as the old muffler was a support for the sub frame. :funmeteryes:

P/S after reading jjriders comment about the offset piston pin I checked my old XT piston and it definitely has the offset pin ! its there to counterbalance the thrust and my aftermarket piston had it to. bier

Are you sure exhaust makes support? Have been riding for 7years with aftermarked and no problems.

Ok, no big fat lady on this then! What difference did they make on the next model for not having this support?

On the 96-up models theres a piece of frame from around the right rear footpeg, that goes up and supports the "subframe"

Ok i see, well i dont think anyone have to worry. Have been riding with alot of weight all years and no bending on the frame.

I see you are running 660 carbs are they both vacuum carbs ? was it easy to fit them ? ( do I need 660 manifolds to fit to the head ) and the big question !! do they make a big improvement ??? :confused1: I wondering if it worth the money ? Thanks.

Frame flex due to aftermarket exhaust: haven't noticed any. However the rear subframe will be cut off someday once I do an YZ/WR (or similar) rear end swap.

Carbs: everything is in my bike's thread. It's a CV (constant velocity) carbs.
They do fit in the original XT's intake boots, you just need to trim them down a bit (1-2mm) where the boots touch the carb and doesn't let it "deep enough" in the boots. Also you need different choke, different air filter...
After everything bought and shipped the conversion cost me around 400Euros.
But the improvements were... Quite significant. After the first ride I came back all shaking with excitement and with a huge grin on my face :biggrin:

ya they are now that I looked , I knew they were different than the raptor/grizzlies though, just thought the XT's were the ones that I had that were centered. Raptor/Grizzlies are .164" offset , the XT's are .079" so still not meant to be swapped.

jjrider, I would understand that if it was just the seller, listing a Grizzly pistons and claiming it will fit an XT, but is the manufacturer lying too?

When checking the part number I found this on the Wiseco web page:

4607M09800 Product Detail Information - Wiseco Piston Inc.

Check "Applications" section. It says:


Yamaha YFM600 Grizzly (1998 - 2001)
Yamaha SRX600 (1984 - 1996)
Yamaha XT600 (1984 - 1996)
Yamaha XTZ 600 Tenere (1984 - 1996)

I can measure the piston once I receive it.

Great home work :thumbup1: So I read up on your carbs wow that looks like a lot of work from the carbs BACK ( air filters ect ) tonight as I put my bike into 2nd and it was I was still able to hold the front wheel in the air I was wondering if this is only a fraction of what it could do with 660 carbs ? My bike has never done this before and I need to know if this is how it should have gone before I hotted the motor up or is this how yours preforms ?? sorry for :offtopic:

There are 2 grizzlies, one earlier for a couple years were they obviously used the XT's piston, the later is with the Raptor, which is the version I've been working with and measured at home. Forgot about that other one. Hence the difference.

jjrider, so your verdict: it should fit, right?

Scott, it's a bit of work, yes. My "setup" isn't completely finished yet though. It might change over time...
Well, if I tried hard I probably could do a wheelie in a 2nd gear (not that I'm a pro at wheelies), but bear in mind the sprocket sizes, engine wear, etc.
My sprockets are 15 in front 40 in the rear. So it's quite tall gearing.
Also my engine is (or rather WAS :innocent: ) pretty worn (see piston ring gaps...), so it didn't have much compression and not much torque to pull a wheelie.

But anyway, considering the costs and benefits, I still would do a conversion.
Now I'm wondering about flatside Keihin FCRs or Ninja fuel injection kit... MAYBE one day, haha!

Ya, it is right, I had the later version in my head which isn't the right one. I used it in a hybrid motor with a 660 bottom and the old XT topend.

There was a guy around here that could wheelie his moped, looked like it had been wiped out on a few occations.

WOW thats some balance ! no I cant do that I was talking power stands not on the ballance point I can power stand up hills well ( on my fuel injected 450 Sherco ) but not on the road like that chap :clap: I'm just trying to get a comparison of HP as I have never ridden another XT 600, I'm running 16 45 gearing for memory, so that sounds close to yours. bier Thank for that !

The shiny bit (the piston) has arrived. I'll post the pic later on.

The instructions added only say what piston ring gaps should be, but no info (or I'm too blind to see) on what should be the piston-cylinder clearance.
Anybody knows that?

The Yamaha shop manual says piston to bore clearance should be 0.045 - 0.065 mm, or 0.002 - 0.003 in, with a limit of 0.1 mm or 0.004 in.
But if you're using a non-OEM piston, then I would check what the piston manufacturer's specification is, as the piston expansion rate might be different to OEM.

Bob

This is the civilized forum !:innocent: We're not from Aussie :whistling:



censorship !

A forged piston has a larger piston to cylinder gap. I believe wisco requires .004 in. THUMPTHUMP

Oh yes, I'm blind...

I was too busy playing with the box contents and searching the instructions for the clearance. But the clearance is on the package: 0,003 in or 0,076mm. doh

Does anyone know where I could buy a lower cam sprocket (the small one, on the crankshaft)?
Seems like there's a lot of top sprockets, which bolt on the cam itself, but I can't find lower ones...

Buy from yamaha dealer.

Ohhhh yeah. Yamaha dealer here quoted me around 640Euros for a crankshaft kit (which includes both timing sprockets, crankshaft, con rod).

I've got a connecting rod kit already, paid around 100Euros for it, and I'm not spending extra 540Euro on a single sprocket I need plus something I don't.

Once I take the engine apart I'll check the condition of the smaller sprocket, and I might replace only the bigger one... Or keep both used, as they look good anyway.

Partzilla/boats (same company) cheapest prices. :thumbup1:

Mezo.

Second the Partzilla/Boats.net for parts. They have recently expanded their local storage and have more parts in stock. I used them all the time. Their on-line parts manual is good, if it shows up there, it is usually available from Yamaha.:clap:

Not working either... There's no part I need.

Yamaha Motorcycle Parts 1993 XT600EEC CRANKSHAFT PISTON Diagram

Not on the list. Or anywhere else...

Half of Kingdom and a Princess to someone who can show me exactly where I can find the damn sprocket to buy :rofl:

That sprocket isn't a separate part, I think they figure it is part of the crank assembly since it get pressed on so hard. About the best bet otherwise would be to buy another used crank if you can find one with lower miles and either use that or press off the sprockets. I know other brands do the same thing with that sprocket, I wanted to change it on my klr but it wasn't an option to buy, just bought another low mileage crank.

maybe?
 

hi I don't know if its the same as the xt/sr500 one that kedo sell, item 28342, give them a call they might know or be able to measure one for you, hope this helps, steve

Partzilla has that listed also, can't say it'll fit though ,Yamaha Motorcycle Parts 1979 SR500F CRANK-PISTON Diagram

Bearing on the other side is the same, I don't know if thats the same as the sprocket side on the 600 though, that would make it the same id at least.

Its one part (well i mean you cannot buy parts separate) i may have to buy the whole crank assembly myself & at $300 its cheap as chips, earlier XT`s are more than double that price.

Mezo.

Correct. Yamaha do not supply the crank sprocket loose.

Reason given; it is not keyed and Yamaha don't think customers/workshops can refit it exactly where it was.

You only need to remove it if you want to renew the bearing, where a new crank half is their preferred option.

But it can be done.

To quote ActionManMelb: Step away from that puller until you measure and record the position of your gear.

Click any pic to enlarge. This gear the outer edge of tooth is 20mm from bearing face, which is regarded as correct.

Aligning the gear with the key-way is not difficult and a fraction of degree out would not be noticeable on performance.

p

Thanks on the replies guys.

And no, the XT500 sprocket is different, as the chain is different (500's chain links are round, 600's links are flat).

300$ isn't much, yes, but I've already bought the con rod kit, and I'll see what I do once the engine is completely disassembled. I might have to buy the kit... To be continued.

Anyway, worst case scenario I'll mark the sprocket, take measurements, and put it back together as it was.

hi whats wrong with the sprocket or are you just wanting to replace the bearing behind it? as kedo do a pressing off/ pressing on service DL40 if your sprocket is good to reuse ,if not give them a call as they may have a good condition one as they do crankshaft work ,steve

gasket / year compatibility
 

plan to take some care to the top end of my '02 xt this winter.

Earlier I was thinking to order https://www.ebay.com/itm/Yamaha-XT-6...9Z2xkx&vxp=mtr

then, found this option - https://www.ebay.com/itm/ATHENA-FULL...dYyNjQ&vxp=mtr
there's some more stuff, and price+postage is same for me. btw, "image is for reference only" is noted here.

I think that gasket set suitable for 1995 xt will be suitable for 2002 as well.
if not, what about listings like this? - https://www.ebay.com/itm/Yamaha-Comp...JZdkMt&vxp=mtr
they indicate almost all years...

So, is it safe to get second option, or there still might be some major difference?

Check out KEDO - Performance Products. They're much closer to you, do the full and top gasket sets and I think might work out cheaper for you.

Thanks connal
seems there're nice options, but still need some help..

I've found that ones and not sure which of them will be suitable for '02 xt600e:

KEDO - Product Details
>> here application is indicated "XT600-'88, XT600Z-'87, SRX600"

and
KEDO - Product Details
>> here "TT600S/E/R/RE, XT600'89, XT600Z'88-, XT600E/K" is indicated..


And another point - Is there some difference in the quality/durability of KEDO and Athena?
I mean mostly cylinder gaskets and rubbers, the "paper" ones I cut from different material anyway..

: )

The number 2 is listed for E models, which you've got.

Thanks : )

Probably will get them instead of Athena, if there's no significant difference in the quality.

It was like a small surprise - gasket-set-level compatibility of TT and XT.