[motopreserve]

Hey folks. Just joined the forum, but I’ve been lurking for a while doing research on the 300. Want to thank all of you for providing such great info on these bikes.

I finally pulled the trigger on a beat up 2015 to use as a track-only bike. It’s rough, but I’m ok with that - since it gives me an opportunity to get to know the entire bike.

Cleaned up some electrics and replaced the steering stem ball bearings with tapered bearings. Everything went well.

But now it’s looking like I need a head gasket replacement.

The oil was classic milk colored. I flushed with fresh oil until it flowed clean(ish). Filled again with fresh oil but after running it for just a minute, the oil was completely emulsified again. Cold start with the coolant cap removed produced a geyser. When I removed the spark plugs there was moisture in the right cylinder, which spit out while turning the engine over. Think it was just water. So there is definitely gasses getting into the coolant system.

Best I can tell, all the tests point toward the head gasket being blown (or worse???). If anyone has any other tests I should try, please chime in.

I would like to make sure I have everything I need for the replacement. I have the shop manual, and will order OEM head gasket and exhaust gaskets. Are there any other gaskets/o-rings etc that should be ordered before I start?

I read a post stating that while doing the head gasket it’s required to lap the mating surfaces. Is this the consensus (I think he was talking about an ex500)? Or can the lower half be left on the motor? If I have to remove the lower from the crank case, I guess I’d need that gasket as well

I apologize for the long 1st post.

Any other tips and tricks are welcome.
Thanks!

scott

 

[jkv45]

We blew a head gasket on our Ninja (EX) 500, and yes - lap the head.

On the 500, we needed to remove at least the intake valves, if I recall correctly.

We didn't remove the cylinders, just cleaned the surfaces well. The head is the issue.

 

[motopreserve]

Thanks so much for the reply and the clarification. Any other things I should be aware of heading in there? Do you recall the gaskets/o-rings you needed to replace? I’m not finding those details in the shop manual - but I’ll look again.
Appreciate the help!

We blew a head gasket on our Ninja (EX) 500, and yes - lap the head.

On the 500, we needed to remove at least the intake valves, if I recall correctly.

We didn't remove the cylinders, just cleaned the surfaces well. The head is the issue.

 

[Topaz]

Welcome to the forum! Nice project to got into. I hope you find answers and help here.

Are you planning to keep the ABS for track riding?

Keep us posted on your progress.

 

[jkv45]

Thanks so much for the reply and the clarification. Any other things I should be aware of heading in there? Do you recall the gaskets/o-rings you needed to replace? I’m not finding those details in the shop manual - but I’ll look again.
Appreciate the help!

We replaced the head gasket only, but it was a 500, so it wasn't exactly the same.

There are o-rings for the coolant pipe on the top of the 250's valve cover that you will want to replace.

Pay close attention to the cam gear and crankshaft position, and don't spin it over unless you need to. You will need to confirm that the cam timing is correct as you reassemble it.

We used a piece of Quarts counter top material and valve lapping compound to do the lapping of the head. Granite will work as well. A shop that does solid counter tops will have plenty of scraps you can have for free most likely. A cutout for a sink should be big enough, and easy to get.

 

[motopreserve]

Welcome to the forum! Nice project to got into. I hope you find answers and help here.

Are you planning to keep the ABS for track riding?

Keep us posted on your progress.

Thanks for the warm welcome. I’m glad to finally be part of the ex300 crew

The ABS had been disabled by the previous owner - but I would have disabled it anyway.
So far I’ve found a ton of info here - really great forum.

I’ll keep you updated. Let’s hope it’s nothing worse than the head gasket!

 

[motopreserve]

We replaced the head gasket only, but it was a 500, so it wasn't exactly the same.

There are o-rings for the coolant pipe on the top of the 250's valve cover that you will want to replace.

Pay close attention to the cam gear and crankshaft position, and don't spin it over unless you need to. You will need to confirm that the cam timing is correct as you reassemble it.

We used a piece of Quarts counter top material and valve lapping compound to do the lapping of the head. Granite will work as well. A shop that does solid counter tops will have plenty of scraps you can have for free most likely. A cutout for a sink should be big enough, and easy to get.

Appreciate the help! I’ll check the parts diagram for those o-rings (I assume the 300 is the same as the 250 you mentioned?). I have a metric ton of nitrile rings here at the shop - not sure if the manual states the dimensions. Worst case I’ll order them as well.

I have a couple pieces of granite that I use for rough surfacing. I was planning on using that. I have a surface plate - but i don’t want to ruin that with lapping compound.

I’ll definitely keep an eye on the timing gears. I was a bit confused by the manual’s photo - but finally realized they were counting chain pins between the plane of the head. The rest of it seems fairly straight forward with lining it up - but I’m sure I’ll have some questions.

I’ve got the electrics all labeled and out of the way. Throttle bodies out. Coolant system off. I’m just about ready to pull the motor. I’m thinking of welding up a motor stand first -before I pull it. Should make it easier to deal with on the bench.

 

[jkv45]

We didn't remove the engine to do the head on the 500.

It was really tight, but it came off.

 

[motopreserve]

We didn't remove the engine to do the head on the 500.

It was really tight, but it came off.

I was debating keeping it in the frame - but the whole bike is so worked I figured it would be a good opportunity to check and clean everything.

While I was busy unplugging what seemed like 1000 electrical connectors, my buddy welded up a quick engine mount for the bench. Not pretty, but it will do. Need to figure out a better way to attach the front. For now it’s on there solid enough.
Researching the o-rings I’ll need now. Seems partzilla has a decent stock of OEM parts. You guys have a better vendor you like?

 

[jjmaine]

Sweet project! I always check all of the vendors for a specific part I need (partzilla, revzilla, rmatv, motosport etc) because sometimes their prices vary wildly for whatever reason. Always worth a quick check to save some cash. Good luck.

 

[motopreserve]

Sweet project! I always check all of the vendors for a specific part I need (partzilla, revzilla, rmatv, motosport etc) because sometimes their prices vary wildly for whatever reason. Always worth a quick check to save some cash. Good luck.

yep, I ended up checking a few different places. You’re exactly right - no reason for the prices to vary so much. Partzilla had the better part of what I needed. So I ordered from there. I will grab some misc stuff from some of the other vendors because partzilla allowed adding to cart but shows “no ETA.” Ugh.

Got the head lapped in under the manual’s stated spec. That was wild. Fear of going too far. Checking every few minutes etc. glad I got it done though.

Biggest challenge is getting all the damn milk-oil out of the crevices. It’s f*cling everywhere!

On to rebuilding the forks while I wait for gaskets and o-rings for the engine. Putting a hard deadline for button up and shakedown for end of the month so I can try for last east coast track day November 5th. Finger crossed!

 

[motopreserve]

EDIT: Now I’m really losing it. I was confusing head bolts with valve cover bolts. Still need to know whether these head bolts are TTY on 2015 (or later) and whether I need to replace them.

Also, it seems that parts suppliers do not have the washers (mentioned in the manual to replace) listed as an individual item. Anyone know if these are special in some way?

I have another question for you fellas (and ladies if you’re along for the ride)…

I have been searching the net trying to find whether the head bolts (7 M8 + the little M6) torque spec is different for the 2015 than is stated in the 2013/2014 shop manual I have.

I also read about some head bolts possibly being Torque To Yield. But again, this older manual makes no mention of it. Anyone know if these bikes (model year 2015) require replacing the bolts???

thanks so much

 

[motopreserve]

Got the head lapped and the jugs clean(er). Still have a bit of work to get it spotless.

I think I’ve settled on reusing the head bolts. I read that if a bolt is TTY, the torque spec would be given as an angle. The manual has it listed as a typical torque spec. So I’ll hope that logic holds (no pun intended!).

 

[iahawk]

following along, looks good so far!

 

[motopreserve]

following along, looks good so far!

Appreciate it! I’m definitely getting to know this bike inside/out . Better off since it was so thoroughly abused. Also glad that it allowed me easy access to check the valves. Exhaust was out of spec - so a shim kit ordered/arrived and that will be another thing off the list.

My next big move is to remove the oil pan. I’m afraid to see how much milk is in there! Trying to figure out a way to flush the lower cases gently. would rather not waste quart after quart of oil to clean it out.

Waiting on a few parts to come in from partzilla. Then I’ll begin to button it back up.

 

[Ghostt]

Could use mineral spirits to flush it out

 

[motopreserve]

Could use mineral spirits to flush it out

Good call. I didn’t think of that. Next time I’ll try that. I did put some Marvels in there and let it drip out the open bottom.

But in the end, removing the pan was a big to-do about nothing. I pulled the pan and there was only a dime-size puddle of white milky oil. Almost disappointing

I guess the oil change and flushing had helped. I’ll have it buttoned back up and hopefully in the frame by tomorrow. Then on to getting the electrics cleaned up and plugged back in. I think there is some stuff I can get rid of (blinker, horn, head/tail light leads etc) and need to wire up some a new switch (double button switch that will have both starter/kill).

If all goes well with the motor - I’m looking forward to learning how to fiberglass to repair the race fairings…

 

[motopreserve]

Ran into my first real issue (not counting the head gasket and colossal abuse by the PO)….

Valves needed adjusting. The Hot Cams pack has a ton of sizes, 3 of each. But of course I need 4 of a single size. Gambled on a hair larger than calculated. A hair smaller than calculated. Both put the adjustment out of spec. Ugh! Ordered a refill kit but it won’t arrive til monday. I’ve now taken the top end apart 3 times in 2 days. Monday will make 4!

Something I realized while reassembling the top end is that when you place the cams in the position displayed in the manual - the exhaust cam lobes on cylinder 1 (left) are putting pressure on the lifters/springs. It makes it impossible to seat the cam and put the cam caps on the exhaust side, without trying to force it down using the bolts.

That seemed suspect - so I lined up the timing chain and sprockets and then gently moved the crank into position where there was zero tension on the lobes/lifters. When I did this, I kept a bit of pressure on the cam chain so as not to skip a tooth. After tightening the caps, I rotated back into position, lined up the timing marks and counted the pins. It was still perfectly aligned. Phew.

Did anyone encounter this? I could not find mention of it at all in the shop manual. I can’t imagine they want you to try to force the valve springs using the pot metal cam caps. There have been some other frustrations with the manual - maybe it’s just an omission. But damn! It’s a pretty important part of the process.

Plenty more to get to while I wait on more shims…

 

[Topaz]

Do you have the kawi service manual or an aftermarket one? I did the valves about two years ago. I don't remember having any trouble putting all back together. I followed the instructions in the service manual. I have the kawi manual.

I checked the chain alignment and counted the links at least three times, then torqued everything and spun the crank shaft to check that everything was moving smoothly. Then check the clearance again and closed.

Hot Cams sells shims by the unit and in packs of five as well. You may call the local dealers to check if they have something in stock.

Moose 7.48mm x 2.80 Valve Shim - 0926-1890 Dirt Bike Motorcycle - Dennis Kirk
Amazon.com: DB Electrical 5PK748280 Hot Cams 2.80Mm 5-Piece Shim Refill Compatible With/Replacement For 2007-2016 Honda Crf 150R 5Pk748280 : Automotive

 

[motopreserve]

Do you have the kawi service manual or an aftermarket one? I did the valves about two years ago. I don't remember having any trouble putting all back together. I followed the instructions in the service manual. I have the kawi manual.

I checked the chain alignment and counted the links at least three times, then torqued everything and spun the crank shaft to check that everything was moving smoothly. Then check the clearance again and closed.

Hot Cams sells shims by the unit and in packs of five as well. You may call the local dealers to check if they have something in stock.

Moose 7.48mm x 2.80 Valve Shim - 0926-1890 Dirt Bike Motorcycle - Dennis Kirk
Amazon.com: DB Electrical 5PK748280 Hot Cams 2.80Mm 5-Piece Shim Refill Compatible With/Replacement For 2007-2016 Honda Crf 150R 5Pk748280 : Automotive

Thanks so much for the reply. I do have the Kawi service manual. It’s for 2013-2014. My model is the 2015. I had read that very little changed between manuals - that I should be ok with the one I have. Not sure if this procedure would be different between model years.

What i found during reassembly is the position of the exhaust cam - crank as described in manual (#2 at TDC, 2T in the sight area) - looking from left side, the cyl #1 lobes are pointed at the 7 o’clock position - which puts them in the beginning of tension on the lifters. The cams/sprockets are placed in the journals as the manual pic shows (attached below).

The alignment after tightening everything down seemed to check out ok, as best I can tell. Maybe I’m reading the pics wrong??? If you look at pic #2, it shows the closer lobe (cyl #1 exhaust) in the 7 o’clock position. This assumes looking at engine/pic from the left/#1 side.

I ordered up the replenish packs for the hot cans shims. Won’t be here til monday. But a shop near here that I do some work for may have one that I can steal/replace.