[motopreserve]

Hey folks. I've been encouraged to start a build thread by all of the help I've gotten from members here (@jjmaine @SparkyMJ @jkv45 to thank a few). This tale is about my first ever track bike, which is based on my first ever Ninja 300. I've had some real ups and downs on this build, so maybe it will help some others in the future.

Quick(ish) Backstory: I have been riding and wrenching on bikes for nearly forever. Mostly vintage 70's bikes, but with a few modern bikes thrown in for good measure. Over the past 15 years or so, I've procrastinated doing track days for various reasons (too expensive, bikes weren't good enough, questioning my skills, too far away etc etc). I've attended a bunch of vintage races (mostly AHRMA) as the "pit crew" for friends. This past year I finally attended an actual track day to see what the experience was like. Drove down to New Jersey Motorsports Park with my buddy to help him set suspension, tweak the tires and fuel etc between sessions. I had such a great time, and seeing the goings-on up close - I became obsessed with finally experiencing a track day for myself.

Although I own a bunch of bikes, a ton of research and talking to friends convinced me that it would be best to start my on-track experience with a small displacement bike. Something I could dedicate strictly to the track. The catch was; I needed to keep it as cheap as possible to leave as much cash for session fees, travel expenses etc. I settled on the Ninja 300 for several reasons, not least being that it was old enough to be cheap(er), used parts readily available, yet still packed the fun factor (I don't need to tell you all!). So I started scouring listings in my area. The goal was to get a bike, give it a once over/tune-up and head to the last track day of the season. Wishful thinking!

With about 3 weeks 'til the big day, I finally found a track-only bike way down in Maryland. The price was right, the seller seemed like a decent dude, and my buddy offered to help me pick it up in his truck. The previous owner listed it as being a 2015 ABS model, with a bunch of track-specific upgrades. Maybe we could make that last track day after all??? Well, not so fast...

This is how she looked when I picked her up...

Brake MC scraped to hell...

Going to need to learn fiberglass repair...

I knew going in that the bike had been down (perhaps a few times), leaving the bodywork cracked and scraped, some damage to the front brake MC, but overall it looked OK. When I met the owner, it fired right up and we let him ride it a bit to show us how it ran. I didn't ride it myself because it was pouring rain, and he mentioned that the neighbors had called the cops on him for riding it on the street. I figured better he get hassled by the cops than me. That may have been a mistake...

When we got it home and up on the lift it started right up, but was running rough. No smoke out of the exhaust, so I removed the plugs to have a look. Plug 1 looked fine. But when I removed plug 2 it was wet. With plug 2 out of the engine, I hit the starter and water shot clear to the ceiling! Oh boy. I hadn't thought to look at the oil sight glass - but a quick glance showed what looked like coffee ice cream. Time to drain the oil. If it wasn't coming from my motorcycle engine, I'd almost enjoy the abstract art it formed. That track day was looking like it was farther and farther away...

mmm...mmmm...good.

Time to pull the engine and get a look inside...

To be continued...

 

[jjmaine]

Awesome! Looks like the previous owner spent more time sideways then he did on two wheels lol. That's what they're for though and should be a nice project to fix right up. Should be a nice season this year with plenty of track days!🤗

 

[motopreserve]

@jjmaine Let's hope so!!!

Despite there being no white smoke from the exhaust, best bet was a blown head gasket. More coolant in the oil than to suggest simple condensation, it was time to get the motor out of the frame and see what we were dealing with. Mechanically this was not tough - but MAN! there are a ton of electrical connectors to deal with.

Can't think of a better way to get to know a bike...

Decided to weld up a quick stand to secure the engine on the bench. A while back some kid gave me a bunch of parts, along with this brick sh*thouse lazy-Susan (I think it's meant for swiveling your bike while on a center stand???). Never had a use for it - but couldn't toss it. This thing was perfect for turning the motor for best work angles.

Not your dining room table lazy-Susan...

Time to dig in...

I am thankful for paint markers every day...

I don't have a ton of photos from this time, I was racing the clock. So I opened up the shop manual and started opening up the top end. I was hoping that there would be some type of obvious damage to the head gasket, but it wasn't as dramatic as I expected.

It didn't seem perfect - but based on the water shooting sky-high, I expected a neon sign pointing to the issue. No such luck. I could see plenty of moisture though. Clearly something was allowing coolant to cross over from the head jacket into the cylinders. I ordered a head gasket and since I had some time to wait for it to be delivered, I started on cleaning up the tops of the pistons.

Takes a while, but it's satisfying...

 

[motopreserve]

While I waited for the parts to arrive, I decided to check out the rest of the bike. So far, this thing had been more than I'd bargained for - but then again, a bargain often brings issues. The previous owner, in addition to finding himself on the ground a lot, seemed to have never heard of a rag or a bike cover. The thing was filthy - inside and out. I found a ton of debris from crashes, but also several areas where little critters had taken up residence.

Mouse blanket?

Worms? Baby corn? Don't know, don't WANT to know...

When I asked the PO what type of shock was on the bike - he honestly did not know. Clearly this bike had been set up by an owner before him - and he had bought it and crashed it. Often! So I dug under the bike to unearth the shock, and after scrubbing away years of grime, I unearthed the name PENSKE! Sweet. These shocks cost a ton, and it's nice to see something of value on this thing....

I tried a ton of degreaser, but couldn't get all the crap off the shock. So I finally decided to remove it. After getting it on the bench, I realized that this thing was desperately in need of service. Fortunately there was a sticker on the shock with the name of a dealer. Several of the parts/work on this bike had been done by MRP Motorsports down in Maryland. In addition to the shock, the ECU had been flashed there, and some fork internals had been installed. When I contacted them, they were super helpful, and offered up all the info they had on file. Now I was getting somewhere!

Why abuse a poor, defenseless shock???

Turns out the ECU flash contained options that no longer existed on the bike. UGH! Since I was sending the shock to them anyway, I asked how much it would be to reflash the ECU. Despite not being the original customer, they said the flash would be free, since it had been done there before. Wow. Not the kind of thing I have come to expect from dealers, but a pleasant surprise. Off in the mail they went, as I waited Impatiently for the head gasket to arrive...

 

[Frank]

I would check the head itself carefully for cracks but hopefully it's just the gasket. For future reference Spears sells a thinner head gasket to give a bit more compression. Fingers crossed for you...

Sent from my SM-T380 using Tapatalk

 

[jjmaine]

Sweet score on that shock! What did that guy use for chain lube, crisco? Kudos to MRP as well they seemed awesome when I had my ecu flashed and its good to know if I need something changed in the future they will help me out.

One good thing about your bike needing a complete overhaul is you get to correct abd clean everything and you know you’ll be starting on a solid bike. Nice progress!

 

[motopreserve]

I would check the head itself carefully for cracks but hopefully it's just the gasket. For future reference Spears sells a thinner head gasket to give a bit more compression. Fingers crossed for you...

Sent from my SM-T380 using Tapatalk

Unfortunately I didn’t start this thread while I was doing the work. I’m writing all this after the fact. So all these issues are coming up in future posts

 

[motopreserve]

Sweet score on that shock! What did that guy use for chain lube, crisco? Kudos to MRP as well they seemed awesome when I had my ecu flashed and its good to know if I need something changed in the future they will help me out.

One good thing about your bike needing a complete overhaul is you get to correct abd clean everything and you know you’ll be starting on a solid bike. Nice progress!

I had planned on taking the bike down to nuts and bolts at some point - but was hoping to do that AFTER I hit the track for the first time. While this was surely wishful thinking, I was trying to be positive and keep my hopes alive

After getting into it deeper, I realized that based on the abuse and neglect by the PO, it was better that I had to do this. The whole bike was riddled with issue large and small.

 

[jjmaine]

So you sent the shock to Mrp too? I didn’t know they did suspension stuff probably because I mever checked. I could have had them do mine for maybe less money than Traxxion. I’m happy though since I wanted it revalved as well. I bet that Penske will be awesome.

 

[motopreserve]

Yep. It turns out they had originally sold the shock to one of the previous owners. I didn’t need it revalued since the shock was set up for my weight already. That’s one of the few things that has been smooth on this build!

In a post coming up I’ll show the front fork internals they had installed as well. And despite the manufacturer not responding to my emails - MRP had data saved in their computer. So they were able to tel me exactly what was used, setup and rebuild specs. Gotta love people other good records!!!!

 

[SparkyMJ]

Wow this is a great thread you've got going! Shocking to hear about the water in the oil and cylinders.

IIRC, your old head gasket looked remarkably similar to mine when I pulled mine off, and mine did not leak. So as stated, get out a magnifying glass. If the bike was ever overheated, the cylinder could have gotten warped or cracked. You've already got the head off, take the cylinder off and see how those piston skirts and the rest of the cylinder itself look. Might be time to bust out some dial indicators and micrometers.

I had my cylinder honed and, since I was in there, did my rings too. If you have any piston or cylinder wall damage at all, might as well do the hone, rings, and pistons if yours are damaged or out of spec.

Another thing that looks odd to me is how corroded/rusted your water jacket is on the cylinder. When mine came out, the cooling channels were spotless, except for some dried coolant stains. Coolant is designed to be anti-corrosive and protect your cooling channels of course, so to see anything in there means a lot of something else got in there. Only other places to inspect on this engine for coolant contamination besides the head gasket is the water pump mechanical seal. That could also be causing your milky oil, worth digging into. Although you may find my other thread on here about when my water pump finally died, and turns out they don't sell every OEM part of the water pump separately... So they are only partially rebuildable. Sucks. So I just bought a whole new pump and life has been good.

Good find on the shock! Hope it serves you well.

Do you know if any previous owners ran race gas? If they ran it with race gas while it overheated/warped/leaked at the head gasket, that could explain some of the internal mess perhaps, but I have no experience with race gas personally.

These bikes are pretty bulletproof so long as you have coolant and oil, so maybe at some point this engine was missing one of those things. But it's up to you how much power you're trying to choke out of these little engines, trading off reliability. I kept my engine stock except a MCCT and haven't flashed the ECU and it just keeps running forever, only normal wear and tear at 60,000 miles with track days. So if it was my bike, I might have the ECU reflashed with mostly factory settings except the fuel/ignition, since you're getting it flashed anyway.

Regardless, my point is that getting into track, you will be served a thousand times better with a bike that simply runs and works than something that may have issues one day because of some mods. Especially getting into track. Nothing worse than your bike failing to work the morning you unload it in the paddock.

Glad you made the thread for us to follow! I will be reading all your updates. Thanks for sharing!

-Mike

 

[motopreserve]

Wow this is a great thread you've got going! Shocking to hear about the water in the oil and cylinders.

IIRC, your old head gasket looked remarkably similar to mine when I pulled mine off, and mine did not leak. So as stated, get out a magnifying glass. If the bike was ever overheated, the cylinder could have gotten warped or cracked. You've already got the head off, take the cylinder off and see how those piston skirts and the rest of the cylinder itself look. Might be time to bust out some dial indicators and micrometers.

I had my cylinder honed and, since I was in there, did my rings too. If you have any piston or cylinder wall damage at all, might as well do the hone, rings, and pistons if yours are damaged or out of spec.

Another thing that looks odd to me is how corroded/rusted your water jacket is on the cylinder. When mine came out, the cooling channels were spotless, except for some dried coolant stains. Coolant is designed to be anti-corrosive and protect your cooling channels of course, so to see anything in there means a lot of something else got in there. Only other places to inspect on this engine for coolant contamination besides the head gasket is the water pump mechanical seal. That could also be causing your milky oil, worth digging into. Although you may find my other thread on here about when my water pump finally died, and turns out they don't sell every OEM part of the water pump separately... So they are only partially rebuildable. Sucks. So I just bought a whole new pump and life has been good.

Good find on the shock! Hope it serves you well.

Do you know if any previous owners ran race gas? If they ran it with race gas while it overheated/warped/leaked at the head gasket, that could explain some of the internal mess perhaps, but I have no experience with race gas personally.

These bikes are pretty bulletproof so long as you have coolant and oil, so maybe at some point this engine was missing one of those things. But it's up to you how much power you're trying to choke out of these little engines, trading off reliability. I kept my engine stock except a MCCT and haven't flashed the ECU and it just keeps running forever, only normal wear and tear at 60,000 miles with track days. So if it was my bike, I might have the ECU reflashed with mostly factory settings except the fuel/ignition, since you're getting it flashed anyway.

Regardless, my point is that getting into track, you will be served a thousand times better with a bike that simply runs and works than something that may have issues one day because of some mods. Especially getting into track. Nothing worse than your bike failing to work the morning you unload it in the paddock.

Glad you made the thread for us to follow! I will be reading all your updates. Thanks for sharing!

-Mike

Stay tuned. All of this will bear itself out in the coming posts. Have already been down several rabbit holes with this bike - just didn’t post a thread til after it was just about done.

Interesting thought on the race fuel. I know the kid before me didn’t use it - but somewhere in the past I assume it was, because there was a fuel map button and it was on the ECU flash (more great records kept at MRP!). I removed that and when reflashed did the stock + few slight changes.

I’m with you on wanting a basic, running bike for the track. I just want to learn. I don’t mind wrenching, but NOT at the track if I can help it!

 

[motopreserve]

As mentioned in the previous posts by @SparkyMJ and @Frank - it became pretty obvious that the level of abuse to this bike could very well have included overheating, and damage to the head. I figured I'd remove the head and check it on my surface plate, which would give me the most accurate readings. But I didn't even need to get that far - a simple machinist's straight edge across the head showed warpage. Not good. Looks like it's time for some lapping.

Unfortunately I don't have any photos of the lapping process. I was still racing the clock to try to make it to that track day - so I dove right in.

If anyone is interested, this was my process: With the straight edge laid across the head in various spots and angles, I measured the gaps with feeler gauges. The worst of it was between the 2 cylinders. I was getting a measurement of between .003" and .004" which according to the manual, is over 2 thou out of spec (spec is .002"). Other areas had a slight gaps, but nothing as dramatic as the center section. The manual states very matter of factly that if it is warped more than .002," you are to toss the head in the garbage and buy a new one. This seemed crazy to me. I understand these machines are built to tight tolerances, but come on! Next time you want to give yourself a heart attack, take a look at buying a replacement head. I just had to try to get this thing flat. Time to get lapping...

Thankfully there is a 12% discount!

There was no way I was going to ruin my surface plate with lapping. So I grabbed a 12"x12" marble sample tile I have, which is pretty damn flat, and some valve lapping compound. After spreading a thin coat of compound on the marble, I moved the head in a figure-8 pattern...over...and...over...and... I couldn't find anything on line about how much clearance there is between the piston and valves, so I didn't want to go too far (a full .004") and risk crashing the valves. The only thing I did find was a thread about lapping an ex500, and it was clearly stated that there was almost NO room between the piston and valves. This had me nervous. So I lapped it down to within spec, and stopped there. The only area that still showed some gap (almost the entire head was under .002" at this point) was the very center between the cylinders. I had to hope that the new head gasket would take up this discrepancy - which the manual sort of alluded to.

The straight-edge test has shown the top of the jugs to be OK. Also, the valves passed the gasoline test, so with high hopes I decided to clean it thoroughly, button it back up and give it a shot. I don't mind admitting that optimism rarely works out for me...

 

[jjmaine]

Did you bolt the head on and check piston to valve clearance? I used kids playdough on top of the piston cut-outs on my last engine. I was using a cam with a lot of lift and duration (for that engine) so there was some question whether or not it would leave room☺

But I highy doubt that the oem tolerances are so tight that lapping the head .002” would cause problems…

 

[jjmaine]

I wonder how much power could be gained going balls out on a Ninja 300 engine build? Oversize high compression pistons, cams, ported head, full exhaust and tune? You would probably spend more than the cost of a new Ninja 400 just to get the same power.🤣

 

[motopreserve]

I did check clearance using molding clay. I wasn’t showing a crash, but I had already lapped .002” +/- off the head. It was the additional .002” that worried me.

I’m not sure how much more juice you could wrangle out of these things. I’m sure Spears could tell you. And for a measly $17,493 it could be yours!

 

[jjmaine]

I, for one, think their prices are quite reasonable. They have 21 of these in stock, maybe I should buy them all and sell them on eBay at a mark up.

 

[motopreserve]

@jjmaine Looks like you are on to a whole new business :

Wanted to mention here that before buttoning the engine back up, I did stick a bore gauge in the cylinders. The tolerances were within spec - but close. Since I was still operating under the hopes of making that last track day of the season, I decided to get it all back together and see where were at. I checked the valves and they were on the far end of spec. I had ordered an entire shim pack so that I'd be ready, so I got the valve clearances squared away.

One thing to mention - which I never got an answer to here on the forum, was my concern with the alignment of the cam shaft/chain. When I was reinstalling the valve cover/head, I followed the directions in the shop manual to the letter. And I did it several times. Each time, when lining up the cam shafts as described, it required putting a ton of pressure the front valve cap to reinstall. This is a semi-frail cast aluminum part, so I assumed I was doing something wrong. But again and again, I compared my positioning to the manual, and I was spot on. The #1 cylinder exhaust lobe was putting pressure on the bucket. I thought I might have advanced the cam too far? But again, it was spot on with the manual.

In order to install the cap without pressure, I had to advance the cam to a point where all the lobes were free of pressure (I needed to retard the timing position slightly from the prescribed position). I'm probably not explaining this very well, but what I know for sure is that when following the directions in the manual, there was literally no way for me to get that cap on without fear of breaking it. After advancing to a safe position, I got it all button up and torqued to spec. Then I advanced to the position the manual describes and confirmed that the chain, lobes etc were all as they should be. Not the worst thing in the world - but never cool to have to deviate from the shop manual to get something right. Always leaves a doubt in your mind.

While I had the motor apart, I figured I should drop the oil pan to try to remove as much milk from the nooks and crannies as possible. Fortunately the stand I had made allowed me to pivot the engine up and over, allowing me access to the bottom end. Even after draining thoroughly, there was a bunch of milky oil in there, so I'm glad I took the time to flush it out and suck up what I could. Got a shot in there with an endoscope after cleaning.

Gears, gears and more gears...

Time to get it back in the bike...

 

[jjmaine]

I remember you mentioning your trouble getting the cam cap back on the exhaust cam. I did mine same as you by the manual and the cap went on no problem. I just tried best I could to tighten all the bolts evenly little by little and it went on without much force at all, just slight pressure from the cam lobe pressing on the exhaust valve. I did have the cam chain jump a tooth when the pressure on the cam lobe cause it turn suddenly so I just took it back off and started over until I got it.

 

[Frank]

If you ever have the pan off again, Spears sells a heavier spring for the oil pressure bypass which he says is a worthwhile mod. It's an inexpensive mod that makes sense.

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