New '94 KDX: Pictures and some questions

GreensboroKDX · Post by **GreensboroKDX** » 10:13 pm Jul 02 2016

Hey guys. I bought a '94 KDX off of Craigslist today. It is my first 2 stroke bike! I have some questions about some issues that I need to solve, as the bike is definitely a project.

Firstly, I ran the bike without an air filter for 5 min because I didn't know the bike did not have an air filter on. There was a little moisture and grit in the air filter box and I am scared that I messed up the engine, even though it runs fine. Is there anything that I need to do to make sure that the engine is okay? I am definitely putting an air filter on her now that I know that she doesn't have one, and I didn't even think to check before.

Second issue: No brake pressure. The brake handle is extremely east to pull, there is no resistance. Obviously the brakes do not work. What could be causing this? Lack of fluid in the brake line? Brake cylinder issue?

Third Issue: In the pictures I will attach at the bottom, there is a white reservoir. I think this is for coolant, but I am not sure. What is this thing?

Besides changing all the fluids, what do I need to do to make sure my bike is in good condition to ride, and that it will function and not blow up for a long time to come?

I can't figure out how to attach images so I am linking to an imgur album.

Edit: The gunk in the air box may have been oil particulates. It was not gritty feeling, it was gritty and stunk like oil and gas. I did not know but I guess it is normal if the engine is running rich to spew particulates?

Post by **KDXGarage** » 12:33 am Jul 03 2016

Welcoem to the forums and congratulation on the KDX.

White reservoir on the left rear is for coolant.

Big uh oh on not checking the filter before buying it. Who knows how long it was sucking dirt?? Hopefully, you just forgot to put it back on instead of it coming like that.

Off topic, but: I have some shelves like that. They are great.

GreensboroKDX · Post by **GreensboroKDX** » 12:58 am Jul 03 2016

Yeah. I know I didn't remove it because I didn't check it. I am planning on pulling the jug tomorrow and seeing if there is any damage. Bike has been sitting a good bit, and previous owner was planning on fixing it up but got bored I guess. I think he probably took it off. Hopefully there isn't any damage, but to be honest I don't really know what to be looking for. Bike runs good. Compression is really high, it starts easily first kick. If it is messed up, I don't know what I'll do exactly.

Post by **KDXGarage** » 02:40 am Jul 03 2016

There are plenty of "here is what my top end looks like after I took it apart, what do you guys think" threads on here to read through.

MotoArts · Post by **MotoArts** » 08:26 am Jul 03 2016

If it were me....
I'd gently wash out the airbox and install a new filter. Whatever funk is in there doesn't mean much.

Change the gearbox sauce, antifreeze, change/flush the rear brake fluid (nobody ever does that but should) and safety check the rest of the bike. If empty, add a touch of fluid to the front brake and pump it to see where it is leaking from... hydraulic brake systems should never suck air or leak from anywhere (leading to the spongy or no brake power).
It's common for the master cylinders and calipers (both front and rear) to get loaded up with corrosion and other "hazardous waste" crud. Disassembly is easy, and rebuild kits are very inexpensive if required. I've reused original components more often than not. Can use rubbing alcohol or plain water on the parts to clean them. Brake fluid is hygroscopic, which means it attracts moisture... even through the rubber brake lines and seals... and creates corrosion on its own over time. Fluid color other than clear (as in coffee color of any sort) means it's junk.
Regardless of what you may read or what others may tell you, DO NOT be tempted to use DOT 5 fluid in this bike. I won't go into details, but just don't. There is no advantage. Use DOT 3 or 4 only. A fresh bottle is almost free, and you'll be surprised at how little volume the system takes. It's almost scary small, considering the job the fluid does, LOL.

I'd only waste the engine gasket kit if there's an obvious problem at this point, especially if it has mondo compression

.

If it all checked out, I'd pull out the stops and let 'er eat!

GreensboroKDX · Post by **GreensboroKDX** » 11:02 am Jul 03 2016

Okay, sounds good. I haven't measured compression, but she kicks over very, very easy (not the actual kick, but she starts easily). I don't even have to choke the bike at all and she goes first kick. So I am assuming compression is very good. It also takes a swift kick to turn the engine over, I can't do it in tennis shoes because it tears a hole in the bottom. I don't really want to replace the gaskets, and like I said this is my first two stroke ever, and my experience with bikes in general is very limited. My other bike is a CRF150F, which is super simple maintenance wise because I really haven't had to do anything to it except change fluids and lubricate.

doakley · Post by **doakley** » 01:14 pm Jul 03 2016

I don't think I would take the top end apart at this point either if it is running well. I would remove the pipe though and take a look up through the exhaust. Remove the plug, turn the piston to BDC and shine a light through the plug hole while you look inside with a mirror if necessary. A cheap dental scope (online for way under $100) would be a good tool which you could use as a borescope and get a good look at the cylinder walls. You won't be able to tell wear easily but you should be able to see any damage. Otherwise MotoArts has already addressed some key things to check. I'd also pull both wheels and check the bearings. While you have the rear off you might as well pull the suspension linkage and check those bearings and the swing arm bearings. If the air filter is any indication of the PO's maintenance I'd venture it has been quite a while since these received any grease. When I bought mine it looked like the PO had been using rust as a dry lubricant they were so bad. I had to grease the steering stem bearings too. The rear shock linkage was actually binding and I could barely move it by hand after disconnecting the shock. As I moved the swing arm up and down I could feel the drag from the dry bearings.

GreensboroKDX · Post by **GreensboroKDX** » 01:19 am Jul 05 2016

OK guys, figured I would check in with a status report. So I learned some good things today that have me optimistic about finishing this project in a relatively short time span, as well as without spending too much money. First bit of great news: the front brake is operable. The pads are worn so low that you really have to pull the lever to the maximum rear of its travel, but the brake engages. So the guy I bought the bike from gave me a set of pads to go with the bike for both front and rear brakes. I am going to download the linked KDX200E manual on the home page tomorrow, and then I will get down to changing the pads.

I also talked to my uncle today about the bike. He rebuilds and restores cars and motorcycles for a living, essentially. He said he has some equipment to run compression and leak down tests on the engine. He said with a few tests we can determine the condition of the cylinder/ walls with about 80% accuracy, and that there are a few other tips and tricks we can use to get it around 90%. That is acceptable to me. He doesn't seem to think I need to pull the jug, or that there is any major issue, and he agrees that the grimy stuff in the air box was just engine defecation.

I also checked the radiator and found that it was full of fluid. This may seem like a dumb thing to be relieved about to you all, but I am glad to know that there should not be any heat related damage. Oil is also full, and needs to be drained and changed.

On the down side I discovered I am going to need a fork seal and oil on the left fork leg. I will probably see if my uncle can help me out with that. I also know that I need a new chain, sprockets, and a clutch cable.

canamfan · Post by **canamfan** » 06:53 pm Jul 05 2016

At least you didn't fill the radiator overflow bottle with two stroke oil, thinking it had oil injection and then run straight gas in it. Someone did that once not me.

GreensboroKDX · Post by **GreensboroKDX** » 01:12 am Jul 06 2016

@canamfan

Yeah, when I got the bike, my dad said "This thing is going to need like 2000 dollars in parts, look at that tank. Its for the oiler, I bet that the oil system is broken."

So you aren't alone in thinking thats what it was.

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