Vintage Dirt Bike Q & A

Hello everyone, I'm a proud owner of a 1973 MT250. Not only is this my first Elsinore, but actually my first dirt bike of any kind! Though not my first motorcycle. I've got a 1970 BMW R60/5, and I have had a couple of new Ducati's in recent years.

I love older bikes, and ever since watching "On Any Sunday", I've always had my eyes out for a classic dirt bike. Finally this one came along. It was the right bike at the right time, at the right price.

Once I got the bike home yesterday and started looking it over, I was very happy to find that most everything is in really good shape. The first thing is that someone previously stripped the street gear off to make this a dedicated off-roader. Luckily, they didn't just go in and start cutting wires. I got a bucket of parts with the bike that included the main harness, headlight, taillight, speedo, battery, ignition switch (no keys) and various other odds and ends. Everything is in good shape, just some minor chrome pitting.

The biggest issue I found right from the get go is that someone removed the oil tank and plugged up the oil pump. So I guess that means I'll be mixing my own gas huh? As least for a while. I would like to put it back to original sometime. Which brings me to my first question:

1. Where does the oil pump send oil to? I'm assuming the carburetor, but which port on the carb is right?

After searching and searching for a while, I finally figured out how to open the seat. I found that someone had broken a key off in the seat lock, but I could still turn the lock with a screwdriver, thus popping the seat. Under the seat I found two big surprises. First, the tool tray was there, and had the tool kit with it! I opened the kit and it actually looks like everything is there, except for the shock adjusting wrench. All the tools are in great shape and look like they've never been used. Unfortunately, that was the end of the good news. I saw that there was nothing holding the air cleaner top on. Underneath, I found a what appeared to be a shredded paper filter. This thing was really, really bad. It almost looked like blown in attic insulation! My jaw just dropped when I saw this! After all, I know the guy that sold the bike to me had been playing around on it in his shop's yard. Now I'm wondering how much of that stuff got sucked into the intake? So here's question #2:

2. What is supposed to make up the air filter? Is there supposed to be a paper filter around the cage, and then foam around that? Or is there just a foam filter around the cage? I saw a foam filter on Ebay, but it was for a CR250 of the same year, will a CR filter work on an MT?

Luckily, I know the engine is running well, so I'm guessing that if any of that junk got sucked in, it just burned up and went through. The last issue I found was the kickstand. The bolt that holds it on apparently backed out at some point, and the mounting holes got bent badly. I can fix that, but the spring is also missing, so hopefully I can track one of those down without having to buy another whole stand off ebay. Which brings up question 3:

3. Does Honda still make parts for these bikes? BMW is VERY good about keeping parts going for old bikes, I'm hoping Honda is too? If not, do you guys have any particular favorite online parts sources?

Well, that's probably enough for now. My fingers are getting tired, and I'm sure you're sick of reading! So, thanks in advance for any help you can provide, and here's a couple of pictures of my new ride.

Hi George,

Congrats on your new bike! I don't own one myself, but my buddy has one that gives me all the frustration of ownership without any of the rewards (it needs 30+ years worth of maintenance done, but he doesn't want any money spent on the bike, by anyone). :>(

Your oil pump may have destroyed itself due to lack of lubrication, which will complicate returning it to stock even if the other parts are available. I would make the effort to put the oil injection back if it were my bike, but that's just a personal preference.

My MR175's air filter box was filled with shredded paper, mattress stuffing, etc. too. It wasn't until I found the acorns at the bottom that I realized what I was looking at (a squirrel's nest).

The 17212-358-000 OEM foam air filter is discontinued, but I have a spare/used one I can send you N/C if you want it. This filter was used for about a year, and cleaned twice (it still is in perfect shape). It fits over the cage, with the bottom edge of the cage fitting inside a slot that runs around the inside of the lower plastic filter edging. Provided the foam gasket in the bottom of the airbox is intact (it may not be), this setup should provide a very good seal. If the MT airbox is like the MR's, there's a metal screen that will prevent anything large from being sucked into the motor.

Here's an extremely condensed version of my parts procurement procedure:

1) Get a part number from Parts Nation:

http://www.hondapartsnation.com/pages/O ... 1000001//1

2) Enter the part number into the the Bike Bandit search engine to see if it's still available:

http://www.bikebandit.com/oem-parts

3) If it's not, try eBay or Google.

If you're really serious about getting parts, you'll be able to find most anything you need - but some may not be easy. There are many actual MT250 owners here that will surely be able to help more than I will.

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric

The oil pump discharge line goes to the right side of the intake manifold. There should be a bolt there plugging the hole. If you don't plan to street ride the bike, I would just run Honda CR pre-mix @ 32:1.

Sounds like you have/had a rodent of some type make a nest in your air-box. Air filter foam can be purchased in flat sheets at most dirt-bike stores. You may have to buy some foam & make your own filter.

Good luck
~JM~

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WWW.CADDY500.COM
The High Performance
Big Block Cadillac Forum

I had another interesting day of discovery on my Elsie. I spent a lot of time just cleaning gunk, and oiling the chain. First thing needing repair was the side-stand. It was loose when I got the bike home, and today I found why. The bolt going through the top of the stand was loose to the point I could pull it out by hand. Then I saw that the threads were boogered, and the tabs were bent. A little heat from my oxy torch fixed the bent tabs, but the threads weren't quite so easy, it took a while for me to figure out they were 10mm x 1.25. But once I did, all was good. A new lock washer and nut on the back side, and job done.

Since the gas was questionable, I drained it, and made up a fresh mix of 32:1 Honda Pre-Mix Oil and 89 octane gas. After the refill, it was time to try it out. The engine started right up and runs great. MUCH less smoke now out of the exhaust. After a few runs up and down my hill and I find that the bike is bogging down under heavy throttle. Since the inside of the gas tank looked a little rusty, I decide to check the fuel delivery. First thing's first, I pull the fuel sediment bowl, and TA DA! The bowl was FILLED with crud. No, really, it was totally FILLED!!! I've never seen anything like it! The screen inside was completely trashed. So that's next on the shopping list.

Last thing on my to-do's for today was a clutch adjustment. I saw in the owner's manual that the lever at the end of the cable should be pointing at the mark on the engine case and mine was WAY off to the left. Then I found the slack adjuster on the hand lever was completely screwed out of the housing. So I carefully screwed it back in and adjusted the clutch exactly as the manual states. Lining up the lever to the mark, then turning in the screw in the right-housing. However, it doesn't work. With the clutch lever completely in, the clutch is still grabbing. So what's wrong with this picture? Is the clutch cable just stretched out maybe?

Ah well, enough frustration for tonight. More digging tomorrow.