Vintage Dirt Bike Q & A

I've begun restoring my mr 175, after making sure the engine would even run I began dissembling to check the fluids or for any obvious wear. after using a bolt extractor to finally get every screw off the stator cover I found out there wasn't any fluid at all in there. should there be any oil in there? and where do the two nipples on the side at back of the engine go to?
and aside from the engine oil that goes in on the other side is there anymore I should know about it? like is there separate transmission fluid or does the engine oil lubricate that as well?

I would greatly appreciate it anyone could answer these questions for me.

The stator/flywheel area should be bone dry.

All my MR175 motors have only one hose nipple at the rear, for the gearbox vent hose which runs down ahead of the swingarm pivot.

The gearbox oil capacity is 850ml. Be sure to use motorcycle-specific 10W-40 or 20W-50 oil, NOT car engine oil.

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

ah well, my motor has a nipple on the flywheel compartment. see I put pre mix oil 2 stroke oil into the hole with the cap that says oil because I'm under the impression that the oil that gets injected into the motor doubles as a transmission fluid.

Like ray said engine oil in the tranny is the way to go even states this in the honda shop manual. I have an mt not an my so I dont know if the mr had injectors but dont think they did. Even if they did it would have a tank under the seat for that oil, it still wouldnt go in the engine. Thats how the mt is a tank under the seat but its a street bike and was titled as such. I dont think the mr was but dont know for sure, how many street legal mr's out there? So I would drain the pre mix you put in the tranny and put it what ray said earlier. I would also mix the premix into the gas at the ratio on the bottle as they do vary with oil type. Ray stressed the no car oil because some oils have additives that will make your clutch slip horribly or maybe its a lack of additives lol I have heard it both ways. Just make sure its oil that is wet clutch compatible it will say on the bottle. Ray knows a lot about the mr175 so he is the one to ask.

Oh so you do have to mix the oil in the gas, see I read that it has oil injection on the honda elsinor site.

Again I dont own an mr so am not sure but I dont think they came with oil injection. Its easy to spot as I said before it will have an oil tank for the premix oil and a line to an oil pump and thenn to either the manifold or the carb. The mt ran the injector line from the pump to the manifold. If your bike dosnt have anything like this its premix only. If you use straight gas and its not oil injected you will find out pretty fast I would just mix it.

The nipple on the flywheel compartment on the left side of the engine is a breather where the points ignition is. The breather hose from this nipple should run to the rear of the engine below the carburator.
The CR125, MR175 and CR250 engines use pre-mix (mix oil into the gas). The MT125 and MT250 use oil injection (separate oil tank under the seat).

the shopmanual will answer your questions.
http://alp-sys.com/honda-elsinore/manuals/MR17575/ShopManual75mr175.pdf

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80 CR250Ra
80 CR250Ra
78 CR250R
80 CR80
82 Bultaco Sherpa 340
78 Bultaco Pursang 250 MK12
76 Bultaco Frontera 370 MK10
76 Bultaco Alpina 250
73 Bultaco Lobito 125 MK6
76 Suzuki RM125A
90 Kawasaki KX250

+1 on all the info and suggestions posted. Since the shop manual is a free download, you might consider using the money saved for an owner's manual, which is less technical and a bit easier to use for the simple stuff:

http://cgi.ebay.com/ebaymotors/Honda-76 ... 51988bf1b5

If your ignition works well, your carb is salvageable, and your fuel tank's not too rusty, hopefully your restoration will go smoothly.

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

Thanks for all the help, my carb seems perfect, the ignition is strong, and the tank is pretty rusty inside. I suspect that the bike will be at least in ride able once I get a new chain and transmission cover as the little piece that holds the clutch cable on broke.
I was amazed that the bike started in 3 kicks after I hooked up the fuel tank from my brother's bike to my carb and quickly hooked up the ignition.
getting the bike to look good again is another story.
p.s anyone got a rear fender?

I use & recommend Honda brand lubes. Honda is a huge company with an excellent R&D department. They can afford to produce the top quality oil formulations that other company's may not.

I use the Honda pre-mix that is designed for use in the CR models. I mix it at 32 to 1 with the best premium gas I can find. (Usually the 76 station or Chevron)

For your gear box, you should use a gear oil. Once again Honda has a great gear box lube. Regular automotive oils do not have the shear strength that a motorcycle gear box requires.

Buy high quality lubes. It is cheap insurance. Just think about what could happen to you if your bike seizes & locks up the rear tire at speed. It usually doesn't happen when you are going slow.

~JM~

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