MZ/MuZ Riders

Hello! I have just started a project to restore a 1995 Skorpion Sport and can use a little communal help from this forum.

The bike has never been dropped and has only 3000 miles. But it has been sitting around for about 10 years. the first eight garaged and covered. The last two years outdoors but also covered. The bike is very clean.

This is my first time being an auto-mechanic. And I figured the Skorpion is perfect for me to learn. I have bought several bike maintenance books and have an e-copy of Yamaha's SZR600 shop manual.

So far, I have cleaned and flushed the fuel tank, and cleaned the petcock; installed a new battery and all lights work; checked air filter; checked spark plug; and changed motor oil and filter.

My first question -- How important is it to clean the wire screen inside the "coarse oil filter", as suggested by the user manual? I am asking because the hex screw is quite stuck... I am thinking to just leave it be. Your thoughts?



As I understand it, the biggest work item for this restoration is the cleaning out of gas residue in the carb. A few questions concerning this:

- How do I remove the carburetor from that tight space between the engine and airbox? Do I just loosen the four clamps that connect it to the engine and airbox and then wiggle the carb loose? or is there a way to create some space for its removal?

- Other than the four clamps, are there other screws / fasteners that "tie" the carb down to the bike?

After the carb, I will replace coolant, brake and clutch fluids, and inspect suspensions and brakes. Hopefully, the bike will then be road-worthy.

Thank you for the help with my questions here.

Wai, in NYC

Should be fine on the course filter.

For carb removal, take off the seat and tank, remove throttle and choke cables from carb, loosen the rear clamps and remove the rubber tubes leading to the airbox. They might be stiff but they have to come out. Then you loosen the clamps mounting the carbs to the engine and pull them out. Again, they might be hard to remove after so many years but if the clamps are loose they will come out. Inspect intake manifolds/boots for cracks after carb removal and replace if necessary. Tip for carb installation - WD40 will help them go right in. Make sure they do slide in all the way. There is a ridge inside the boot that needs to seat in the groove on the carb. With the lubrication of the WD-40, you can feel it pop in place.

Clutch is submerged in the engine oil. No gear oil needed.

How did you check the engine oil level when you filled your bike back up? These bikes have a specific procedure or the level won't be correct.

And welcome to the club.

May as well check the valve clearances while the tank is off too. It needs to be done after the engine is broken in and your bike sounds like it's barely past that point. Once the tank is off, if memory serves me correctly, all you need to do is pull the radiator mount off and let the radiator fall forward, hanging from the hoses. That will give you enough room to check the exhaust valves. The intake valves are super easy to get to. It may sound intimidating for a beginner, but you need to learn how to do this stuff if you want to know the basics of motorcycle maintenance. Get a set of valve adjustment wrenches and some feeler gauges if you don't already have them.

How are the tires on your bike? They may look good with only 3000 miles but don't ride on them if they are the originals. Make sure they aren't dried out and cracking before you get out in traffic.

Thanks edfmaniac... Following your pointers, I managed to remove the carb... However, right now the carb is still "attached" to the bike by the choke cable (the rusted elbow connector in pix below).



Question: How do I disconnect the choke cable from the carb? At the carb-end of the cable or at the handle-bar-end of it?

I tried to unscrew the hex nut but there seems to be tension inside the cable which snaps the elbow connector back into the carb. I want to completely remove the carb from the bike today, so any pointers will be greatly appreciated. Thank you

Wai

There is some spring tension on the enriching device. Unscrew the hex at the carb, and it will come out. A little AeroQroil or your favorite spooge may help. Nice find..

Chuck - I have already completely unscrewed the hex nut, and I can wiggle the nut about the seat of the connection. But the elbow connector is not coming out and I am not sure if I should force it... I am also concerned about installing the cable back in the carb later - since I haven't seen the inside of this part and not sure how difficult it is for installation.

So, should I wiggle it some more and force it a bit?

I recommend ditching the cable and putting a plunger style choke. And yes, if the brass nut is backed off the threads all the way, the choke assembly should pull out fairly easily.

lots of luck this part is stuck on the carb on my mz rt125
and i am having a hard time getting it loose
sea foam is next on my list of things to try

looks like this item needs to be on the clean and service list of every ones bikes

i was riding mine at least every 3 or 4 days and then one day no start
because its stuck
dave

Edfmaniac -- I haven't filled up the bike with engine oil yet. I only dumped the old oil and put in a new filter. I thought I would add new oil at a later stage after other work items are done. I did not know any necessary special procedures. The user manual simply says standing the bike upright on the central stand. What do you suggest?

The tires are original. They look good and can maintain air pressure. But sure, for a 20 year old set of tires, I know it is best to have them replaced. But I will do this last.

Thanks for the tips on valve clearance. I will work on this after cleaning the carb.
Thanks also for the plunger-style choke idea. But as a newbie, I am gonna take this project one step at a time and so will stick with the original set up. I mean, look at how slowly I am moving on this already

So... I managed to pull out the carb today, though it is still "hanging" by the throttle cable. I will wiggle the cable some more tomorrow to try to take it out.

But if that fails (my confidence as a mechanic is also a work-in-progress... books, youtube, and you guys are my only guide), I plan to start disassembling the carb in whatever way I can tomorrow anyways, so to start cleaning out the inside.



One question: I expect to replace the carb's gaskets. Since MZ is not on the database for many US online bike stores, what bike model / carb model should I use for buying a carburetor rebuilt kit?

I don't think there is a rebuild kit. Might be, but I usually disassemble, see which parts need to be replaced and order just those parts. The 94 XT600 has the same carbs. Minimum buy a float bowl gasket and float valve. The valve seat probably needs to be replaced too but I could never get mine out. Worked fine with just a new valve.

Going from memory, the oil fill procedure requires that you put two quarts in the bike, start it, bleed the oil filter housing while idling and then let the bike warm up to full temp. I mean full temp. The oil tank should be hot. Then shut the bike off and immediately check the level. I think you will need a little over half of a third quart to bring it up to full on the stick. Always check the oil after the bike has been ridden or idled for a while. Also it's a wise idea to soak the element on your oil filter before you install it. Just pour some of your motor oil in it and roll it around until the entire element is soaked. That way, when the engine starts, you don't have to wait until the filter is finished wicking up oil before it starts flowing through the engine. Don't ask me why the oil has to be done this way but I've messed it up a few times and ended up with my oil tank filled the rim. I guess some of it settles back into the engine under gravity and filling it before you warm it up leaves you with too much.

Also, in case you didn't know, the bottom of the three bolts holding the oil filter cover in place needs to come out first when you go to do your oil change. It allows the oil in the filter chamber to drain into the crank case so you don't have much spillage when you remove the cover and pull the old filter. Do this when hot so more of the old oil run out of the engine instead of clinging to the parts like honey.

Here's what the owner's manual sez about changing the oil.
Remove the drain plug
loosen the oil pipe (2 screws) watch the o ring.
loosen the filler cap
for changing the filter, loosen the bottom screw 5 turns. this lets the filter cavity drain into the engine.
change out the filter after soaking as mentioned.
To fill
pour 2 liters of oil in the tank and close the cap.
Start it and let it run at least 5 minutes.
Let the engine run in neutral for 30 seconds. At the same time, ventilate the oil filter by loosening the screw at the very top of the filter housing and then tighten it again.
Turn the engine off.
Add .55L of oil.
Nothing to it.
I've noticed that it takes a little less than 3 quarts to completely fill it.

edfmaniac wrote:I recommend ditching the cable and putting a plunger style choke. And yes, if the brass nut is backed off the threads all the way, the choke assembly should pull out fairly easily.

GEDC1088.JPG

So, is that plunger choke a Yamaha part?

Chuck in Indiana wrote:Here's what the owner's manual sez about changing the oil.
Remove the drain plug
loosen the oil pipe (2 screws) watch the o ring.
loosen the filler cap
for changing the filter, loosen the bottom screw 5 turns. this lets the filter cavity drain into the engine.
change out the filter after soaking as mentioned.
To fill
pour 2 liters of oil in the tank and close the cap.
Start it and let it run at least 5 minutes.
Let the engine run in neutral for 30 seconds. At the same time, ventilate the oil filter by loosening the screw at the very top of the filter housing and then tighten it again.
Turn the engine off.
Add .55L of oil.
Nothing to it.
I've noticed that it takes a little less than 3 quarts to completely fill it.

Wow! My brain still functions at an acceptable level. I was pretty close.

Chuck in Indiana wrote:

edfmaniac wrote:I recommend ditching the cable and putting a plunger style choke. And yes, if the brass nut is backed off the threads all the way, the choke assembly should pull out fairly easily.

GEDC1088.JPG

So, is that plunger choke a Yamaha part?

Yes. A lot of things on our bikes also came on the '94 XT600. It's pricey but not if you are working on the bike all the time and are tired of dicking with the choke cable. 2KF-14371-01-00

Keyster do carb kits

http://www.siriusconinc.com/search_resu ... &x=24&y=16