MZ/MuZ Riders

Just had my MOT and the tester told me that the bike was burning oil and was right on the limit for an emissions fail, so I'm going to rebuild the top end. Bike has 99500+ km so it's lasted pretty well. Here's my question; is it possible to get the barrel off the engine without removing the engine? If not has anyone built an engine stand or is it easy to work on without one?
Ta

Justin

You might find this useful

viewtopic.php?f=3&t=4485

Terry

Yes the top end can be removed without dropping the motor completely.
Remove all engine mounting bolts and swingarm bolt except for the bottom rear and the motor drops forward.
Have done both my skorps this way.
Cheapest supplier for parts was http://www.partsharkworld.com/

List of parts needed if you want to do the job properly.

SKU: 3YF-12111-00-00
VALVE, INTAKE x 3 $16.02

SKU: 3YF-12121-00-00
VALVE, EXHAUST x 2 $24.90

SKU: 5H0-12119-00-00
SEAL, VALVE STEM 5 $8.07

SKU: 3YF-11181-00-00
GASKET, CYLINDER HEAD x 1 $37.82

SKU: 93211-01467-00
O-RING 1 $5.30

SKU: 3YF-11351-00-00
GASKET, CYLINDER x 1 $10.28

SKU: 3YF-11636-00-00
PISTON (0.50MM O/S) AP x1 $69.42

SKU: 3YF-11610-20-00
PISTON RING SET (0.50MM O/S) AP x 1 $26.01

SKU: 3YF-11633-00-00
PIN, PISTON x 1 $17.08

SKU: 93450-24028-00
CIRCLIP x 2 $1.22

SKU: 94590-27126-00
CHAIN x 1 $59.86

Thanks for the replies.
Skorpion660, I tried to search the forum for the answer but missed that post. My workshop area is pretty small (full of woodworking kit) so it would be much easier to leave the engine in the frame.
Mz Oz ,thanks for the parts list, I can use the part numbers but shipping and import duty from the U.S. to the U.K. is prohibitive. Pretty sure I'm going to put in a wiseco 10:1 piston (+.50) and will definitely put in a new camchain. Did you find it necessary to replace all the valves or was it preventative maintenance?

Ta
Justin

My opinion of replacing the valves is, if you have got it pulled apart that far you may as well do the lot, everything is back to square one.
I think you'll need to replace the valve stem seals anyway, which will mean pulling the valves and getting them reground and the seats recut.
Don't know what the import situation is in UK but we are duty free if under $1000.
Those part numbers are genuine Yamaha numbers by the way.

Unfortunately in the UK we get charged 20% VAT on orders over £15, and customs duty and VAT on orders over £135. Add to that the fact that if it is charged they include the postage and shipping insurance in the value, plus however mcuh the courier charges to collect the taxes ( somewhere between £8 and £15) and it all gets rather expensive!

I am following the method suggested above but cant get the swinging arm bolt to come out. It turns easily enough but feels like the bearings are knackered. I've tried using a drift but I am nervous of ruining the thread on the bolt. Have I missed something obvious? I am trying to push it out on the left hand side as sat on bike, but I can't see that it would make any difference. Have used plenty of plusgas on the four points you can get at the bolt. Any ideas/suggestions?

If you have the exploded view of the swingarm assy from the Grahams website you'll see that there are 2 sleeves that run in the bearings and that the bolt goes through these.
Does the bolt rotate in the frame sections ? If so, what has happened is the bolt is seized in these sleeves and sleeves are moving in the bearings.
It is just a matter of judicious use of brute force and persistence to get it moving. Use good heavy hammer (short handle,heavy head) and a length of brass rod as a drift so as not to damage the thread too much.
This is the reason we should pull the swingarm bolt regularly and lubricate it. Many the time I have had to cut swingarm out of bikes when I was working in the repair game.
Good luck with it.

Emissions check for motorcycles? In the UK MOT?

There isn't one!

http://www.motuk.co.uk/manual/mc_contents.htm

If the only reason you're rebuilding the top end is from what the tester has said, save the cash and find a better MOT garage.

If I was limited for space and I am, and If I was limited for time which I am as well, and I dont have a crazy inspection process where they check this or that like oil burning, emissions etc etc which they dont in my area - my first option on a skorpion for removing the head if I needed to would be to cut the cross member and make a milled 1/2 pipe type of fitting and weld it onto the frame. That way the tank can ride on it and I can take it off as needed to get the head cover/head etc off.

I've hacked off that member on other frames in the past one even more critical IMHO and made it unboltable - On a GS500 to fit a GR650 motor you have to take it off, else you'd never get its valve cover off without having to drop the motor. 3500 mile adjustments and it starts needed them pretty much at that interval after about 30K, and had no ill effects. The GS one is triangulated too, connecting the steering neck to the cross bar between the frame spars. It keeps the flex under braking down. Unboltable is fine. Works the same.

Cool.
Srinath.

arry-b you are right. I've been done up like a kipper. Will have a word with him to see what his game is. Bike does need work though and got the engine out this morning with the help of Tigcraft. Soon as the engine and rear suspension is rebuilt will get back to fitting GS500 wheels........probably be all done in a couple of years

I ran one of my Skorps to 100000+ km, and it was running great until the accident. Not burning more oil than usual ~.5 qt in 1500 kms
Do you have blue smoke ?

Oil consumption has little to do with miles travelled.
My Tour which I bought new was used conservatively daily for commuting and touring and maintained regularly made it to 120,000 K before the oil consumption got to a point which I considered was excessive but it wasn't blowing any smoke.
The secondhand Sport on the other hand, (I knew owner) was ridden hard and not on a regular basis got to 40,000 k before being stored out in the open for 2 1/2 years, I put another 15,000 on it before it began blowing clouds of blue smoke on start up and exhaust pipe had oily residue.
Both have had a topend rebuild as per parts I listed and have each got about another 40,000 k and no sign of oil usage.

Did you ever do any mild porting to the head ? and did the top end rebuilds + new cam chain run appreciably better ?

My new 2000 Tour always burned oil from new, my 1998 Traveller bought used doesn't.....burn much.
2000 Tour ran stronger and started better than my 1998 Traveller.