1982 GS 550 MZ engine rebuild from zero

[gabos666]

That is sounds fantastic!! Thank you Ricky! First I just want to restore the engine's crankcase, than I can think about 650 conversion. Every help is heavily welcome

[gabos666]

I almost forgot the most important thing:

I found broken oil ring pieces in the engine. My theory is: in the past a broken ring damaged the OEM cylinder wall. PO bought a secon hand engine and swapped cylinder jugs and the pistons. But they left the metal flakes in the engine.

[ashdricky]

That is sounds fantastic!! Thank you Ricky! First I just want to restore the engine's crankcase, than I can think about 650 conversion. Every help is heavily welcome

having done the 674 conversion before my suggestion is that you plan out you modifications before you get too far in, and also be sure to calculate your budget. That is one thing I would have done differently, the more i learned from working on the motor the more I wanted to do to it. for me it's been almost 3 years, and alot of $ and I am still doing things.

on a side note I will actually be riding through Eger, Hungary on the 30th if you are in that area I may be able to stop by in person, just let me know.

[Wallowgreen]

Watching this one with interest....

[Sci85]

Ashdricky, I too am fixing to do this swap on my 550MZ. I have my motor out and have been looking around for the cylinder, head, cams, and pistons from a 650. Besides those items, what else should we plan for as far as major expense items? I did notice new rings are not cheap...

Thanks!

[ashdricky]

Ashdricky, I too am fixing to do this swap on my 550MZ. I have my motor out and have been looking around for the cylinder, head, cams, and pistons from a 650. Besides those items, what else should we plan for as far as major expense items? I did notice new rings are not cheap...

Thanks!

I had a very neat list of required and optional parts typed out then my computer froze so here is the condensed version I will avoid mentioning piston rings as if you end up getting weisco to machine new pistons for you they will come with rings;

Required;
1-550 8-valve Engine
1-650 8-valve Engine
1-Gang of 4 Mikuni BS32SS CV carbs
1-550 Gasket set (search ebay for GS550 gasket set)
1-650 head gasket (I bought both 550 and 650 sets but the head gasket can be purchased separately)
1-650 Base Gasket
2- crank end seals you can get them as NOS from bikebandit.com as you will likely destroy them when you split the case.
1-Oil Filter
X-Quarts of oil (Be sure to calculate the volume of an oil cooler if you fit one, and they do help to dissipate the increased heat of high compression pistons)
Note: It is necessary to bore the crankcase out slightly so the larger cylinders will fit, I suggest having this done by a shop (which is NOT what I did) as it makes fitting the cylinders much less of a headache.
Optional (but recommended)
1-New Cam chain (it may be possible to reuse the old one)
1-Manual cam chain tensioner
1-Digital Igniton such as the dyna s or better yet a dynatek 2000 or 2000se
4-New sparkplugs
1-Set of new wires
2-Dyna coils

I won't go off about transmission mod's as they are costly, however for my project the transmission was an absolutely crucial element in achieving the desired characteristics, the required machining must be done before you reassemble the case halves(obviously). Let me know if you want more information on this.
and of course there is always, conversion to fuel injection using microsquirt or one of the many other EFI microcontollers out there. you could do forced induction with an AMR300 compressor ect...

lookup Dansofield550 he has the finest example of a GS674RR that I have EVER seen(photos of) excellent work.

[Sci85]

Cool. Thanks Ashdricky! Quite a list. You really did it up. I may hit you up on the tranny part as I already know I have a transmission issue with 2nd gear.

I will look for Dansofield550's build.

Keep us posted gabos666!