Upper right cylinder seizure.....damn it!

[maser01]

Hi fellow RZ500 enthusiasts, My STD lock/stock and barrel 84 RZ500 has seized!
after recent top end rebuild ie 4x Matika STD piston kits (hone only rebore not required), carb rebuild/tune to STD spec, extensive exhaust system clean/de-carbon, reed upgrade, new oil delivery line kit (Pump primed of air and all 4 oil lines primed by running engine on pre-mix until evidence of oil flow from all pipes) YPVS and oil pump adjusted as per manual.............test rode bike 3 times on different days totalling approx. 60 Km's of slow n steady run in type riding............nipped up upper right Cyl on 3rd outing when taken up to 8k to clean out oil load up $%@# it! Bike was running beautiful until $%#@!!!!!!

Going to re-use Stock Yam upper pistons (still within spec) with new OEM ring kits, bores cleaned up of alloy nicely.....minor scuffing only mainly below ring level. &*^% new pistons!

Has anyone worked out why this is such an overwhelming issue with so many of these grand old bikes or is it like buying a lottery ticket!!!!!!!

Regards,

T Newts

[nzminis]

when my rears went it was from the clearance being set to tight , as like you everything was perfect

would be interesting to see your pistons and what your clearance is like with new pistons

[maser01]

when my rears went it was from the clearance being set to tight , as like you everything was perfect

would be interesting to see your pistons and what your clearance is like with new pistons

Well mate, I'm pretty surprised it happened as I was very "anal" when rebuilding due to the rep these ol girls have of seizing!

Used new STD Matika piston kits on STD bore so one would think that the tolerance would be on the "Run in" side unless Matika STD size piston kits for these bikes are borderline big? I trust I was supplied the correct rings to suit STD pistons as they were separate boxes but it went together nicely with no tightness? I will measure the ring end gap on the good upper piston to make sure. The new gasket kit they supplied me is very questionable........the head gaskets dripped coolant from day 1 and the water pump gasket also drips.........disappointed as there were no leaks prior to pull down! I see others have had similar issues with gaskets on here.

Have resorted to OEM head gaskets @ $70-AUD ea &*$#@! and will re-use the OEM STD pistons and OEM ring sets.

Can anyone on here tell me the acceptable crank big end con rod/thrust washer side play........the manual states .004" (.01mm) which appears a very small clearance given the copper thrust washers wear rate? What are we tensioning cyl heads down to these days as the manual states 22Nm from memory?

Given the huge percentage of these bikes that have a tendency to seize the upper cyl.........right upper more so, there MUST BE an inherent fault with this engine or am I missing something ! There's just too many to put it down to a number of different reasons! If the engine is tuned right with no mechanical problems, receives the correct amount of oil, has the correct piston and ring clearance, cooling system is operating correctly with correct ignition timing, they should not seize!!!!!!!!

I feel that on the basis that a seizure is due to excessive heat during combustion ( for which there are a number of causes I realise) it appears that the rear cylinders run hotter than the front which is not new news however I think as this is a characteristic of this engine design, certain precautions need to be put in place for the uppers to cope with the heat to hopefully prevent seizure and &#$@ costly repairs!

Unless someone can come up with a more logical reason I'm going to have a crack at making a few suggestions which I will try on my own bike and hopefully help others avoid the RZ 500 "Big Bang" flaw.

Watch this space

[pstamper]

Sorry to hear about the engine problem. They can be a handful to sort out but it will be worth it. I would rather ride my RZ than my Ducat. I did not rebuild either of my engines but both have held up nicely. Even the track bike that is used on the street. Could be anything from carb issue to piston clearance. Rick recommended break in running a full tank of Suzuki CCI oil and lots off heat cycling. My rides were 8 hour night rides with 30 to one hour stops. What ever he did worked on both. I am sure my track riding is adding wear quality race gas, injection oil, once a year carb sync, and improved shifting has surely helped. Best of luck on fixing and more important finding the cause. It is sad that someone that is going to ride there bike has this happen. Let us know what you find out.

[nzminis]

aftermarket head gaskets are shit , they will always leak 100% not worth it

it could have been sucking water in and washing away the oil
Matika piston are good . so you should have been all right there

there might have been a size issue , did you measure anything prior to assembly or did you just assume like you said above being stock bore etc ?

[maser01]

aftermarket head gaskets are shit , they will always leak 100% not worth it

it could have been sucking water in and washing away the oil
Matika piston are good . so you should have been all right there

there might have been a size issue , did you measure anything prior to assembly or did you just assume like you said above being stock bore etc ?

Appreciate the comments guys, and yes pistons were measured and all good just didn't do a ring gap check but it all went back together without a hitch (no tightness etc) indicating correct rings but I'm going to do a ring measurement to double check.

Really pissed off about those non genuine head gaskets and have learned a valuable lesson.........DO NOT USE THEM!!!!!!! I will be posting the maker name (not supplier) on here for all too see as a BIG WARNING........only fair thing to do I feel.........they were purchased form a well known Yamaha parts supplier who spoke highly of them and you guessed it, apparently my problem and they haven't had any issue with hundreds of kits sold.........BOLLOCKS! STD answer one thinks!

Anyway, I'll get to the bottom of the problem in due course and post as I go

[maser01]

NOTICE TO ALL MEMBERS

WARNING!!!!!!

Non OEM gasket kit made by NE "Super gasket" are rubbish...........avoid like the plague, they leak and may cause engine damage as a result!

[nzminis]

well not 100% true

just dont use any aftermarket head gasket, the rest of the gaskets are fine . i have used NE kits on over 10 bikes and all have been perfect ,

i always thought it was common knowledge not to use any aftermarket head gasket on any yamaha water cooled 2 smoker , its posted far and wide

[maser01]

well not 100% true

just dont use any aftermarket head gasket, the rest of the gaskets are fine . i have used NE kits on over 10 bikes and all have been perfect ,

i always thought it was common knowledge not to use any aftermarket head gasket on any yamaha water cooled 2 smoker , its posted far and wide

The damn water pump gasket out of the kit leaks as well........you pay good money for a gasket kit that's recommended by the seller and it fails is just crap as far as i'm concerned and creates unnecessary work and expense, all gaskets in kit should do the job as intended or it's just rubbish my friend.

Don't trust them......once bitten twice shy me!!!!!

[Speed Freak]

Just as a side comment,

The Vesrah aftermarket gasket kit looks quite good.
Thes use the same Japanese gasket material for the paper gaskets.

Only the cylinder base gaskets are paper instead of rubber coated metal gaskets - could work but i preferre original parts.
Head gaskets (for me) look like the OEM gaskets were made by Vesrah (same manufacturing method and a lot of small details are same on both), only the coating is different.

Hard to say if they are as good as the original Yamaha gaskets as they maybe have used cheaper material and coating.


But i have also a lot of bad experience with aftermarket gasket sets, i do not use them anymore, even if the head gasket for my R1 costs 110€

When there is time i will upload a comparison Vesrah-Yamaha with pictures

[maser01]

Yes thanks for the non-gen gasket feedback good sir. I reckon it's an important issue that RZ500 owners need to be up to speed with...........what's usable and what's just rubbish. It's just 1 preventative measure that may save owners a lot of grief!

Who's the best person to talk to on here regarding crank acceptable tolerances etc as the manual figures seem a little "overkill" with some measurements......especially when using the bike to just play around on the roads and not the track. Don't want to be too "anal" with the cranks as it's a heap of work and expense to rebuild them!

About myself..........I'm a qualified Automotive Tech with many yrs experience working on bikes (Like many on here I assume) so I have some knowledge of how things operate however, I don't claim to know everything and always appreciate good helpful info and share both good and not so good experiences.

Regards to all

[pstamper]

Just home and take this as you wish. I have finished a bit of wine since my house just sold. . These engines are no a normal slap together go tear it up type. I consider myself fairly mechanically inclined but opted to have Rick Lance do my first RZ. I had a seal failure on an engine he did. It is a mechanical item and you can only put a great engine together if all the parts were manufactured great. Rick stood behind his work and I did plenty of track days with the bike. I enjoyed it so much I bought another bike with his engine work. Flawless performance at the every track day and weekend ride.

Do not cut corners on your bike. Build it right. Maintain it and should be a pleasure for years. I hope you get it sorted and do not let it get you down.

[silverstrom]

..

[maser01]

Well thanks to all and I'm well aware of all that has been mentioned but I get back to my original post..........has anyone got to the bottom of why SO MANY of these bikes seize the upper cylinders when they shouldn't????????

The million dollar question that I guess will go on to be debated but there must be a logical answer!

As per the cranks.....all I'm asking is there any reasonable "Room to move" Re: crank tolerances or it sounds like everyone just likes to stick to the manual? In particular the big end thrust washer side freeplay........0.1mm (0.04") appears a small tolerance given how quick the brass thrust washers can wear?

[pstamper]

Why do they seize? There is no set answer I believe. You just to need to put it together as well can be done by a knowledgable person, make sure all parts are new or within specification, and break the engine in gently. The Pistons will form to the bore if clearance is correct as it heat cycles. Rick told me how to break in and I followed his instructions. Is there other ways to do this? I am sure but it has worked on two great engines which have been very reliable and smooth. There is no silver bullet reason out there. Best wishes on the repairs.