500 Two-Stroke Tech

Hybrid, not to throw a wrench into any of this but,

#1 is the lower (next to flywheel) cylinder, thats how I think everyone looks at it.

Yamaha has the upper left as #1 and the cylinder closest to the flywheel (lower left) as #2

are you using Yamaha's way, or the other way, it just seems like everyone looks to #1 as the lower left.

Gus,
yep, I class lower left (flywheel side) as #1 and upper right as #4.
They should both be at TDC together.
However, if I use the standard indents on the gear and collar, it leaves me with #2 and #4 at TDC together. I think that's why the indent is crossed out on my lower primary gear.

to have 2 and 4 together you need a twingle crank but I know what you mean, do you think they had all their stuff made with #1 being the upper left like the book says and then someone came along and said make the lower cyl. #1 and thats where the x out came into play?

Well its either that, or they had a batch of front cranks that were built 180 degrees out.

I dreamt last night that the bike was as smooth as silk now, so it must be all good

My dream was right.
The bike is back together and the vibes are gone.. except for the slight decel vibe that they all have.

hybrid your picture are very helpful. but I still have a question.

If your pictures are right my RZ500 has been setup incorrectly by the previous owner.

It was setup like yours except the balancer shaft gear mark has been lined up with the punch mark with the X through it.

Are you still happy with your results?

Hi, I am Malaysian, it have been so long I didn't post any comment in this forum (bz with work load and new baby girl ).

I have followed the instruction as pictured ......and my bike running fine since now. It was rebuild last 3 years....... I believe the setting is correct.

I have taken 3 RZ's to rg500.com and he get the mods done very quickly and the bikes run smoother. If you guys are in the area give him a try. It works.

adee56: I'm not saying that everyones bikes will be the same as mine.
I honestly think that at least one of my cranks was built 180 degrees out.

Yes I'm now happy with my setup.. there are no vibes any more except for the ~4000rpm vibe on deceleration that they all seem to have.

Recently I bought 4 pcs TZR125 pistons, I follow the modifications exactly and the carb turning as well. I can feel the power increase at low and high speed. fuel consumption not so bad...

latest pic:

IS IT THE VIBRATION DISAPPEAR?MY ENGINE IS STILL ON GOING TO ON...HEEE

Having read all the above posts, no one can clearly follow how to do this modification in setting up the crank balancer shaft !! ??

I now have the above two report sheets, plus another YAMAHA TSI Report on the 1984 model.
(I really wonder if there is any actual difference between the 84 & 85 balancer shaft )
These reports leave you not knowing what is right or wrong = confusing to say the least.

http://www.rzrd500.com/500phpBB3/viewto" onclick="window.open(this.href);return false; ... highlight=
The link to the clear images of the gears in question are a great start to resolving this dilemma once and for all.

After doing this mod as per instructions, rotate the engine 180 degrees and the stock crank timing marks will be aligned with the pointers on the case.

Thanks for letting us know

i have a magazine that says . the most disappointing aspect of the motor is the rumble that emanates on trailing throttle between 4500 and 7500. backing off at around 6500rpm produces behaviour reminiscent of running over a pile of bricks

i have 4 Rzv500s now all of them bar one bike vibrate to some degree

one bike feels like a well put together 4 stroke . its amazing how smoothe it is at all rpms . i have not had this bike apart

so doing this mod might not change anything at all


i thought the later bikes that were driven off the other crank had a funny fly wheel on the end aswell to even things out ?