Tarwetijgers Winter Works

[spondontrx]

Hi, there are numbers on the crankshaft (two numbers for the big end) and on your piston rods , use these to determine the bearing size (color) . (all this info can be found in a workshop manual off corse )
Maybe there's some color left on the bearing shells (on the side) so you can see if the calculation is right.

Good luck

[cobbadiggabuddyblooo]

Have a look on my rebuild thread as it has photos of what your looking for and an explanation of it all.. There should be a series of numbers/ letters stamped on the back end of the cases also around about inline with the swingarm pivot

[Tarwetijger]

I got it lads, thanks a lot. Indeed it is in the Haynes manual and the Yamaha service manual.
In my case it is exactly like the example in the Yamaha service manual: 4 - 1= 3, brown.

One more question, do I have to replace the bolts of the con rods? In the manual(s) it is not mentioned at all, but I reckon that in these places of an engine 'stretching bolts' ( don't know the official name in english), which can be used only one time, are quite common.

[dandywarhol]

I would always replace conrod bolts and nuts. i don't think they are actually "stretch bolts" but I wouldn't and never have taken a chance on big end bolts

[Tarwetijger]

I would always replace conrod bolts and nuts. i don't think they are actually "stretch bolts" but I wouldn't and never have taken a chance on big end bolts

The workshop guy advised me to replace the bolts too, so I ordered them along with the shells.

Appeared that the R1 race bike in the shop was from him. He wouldn't tell me any laptimes so maybe I can keep up with him if we meet on track some day.

[Tarwetijger]

Waiting for orderd parts, I changed the cam chain last weekend. I had one on the shelf.
While I had the oil pumps in my hands anyway, I checked the tolerances and they were all within spec. That's good to know.



And then there was time left for the most fun part: cleaning up all the dirt.
This wasn't what I was hoping to see:


But the rest of the engine looks good and clean. And I saw a remarkable lot of rough edges on internal aluminium parts. So I think that is what I found in this filter.

[Tarwetijger]

Sorry for those who were also interested, but... I bought the carrillo rods from Ebay.
I receieved them today and put them on a scale: 800 grams. The original rods with bolts are 925 gr.
Combined with the heavier JE pistons and pins, this brings the total weight more or less to the original level.
For now, i don't have a clue how to fit them. The bolts have to be tightened according to stretch instead of torque. How are you supposed to measure that while fitting them?
And i just ordered new bearing shells for the original rods. The numbers and color codes can not be used with these rods. I have plastigauge so i will measure it of course. But if not within spec, how do I know which bearing shells i should use to get it right...
Well a little research have to be done. To be continued.

[dandywarhol]

I wondered what had happened to them - the auction ended early - I hope they weren't removed by the seller because he suddenly found they were damaged - seems to be a lot of things get damaged between the start and finish of auctions

Good luck with them

[Tarwetijger]

He stopped it because the price did not go up. It was described in the ad (despite the auction was stopped). I contacted him, and got some good information with it too.



Can I pull this off? Nah, I admit it is just a pic to show off...

[spondontrx]

I receieved them today and put them on a scale: 800 grams. The original rods with bolts are 925 gr.
Combined with the heavier JE pistons and pins, this brings the total weight more or less to the original level.

Nice stuff.. , but the balancing weight of the conrod + pistons is divided in two parts : 100% of the rotating mass( big end part of the rod ) and a percentage of the small end +piston and rings (reciprocating mass) which is called the balancing factor , you can't use the total weight to compare them.
The two weights of the carrillo conrods is maybe on a card that comes with it .

[wiemer]

The bolts have to be tightened according to stretch instead of torque. How are you supposed to measure that while fitting them?

.I have encountered those bolts I think in BMW r-series conrods.

This is a nice story about stretch bolts...

The method is somethink like: bolt is tight, then turn one revolution, turn back 1/4 rev, and then add 270 degrees.
........or something like that, depending of specific bolt etc.

http://www.gomog.com/allmorgan/stretchbolts.html

wiemer

[dandywarhol]

Another well tested method is to torque the bolt up until it shears and then back half a turn..........................

[cobbadiggabuddyblooo]

I receieved them today and put them on a scale: 800 grams. The original rods with bolts are 925 gr.
Combined with the heavier JE pistons and pins, this brings the total weight more or less to the original level.

Nice stuff.. , but the balancing weight of the conrod + pistons is divided in two parts : 100% of the rotating mass( big end part of the rod ) and a percentage of the small end +piston and rings (reciprocating mass) which is called the balancing factor , you can't use the total weight to compare them.
The two weights of the carrillo conrods is maybe on a card that comes with it .

I'm just about to have this discussion myself with Grant from Brisbane Crank Balancing. The std rods at 57 grams heavier but where in fact this weight lay ultimately effects the balance. With the JE pistons and Carrillo rods you will find now you have more mass at the top of your rod which ultimately effect the balance factor.
I've got a pair of Carrillo Rods myself with some 12:1 forged side relief piston (. Same design as the std yamaha) which come in lighter than the JE pistons.
All these different weights as they say "every action has an equal and opposite reaction " so it's time to sit down and have a good chinwag with Grant on how this comes into play.
A little less weight may spin up a little faster but it doesn't increase your power but it does affect the parameters to where the power band works .
Sure things may spin faster if a little lighter but you have to get that mass moving to start reach a certain threshold before your crank weights work in harmony with the weights of rods and pistons. This is why Grant needs the information on how the head if flowed so I don't potentially rob myself of useable power . It shall be more benificial to have these working together as such if possible. I can see you have kent cams so there's a good chance he would have flowed things to work around the midrange gains from their design.

407 is the total weight
111 is the reciprocating mass
298 is the rotating mass of the Carrillo rods
I'll endeavour to find the weights of the std OEM Yamaha rods too .

[dandywarhol]

There is a figure buzzing around my head from my automotive engineering student days of the mass of the piston assembly and 0.33 of the con rod equate to the mass of the big end web - but that's just something in number 48,789,458 pigeon hole in my fading brain

[Tarwetijger]

Nice stuff.. , but the balancing weight of the conrod + pistons is divided in two parts : 100% of the rotating mass( big end part of the rod ) and a percentage of the small end +piston and rings (reciprocating mass) which is called the balancing factor , you can't use the total weight to compare them.
The two weights of the carrillo conrods is maybe on a card that comes with it .

I know it doesn't work like that. In fact, I should have the theoretical knowledge to calculate this stuff, because I studied physics for a while... But that's 15 years ago!
It is just that I will not do anything about the heavier pistons. If the con rods would be heavier too, I wouldn't be so sure what to do.