Tarwetijgers Winter Works

[Tarwetijger]

Cheers for that Dimwiddy.

Does anyone know the partnumber of the JE big bore piston kit?
The lad from the bike shop could not find it, even tough he contacted the JE distributor!
I ordered directly from KEDO, so no harm done, but I'm really curious. They stated the kit from KEDO is actually from CP and not JE. (and adviced me to order them myself).
It makes me wonder since to many of you around here ride with JE kit. Or... at least you all say you do.

[dandywarhol]

Depending on how much heavier the aftermarket pistons are, I'd be inclined to remove the excess weight from inside the pistons to make them the same as the originals rather than go to the complete crank out to balance it, unless you think the crank needs overhauled too.

[Tarwetijger]

Depending on how much heavier the aftermarket pistons are, I'd be inclined to remove the excess weight from inside the pistons to make them the same as the originals rather than go to the complete crank out to balance it, unless you think the crank needs overhauled too.

That makes sense. Cheers.

[cobbadiggabuddyblooo]

Yes the original motor is balanced to the weight of the std pistons and pins, even though it may not seem detrimental, but this is where harmonics come into play , bit like doing a wheel balance not really noticable until you get to a certain rpm so balancing the pistons, pins and rings collectively to the std weight is worth the money.
I've just got the crank out so if the pistons get balanced it makes sense to give him the rods and crank to spin and balance the lot to where I'm getting the optimum power from the head and cam work being done also.
It's only costing me $200 to balance everything (around £ 120 ) The pins are heavier on the JE pistons too so taking weight off here in this proccess also adds to that midrange punch out of the corners that I'm chasing.

[dandywarhol]

Yep makes perfect sense when it's apart Cobba.
I've done plenty 2 stroke balancing, useful when the garage paintshop had their own mixing scheme and I could get the pistons and rods down to a gramme.
Makes even more sense if mods allow the engine to rev significantly higher.

[Tarwetijger]

They are huge! And so shiny, it is almost a pity to put them in an engine where you can't see them.


Thanks to TTS performance, they had them on stock.

[Tarwetijger]

First flowbench results, of the original setup.
Inlet 3500 litre per minute
Outlet 3000 l/m
Out is 86% of in, which should be around 75%. I did not know that, it is all new to me.
He stated that the outlet was too good, I replied that my conclusion would be was that the inlet is not good enough. Luckily he agreed with me on that one.
Next numbers will be with bigger valves. And then after flowing.

[emway]

Nice pistons, Tarwetijger. Ziet er wel erg Bling-Bling uit!

[Tarwetijger]

First flowbench results, of the original setup.
Inlet 3500 litre per minute
Outlet 3000 l/m
8<

Bigger valves and flowing; inlet 4000 l/min. Outlet remaind almost the same.
Sadly, he did not measure with only the bigger valves in, before flowing. That would have been interesting to know.

[M.V.]

Yes the original motor is balanced to the weight of the std pistons and pins, even though it may not seem detrimental, but this is where harmonics come into play , bit like doing a wheel balance not really noticable until you get to a certain rpm so balancing the pistons, pins and rings collectively to the std weight is worth the money.
I've just got the crank out so if the pistons get balanced it makes sense to give him the rods and crank to spin and balance the lot to where I'm getting the optimum power from the head and cam work being done also.
It's only costing me $200 to balance everything (around £ 120 ) The pins are heavier on the JE pistons too so taking weight off here in this proccess also adds to that midrange punch out of the corners that I'm chasing.

How do the balance shafts weigh into this? I would assume if you match the new piston weight, everything would remain the same, however if you balance with the new pistons, you may need to balance (alter the weight of) the shafts as well?

[cobbadiggabuddyblooo]

The pistons/pins will balanced back down to the original weight so not an issue. It's where he takes the weight from on the pistons to harmonically balance the motor to the powerband the bike is being tuned to. I'm focusing on midrange torque so I can maintain or gain out of corners and overall more useable delivery of power than just outright horsepower. I'm sure the couple of HP I may loose in outright horsepower will be offset by a decent ignition and coil setup and 520 chain and this will only enhance the midrange even further too. . Then Rod goes and pulls out a supercharger to entice me and throttle bodies he has hidden away the other day... maybe next rebuild...

[Tarwetijger]

the original setup.
Inlet 3500 litre per minute
Outlet 3000 l/m
8<

Bigger valves and flowing; inlet 4000 l/min. Outlet remaind almost the same.

[sanddune51]

Nice to see another set of big valves installed Thanks for the photos

Look forward to hearing how they perform in your head/motor.

Merry Christmas,
Mark.

[cobbadiggabuddyblooo]

And good to see some flow rate figures as a benchmark...

[Tarwetijger]

Following the advise of my tuner, I'm changing the big end bearing shells.
With the misterdimwiddy procedure, I got the engine out of the frame but not splitting cases.

Got the engine out and on the bench on my own. Well I am not doing that again.


From the underside you can reach the con rods. (Whew, unsharp, sorry for that).



And here they are! Shells looking fine. And the rods are marked "3VD", so these stayed the same from the first TDM.


How do I know which size shells I should order? I was expecting some color codes, but didn't find any.
There are some small marks / codes on the backside of the shells, is that it? Some of them are hardly readable...