TS400 crank assembly balancing

[Rgvnfla]

Greetings strokers,
Rebuilding my TS400 engine and I'm wondering about crank assembly balance.
I'm using a forged wiseco piston and have discovered that it weighs 3.088 ozs. more than the standard cast piston which is a 19% difference.
Considering these already vibrate to some degree, what do think? Have the thing balanced or not. 83mm bore ,75mm stroke. Stock bore is 82mm , Suzuki piston I weighed is 82.5 mm.

[busa1300]

I will be getting my TS/TM balanced when I send my parts out, as I have the same piston.
I built an over bore RGV250 into a 300 with a brand new NOS crank, without balancing for the pistons. And it definitely has more vibes than my standard bore RGV's.

[Rgvnfla]

I'm going to be doing an RGV after this current build, not a 300 but I do have a nos Aprilia crank. Who are you using to balance the TS crank?

[IR8D8R]

 Seems like too much to lighten the piston. Piston has some areas that could be cut if this one is similar. You could also bore the pin and shave some off the con rod.

 3.088 oz sounds like a lot. 86.46 grams. Here's the volume of some metals to equal that weight: Aluminum 33.27 cc. Steel 11.01 cc. Lead 7.62 cc. Tungsten 4.41 cc.

 Apparently the TM400 cranks have the crap drilled out of the rod side of the flywheels already, if this photo is typical. Hard to see where you could remove another 11 cc from that side. Drill the crank pin if it's solid maybe? Shallow dimples around the outside rim of the wheels? I'd think that removing weight is preferable. Slugging the crank with tungsten is probably easier. You'd need to compensate for the weight of steel you drilled to fit the slug too.



IR8D8R

[Rgvnfla]

This is my crank from 73 and earlier, l have the piston set up as pictured in your post.I don't think there is anything wrong with my pin or rod so I'm just going to replace all of the bearings and honestly this crank is heavy, haven't weighed it though. I'm going to weigh the piston assembly again
to confirm.

[busa1300]

I believe the early side exit exhaust TS crank is like the TM400. The center exhaust TS has the full circle cranks.
I checked with bill Bune in Minnesota, and they do not do balancing 

[Rgvnfla]

Well it may have to be Crankworks in Arizona $375 balance $100 strip for new bearing

[automan]

Std zuki piston 82.5g
new after market 86.5g
delta +4g

forgetaboutit

cliff

[Rgvnfla]

My standard cast Suzuki 1st oversize piston weighs 455 grams, the wiseco 2nd oversize piston weighs 542.5 grams. 87.5 gram delta.

[automan]

[Rgvnfla]

It's for a 400 cc single with an 83mm
Bore.