Facts:When I started the engine for the first time it was mechanically VERY noisy to the point that I switched it off immediately and asked both Nivea (owner) and Newguy (owner of another DRZ) for advice. This was immediately after the oil leak and highsider and the following repair.
Another mechanic who saw and heard the bike before the leak & fall confirmed that it was already worryingly noisy then.
The engine leaked only about one third of its oil through the damaged shaft seal. I drained about 1100ml of oil from the oil tank and sump. With some oil still being present in the tank I rate it as highly unlikely that the engine ran without oil pressure when the leak occurred.
I filled the engine with Castrol ActEvo 10W40 (as specified by Suzuki). Besides that I topped up the radiator (water level low) and adjusted the valve clearances (all valves at minimum or slightly below).
Nivea then collected the bike. The engine lost power and seized a few kilometres down the road.
Damages:The engine would not turn over. I tried to turn or wiggle the crank towards OT to disassemble the head by using a socket and T-bar on the flywheel. It was impossible to turn the crank at all.
On disassembly I found the following:
The barrel is a 92mm oversize bore OEM Suzuki barrel.
The piston shows seizing on the skirt, corresponding damage can be seen on the barrel. The piston crown is undamaged, rings are free, IMHO the seizing piston was the source of the excessive engine noise
but not the primary reason for the engine seizing up.
The barrel pulled off the piston without any problems.
The conrod does not turn on the crank pin. The crank stands at or near bottom dead centre with the conrod seized solid. And I mean
SOLID 
Various piston kits: 400, 416 (420), 440, 450. Tigers, lions and bears, oh my!Wiseco produces the following OS pistons for the DRZ:
(Standard bore is 90mm, they do a few 90mm pistons too)
92mm 12:1 and 92mm 13.5 :1 part no. 4713- and 4714M09200 bringing the engine to 416cc
94.5mm 12:1 and 94.5mm 13.5 :1 part no. 4795- and 4796M09450 bringing the engine to 440cc
The 450cc kit is NOT a Wiseco but a Wössner 95.5mm piston 8563D550 (12:1) or 8567D550 (13.5:1)
Wössner also does a +4mm 440cc kit with a 12:1 compression ratio.
So how the hell can someone build what he thinks is a 450cc engine and by mistake fit a Wiseco piston instead of a Wössner
My six year old nephew can figure out the difference by looking at the boxes.
Who build that engine?
Repair options:The crank is shot and needs rebuilding. Not negotiable.
Top end options:
Go 400cc. Athena kit. Good value and they seem to last at least like the OEM ones. I can have the Athena kit by tomorrow.
Go 420 (yes, 416, sorry!) again. Get barrel fixed. This is for sure the healthiest of the big bore conversions leaving a healthy wall thickness of 3mm on the bottom of the barrel.
Go 440. Now you put a 94.5mm bore into a 98mm outer dia. barrel skirt. IMHO not the way to build a durable engine. Racer yes. An 1.75mm wall barrel skirt will not be stiffness world champion.
I expected these OS bore kits to go into modified barrels. Nope!
Wössner 450cc. Insane. IMHO if not fitted into a reinforced barrel.
Comment:I agree with some remarks earlier to the point that the displacement increase is secondary to make the bike run lekker, faster, bester. The very nice Yoshi pipe, the open air box and proper jetting made this bike go well, not a rather pathetic increase in displacement of 18cc or so.
My recommendation therefore is to go the way that promises greatest durability. Athena 400cc or Wiseco 4713M09200 (92mm).
I would stay away from the 13.5:1 compression ratio pistons as they IMHO should be run with high octane fuel of 98+ oct. not the normal Caltex soup from the petrol station.
Now if we can please have the following poll options:
398 OEM, 398 Athena, 398 12:1 Wössner, 439 (+4) 12:1 Wössner, 450 (+5.5) 12:1 Wössner, 398 13.5:1 Wössner, 450 (+5.5) 13.5:1 Wössner and the whole Wiseco zoo, low & high compression, +2mm, +4.5mm or standard.
I'll still vote standard.
Topic: Updated - Busted ass drz - poll added (Read 3753 times)
