What I don't like is you get 2 different metals contacting with some liquid. I'm affraid that maybe if you're not careful with the quality of your coolant you might end up with a battery/electroplating situation and corode the hell out of stuff. My other concern is that sleeve not sealing and leaking coolant into the crank case. Not to say it will, but it's possible. Cast iron and aluminum have different rates of thermal expansion.

Back in the early '80's my dad went up to the twin cities and got one of the last few Deloreans when that company took a puke. He just sold the basket case to a guy 2 years ago. The sleeves in that thing would lift right out when you took the heads off. They had tapers on the bottom that would seal off on the block and stack-up heights were really critical. Between that and the horrible electrical system, that car was parked for most of it's life. History's Greatest Blunders even did an episode on the Delorean Motor Company.

So nobody has pictures of these jugs?

 

The Delorean used the same engine as Volvo.
toyota have had alloy head on iron blocks with steel waterpump impellors for years.
just buy the best coolant you can get and change it every year ot two.

 

250 and 351




331



Ron

 

351 gives me a woody!

David

 

It's still hard from those pics to tell if the liner has any material between it and the cooling jackets, which seems to be the concern of some. The flange on the head surface makes it look like it extendes into the jackets, but how big is that flange vs. the OD of the steel liner and the metal left in the original bore? I'm still thinking that this setup is not some new and sketchy method that will lead to coolant leakage. I doubt Bill pursued some new and daring method here for a big bore kit. I'll bet it's like many big bore kits that have been produced over the years with no issue of any concern. BTW...how many 351 kit owners have we heard from who've spouted waterworks in their installation?

 

Umm, let's say for the moment that there was years of galvanic corrosion along the interface of the liner to the head, and a very tiny path finally opened up between coolant passages.... so what? The great bulk of the water flow will still be through the original passageways, so there isn't going to be enough flow through the cracks to make any difference.

If the corrosion gets so bad that the liner is sitting on a million of these tiny cracks, I suspect you'd already know it (mechanical noises) well before the cooling was affected.

 

The only side effects reported thus far is the need for stronger clutch springs

 

Since I am interested in going big bore, I have searched and read all the threads regarding this topic on the KLX250S board. However I still have yet to see a true answer to the question that this thread title asks. What is the reason why Bill Blue offeres all those different bores and what is the upside or the downside to each one? I mean there has to be a reason why he offers them as the price difference is so minimal, why wouldn't everyone just order the 351?

 

People like options.

 

Yes I understand that but what is the upside of the 340 over the 351 other than saving $20?