Help Aftermarket Radiator Replacement - FZR 2KR

Traditionally, reverse flushing is the starting point. High pressure water in via the usual outlet.
If there's a radiator repair shop in your locale, they probably have solutions.

 

two things.
imho, theres no such thing as a "blocked radiator". more on that in a second.

the "coolant through frame" of the 2kr... has an issue. theres an air pocket. from above the hose to the welded in casting at the bend...

i threw a tiny little hole in as high as possible, bled it out, then threw a self tapper in with a fiber washer and some sealant. (or a bit of teflon tape...) no more issues caused by trapped air pockets making it boil over... coolant systems are supposed to be full of water. air pockets tend to make them boil over (my old zuki vx800 was notorious for it until i "fixed it"... same method!).

unless you wanna weld or braze a lug on, dont go over M3... pretty thin there.


only need enough hole to let the air out.


as for "blocked radiators"...

had a cr125 that was TRULY blocked. several years of sitting there, with a leaking oil pump... soap and rust and magnesium goop... nasty stuff.

sulfamic acid.

sold here as "scalex". bunnings. cleaning products...


cus the CR has twin radiators, this was fairly easy. plumb them together to make a loop. a heat gun on one, and a fan on the other. thermosiphon...

after about two days, those cores were like new. it took several flushes, admittedly.

theres probably other acids that work, but dont be tempted by pool acid aka muriatic aka hydrochloric, or battery acid , aka sulfuric. vinegar should work? doesnt react with aluminium. its fairly mild.

do NOT, repeat, DO NOT try caustic soda aka lye aka most drain cleaners...

other ones, ive filled up with hot water and a few spoonfuls of the sulfamic, then strapped to a concrete mixer... well, can you think of any other way to keep them constantly agitated and sloshing around? iirc, i had to do that with the CR radiators as well, before they cleared up enough for the thermosiphon principle to work...

unless the thing has its end caps coming off, dont bother with radiator shops. they dont take the care that they did, say... forty years ago. like everywhere now. no-one gives a flying... friend had a local one 'repair" his forklift rad... i almost cried when i saw wtf they had done. brass and copper, not like these modern ali ones... they butchered it.

i definitely laughed when it popped in the first five minutes.