Suckin' coolant

[Gerard De Ruyter (Twistandshout)]

I know the early cr water bottles were well known for this, and mine (250RG) sucks half a cup of coolant into either the motor or gearbox thru a race day.  So guess should change both the oil seal and the water seal.  Any tips to doing this?

Will check out the state of the internal pump cases while i'm at it....of course....

[Hoony]

G'day Twisty,

your CR runs 2 seals with a air gap between them and a drain at the bottom of the case in the air gap so any coolant will drop onto the ground. i would say the water pump shaft and/or seals are worn. if not the case must have a pin hole from electrolysis in it.

Pm me if you have trouble mate.

[Gerard De Ruyter (Twistandshout)]

thanks hoony.  i guess i better measure the shaft and see if worn (presume my workshop manual has tolerances) otherwise it will just keep doing it.  you wouldn't know where i could get my hands on an owner's manual would you?  i got a clymers and honda service manual, but neither have diddly squat on suspension adjustment etc.  haven't seen one come up yet on evilbay either.

[Hoony]

Ebay is your best bet. i regulary see full service manuals for my 500 (got one for US$20) so ireckon keep an eye out for a 250 one.

i have one for the RG so if you need any info email me mate. as for the water pump shaft it will be easy to spot visually, they still should be available as i bought one for the one i have for sale back in 2004 and it was ex stock at honda Oz.

[Hoony]

Twisty, i looked in my workshop manual and it does not give a wear limit spec.

Last one i bought cost $87 in Jan 2004

part # 19240-KA4-770 WATER PUMP SHAFT   

[Gerard De Ruyter (Twistandshout)]

Cheers mate.  I would have thought the seals would wear out rather wear the shaft, but I guess over time they do thin a bit (especially in that caustic mixture inside there...).  I'm sure it'd be best to replace shaft too, to make sure all within spec.  I'll see if one's available.

[Hoony]

pull it apart first and check, you will soon know if it needs replacement. the seals (and maybe the bearing) are a definate. also you need to check the case for corrosion and pin holes as this may be your problem.

[magoo]

Hey Super Gee, I've got  a proper Honda shop manual. I'll copy the pages in regards to the water pump if you want. Otherwise, I could fix it for ya.

[ianscr250]

the only time you relisticaly should see wear on the shaft is if the bearing behind it fails and lets the impellor shaft drop other then that a mechanical seal is about 80 bucks and i think the other seal is around 15  try econohonda

[Hoony]

Ian, Different setup on the 86' models to the earlier ones, they run 2 oil seals and they do wear the shaft

[Gerard De Ruyter (Twistandshout)]

thanks for the offer magoo, but i got both a clymer workshop manual and a honda service manual so ok in that respect.  but i am keen to get an owners manual for the RG.....to find out which way to turn things to adjust damping and such.  if you got an owners manual hoony, would appreciate some photocopied/scanned pages on suspension setup?

interestingly, this bike came with a Mikuni TM series flat side carbie instead of the Keihin flatside...presume adjustments pretty much the same (mainly hope turning out air screw does the same as on a keihin not the opposite....).

[utsman]

It's almost certainly the water pump casing itself. I used to have that bike and the case erodes easily and leaks the coolant into the tranny. I bought a brand new rh crankcase cover from honda for 300 big ones (the water pump is part of this case cover) and after 3 hours of use the same thing happened.  I erupted.

However the fix is easy. Remove the cover and coat the entire inside of the waterpump with Devcon plastic steel. Make sure you do everything including the spouts where the hoses clip on. This fixed mine for good. Every now and then I would check to see how the devcon was holding up by just removing the small water pump cover. It would very slowly wear away near the impeller, but o so slowly.  It was a good fix. Lasted years

In later models they made the inside aluminium I think, and this solved the problem

UTSMAN

[holeshot buddy]

simple get rid of those early eightys hondas and buy a kawasaki or suzuki no more problems  i bet the housing is rooted  honda riders need to drain all the coolant out between races or the side covers will corrode and fall off






it ran last time i started it 

[Gerard De Ruyter (Twistandshout)]

That sounds like the ticket UTSMAN.  I'll certainly check out the condition of the inside of the pump housing...but sounds like should treat it with this fabulous sounding devcon anyway.  with that, new rotor and seals, i'll fix that sucker!!

[Gerard De Ruyter (Twistandshout)]

Devcon rules!  I chased down a pack and spent a nice morning liberally coating all mag surfaces in the pump - including a hairline crack i spotted in the inlet pipe.  That, combined with the new rotor shaft and seals, should mean no topping up in between races (touchwood).  Where would we be without our chemicals (and mechanical devices and workshop space)?