Honda Water pump impeller & shaft

[Digga]

Looking for some help with my 1982 CR250.

My water pump impeller is a little second hand with a bit of damage from a previous life & was looking to replace it but cannot find one. The same part (19215-KA4-000) is shared with:

1981 CR125R A WATER PUMP 81
1981 CR250R A WATER PUMP 81
1982 CR125R A WATER PUMP 82
1982 CR250R A WATER PUMP 82-83
1983 CR250R A WATER PUMP 82-83

So was looking at the next model up being 1984 (part # 19215-KA3-710 ) & can find a few of these around. However it appears that this part looses the old previous design of a separate lock nut & is now threaded into the impeller casting itself. So was wondering if anyone knows whether I can simply fit the 84 impeller straight onto the 82 shaft? If not, then do I have to repalce the 82 shaft with the 84 one & if so, are they interchangable?

The 82/83 shaft (19240-KA4-000) looks the same or very similar to the 84 one (19241-KA4-740) so not not sure if this swap would work either. Bit hard looking at drawings on the web to know for sure 

[Fenno]

Digga

84 shafts are not interchangeable as the 84 has the first power valve.
from what I can see on www.cmsnl.com the impeller is spline'd and retained by a nut up to and possiblly later than 87
they attach the same as the the 82/83 only the drive end changes for the power valve.

An 84 impeller should work fine and are available new on cmsnl.

some other members may have a second hand 84/85 impeller or could measure theirs for a comparison to be 100% sure, but i feel that they are the same. I'm not sure what new ones your looking at possible are not 84.

Cheers fenno

[Digga]

Thx Fenno
So maybe the 84 impeller will do the job but my only concern is the embedded thread in the actual impeller 84 compared to the 82/83 part. I will grab a pic of both & see how they match up, cheers 

[Digga]

This is the 82/83 impeller


The 84 impeller

[Fenno]

Having another look on cmsnl, it appears that the photo is generic but still shows the 84 impeller without the incorporated nut( no longer available)
85 is available but is like your picture which won't work because it is not splined and they don't have the recess in the rear of the impeller for the mechanical seal.
Russell Brown  on face book is magic with sandcast fabrication , he makes new alloy water pump covers for 82 on wards maybe he could do some impellers
Forum name is kdx175 I think

[Paul552]

Having another look on cmsnl, it appears that the photo is generic but still shows the 84 impeller without the incorporated nut( no longer available)
85 is available but is like your picture which won't work because it is not splined and they don't have the recess in the rear of the impeller for the mechanical seal.
Russell Brown  on face book is magic with sandcast fabrication , he makes new alloy water pump covers for 82 on wards maybe he could do some impellers
Forum name is kdx175 I think

84 definatley has separate nut and splined shaft

[bigk]

Nothing in my '82 parts box but I found an impellor amongst the '84 parts, looks like the top photo, definitely doesn't have  nut cast into it & has a fine spline. The one I have could pass for a new part, might be the one?
Cheers,
K

[Digga]

Thx for all the input but no closer & a bit more confused now 

This is what has come of my 82 CR250. Looking from the LHS, the crankshaft rotates anti-clockwise & the impeller rotates clockwise, so the blades push fluid outwards not pull fluid inwards. Not sure if this is correct??? Please note the broken blade in the 12 o'clock position in the 2nd pic which is why I wanted to replace the impeller.




Here is the 84 model impeller which will not fit (no spline) & note the direction of the blades. Coming from an 84 model & looking now from the RHS (water pump is on the RHS after 83), then the crank rotates clockwise & the impeller rotates anti-clockwise. Hence the blades are a mirror image reversed from the 81/82/83 LHS set up



Big K, here is the pic of the impeller you have which (if the direction of the blades is the guide) then maybe yours is an 84 after all but maybe before they incorprated the nut/thread into the casting?



So now I guess my next question is which way are the blades suppose to go for correct fluid flow?

[Simo63]

The 84 impeller

I've had multiple 84 CR250's over the years Steve (4 or 5 from memory) and I have never seen an impeller with an integrated nut setup like this one on any of those 84 CR250's???

Unlikely that they would all of been changed from original?  Unless there was a model change or updated part?

[sa63]

my 89 250 has the threaded style impellor.

[Fenno]

85 is when they changed I believe.
Digga I have broken one the same as yours out of a 83, Big K I think yours is 84 as the veins run to opposite way.
Im picking up an 83 250 tomorrow, Ill pull the cover off and provide an update.

fenno

[Paul552]

Why don't you tig up your current impeller?

[Digga]

I dont even know what a TIG is let alone know how to do it

If I cant buy it & replace it, then I'm out of my depth 

Same as a car, put fuel in it, drive it, get it serviced........you now how it is 

[smed]

The 84 impeller

I've had multiple 84 CR250's over the years Steve (4 or 5 from memory) and I have never seen an impeller with an integrated nut setup like this one on any of those 84 CR250's???

Unlikely that they would all of been changed from original?  Unless there was a model change or updated part?

My 85 CR125 has this type of impeller

[Rossvickicampbell]

is that much damage going to make too much difference?