Board logo

Blade cooling
the_fbi - 17/4/06 at 12:54 PM

Few little simple questions which have me pondering....

1) What size is the lower exit from the water pump on a RRW? I believe its 25mm the same as the thermostat jobby under cylinder 2 but just got covered in coolant when I went to check so if somebody knows that'd be great!

2) Pressurised vs. un-pressurised. My 954 was an unpressurised system. I presume the RRW is the same. So doesn't need/want a pressure cap?

3) As a bike the cooling system is very small, 25mm hoses and not much of them and a small radiator. Most of my system is 38mm pipe (long story) and clearly has about 3x the capacity of the bike. Is this going to cause issues will slow coolant travel or?

ta
Chris.

ChrisGamlin - 17/4/06 at 02:35 PM

1 - I used the original Honda hose on it but that fitted into 25mm aluminium hose, so its there or there abouts. Are you sure you havent got 1" hose, which would make it 25.4mm so fractionally bigger and more likely to leak?

2 - The radiator I had (from an early 893 engine) had a pressure cap on it, so I guess it really depends on which radiator you use.

3 - Not sure on that one but I never had any problems with the water pump when running longer hoses etc. Although bigger hoses will increase the capacity, I dont think it will slow down the water flow in the critical areas (ie engine and rad), because the flow speed into and out of these pipes will be dictated by the inlet and outlet pipe diamters of the ater pump and radiator, not the diameter of the pipe itself.

Chris

the_fbi - 17/4/06 at 02:52 PM

quote:
Originally posted by ChrisGamlin
1 - I used the original Honda hose on it but that fitted into 25mm aluminium hose, so its there or there abouts.

Thats what I need to do, just wanted to get the right joiner. 22 is too small and 30 was too big, I didn't have a 25 or a 28 but guessed it was 25.

quote:
Originally posted by ChrisGamlin
2 - The radiator I had (from an early 893 engine) had a pressure cap on it, so I guess it really depends on which radiator you use.

Good point, the rad does have a pressure cap. The expansion tank has a cheapy plastic clip on, rather than screw on so I'd figured it wasn't pressurised.

Bottom hose is really annoying me.

I need to get from 25 at the pump end, to the 38 elbow which comes off the radiator.

Nobody seems to do a 25-16-25 alloy T piece so I can get up to the header tank. Pacet do a nice 38mm T piece with a centre tapped to M14 or M16, but nobody does a M14/16 Tail with a 16mm OD tail.

Its just going to be a mess of reducers etc which I really didn't want

Unless I can get my 16mm T welded onto my 38mm bottom aluminium pipe, which would be ideal

JoelP - 17/4/06 at 02:58 PM

hi mate, just do it in copper. Much easier! You can get 35 or 38mm copper, cant remember which, but if its 35mm, you can enlarge it with either an olive, or alternatively cut a solder ring fitting in half, and solder this over the end. The extra thickness will make it a good fit, and leave ridges to hold the hose on. You can then also go via 28 and 22mm pipes to 16 or beyond. If you need a 25mm connection you can enlarge a 22mm fitting in the same way as described above. It sounds like a bodge, but it 100% works well.

1" hose onto a 25mm pipe isnt going to leak at all if you tighten up a jubilee clip, ive made 28mm not leak in the past.

[Edited on 17/4/06 by JoelP]