Water cooling the Bucket

**F5 Dave** · 21st August 2010, 11:18

erm, the oversize capacity on 100s is 104cc & has been for as long as I can remember. Wiseco pistons have been legal for over 10 years (pistons free). So it was (is now) legal. Sorry.

I thermosyphoned my MB50 decades ago, was easy in that frame to run a rad above the head but below the steering. Still worked ok.

I made a later one but made the mistake of not using enough material. Too thin means no thermal mass = warp.

**jasonu** · 21st August 2010, 12:32

Looks like you made a very nice job. About the only thing I question is the lack of a h2o pump. You can get very nice (and small) inline electric pumps and compact rechargeable batteries that do a good job.

**Kickaha** · 21st August 2010, 12:54

Originally Posted by jasonu

Looks like you made a very nice job. About the only thing I question is the lack of a h2o pump.

If thermosyphon works correctly he wont need one

**jasonu** · 21st August 2010, 14:57

Originally Posted by Kickaha

If thermosyphon works correctly he wont need one

Your statement is correct 'IF' it works...

**Sketchy_Racer** · 21st August 2010, 15:59

It will, I will make it! I have a couple of different radiators to try if this one isn't sufficient.

**SS90** · 21st August 2010, 21:47

I say go for it, it will work, it just takes a bit of time to set up.

Jasonu is right though, the modern water pumps are great.

**schrodingers cat** · 22nd August 2010, 09:53

Would it be possible to oil cool the head using engine/GBox oil? No need for a radiator then.
Nice consistent shifting them too

**gatch** · 22nd August 2010, 15:11

Originally Posted by schrodingers cat

Would it be possible to oil cool the head using engine/GBox oil? No need for a radiator then.
Nice consistent shifting them too

Anything is possible. My guess is you might need a tougher oil pump and probably an oil cooler.

Though you could probably be clever and use a dry sump set up and use the oil tank as a heat exchanger ?

**Sketchy_Racer** · 22nd August 2010, 15:17

Originally Posted by gatch

Anything is possible. My guess is you might need a tougher oil pump and probably an oil cooler.

Though you could probably be clever and use a dry sump set up and use the oil tank as a heat exchanger ?

haha how to make a simple job very difficult!

**Kickaha** · 22nd August 2010, 15:51

Originally Posted by Sketchy_Racer

haha how to make a simple job very difficult!

He must be an engineer

**TZ350** · 22nd August 2010, 15:54

Originally Posted by Kickaha

He must be an engineer

Or a Manager...........

**gatch** · 22nd August 2010, 16:35

Originally Posted by Sketchy_Racer

haha how to make a simple job very difficult!

Piece of cake !

I'm not going to do it though, because um, I ahh, am too busy..

**SS90** · 22nd August 2010, 20:37

Originally Posted by schrodingers cat

Would it be possible to oil cool the head using engine/GBox oil? No need for a radiator then.
Nice consistent shifting them too

Worked fine for Sukuki (albeit with an oil cooler) for 2 decades. The reliability of their SACS equipped bikes is still stuff of legends.

On two strokes though, it could be an issue, perhaps overheating the oil?, I know that on some prototype stuff, some gearbox oil cooled KTM kids biks had a problem of over cooling the oil....... unlikely if you didn't run a cooler.

It would be too hard to impliment..... although Suzuki RGV's, Yamaha TZR's and Cagiva Mito's all had pressure fed gear box oil, (all except the mito on cassette gear box's), it would really only be tangeable on a 4 stroke.

**speedpro** · 22nd August 2010, 22:27

I did a thermosyphon watercooled cylinder AC50 in the early '80s. The radiator was mounted behind the cylinder on top of the cases. It worked so well I had to tape off the whole radiator except for about 10mm. The radiator was a custom built one but only about the size of an RG50 one. When it rained I had to duct tape the whole radiator front and back.
I've just got the MB thermosyphon system working. You don't need any height difference between the radiator and the hot bit. As long as the heated water can flow up and into the radiator where it can cool and flow down and return to the hot bit. They can be mounted at the same height. Check the #6 thread for what I mean.