Hi all, just 5 years after I fitted a nice K1100 radiator it's now leaking and I'm looking for another one. I see plenty on ebay but it'd be nice to help out a fellow forum user if anyone has got one for sale?

Also, if anyone has some of those ridiculous brightly coloured silicone coolant hoses going cheap from an abandoned cafe racer project or similar, I could be tempted..

I don't know how much you are willing to pay but try this guy out of the U.K. He even has a 6 month warranty on used parts.

https://www.ebay.co.uk/str/jamessherlockltd

You must be able to get it repaired/record locally. Or motorworks offer a good service 

I have seen what Sherlock has to offer, and honestly he has a couple of rads up for £100 that are very tempting, in fact the front runner. I particularly like the look of this one, it's still nice and black unlike most of the others. There are some nice ones for sale in Germany, Lithuania and the USA as well but once tax is added on (grumble grumble) the rad from JS is only a bit more and it'll arrive a lot faster, and probably with less hassle.

Moriarti - I pretty much assumed having it repaired would be uneconomical? Any idea how much it might cost? I still have the first one that leaked too, so could have that done and keep it as a spare for when I'll need it in 5 year's time..

I'd check that the relief valve on the radiator cap is working properly.

Interesting thought, though it is an 1100 item which got fitted when the rad was last changed and there's nothing to see on the underside so not sure how to do that! There are no little flaps like the earlier caps have got. The 1100 caps are supposed to be reliable though.. Unlike the original which was letting the bottom hose collapse under suction when cold!

I never had any of these problems with air cooled machinery

Not familiar with k1100, but if the overflow hose goes to the radiator cap area, I'd have a close look at the cap for a vacuum valve and relief valve, it might be the full internal diameter. Possibly a blocked vacuum valve caused the first radiator to leak, possibly a blocked relief valve caused the latest leak.

@Snod Blatter wrote:I have seen what Sherlock has to offer, and honestly he has a couple of rads up for £100 that are very tempting, in fact the front runner. I particularly like the look of this one, it's still nice and black unlike most of the others. There are some nice ones for sale in Germany, Lithuania and the USA as well but once tax is added on (grumble grumble) the rad from JS is only a bit more and it'll arrive a lot faster, and probably with less hassle.

Moriarti - I pretty much assumed having it repaired would be uneconomical? Any idea how much it might cost? I still have the first one that leaked too, so could have that done and keep it as a spare for when I'll need it in 5 year's time..

Local RAD shop will do a pressure test for free,and then give you a price for repair, £100 budget will get you a lot of work done i think

James Sherlock is usually bloody expensive, but this time he's in the ballpark with £100 and surprisingly cheaper than Motorworks. Have you tried chucking a bottle of Radweld in? I had a leaky radiator on Low Flying Brick about three years ago and I tried the Radweld trick while I sourced a new radiator.

I'm still looking...

daveyson - on the underside of the 1100 cap there is just gauze to be seen, no valves that I can get to. See here..

moriarti - a quick google suggests there are at least a couple of places in Leicester that do rad repairs so I'll give them a poke and see what they say. Maybe they'll even do me a bulk discount for having two of them fixed!

Dai - I have not tried Radweld, to be honest I don't really want to risk knackering/clogging up the pump, being the nightmare to replace that it is. But I don't know much (anything) about the stuff so that caution may not be warranted? And yes, imagine my surprise when I was Motorworks want £130 and I couldn't even choose the one I wanted!

There is also a rad going cheap in Northampton, also on ebay, but it's so scabby I think it'll be a waste of money.. Looks like it'd last about 5 minutes.

I think I see two seals. If you push down on the higher, inner seal, it should move against spring pressure. It looks like it would be difficult to lift the inner part against spring pressure, to check the vacuum valve, but it sounds like that's OK anyway.

The level in the expansion tank should be higher after a ride with the engine warm, and return to its cold level after its cooled down, and there shouldn't be any bubbles at idle or revs.

You guys are talking about two different things by the look of it. Snod Blatter seems to be on about the filler cap and Moriarti seems to be on about the thermostat cap. 

Jack: Radweld stays in suspension until it finds a hole, at which point it seals the hole and the rest still stays in suspension. If you want to try it and be cautious, follow the instructions on the bottle and if it works, you can always dump and replace the coolant. Should you need a lower thermostat seal (the one that seals the base of the thermostat against the radiator), pm me. I've got eight of the things, courtesy of Indian036.

@Dai wrote:You guys are talking about two different things by the look of it. Snod Blatter seems to be on about the filler cap and Moriarti seems to be on about the thermostat cap. 

Jack: Radweld stays in suspension until it finds a hole, at which point it seals the hole and the rest still stays in suspension. If you want to try it and be cautious, follow the instructions on the bottle and if it works, you can always dump and replace the coolant. Should you need a lower thermostat seal (the one that seals the base of the thermostat against the radiator), pm me. I've got eight of the things, courtesy of Indian036.

Not me Dai i suggested repair of rad. I'm with you on Radweld good product does what it says on the tin,used it on small/large systems no problems.

+1 for James Sherlock. I bought a used K1100 rad from him last year to replace to collander on mine. £100 posted. Clean, leak free, relatively low mileage item; came with a good cap and thermostat too. I see it lasting as long as the salt and muck is hosed off and coolant is changed every few years.

I asked a couple of local auto radiator specialists but they didn't repair aluminium. If you find someone who does, please let us know.

James Sherlock has my vote of confidence. A couple years ago I bought a Paralever driveshaft from him. Postage was very reasonable as was the price which I recall was $240US, and the splines as well as the u-joints looked and felt as new. Arrived quickly considering the ocean and customs, was packed very well. A first class operation in my opinion.

I never even considered daveyson could be talking about the thermostat cap, haha! No it's definitely the rad, there's a nice wet patch about midway up the right side as you look at it from the front. The side far away from the thermostat..

I rang Leicester Radiators and they found it very amusing that I had £100 to spend, as if that wouldn't even touch the sides. Then I rang Poxon Radiators and the guy turned up in his van and took my old/original radiator away! I'm guessing he'll ring me back with a quote after checking it out at his workshop, but he also knows I only have £100 to spend.. When I picked it up off the shelf it left a load of white aluminium oxide dust behind, I'm not that hopeful about its survival!

Since the leaky 1100 rad is still on the bike, I am vaguely warming to the idea of Radweld. It's only £8 from Halfords. And I only changed the coolant last summer..!

I probably should have said filler cap, that's a better way of saying it. As well as checking the relief valve, it would be worth checking that both seals are good, sometimes they look good but don't fit good cause they have swelled in diameter. Sometimes one of the seals is even missing.

Well, today I got a call from Poxon and it's beyond repair, he said buy another one. So I had another half-hearted check on ebay since it had been a few days and snapped up an 1100 rad from Germany for £62.46 delivered and taxed.

I'll give the filler cap a good fondle when I get to it, see if I can find any valves to inspect, and report back with my findings. Still interested in brightly coloured hoses if anyone has them, too

As you're fondling your filler cap, give it an overnight soak in a cup of vinegar.