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Post by fozzy17 on Jul 31, 2017 20:18:41 GMT 1
As some you might know I bought a nice hybrid a few months ago that needed finishing, first thing I did was take it to dave Reynolds to get the carbs set up as it had kr1s carbs and pod filters and allspeeds and wanted to be 100% sure its jetted right, anyway the bike had a custom built radiator on it which has a lower pipe and a top pipe and one overflow near the neck of the rad, anyway I get the bike on the dyno and as soon as the bikes revs it pisses antifreeze, dave says straight away head gasket, I manage to sort the jetting and head home, I order a copper gasket and joining compound and fit the kit, top it up with antifreeze , I take it out for the first time yester (running 33/1 premix) and the bike runs great but after a few miles its drop a cylinder, luckily it was outside a friends house, I pull the bike in his garage, and the rad has emptied and I pulled the head off and I have damaged both pistons (pissed off is a understatement) so barrels rebored and new pistons will be fitted in the next few weeks, i luckily have a rebuilt motor already to drop in it, and will build this on and maybe sell it on...
my question is i think there is a issue with the radiator, the small return on the top of the head was blocked off, and there is no catch tank
so it plumbs in from water pump and then exits via the top hose connection, and just recycles, but pisses out of overflow if you rev it, i wont be running the new motor until i have sorted this, what's everyone else's setup on a rd lc/ ypvs do i need a catch tank, is that right blocking the small connector on top of head?
any help would be great
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Post by rich on Jul 31, 2017 20:45:07 GMT 1
Of course you need a catch tank. Coolant expands when it gets hot so has to go somewhere as it's a sealed system. At the moment it can't so pisses out when it gets hot. Instead of blanking off the overflow in the filler neck, it needs to go into a catch tank so it can return when things cool down. An LC or YPVS tank will be ideal.
Dave should have spotted this being an alleged two stroke 'expert' and I'm sceptical about copper head gaskets and am sure they can cause more issues than they solve. Are you sure you need a rebore? If the bores are ok you should get away with new pistons the same size and a clean up.
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Post by midlifecrisisrd on Jul 31, 2017 20:49:57 GMT 1
Blocking the small pipe on the head is fine as long as the stat has a bypass hole and you bleed the air out the small hole
You need an expansion tank. As the name suggests the coolant expands under pressure so will blow out some fluid and suck in air as it cools
Steve
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Post by dusty350 on Jul 31, 2017 21:05:45 GMT 1
As Steve says, you can drill a hole in the flat part of the stat, if you have blanked off the spigot on the valve head. 3mm is about right. Dusty
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Post by stusco on Jul 31, 2017 21:07:16 GMT 1
Where is the coolant pissing out?
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Post by fozzy17 on Jul 31, 2017 21:32:31 GMT 1
The thermostat did have holes drilled, it's pissing out of overflow
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Post by fozzy17 on Jul 31, 2017 21:34:25 GMT 1
Anybody got a exploded view on a ypvs cooling system, I know the coolant bottles are in different places
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Post by jessy03 on Jul 31, 2017 22:17:23 GMT 1
The spigot by the rad filler runs back to your catch tank by you oil tank (LC) The outlet on the head is blanked off. 3mm hole drilled in your thermostat. If it's pressurising still your head gasket is still faulty. Jess
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Post by oldelsieboy on Jul 31, 2017 22:22:38 GMT 1
Anybody got a exploded view on a ypvs cooling system, I know the coolant bottles are in different places Courtesy or Xaviers RD350LC.net website. OEB
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Post by fozzy17 on Jul 31, 2017 22:41:34 GMT 1
Didn't realise catch tank had only one pipe, thanks guys for imput
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Post by rigga on Jul 31, 2017 23:18:32 GMT 1
Believe it or not, but I use a turkey baster on my ccm as an expansion tank, not one fitted as standard and I got pissed off with constantly topping up the coolant, its just somewhere for the hot expanding coolant to go to, then when its cooled it retracts back into the radiator.
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Post by dusty350 on Aug 1, 2017 7:07:51 GMT 1
I've done the 3mm hole in the stat on a previous build with no issues at all. On my blue hybrid, I bought one of Martin Browns lovely GMX made rads, and asked for the extra spigot, for the Ypvs expansion hose from the head, to be welded on below the standard one for the expansion tank. Just another option that keeps it more like the standard set up. Dusty
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Post by LC_BOTT on Aug 1, 2017 7:45:24 GMT 1
have you checked the rad cap to see if it's holding pressure? Sound like you lost a lot of water, can't have all gone through the overflow pipe can it??
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Post by fozzy17 on Aug 1, 2017 12:16:00 GMT 1
yep out over overflow, only when you rev the tits off it.
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kevm
Drag-strip hero
Posts: 206
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Post by kevm on Dec 14, 2017 23:32:44 GMT 1
Hope we resolve this tomorrow Dave aka muttsnutts
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Post by botty on Dec 15, 2017 0:56:15 GMT 1
Hope we resolve this tomorrow Dave aka muttsnutts If the 3mm hole has been drilled in the thermostat, it won't need sorting. It's sorted. Had the same engine set up in an aircooled chassis. 3mm hole drilled, no problems.
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Post by muttsnuts on Dec 15, 2017 10:45:46 GMT 1
Hope we resolve this tomorrow Dave aka muttsnutts um, that don't sound so good, I'll take a look and see what I can figure out.......is this the same bike you have just bought off him that is coming to my place today?
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