john b Posted October 20, 2007 Report Share Posted October 20, 2007 At a trial this afternoon, and arrived at the first section (right next to the car park). Coolant was coming out of the overflow (I have the overflow pipe cable tied to the frame, directed at the exhaust). Didn't think a great deal - rode to the second section, and it was the same, and the third and so on. Not constantly coming out, but regularly. Finished the first lap and topped the water up - there wasn't a great deal had gone out. Second lap - exactly the same - regular overflow of coolant - and (couldnt figure this out) - the fan was constantly on....... After the second lap, decided to retire - Im not a quitter, but engine preservation was top of my list! Had a brief look - took the rad cap off, started the bike up and coolant was circulating. No gunge in the oil, so water pump seal presumed to be ok. However, regarding the rad cap, you can blow through it from the rad side, with no restriction (it is restricted, - but mainly due to the fact you are blowing through a 5mm bore pipe !) Surely the rad cap should be sealed, and open under water pressure when water is boiling ? Thinking about it, after last weeks trial, when I was washing the bike, noticed the overflow tube was detatched from the rad cap. Snapped it back into place and never thought anything about it ? - Is this linked or a coincidence? Summary ...... I think it's the rad cap which is not letting the water get to pressure, and allowing it to come out of the overflow pipe. Is the fact the rad is not getting to preddure the reason why the fan is constantly on ? Help would be appreciated ! cheers John. Quote Link to comment Share on other sites More sharing options...
sr34 Posted October 20, 2007 Report Share Posted October 20, 2007 (edited) At a trial this afternoon, and arrived at the first section (right next to the car park). Coolant was coming out of the overflow (I have the overflow pipe cable tied to the frame, directed at the exhaust). Didn't think a great deal - rode to the second section, and it was the same, and the third and so on. Not constantly coming out, but regularly. Finished the first lap and topped the water up - there wasn't a great deal had gone out. Second lap - exactly the same - regular overflow of coolant - and (couldnt figure this out) - the fan was constantly on.......After the second lap, decided to retire - Im not a quitter, but engine preservation was top of my list! Had a brief look - took the rad cap off, started the bike up and coolant was circulating. No gunge in the oil, so water pump seal presumed to be ok. However, regarding the rad cap, you can blow through it from the rad side, with no restriction (it is restricted, - but mainly due to the fact you are blowing through a 5mm bore pipe !) Surely the rad cap should be sealed, and open under water pressure when water is boiling ? Thinking about it, after last weeks trial, when I was washing the bike, noticed the overflow tube was detatched from the rad cap. Snapped it back into place and never thought anything about it ? - Is this linked or a coincidence? Summary ...... I think it's the rad cap which is not letting the water get to pressure, and allowing it to come out of the overflow pipe. Is the fact the rad is not getting to preddure the reason why the fan is constantly on ? Help would be appreciated ! cheers John. i must agree sounds like a faulty cap to me as well you shouldnt be able to blow through it from the rad side as you say Edited October 30, 2007 by Slapshot 3 sorted quotes Quote Link to comment Share on other sites More sharing options...
john b Posted October 28, 2007 Author Report Share Posted October 28, 2007 Update .......... Replaced the Radiator cap - speaking to Nigel Birkett, next port of call is the cylinder head - but very unlikely to be this. Trial teasterday - and it's still dripping !! Not vast amounts - and the bike runs as well as ever - fan kicks in and out - bike runs great. Have had a look at some threads on here, and there is mention of dropping the engine out to change the head gasket ? I've had a quick look, and although it looks tight, looks like it can be done. Any help on either the coolant dripping issue (is now the only option the cylinder head ?) or replacing the cylinder head would be appreciated. cheers John. Quote Link to comment Share on other sites More sharing options...
drhud Posted October 29, 2007 Report Share Posted October 29, 2007 Sounds like it might very well be the head gasket. When I was having my troubles, that issue came up. Seems if the head gasket is leaking, the pressure from the cylinder will released into the coolant system. With no where left to go, the coolant is forced by the cap and out the overflow. A MX mechanic mentioned this to be a common problem. A quick check.... place a bit of soapy water or even spit, yes spit, and if the head gasket is leaking, bubbles will form. Don't know if is relaible, but this is what I was told. Replacing the head gasket is not a big deal. You shouldn't have to remove the motor, just the tank. Be sure to tighten the head bolts with a torque wrench and in the "star" pattern. good luck. Quote Link to comment Share on other sites More sharing options...
john b Posted November 3, 2007 Author Report Share Posted November 3, 2007 Update......! Replaced the radiator cap - still dripping Did a trial like this - the bike ran no problem - just the odd drip from the overlow. Phoned Nigel Birkett (who have been very helpfull) and decided to bite the bullet and replace the head gasket. Good tip from Nigel - to avoid taking the engine out, replace the studs in the barrel and replace with Alan bolts. Stripped down - looked like this was the problem, as there was an area where it looked like either the coolant was leaking, or it was blowing past as there was slight 'browning' inside the water passage. Put back together - fired up - sounds very crisp. Ran for a minute or so....................THEN STARTED TO DRIP !!!!!!!!!!! Completely unsure where to go now - nothing left to replace ! Water pump seal must be ok - no water in the oil - oil is clean as a whistle replaced one hose - other is ok Radiator ok - no leaks replaced rad cap replaced head gasket aaaaggggggghhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!! john. Quote Link to comment Share on other sites More sharing options...
kawasixtyfour Posted November 4, 2007 Report Share Posted November 4, 2007 --> QUOTE(John B @ Nov 3 2007, 04:24 PM) <{POST_SNAPBACK}> Update......!Replaced the radiator cap - still dripping Did a trial like this - the bike ran no problem - just the odd drip from the overlow. Phoned Nigel Birkett (who have been very helpfull) and decided to bite the bullet and replace the head gasket. Good tip from Nigel - to avoid taking the engine out, replace the studs in the barrel and replace with Alan bolts. Stripped down - looked like this was the problem, as there was an area where it looked like either the coolant was leaking, or it was blowing past as there was slight 'browning' inside the water passage. Put back together - fired up - sounds very crisp. Ran for a minute or so....................THEN STARTED TO DRIP !!!!!!!!!!! Completely unsure where to go now - nothing left to replace ! Water pump seal must be ok - no water in the oil - oil is clean as a whistle replaced one hose - other is ok Radiator ok - no leaks replaced rad cap replaced head gasket aaaaggggggghhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!! john. Quote Link to comment Share on other sites More sharing options...
kawasixtyfour Posted November 4, 2007 Report Share Posted November 4, 2007 --> QUOTE(John B @ Oct 20 2007, 05:48 PM) <{POST_SNAPBACK}> At a trial this afternoon, and arrived at the first section (right next to the car park). Coolant was coming out of the overflow (I have the overflow pipe cable tied to the frame, directed at the exhaust). Didn't think a great deal - rode to the second section, and it was the same, and the third and so on. Not constantly coming out, but regularly. Finished the first lap and topped the water up - there wasn't a great deal had gone out. Second lap - exactly the same - regular overflow of coolant - and (couldnt figure this out) - the fan was constantly on.......After the second lap, decided to retire - Im not a quitter, but engine preservation was top of my list! Had a brief look - took the rad cap off, started the bike up and coolant was circulating. No gunge in the oil, so water pump seal presumed to be ok. However, regarding the rad cap, you can blow through it from the rad side, with no restriction (it is restricted, - but mainly due to the fact you are blowing through a 5mm bore pipe !) Surely the rad cap should be sealed, and open under water pressure when water is boiling ? Thinking about it, after last weeks trial, when I was washing the bike, noticed the overflow tube was detatched from the rad cap. Snapped it back into place and never thought anything about it ? - Is this linked or a coincidence? Summary ...... I think it's the rad cap which is not letting the water get to pressure, and allowing it to come out of the overflow pipe. Is the fact the rad is not getting to preddure the reason why the fan is constantly on ? Help would be appreciated ! cheers John. hi there john, having assumed that when the cylinder head was removed it was checked for visable signs of cracks or disortion? If you are confident that this was not the problem having realised that after all this work you still have the problem (after all this is process of elemination). with coolant you have to look at where the coolant passes, first the rad then the pump then through the crankcases then through the cylinder wall then through the cylinder head then back to the rad. sounds easy but then think of where pressure maybe forced in. two strokes need crankcase pressure to run.not saying this is entering from crankcases but maybe from crankcase to cylinder joint (base gasket). really in my opinion i would have the cylinder head pressure checked and milled or skimmed as i have seen so many people doing work they didnt have to, while the cylinder head is off check the cylinder too it may be worth changing the base gasket while it is in bits but my suspicion is with the cylinder head being cracked or more than likely warped. thanks for reading. steve. Quote Link to comment Share on other sites More sharing options...
coldcake Posted November 18, 2007 Report Share Posted November 18, 2007 Any news?Have you fixed or found problem. Quote Link to comment Share on other sites More sharing options...
john b Posted November 20, 2007 Author Report Share Posted November 20, 2007 Hi Took the bike out to try practicing, and there were a few drips at first - then stopped. Bike ran like a dream, so thoughts are that there must have been a problem - more than likely fixed with the Cylinder Head gasket (as I mentioned there was some 'browning' on one of the water jackets on the Cylinder head) - and the few drops that came out were just the radiatior finding it's own coolant level (apparently quite common to spit a little water out until it finds its level). Anyway - sorted now - bike runs fine. Thanks for the input ! cheers John. Quote Link to comment Share on other sites More sharing options...
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