riversbikes Posted April 4, 2014 Report Share Posted April 4, 2014 Heat cycling my newly rebuilt engine and I have a base gasket leak... some coolant weeping out between the cylinder and the case. Very minimal, but not ideal on a race engine. Only 2 weeks until the first scheduled trackday, and I need to strip and rebuild the top end! I've got it out of the frame and set up ready for the swap of new gaskets, which will hopefully arrive sometime next week. I must have made some sort of error, or perhaps the mating surface was contaminated with something... I haven't taken the pots off because I don't want the pistons dangling on the rods for a few days... safer to keep everything together until I am ready to go. Any common advice people can give? Its an 08 ER6 supertwin. I've rebuilt engines before, so this was a surprise to me to see this happen. THe manual does not call for any sealant of any kind (gasket goes in dry)... Link to comment Share on other sites More sharing options...
Evilchicken0 Posted April 5, 2014 Report Share Posted April 5, 2014 Use some carb cleaner on the mating surfaces to clean them before assembly. Put some cleaner on a rag and wipe the gaskets over to take anything off. You could have been unlucky or got some oil on the gasket when you put the barrels on. Link to comment Share on other sites More sharing options...
ronenige Posted April 6, 2014 Report Share Posted April 6, 2014 I always clean mating surfaces with a carborundum stone and gt 85 or similar, just make sure its sitting on at least 2 sections to make sure it's flat, obviously don't use one that you've used for anything else as it's got to be in as new condition Link to comment Share on other sites More sharing options...
riversbikes Posted April 6, 2014 Author Report Share Posted April 6, 2014 thanks for the tips! Link to comment Share on other sites More sharing options...
Marb Posted April 6, 2014 Report Share Posted April 6, 2014 http://www.ebay.co.uk/itm/VHT-COPPER-CORK-PAPER-METAL-WATER-PUMP-SUMP-HEAD-GASKET-SEALER-CEMENT-SP21-/251474986373 Seriously, one of our CB750's kept blowing base gaskets. Different cilinders, skimmed cases, wiseco gaskets, extra crank vent nothing stopped it. We think it was due to the fact that the engine was being used as a partly stressed member. Anyway, a good spray with that stuff and its held up for a year now. Was recommende by a bloke who dragraced cb's and had similar problems. Link to comment Share on other sites More sharing options...
riversbikes Posted April 7, 2014 Author Report Share Posted April 7, 2014 That;ll be the next step, if it keeps weeping. Also bought a better quality torque wrench... actually made in England (rule Brittania!), rather than in China, like my last one. Link to comment Share on other sites More sharing options...
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