johny Posted April 3, 2023 Report Share Posted April 3, 2023 Doesnt matter what people think the manual is your friend: Link to comment Share on other sites More sharing options...
Puglet1 Posted April 4, 2023 Author Report Share Posted April 4, 2023 On 03/04/2023 at 18:26, johny said: Doesnt matter what people think the manual is your friend: Hi Johny, I think the drawing is telling me that the PO had set the bottom plate valve and spring incorrectly. Not sure if this would account for the continuing loss of power but will drive it again before moving onto the carbs. Many thanks. Pete. Link to comment Share on other sites More sharing options...
johny Posted April 4, 2023 Report Share Posted April 4, 2023 Yes does sound that way and would increase vacuum in engine but is rocker box cap proper vented type as shown in manual? Link to comment Share on other sites More sharing options...
Puglet1 Posted April 4, 2023 Author Report Share Posted April 4, 2023 I believe the alloy rocker cover originally came from Rimmers. I have removed it and it is possible to blow and suck air through the vent hole. I have attached photos because I’m not sure what the original should look like. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 4, 2023 Report Share Posted April 4, 2023 the cap on the alloy covers only has the small vent hole it is really only there to allow a fully sealed block to breathe so changes in atmospheric pressure does not create any pressure when parked up and make oil leaks so its not a main breather just a small metered vent easily overcome by the PCV well something like that . the original steel RC has a simple flap vent valve in its filler cap does a similar job seals when running opens when static or thereabouts Pete Link to comment Share on other sites More sharing options...
johny Posted April 4, 2023 Report Share Posted April 4, 2023 The free to download workshop manual shows the cap and much more. Your cap should be ok once the pcv is working correctly👍 Link to comment Share on other sites More sharing options...
Puglet1 Posted April 6, 2023 Author Report Share Posted April 6, 2023 On 03/04/2023 at 12:09, Pete Lewis said: the pcv should only lift when crank case pressure is detected the manifold vacuum is used to remove the pressure till its less then the valve closes the manifold off till next time and so on as a continuous operation of open and closures if its holed or jammed it will suck the crankcase all the time and that keeps your filler cap sucked in place till you stop the engine its a cheap fix Pete Does this mean with the hose disconnected from the rocker cover there should be no suction from the manifold via the pcv? Link to comment Share on other sites More sharing options...
johny Posted April 6, 2023 Report Share Posted April 6, 2023 I think it would be the other way. If the hose is disconnected the pcv will open fully as it tries to maintain a slight vacuum but cant... Link to comment Share on other sites More sharing options...
Puglet1 Posted April 6, 2023 Author Report Share Posted April 6, 2023 45 minutes ago, johny said: I think it would be the other way. If the hose is disconnected the pcv will open fully as it tries to maintain a slight vacuum but cant... Thanks johny. the reason I ask is after I changed the position of the pcv parts- to what I think is “ as per workshop manual “ the vacuum force to remove the oil filler cap from the rocker box is much reduced- but I can still feel manifold depression through the pcv hose when it is disconnected from the rocker cover. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 7, 2023 Report Share Posted April 7, 2023 believe the spring inside modulates the vacuum so there is always a light vacuum when running im sure its primary operation is all written down somewhere just have to find it Pete Link to comment Share on other sites More sharing options...
Puglet1 Posted April 7, 2023 Author Report Share Posted April 7, 2023 54 minutes ago, Pete Lewis said: believe the spring inside modulates the vacuum so there is always a light vacuum when running im sure its primary operation is all written down somewhere just have to find it Pete Thank you Pete. It seems such a simple thing but without previous knowledge or any comparison of its function I am struggling to understand if it’s ok or not. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 7, 2023 Report Share Posted April 7, 2023 Crankcase ventilation system - Wikipedia this says lots of nothing about its actual working process but makes some reading on a good friday Pete Link to comment Share on other sites More sharing options...
johny Posted April 7, 2023 Report Share Posted April 7, 2023 Make sure the felt seal around the oil dipstick is good and doing its job👍 Link to comment Share on other sites More sharing options...
Puglet1 Posted April 7, 2023 Author Report Share Posted April 7, 2023 Pete and johny. Thank you for your comments and support 👍. Today I removed the fuel pump. I could not believe how much crud was in it. I cleaned it, and replaced the hose going from the pump to the carbs. I removed the carbs, cleaned them, checked the float heights and upon removing the float valve I found the largest piece of rubber in the float chamber cut off valve. I have refitted, balanced and adjusted the carbs and been for a drive. Guess what?……. It’s perfect 😁. Cam home and removed the oil filler cap to find previous work on the pcv has also worked. Happy Days! Once again…. Many thanks for everyones help! Best regards. Pete. Link to comment Share on other sites More sharing options...
Pete Lewis Posted April 7, 2023 Report Share Posted April 7, 2023 rubber slivers you have been well and truly caught these breed like rabbits happens when the old hoses are disturbed and refit slices a bit off when you insert the metal pipes hi grade stuff like gates barricade does work well and is harder than the fake stuff sold by many its a bit like the more you meddle the more you can make Ha! pete 1 Link to comment Share on other sites More sharing options...
johny Posted April 7, 2023 Report Share Posted April 7, 2023 Sounds like a filter in the line to the pump would be a good idea.... 1 Link to comment Share on other sites More sharing options...
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