dave.vitesse Posted November 22, 2017 Report Share Posted November 22, 2017 Sorry that was a bit confusing. 3b is 0.10" used on HS6 carbs. Your carbs are HS6. 3a is 0.09" used on HS4 carbs e.g Spitfire. Dave Link to comment Share on other sites More sharing options...
Danwedges Posted November 22, 2017 Author Report Share Posted November 22, 2017 Are you sure I was under the impression hs6 carbs had an external fuel bowl I thought my carbs were hif of some sort? Link to comment Share on other sites More sharing options...
dave.vitesse Posted November 22, 2017 Report Share Posted November 22, 2017 Sorry, yes you are correct. Yours are the next generation on from the HS6. Link to comment Share on other sites More sharing options...
dave.vitesse Posted November 22, 2017 Report Share Posted November 22, 2017 The top of the jet should still have a grove to indicate its 0.10" bore on the HIF carbs. Dave Link to comment Share on other sites More sharing options...
Danwedges Posted November 23, 2017 Author Report Share Posted November 23, 2017 Any idea if my carbs are ball bearing suction chamber type or not? Don't know wether to order auc1170 or jzx1088 springs to go with bae needles Link to comment Share on other sites More sharing options...
dave.vitesse Posted November 23, 2017 Report Share Posted November 23, 2017 I take it these are the bias springs at the base of each needle. You should be able to use the existing ones. By carefully pulling them off and then refitted to the replacement needles. Not sure if they are ball bearing suction chamber type. Dave Link to comment Share on other sites More sharing options...
Danwedges Posted November 23, 2017 Author Report Share Posted November 23, 2017 I assumed that they were the big spring above the slide? I can see any identifying colours on either but have been recommended green springs with bae needles Link to comment Share on other sites More sharing options...
JohnD Posted November 23, 2017 Report Share Posted November 23, 2017 All most erudite, but beyond me. I went Pi long ago. But I retain some ideas on carbs, and the dashpots might be to blame. Are they full of oil? If not then they will allow too quick a piston rise, and the mixture will weaken as press down on the throttle. JOhn 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 23, 2017 Report Share Posted November 23, 2017 Good point John, dashpots are dampers and need engine oil, in them to give acceleration without a flat spot we dont want 3 in1 in here This is all the troubles you get whem you harang a load of parts away from standard and hope it all works without a development or experimental emmision dyno to research the running as manufacturers did or do. Pete Link to comment Share on other sites More sharing options...
Danwedges Posted November 23, 2017 Author Report Share Posted November 23, 2017 Dashpots did have oil in but I will be replacing with proper dashpot oil when I replace the needles Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 23, 2017 Report Share Posted November 23, 2017 Normal engine oil is fine , the orig stuff was generally sae 20 but use what's in the can No silly skinny stuff Pete Link to comment Share on other sites More sharing options...
JohnD Posted November 23, 2017 Report Share Posted November 23, 2017 Official Triumph Workshop manual, "Use appropriate Current Engine Oil" Link to comment Share on other sites More sharing options...
Danwedges Posted November 23, 2017 Author Report Share Posted November 23, 2017 So will 20w50 work fine or would this be too thick? Link to comment Share on other sites More sharing options...
Clive Posted November 24, 2017 Report Share Posted November 24, 2017 perfect. Too thin means the fuel enrichment is too short (people seem to think the piston moving fast is a good thing, it isn't! ) 1 Link to comment Share on other sites More sharing options...
dave.vitesse Posted November 24, 2017 Report Share Posted November 24, 2017 If the oil is thin then you will have a lack of power when you push down on the throttle and maybe a flat spot. 20/50 oil is OK. However, BDB needles on a MG prefix engine with K&N filters give a very weak mixture. BAE will give a rich mixture. Try either BDM or BDC with Green springs. The Green springs are the large springs which return the piston to the bridge. Dave Link to comment Share on other sites More sharing options...
Danwedges Posted November 29, 2017 Author Report Share Posted November 29, 2017 Fitted new jets bae needles and cleaned the carbs out set the timing to 8btdc and the car runs spot on now pulls all the way through the revs a little bit of overrun every now and then but that's probably carbon build-up on the head and hopefully will get better with use Thanks for all the advice to everyone who helped out hopefully the weather perks up so I can enjoy the car some more 1 Link to comment Share on other sites More sharing options...
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