235 CI engine. I Tested 2 different carbs today of the same model, 1955 Rochester 1 barrel carbs with autom. choke but i cant get them work proparly and wonder why it is like that? I cleaned them and replaced everything inside but they work so unstable. The floating level and drop level is correct. The air blender scew and the staionary screw are not really reacting good. The engine timing is proparly adjusted at the floatball point 1-6 cylinder at tdp. Used a timing lamp to get it right. The vacume connection is mounted right to the ignition device. The ignition device works fine and the coil to. Does somebody have any good suggestions ? Is the Carter YF carburator with autm. choke maybe a better alternative? Martinius.
Rochester Series 'B' Carbys O.K. , first off , the mixture screw is a fuel bleed screw , not an air bleed screw so it works exactly reverse in which way you turn it . You don't explain how it's not working but yes , a good Carter YF carby is a vast improvement (says the guy who still runs a Rochester 'B') . FWIW , Carter rebuilds the Rochesters , I installed one on a listers truck 7 years ago when he thought his engine was Kaputi , it is still running fine and working hard..... Never , EVER turn in your old carby until the job is done and it's running well as some ' rebuilders ' will keep your good old carby and send you a worn out junky one .
Hey Nate how are you ? The weekend weather here is amazing today, sunny , apple trees are in blossem and it smells oil and grease from the tractor working out on the fields. People are driving there cabinboats on the fjord drinking bear and lying in the sun. That could be nice to do for a change. And then this truck 235 engine. We swapped the 216 flywheel as recommended and put it in its right position in the engine. The floatball on the flywheel and the needlepoint comes together when the 1-6 cylinder are on tdp. We used a stroboscope ignition lamp to check the right position o.k. The automatic choke carburator is mounted as it should be and all the inside screws and gaskets ect. are changed out new. The boks on top of the carburator has an airow (lean and rich) this mark stands on the top of the round box. i use a old fashion oil bath filter that belongs to the carburator. When i start up the engine it goes up to the right temperature.At 500-600 rpm the carburator is`nt reacting really good.Tryed to put the inside bleeder screw at 1 1/4 turns around ( the one on manifold side)the other one the stationair screw is`nt really reacting good eather. The engine flyes away to higher rpm and suddenly it goes down again. At 800-900 rpm the trotle reaction is more constantly and it the engine reacts better, but offcourse running much to fast stationair. I am scratching my head ?
O-Kay then ; I am not sure about the " The boks on top of the carburator has an airow (lean and rich) this mark stands on the top of the round box. " part as I've never seen this part , maybe it's an add on ? . A picture would be good . Next up is to check the intake manifold to cylinder head joint for intake air leaks , engine idling as slowly as it will , spray onto each of the three ports where they join the head , use a plastic snorkel and spray underneath too as that's where mine leaks , from underneath but not on top . if the engine speeds up or begins to miss as you're spraying , you need to remove the entire manifold and have it planed perfectly straight again . To adjust the mixture screw (the inner one) , look up my old posts about Tune Up and use a vacuum gauge or if you have a shop , the exhaust gas analyser to run the CO down until the HC begins to rise , then go the other way on the mixture screw a tiny bit until the HC drops again . Then you may re-adjust the air screw (we call this the idle speed screw) on the throttle linkage , once you've done this , NO touching the mixture screw again ! . it all must be done on the correct order ! . I assume you're setting the spark plugs to .035" (never trust them to be gapped properly !) and using only copper cored spark plugs as platinum plugs will foul and cause wierd running issues . I also assume that when you have the engine OFF and look down the carby and depress the throttle , you instantly see a healthy stream of fuel spraying out ? if not , it'll have terrible flat spots when running . Lastly , I'm O.K. , the Dr. said yesterday I may never ride a Moto again , I cannot imagine anything filling that void .
Thanks for the reply. I will check out everything next week. The checkpoints are easy to do. The round box on top is where the bimetallic spring is installed.It works well. The ACE Delco R 45 sparkplugs i bought from CPOA i dont know if they are copperwired? What do you recommend i should use? I bought a Carter YF with aut.choke from EBAY yesterday, quite expencive but a NOS carb that has been looked over by the owner . They saythe Carter carbs are very well build and are bolt in carbs for the 55 bluflame engine. MOTO cross is a sports i really, have been driving quite a bit myself in earlyer days to, but i am 53 now so i leave it to the youngers. Hope you get back into the sports you really like the most. Have a nice weekend Martinius.
Choke Control O.K. , now I got you ! the way to adjust that black cover that holds the bimetallic spring is : Early morning engine stone cold , hold the throttle open and loosen the three screws holding the cover , rotate it until the choke plate just closes , then snug up the screws again . That should do it , to cold start the engine , depress the throttle to the floor once release and crank the engine without touching the throttle ~ the engine should instantly start and go to a high idle . If everything else is properly adjusted , the engine will start without further touching the throttle . I hope you have the choke stove and heat pipe installed onto the exhaust manifold ? .
Nate Installed AC Delco R 45 sparkplugs . I dont know if they are copperwired? What do you recommend i should use? The choke stove is on its place and works well. Martinius.
Sparkplugs R45's are good , be sure to check and adjust the gap to .035" using a wire typ gauge , sorry I don't have it handy and so don't know the Metric equivalent off my head When those wear out , try NGK's , I've posted the part # before but no need to change them out unless the center electrod has rounded shoulders....
