Working on restoring my grandfathers 1950 "B", wasn't running right, pulled head and left side exhaust valve was gummed up and didn't appear to be seating properly. So, had valves ground by local shop. Have everything back together and it's backfiring again. So that has me thinking maybe I don't have valves set correctly on reassembly. I didn't mess with rocker arms at all, pulled whole assembly and put back on as one unit. I can't seem to find how you set the valves on this anywhere on the internet. Wondering if someone has a link to a website or video that shows in depth how to do it. Assuming I'll need to pull flywheel cover off to see timing marks?? Any advice would be appreciated guys. Thanks in Advance
- Thread starter BenH97
- Start date
RandyB(MI)
Well-known Member
"Backfiring" can and usually is caused by a lot simpler and easier to fix conditions that valves and/or internal engine problems. You'll need to give a few more details on what it does/when it does it and if and when you heard it run correctly last. RB
Ben, when valves are ground they "tighten up" and besides, you ALWAYS need to reset the tappet clearances when the head has been R+R'd.
HOW did you know the correct torque for the head nuts without a shop manual (that would have also given you the valve specs and setting procedure)???
The clearances are .020 for both valves, and the LH side is set when the mark for LH SPARK is lined up @ the flywheel, then turn the flywheel exactly 1/2 turn CCW and set the valves on the RH side.
(Oh, yeah, and GOOD for you for attempting to get a classic piece of family history running again!)
HOW did you know the correct torque for the head nuts without a shop manual (that would have also given you the valve specs and setting procedure)???
The clearances are .020 for both valves, and the LH side is set when the mark for LH SPARK is lined up @ the flywheel, then turn the flywheel exactly 1/2 turn CCW and set the valves on the RH side.
(Oh, yeah, and GOOD for you for attempting to get a classic piece of family history running again!)
borrowed shop manual from mechanic friend, then returned it as he had another customer wanting to borrow it. I'd go borrow it from him again but he still doesn't have it back yet. Trying to get this running again ASAP because grandpa likes to start his antiques weekly, and he's been hurting not being able to start it! the only marks on the flywheel are LH exhaust open and LH impulse. I'm assuming that the impulse mark is the spark?
I think it ran right up until maybe a year ago then sketchy performance after that. The valves did need to be reworked. I think some of this tractors issues come from not being worked much if at all. It'll pull a few loads of hay but other than that no load on it really. I'd like to find a plow for it someday and plow the garden with it or something like that
old popper
Well-known Member
On the '50 B you should be able to pull the center of the flywheel cover and pull the plugs. turn the flywheel ccw with finger on plug hole till you feel compression, then watch (there should be a punch mark visible on the flywheel, and a hash mark in the cover), That will be your LH impulse point. Set left cyl to .022, or .023, both valves, turn flywheel exactly 180 degrees ccw and set right cyl. .022 will give you your .020 hot setting. I always feel it is better to be a little loose rather than to tight.
Hope you can make sense of my ramblings, but that is how I do it............Dale
Hope you can make sense of my ramblings, but that is how I do it............Dale
RandyB(MI)
Well-known Member
Random backfiring can also be caused by lean mixture which can be caused by restricted fuel flow from tank , restrictions in fuel passages in carb, air leaks in carb/manifold/gaskets.Also fouled spark plugs will do it. Double check your work on the mechanicals but you may very well have them correct. Unless someone has changed timing since it ran good , it probably is still on. Tell us how and when and how often it backfires because it makes a difference. In 2 cyl JD,s the "keep it simple" method usually cures 90% of their running problems.
JohnDeereJimOhio
Member
Google and YouTube are your friend. Google the specs for a john deere b they will come up many have asked the question. If you don't know how to set valves in a 2cly YouTube it and watch a few videos, not hard and wont take you long...
buickanddeere
Well-known Member
The good news is that you an obtain your own shop manual and operator's manual from 1-800-522-7448 . Don't waste your time with an IT manual.
What is the compression psi ?
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