By joining you will help ensure that we can continue to provide this service
JOIN HERE!
Engine wants to suffocate when opening throttle
- Micha
- Posts: 763
- Joined: Fri Oct 12, 2007 2:24 am
- Location: Israel
- Has thanked: 10 times
- Been thanked: 5 times
Engine wants to suffocate when opening throttle
While opening the throttle slowly - it revs up ok.
I am aware that after adjusting according to the instructions, a more subtle calibration is needed.
I would be happy for instructions and explanations (it is also a hard starter but when idling it is neat as a sewing machine).
Thank you.
R51/3 1952
Engine Nr. 529466
- schrader7032
- Posts: 9040
- Joined: Fri Oct 27, 2006 3:00 am
- Location: San Antonio, TX
- Has thanked: 2 times
- Been thanked: 34 times
Re: Engine wants to suffocate when opening throttle
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- Micha
- Posts: 763
- Joined: Fri Oct 12, 2007 2:24 am
- Location: Israel
- Has thanked: 10 times
- Been thanked: 5 times
Re: Engine wants to suffocate when opening throttle
Thanks for your interest.
I did exactly as these instructions say:
I think I might need help like whether to enrich the mix or something like this, no?
What do you think?
R51/3 1952
Engine Nr. 529466
- schrader7032
- Posts: 9040
- Joined: Fri Oct 27, 2006 3:00 am
- Location: San Antonio, TX
- Has thanked: 2 times
- Been thanked: 34 times
Re: Engine wants to suffocate when opening throttle
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- jwonder
- Posts: 784
- Joined: Wed Nov 23, 2016 7:50 pm
- Location: Long Island, New York
- Has thanked: 3 times
- Been thanked: 7 times
- Contact:
Re: Engine wants to suffocate when opening throttle
I really wanted someone else to chime in to see if I am wrong, but I figured no one else would. My R51/3 does exactly the same thing. The carbs are small bore and I think it’s just what they do.
When I have it in gear and it’s pulling, or getting rolling in first gear, it takes the throttle happily. I can open the throttle quickly in every gear with no bobble.
If it comes off idle when not in gear even moderately quickly I would happily ride it!!
If anyone else has an idea please chime in.
Vice President, Vintage BMW Motorcycle Owners
2022 BMW Friend Of the Marque
Long Island, New York
- Micha
- Posts: 763
- Joined: Fri Oct 12, 2007 2:24 am
- Location: Israel
- Has thanked: 10 times
- Been thanked: 5 times
Re: Engine wants to suffocate when opening throttle
I will find some time this afternoon and warm her up and try again.
If there will be no change, I will live with this phenomena happily.
Take care.
R51/3 1952
Engine Nr. 529466
Re: Engine wants to suffocate when opening throttle
- Micha
- Posts: 763
- Joined: Fri Oct 12, 2007 2:24 am
- Location: Israel
- Has thanked: 10 times
- Been thanked: 5 times
Re: Engine wants to suffocate when opening throttle
The carbs are disconnected from the suction pipes I just removed.
It is very difficult to start the engine: When opening the throttle a bit more then normal, the lever kicks back and the nozzle of the idle screw on that side spits fuel.
So it lasts about 10-15 kicks until the engine wakes up.
When finally engine works and I warmed her up:
The left seems to be the one that is taking all the work: Left side becomes really hot, it beats strongly. I can actually hear the suction from the carb intake. On the EMPI synchrometer I get a reading of 5: I have no idea if it is good or not but on the right side carb - there is nothing. When I block the air entry to the right carb with the palm of my hand nothing happens. When I do so on the left carb, the engine stops. The right side is unable to proceed alone. On the right side by the way I have a fuel leak from the idle screw nozzle.
When standing behind the working bike, the left exhaust really beats and breathes, the right exhaust just participates and mechanically knocks.
On both sides the valves where carefully set.
Both sides get fuel supply and there's a spark on the new plugs. It is like the left side is not working, although it gets now much hotter on the exhaust pipe (not as on the l/h which I can not touch, but quiet warm).
I will arrange again from my friend the pressure gauge to read what the right cylinder has to say, but I am truly worried, that I will not be able to escape an engine head & cylinder dismantling.
R51/3 1952
Engine Nr. 529466
- skyler.robbins
- Posts: 227
- Joined: Sat Sep 22, 2018 4:14 pm
Re: Engine wants to suffocate when opening throttle
Double check your valve adjustments on compression stroke.
Are you getting good spark on both sides?
Correct fuel flow to both carbs?
Re: Engine wants to suffocate when opening throttle
I seem to recall you rebuilt that motorcycle from a real beater?