Choke problems, I need your help!

Hi, I'm new to this forum as I have just bought a VFR750FN. I used to have an FL back in the 90's but I never had to do much maintenance on it as it was almost new. This one however is a different matter being 20 years old. I don't have any history with it but I was told it had been laid up in someones back garden for many years before being rescued. Since I have had it, I have changed the fork seals, and fitted a new fuel pump. The problem I have is that the choke doesn't seem to work! I know that it isn't the usual sort of butterfly arrangement, and I can see that both pistons (if that's what that's what they are) are moving freely when the choke lever is moved, but this doesn't does absolutely nothing to the RPM. I thought at first that the cable had snapped but it is fine. Has anyone got any ideas, as when the bad weather comes next winter I am going to need it working properly. I'm not much of a mechanic but I have a Haynes manual and am willing to attempt most things. Many thanks
Paul

 

Hey TSG and welcome. I just had to rebuild the carbs on my bike because mine had been left sitting too. You probably have a plugged up idle enrichment circuit (choke) to fix that you have to pull the carbs (dont remove them from manifold, take them off as a unit). Then take each float bowl cover off and put a piece of guitar string down it and hope that it goes through. If not, work it around and try to get it to break through until it will slide freely in and out. I found a high B string to work best. While your in there, you might as well remove the main jet and the slow jet from the carbs and clean them too and generally do a thourough cleaning.


I removed and cleaned mine and found it best to remove the unit, all the rubber (transfer tubes, diaphragms, springs, floats, jets) and boil the carbs in water and lemon juice, some people soak in pinesol for a few days, works just as well. Reassemble, set float height and do a quick bench sync, reinstall, and do a running sync, should be good to go.

 

That picture is exactly what you will find, the one with the red arrow is the one you have to unplug. the other 2 unscrew and you can clean. however, the idle one is non removeable, so dont try!

 

The wire i use is .012". Don't know what note it corresponds to, but you really need to poke and peck and twist the wire to WORK it through the usual obstruction in the choke pick up tube at about 15mm depth but all the way down to about 35mm depth to make sure it's all clear.

 

Thank you for the quick replies, it is as I feared going to entail removing the carbs and taking them apart. This is not something I have done on a 4 cylinder bike before but I'm sure the trusty Haynes manual will guide me through it. Thanks again.
Paul

 

You should find an on line FSM at least. There is no such thing as a "trusty Haynes/Clymer" manuals ever made. If you can't find one let me know.

 

Before I start stripping the carbs is there any kind of fuel additive that could solve the problem for me? I will strip them down but it is a little bit daunting having never done it before.
Thanks
Paul

 

this isn't as horrible as you think. go slow and don't mix anything up..( the parts you take off of each carb should go back on the same carb..... deep breath and jump on into it...

 

Right, I am almost ready to start this, (not quite but almost). I don't mind doing mechanical things but this is a little bit technical. Once I have cleaned them, probably not boiled with lemon juice, but reasonably cleaned them, people have spoken about bench sync and then running sync, as I have said I am a complete newbie to doing anything with the carbs. I want the bike to run when they are reinstalled, if I have to take it to a professional to balance them properly then so be it. What should I be doing??
This is a great site with some fantastic people, I sincerely hope that one day I can help someone as much as I am receiving help from you guys, keep it up!!

 

OK, i'm all for working on and fixing all your own stuff, but if you can find a reputable shop with a nice but grumpy old man who works on carbs for a reasonable price and guarantees his work, take it to a real professional instead of trying to do it yourself. Lots cheaper to clean carbs when they're off the bike to start with, and noobs never get it done right.

C'mon Guv, the specialist shops with qualified personnel around a word-class city like London should be plentiful !