As most of you are aware I’m nearly there on finishing my VF1000r… I had the carbs refubed, full service, new batt…fuel relay etc
problem is… it starts eventually, just before the battery goes flat…full choke no throttle…. once it’s started and been running it starts every time… then I leave it for a week then I’m back to the same not starting problem…
Shall I change the fuel pump, coils and leads or is it a carb problem still… I’m at a loss…
the bike done 12000k and been garaged for 30 years before I took ownership of it 6 months ago…
the carb was fitting with all original jets and parts.
What are your pilot jet and float height settings…?? Compression ok…?? Valve clearances ok…?? These bikes don’t actually need a fuel pump, they’ll happily run using just gravity feed. If full choke is needed she may be too lean to start with, or you have other issues. I run my bike slightly rich on the pilot settings as we have silly ambient temps where I am…helps keep things a little cooler if idling in heavy traffic etc. My bike starts fine with no choke during summer months. I also have a high CCA Lithium battery, new high output “Carmo” spark units, high output coils, new leads and plugs.
I’m gonna take the carbs off weekend and have a look… I am sure compression and clearance are ok as dad never did over 70mph … in all the 12000k it did… what I did notice it back fires when am trying to start it? I’ll let you know regarding jets, I have set mixture screws 2 1/4 turns out from seating position… thanks again
You mentioned float height, not sure what that is?
I’m coming out to Australia soon to see my son who lives and works in Byron bay and is getting his citizenship so looking forward to seeing him and chilling out for a few weeks
Just saying the compression and valve clearances are ok because your Dad never did over 70mph means nothing, they need to be checked thoroughly, the bike is over 40 years old, things deteriorate over time. Backfiring and poor starting means something is not right. Ignition system needs to be at it’s best too.
Float height is also very important, if too high or too low…or if you have sticking floats or blocked valve filters it will cause all sorts of issues…all these things need to be checked.
I’m not “too far” from Byron Bay…if you want to take a run up to Brisbane’s northside and see my RE and talk all things VF whilst you’re here in Aus…! Plenty of tea and biscuits on hand.
It sounds like the carbs aren’t full enough to start it until it’s cranked for a while after a lay up. My FF is the same.
What a lot of people do is fit a relay bypass switch behind the sidepanel; the pump only runs when the relay’s closed, and the relay only closes if it gets a signal to do so from one of the coils. The coil only signals the relay if it’s sparking, ie the engine’s turning over. If the carbs are empty enough, the battery will be flat before the pump’s had time to fill them. The bypass switch means that you can turn the switch on and the pump will run, cranking or not, and fill the float bowls up.
I use this switch after every long-ish period of inactivity before I try to start it. It always starts first push afterwards.
Worth a try?
Another benefit of said switch is when the relay inevitably fails, undoubtedly when you’re miles from home, you simply flick the switch to hard wire the pump and carry on with your journey.
These bikes don’t need a pump to run…they’ll happily run with just gravity feed. My old VF never even had a pump fitted and ran fine for years as long as I didn’t let the fuel get too low.
That’s correct Smithy, it ran OK for years because there was no pump. If a pump is fitted, it can and usually does act like a valve and restricts the flow of fuel. ChrisB is also correct, you need to install a bypass circuit to run your pump before you try to start it when it has been standing. Make sure that your pump and the whole ignition circuit is actually working properly when it should be. If you need to know how to wire the circuit, message me and I can send you a mudmap wiring diagram to follow. sometimes when these bikes have been sat around for a while the inlet for the fuel in the tank can rust up a little which also can restrict fuel flow, a running pump helps to get fuel to the carbies when this happens. Start at the top(valves) and work your way down to check that everything is set correctly then check to see that everything works when it should.
Yes and yes…7.5mm is correct for the float level, pop the float valve seat out and check the little gauze filters for blockage whilst you’re in there…There were Honda service bulletins for some V4’s in the 80’s which had 0.004" as the valve clearance but 0.005" is correct.
Measure between the valve stem and the adjustment screw, not between the cam and rocker…Be sure to do both valves on each rocker at the same time using two 0.005" feelers to prevent incorrect readings. Once set correctly I like to “just hear” a “tiny” bit of tappet noise at idle.
Ok that’s cool…thankyou
I have just watched a tutorial on YouTube on the vf1000f on valve adjustment… I will give it a go after I have removed and checked carbs this weekend… and ordered some feeler gauges cheers smithy
… in all the 12000k it did… what I did notice it back fires when am trying to start it? I’ll let you know regarding jets, I have set mixture screws 2 1/4 turns out from seating position… thanks again
cheers smithy