First Bike VFR 750

You bypass the relay. It is not permanent or hard.

Pump does not operate with just the key. Bike either needs to be cranking or running for the pump to pump.

Disconnect the fuel cut relay and use a small jumper wire and connect the black and black/blue wires in the connector on the wire harness side. Pump now operates with the key on. Pump will still shut off when pressure is reached as normal.

Prime your fuel system (pump stops clicking) and then start the bike.
When done, plug relay back in. Battery and starter motor have been spared the abuse.

 

I was riding my 88 with a jumper just in case and first long ride out my pump relay failed. Been running with the jumper installed ever since.

 

Hey guys I‘m back with a little update.

I think I forgot to mention that the battery drained on the way home when buying the bike and the engine just stopped on the highway.

Anyway I got in contact with the previous previous owner, who actually was a little bit knowledgable and told me about the R/R and that he had installed a 30€ amazon no name R/R.

I am already informed about the R/R issue on the VFRs and mine is definitely shot, since it reads 16-18 volts with engine idling (choke on). Also Lights flickering etc.

Question now is, can a faulty RR cause similar symptoms to clogged idle jets?
Swapping an RR sounds way better than pulling the carbs. I‘m not putting too much hope in it, but if you guys say the jets are definitely clogged and RR is not the cause of my issue, I will do that while waiting for a new RR to be delivered.

Issue: Bike wont idle/dies when choke is off

 

First of all... What R/R did you order?

 

I haven‘t ordered yet.
Im still deciding my options but I‘m willing to buy a cheap one for 15€ for starters to further diagnose. That one comes with a new connector, which is why it‘s interesting because I assume my connector is toast.

Even if it lasts 3 months, until then I‘d have saved up enough money to get a quality one. But for now I still have time because I got my driving test next month and cant ride the bike before that anyway and money is running out.

But back to my question of a faulty RR would cause similar symptoms as clogged pilot jets?

 

"Even if it lasts 3 months..."

And then fucks you in the ass in the middle of nowhere (after 3 weeks) and potentially ruins another battery and possibly compromises your stator. Not a good plan. Sounds like it would be driveway testing anyway, but if money's tight, buying known shit sure sounds odd.

Yes, a failing charging system that is under or over charging will def cause runability issues eventually. Does it act like dirty carbs?... Maybe. But not usually. Usually the tach and lights start acting really funky, and then the bike starts dying. Did the bike idle properly before the battery got over charged and started fucking with your ignition system?

Is this the bike you would be riding for the license test?

 

Never idled properly from first seeing it to finally having it home. I‘m pretty sure the RR was causing overcharge since before I bought it because the kid I took it from didn‘t know much about bikes and rarely rode it for the 3 months he had it

License test will be done on a driving school motorcycle.

 

https://www.harborfreight.com/12v-alternatorbattery-checker-59376.html

mounted this on many honda bikes. cut off huge clamps, mount it with zipties somewhere u might see it.

can be made alot smaller by spliting the case to extract the much smaller circuit bord.

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if your bike only idles on choke, its dirty carbs, not voltage.

 

You need all three:

- PROPER carb clean
- QUALITY R/R
- SMILE, you got a really cool Honda. Hopefully these things will get it sorted and it will be a good first bike for you, because it is a good (great) bike.

 

Hey guys back again.

This week I‘ll start with the RR
I ordered a chinese mosfet RR with a connector kit as temporary solution until I can either source a used OEM one or one of the known aftermarkets. To me it‘s important to first get the connectors all ready for when I get a good mosfet RR.

One Question to which I find no answer though is:
Does it matter which of the three stator wires goes into which pin or are they interchangeable on the RR connector.

Second question. If anyone has it at the top of their heads, which wires I have to short on the connector to the fuel shut off relay, so I can prime the carbs before starting when I‘m done cleaning them.

Also, even though I done lots of research, and am fairly confident, I would appreciate any advice, tipps and tricks, what not to do, what to look out for etc.

 

3 yellow wires make no difference, that's why they are all the same color.

Top of my head... black and black/blue. But it's pretty easy to find the right pair, there aren't that many combos. When the pump starts clicking with just the key on, you found the right two.

 

Alright guys I did it. Sorry for the long post. It‘s a bit detailed for future members

Mosfet RR is wired and crimped and connected
I got positive and ground going from RR directly to battery. I had to delete passenger pegs for now so I can mount it in a tilted way to use the already existing hole for the 10mm bolt until I can find someway to drill a new hole and mount it right.

I also pulled the carbs today.
I am surprised how easy it was, I was shttng myself at the thought of pulling them alone that I might break something while prying it off.

I loosened both clamps on all 4. Then twisted the rubber back and forth then pryed at the rear 2 ones while pulling the backside and they just jumped up. Same with the front, but one has to be very careful where to pry.

When reinstalling them dont fully seat the rear rubber onto the engine. The front ones you can fully press in, then put the carbs in front first and then press in the rears together with the rubber. I used a tiny bit of silicone spray (careful you dont buy spray that swells rubber). Putting them back on was the easiest thing today

So pulled the carbs and sadly the idle jets looked pretty okay. No clogs, I sprayed idle and main jets with carb cleaner and poked through all the holes, even the little ones on the sides, with a carb cleaning tool that comes in various sizes. And confirmed that you can see through the idle jets.
Only the caps were pretty gunky at the (overflow) screw (not sure thats what its called). I sprayed some cleaner on it and with a tissue cleared everything. It seemed like the cleaner dissolved said gunk though I‘m not sure.

I put everything back together, primed the carbs by shorting the fuel pump cutoff relay, it only took like 10 seconds, started the bike and sadly still same.

Choke fully engaged, idles at 1400rpm
So then I decided to try adjusting the screw on the left side (idle screw or something its a rather long wire with a spring that goes to the carbs and is accessible on the left side)
So I tried around twisting left and right until I got the bike to idle with no choke, but when engaging choke the rpms jump to 5000rpm so I know this is not the way to go. Also the rpms and the bike are jumpy/bumpy this way.

I read that most people dont get their carbs properly clean the first time around but like I said I poked through all holes I could find.

I did not mess with any mixture screws on the carbs. They are all approx. seated the same height as you can see in one of the pictures.

I‘d appreciate any advice as to the next steps.
I‘m thinking of leaving it like that, I got my driving test next week and if I pass, I‘ll put some type of carb cleaner in the tank and drive around for a few days.

 

normally, adding any choke will raise idle speed. set at 1200-1300rpm. your carbs might need synching if idle jumps around. a good cleaning includes removing idle mixture screw and shooting carb cleaner through the hole + compressed air. if u skipped this step, its not a proper job.



seems like u did a pretty good job if the bike runs well.

 

There is a 30 amp fuse on the positive cable going to the battery. You can see it in the firet picture its a black box.

One of the previous owners already installed a voltmeter. It‘s the reason I even noticed something was wrong.
I‘ll buy a used oem RR soon too.

Sadly I dont really have access to compressed air and I cant find any for sale here. Would you recommend taking out the carbs and trying again?
Also note I did not spray carbcleaner in the holes where the pilot jets thread in, I read simewhere that it might be clogged down there also there was sand like substance around the holes. Not in them but around. I tried my best to wipe it off.

Other than the idle issues, revving the bike is very smooth. So that means the main jet and everything else like air, compression, fuel and spark is okay right?

 

As squirrelman said, if the mixture screws didn't come out to clean those passages, it wasn't a proper job. Also, the brass tube next to the main jet and pilot jet has to be verified clear.

All the passages in the carb bodies have to be verified clear. Just because a pilot jet is clear, doesn't mean the passage it threads into is, but it is usually just the jet. The thing is, you never know, so you do everything if you do anything.

There is a spring, small washer and o-ring with the mixture screws that must be accounted for before any cleaning or they will be lost.

 

Please elaborate on this paragraph. The bike idled without choke? At what RPM?

And then increases when you pull the "choke" lever down? That's normal, because it is an enrichening circuit adding fuel.

 

I didnt want to mess with mixture screws and the floats mainly because I didn‘t want to f it up and the space I work in has very bad lighting. I was aware going into it that I was not going to fully clean everything properly but I hoped what I did was enough. I‘m still satisfied though because next time it‘s going to be easier.

Now about the idling. I‘m still not sure how to phrase it but let‘s just say: choke engaged = pulled lever down (full choke) and no choke = lever all the way up.

So at first when Choke was engaged, it idled at 1400 rpms warm. Without choke it wouldnt even idle or start
—> carbs halfway cleaned
Now choke engaged and still idles at 1400 rpms
—> decided to adjust on said hanging screw/cable on the left.
Now managed to have the bike with choke engaged at 4000-5000 rpms and when pulling choke lever up (no choke) it idles at 1400 rpm but the needle is not steady. It jumps from 1400 to 1500 rpm.
Giving throttle is very responsive and smooth though.

Quick question: If a bike only idles on full choke, would said idling be at 1400rpms or at 3000rpms like is normal for full choke? What I‘m trying to understand is if a clogged pilot jet also affects the rpms when choke is on

 

You still are sending conflicting signals...

"and when pulling choke lever up (no choke) it idles at 1400 rpm but the needle is not steady. It jumps from 1400 to 1500 rpm."

So it does idle without the choke engaged?

The "thingy" on the left is your idle adjustment. Can you adjust it so it idles 1100-1200 without the choke engaged? (Regardless if it is jumps a little)

 

Yes it idles without choke engaged. But I‘m assuming that right now it is not really called idling because I had to adjust the „idle adjustment“ so its like I‘m giving it throttle or did I understand idle adjustment wrong?

Im pretty sure I had it idling at 1100rpms earlier without choke, but raised it to 1400rpms because it was steadier.
At 1200rpms it felt like it‘s gonna stall (because of the jumping)