carb help on an 86 vfr 700

nope. it had a very very very thin washer but it looked stock, just to keep the metal needal from contacting the plastic slide and wearing though. the screw heads on these carbs look like we were the first ones to crack them open. no damage what so ever. very strange deal so far

 

sssa

There is a post single vs double and I detailed how to do it. Was pretty easy.:crazy:

 

i got a little lazy tonight and just went and blew compressed air through all the holes to make sure thier was no blockages then came inside to do some online research. found this
Carburetors/Tuning - SabMagFAQ

the first paragraph describes putting in a 3mm shim which as i said it does have. i was assuming it was stock but now this has me double guessing my previous assumption. now that everything is cleaned i think i will put it back just how i took it apart and see what it does now that it is cleaned up. check results........... then pull the needles out and remove that thin shim and retest it. if that starts to yeild beter results but is still to rick i might put a size smaller main jet in it. just going to take baby steps on this and keep track of everything as i go. i will try and keep every result documented for future reference in case anyone in the future has the same problems i have at this time:thumbsup:

 

shim

They have one shim under needle stock:thumbsup:

 

DAMN!!!!!!

well there goes that idea:frown:

 

update:

got it all back togeather with the carb cleaned up and stock jets installed. ran a few test runs.

1st airbox lid off no air filter..... wouldn't go over 4000 rpms and peged the air fuel guage at full lean 16.0

2nd tried the lid on with no air filter........... ran like a scalded dog but was to lean at mid 15's for an air fuel reading. no hesitation like the original problem

3rd. installed the airfilter and had it back to bone stock, it richend up to a low 11 to a high 10 air fuel reading on the wideband oxygen sensor. no hesitation above 9000 anymore but still to rich for my taste


conclusion: i am going to purchase a k&n filter in the coming week or so and that should flow a slight bit more air and lean it out just enough to make it have the air fuel mixture i am looking for.

i will update this thread after the k&n filter is installed. hope this helps someone in the future. it drove me bat shit crazy for a period of a couple day lol

 

Air box

They do require an air filter at the very least to run correctly or at all. I have tried every combo possible (dynojet included) and run stock air box with stock needles (shimmed with stock shims,1) one size larger main and 2 1/2 turns on air screw. Not greedy ...could go bigger maybe ..but it does run well.And yes I do run snorkel.I did mill 18 thousands off the heads in 1993 despite being told not to do it and have never had a problem.Gear whine is enough to make Hellen Keller squeal.:thumbsup:

 

deffinatly require the air box with snorkel at the very least. the carbs are bone stock right now with the 118 and 38 main and pilot jets and 2.5 turns on the air screws.

i will get it leaned out a little more and it should be just where it needs to be. if i can get it to read a 12.5 at wide open throtle, or close to it on the air/ fuel guage then i think it will be perfect

 

IMO it would be better to be slightly rich @ WFO rather than lean if possible. I was wondering about the altitude in your area as well. So, if it's all back to stock and the problem is gone were dirty carbs the cause? If so you'd better start draining the carbs or adding some Sta-bil to the gas before you put it up for winter.

 

i live in kansas city misouri so altitude shouldn't be to big of a deal. once i put the k&n in it should lean it out just a little but still be on the rich side. i am aiming for a reading of around mid 12's on the air fuel guage if i can but i believe the k&n will put it around low 12's which is fine also. the carbs looked really clean but the air fuel mixture deffinatly changed a little so i guess thier was some dirt hiding somewhare. i just picked up the bick last year and i did store it with stable over the winter but i can not speak for the previous owners. it has a salvage title due to the guy before me tearing up the plastics which were valued at more than the bike was worth. i got new ones from vfr chuck and got a clean/ post salvage title for it now. it has a good life in the garage with the other toys now:thumbsup:

 

For what it is worth, when I had the 4-2-1 Yosh system on my bike, I had the same problem. The engine would not pull to redline, it would stop around 9-10 thousand RPM due to the mixture being to rich.

As it turns out, you need a SMALLER main for the Yosh pipe to work well. I took off the Yosh pipe and went back to stock. Then I modified the stock exhaust to bypass 2 of the 4 exhaust chambers. It sounds nice, the plugs are white, and I get 55 MPG when putting around.

 

for what it's worth, the plugs should be tan.

 

Tan like Cadbury light milk chocolate, to be precise.

 

I will pull a few plugs and have a look at the colour.
Maybe my "white" is your "tan"?
(Are you using sRBG or ISO RGB? What is your whitepoint? /JK)

With the Yosh pipe and factory jetting (118), they were BLACK and now they are much better.

 

I put the airbox and snorkle back on mine ...it seemed to run better

just saying

 

Hey Volksmech, I don't know if you are on this forum anymore, but if you are, can you give some details on your wideband install? Like where did you install the O2 sensor?

Thanks

 

I just bought a bung and welded it infuriated exhaust pipe where it wasn't sticking out and riged up quick clips for the + & - wires. got my readings then put the cap in the oxygen sensor bung .

 

So it didn't matter if it was near the head or in the back where the 2 to 1 collector was?

 

Mine was after the collector but before the muffler . kinda by where the foot peg is. a little forward of there.