problems with my 83 vf750f

you guys are great. this is very informative and helpful. i'll let you know how it all pans out.

 

You DO NOT want to blow compressed air through the float needles, doing this could/would damage them. Compressed air is a part of the cleaning process, but there are others that are more important such as 1) spray carb cleaner, one can per carb body 2) pieces of small wire to mechanically break up clogged passages. I also run the carbs through my ultrasonic cleaner just to make sure there isn't any residual junk in there.

 

just talked to my guy.. he says the carbs are cool.. the problem as far as recently deduced is that the jets that were in there were 122's when they're supposed to be 128's.. he didn't think that that was too big a dif, but when he was talking to honda, they told him that it's truly a big deal. i guess it's less so with the older bikes. anyway, new jets in tomorrow and hope springs eternal.

 

I really doubt that's your problem. You'd only notice the difference at WOT at high revs. It's also only two jet sizes off which isn't much. I think you'll find the solution to your troubles elsewhere.

 

Hi, JamieDaugherty. My interest was in checking the stripped-down carb body before re-assembly, but thanks for for the emphasis. I generally used compressed air, blowing in the opposite direction of "normal" (on a good day, that is :smile air/fuel flow.

danimal42, did you find out where the dangling hose was supposed to go to? Just curious, as I agree with JD that the main jets are not the issue here. It is the low speed circuits with the problem. And now that I typed that, I do think it is suspicious that all four carbs would have low speed circuit problems. This really sounds "systemic", as in vacuum leak, closed throttle butterflies, low fuel levels in the float bowls, or whatever would affect all four carbs simultaneously. Squirrelman and Jimtt had some good suggestions for overall system checking. Did your guy and/or you check those things? I'm not trying to be a pain here, but fuel flow through the high speed jets is not an issue at this point.

 

i'm concerned about vacuum leak as well. as far as we know right now the hose is supposed to vent to the atmosphere. he said the butterflies were good, springing back well is how he put it if i remember correctly. he's come and checked out this thread and he's on it.

i just have to say this forum is such a great resource, thanks for letting me pick your collective brains.

 

so it turns out the bike hadn't been running on all four. with the new jets and everything cleaned out, things pretty much fell into place and i picked her up this morning. my old tank had been a rusted out nightmare so i bought a new (to me) one on ebay for 50 bucks. it had a few dings. the upside, clean on the inside. the downside, the dent on the side warped the gas cap area so i couldn't get it open when i went to fill her up.. i called the guys and they actually cruised over and met me at the gas station (ok there were on their way to lunch anyway) and they showed me how you could torque it a bit and get her open. not that crazy about that, but i guess my option if i want it perfect is to get an immaculate tank (and pay the price) or have some welding done or something to that effect. i think i'll live with it for the moment.

then i went for a 20 mile ride and it was plain awesome.. my only problem there is that it ran kinda hot.. never overheated, but the temp gauge takes about 10 minutes before it's up at 3/4 and if stuck in stop and go it threatens the redline just too fast to be comfortable... i'm considering getting a manual radiator switch installed, but now that i've shelled out some dough i'm gonna enjoy her 'as is' for awhile. what a sweet ride!

 

Congrats! I'm sure you are relieved. Have fun!

 

VF750Fs tend to run hotter than many owners like. If you want to install a slightly cooler thermostatic switch (lower radiator, right lower corner) you can try a NAPA part - ECHLIN FS130, about $28. It turns the fan on at 191-197F (ascending) and off at 182-187F (descending). It screws right in and it has the same wire connectors as the stock part.

 

Alaskan: THANKS for that info!!!!!!! BRILLIANT!!

I just love it when we can substitute Honda pieces with something from autoparts store ( at drastically reduced price).

GOOD WORK.......

 

:wink: It's good to save a dime now and again . . . .

 

thanks! i'll pick up that part real soon and let you know how it goes!

 

Danimal42, I am assuming that your fans are running. Is that right? Do they come on when the bike gets hot?

 

yeah i hear them when i shut off the engine after the ride, but i'm not sure when they go on.. i know i hear one, but i'm not so sure about two..

 

Next time look at the fans while the bike is hot and idling. Or you can pull the rubber boot off the thermostatic switch and jump the wire connectors with a paperclip and turn the ignition ro the "on" position - the fans should run.

My VF750 is running really cold today - it's 0 degrees F outside this moning! And the wind is blowing at 40 MPH. Ugh!

 

That's fine if you just want the peace of mind but remember that it's not solving the problem. It's common for bikes that sit a lot to have cooling system issues. I'd do a really good clean and flush of the system and see what happens. Replacing the thermostat, as mentioned, is not a bad idea either.

 

Let me take a wild guess that your cooling fans will probably last a looonnnggg time! I've ridden in some cold weather, but NOTHING like that, especially on purpose! Some of you guys (and gals too, I imagine) make me feel like a major wimp. Of course, it could be that I AM a major wimp and just never realized it... Doh!

 

the saga continues... so last night i go for a midnight ride on the streets of LA.. just fantastic. but i started to notice that my clutch was getting a little touchy. i had to squeeze it real hard to get it to disengage. and in first at stops the bike was wanting to creep even with the clutch squeezed tight. then this morning i was all set to jet and the bike would lurch and die the instant i dropped it from neutral into first to go... consequently i never got out of the driveway..

so it begs the question.. is there an easy way to adjust where the clutch engages..? everything else seems cool.

thanks

 

Check the fluid!!! I'll bet it's low in the clutch master cyl.

 

i'm on it! should i just top her off for the moment or should i try to accomplish the full bleed/refill before i ride again?