83 750 carbs on a 85 700

Previous owner of my bike (85 700) must have pulled apart the carbs 3 of the vac diaphrams are torn apart, a spring is missing in the linkage and the cast airbox piece has a crack near where the plastic air filter box bolts up.

Now I can get a set of 83 750 off a running bike, can I just bolt theses on and go? I would like to ride before the weather turns crummy up here in new england.

 

Same carbs. Most likely could get buy. I would at least use gauges to get them sync'd to your motor in order to idle and run smooth. Once you remove and re-install you have a good chance they will be out of sync even on the same bike. Each motor will most likely pull a different vacuum. That's why they need sync'd.

 

So the jets should be ok? I will have to find a shop to sync them but I am just looking to get the bike back together before the summers up.

 

From a VERY reliable source:
"In the early year VF750's the bowls are vented into the airbox base. On
newer years (VF700) the EPA stepped in and made Honda lean the bikes out.
The bowl venting was changed to achieve this, and uses the connector tube
and vents to the atmosphere. The carbs are completely different as far as
fixed jet sizes, slide style, and jet sizes are concerned. It would not run
properly if you mix parts, carb bodies, or change plenum style. Pay close
attention to the carb model style stamped on each carb. VF750 carbs do not
work well on VF700's. The timing advance at idle and curve are different,
and the jetting is also different."

That said, I used a VF750F aluminum air plenum on my VF700F and just plugged the holes in the plenum with a bolt and nut.

 

Mason, thanks for the info good thing I didn't buy them yet. I have a lot on my plate right now and I am looking for a quick easy solution to get my bike back together. I did also see a set of 84 700 carbs on ebay but was hoping not to have to rebuild them. I did see a bike that would be a decent parts bike on craigslist guy was asking way too much money for it considering it had a hole in the block and wanted 800$ for it. Hopefully something will turn up

Matt

 

The carbs are the same except as Mason said was the jetting. The motors use the same pulse generators, coils and I believe the same ignition boxes. But I can't verify the ign boxes. can't find a microfiche on them. The big difference in the motors is your's is de-stroked to make it a 700. The carbs have different main jets, but use the same slow jet. The needles in the slides are different because they have to correspond to the jet size. Your bike may be setup up to burn leaner. Which most likely puts in down on power compared to 83/84 as far as A/F ratios. Whether the timing is different really should not matter. It may come in slower because of the lean fuel setup. It still should run OK with that, just not optimal. I would not change parts between carbs unless you really know what your doing. But to change carb sets should work with a few adjustments. It depends on your knowledge of carburtation and your skills in tuning.

 

I will trade you a rack of 700 carbs for a rack of 83 750 carbs in a heartbeat, let me know if you're interested.

 

Seb,
Ah, well the auction ended and I didn't buy them. But if your willing to sell the rack and they are in decent shape id be willing to buy.

Matt