Keihin VE65AAWE9 - Fully Explained

[ThePowster]

Not giving up on this, and I'm starting to wonder if the black that the carbs do is just a reaction and it's fine.

Anyhoo last night I ordered a sandblasting cabinet and some new media to try that's stronger than bicarbonate of soda.

Whatever I'm left with after this it'll get painted and dynojet kit installed.

I'll fire up more pics as I go and I'd like to do a full breakdown of every component of the carbs for other newbies who wanna know what's what.

[ThePowster]

Update: these are not black, anymore 

I've painted the carb rails black already.

The finish is a tiny bit rough, not much, but if I soda blast again it'll be covered in soda and last time it wouldn't come off, so I'm just going to give a light scotch, then mask for paint and start to assembled with rebuild seal kit and jetkit.

[Bob H]

I have the same reaction to this as I did December 18, 2023

Easy for me to say from the other side of the globe - but I would acknowledge the learning experience and get new (used) carbs.

There is no way to get that coating out of the internal passageways. Running fuel over time is not going to do it, that coating is likely more durable than fuel residue. People rebuild carbs due to fuel residue.

I recently retired, but still at "0" my time is worth more than the effort of putting your new jets and all the other bits into the carbs, getting the 4 back together, hooking all the boots & cables - only to have it run worse than stock or not run at all. The passageways to the adjustable idle screw would be impossible to clean out.

As I understand it, you got a cleaning solution for the ultrasonic and used it full strength. Later it was established that it was supposed to be diluted. Also the heating element on the ultrasonic "cooked" the carbs, got too hot. I would never install those carbs. I would discard them and not offer them for sale.

[ThePowster]

I'd never offer the carbs for sale no matter what, if these don't work they'll go in the bin.

Having had a good look at them though everything that I can see has been cleaned by the blasting process.

The black colour of the carbs was just the metal reacting with the heat or chemicals. It didn't really add anything to the surface, and if it did it was so minor it couldn't be detected by feel or eye, just a colour change.

If it works then great and if not I'll use my current working carbs and just blast, clean and paint them and I should be good to go, but these appear to be fine to me.

I haven't finished with the prep yet. I've some really thin carburettor wire brushes to clean all the orifices and I'll want a light scotch on all surfaces.

If nothing else it's served as an education, but I'm hopeful when I drop these on the bike she'll be just fine. Guess time will tell.

[ThePowster]

Good evening fellow Nighthawkers.

So I've been busy in the background sorting these carburettors out. It's been a real journey of exploration, sometimes frustrating but I've always enjoyed learning.

It's not been a cheap experience, having bought ultrasonic cleaners then compressors and blasting media, then paint, searching stainless hex bolts and pitch sizes and finally jet kits, but today I finally got the carbs finished and started to install them on the bike.

I'm at the stage now where I need to install the choke cable and throttle cables but my backs gone so it'll be next week before I get to try and finish this.

So I've gone from nasty standard carbs, tarnished from being outside for 40 years to sandblasting them and finally painting them in engine enamel black and they look marvellous with the stainless hex head bolts.

I've installed a stage 2 Dynojet kit and I also installed a carb rebuild kit, but the float bowls supplied were white and not orange like the original and they sit lower in the float bowls than the original.

I did snap one jet taking it out but I managed to remove it with a stud extractor.

At present I don't know if this will work. My carbs had a black covering after the ultrasonic cleaner, then after blasting whilst the carbs were clean it's made all the surfaces a tiny bit rough. Not much but it's not shiny smooth let's put it that way.

There also seems to be some residual dust in there from the blast process.

I do have one concern. On these black carbs one of the choke pins has a clip through it and on the ones I've just taken off the bike it has 4 normal choke pistons. Why this other set has a clip through choke #1 I don't know. Anyway I snapped the pin and I've used a paper clip for now but operating the choke isn't great it's a bit stiff, maybe it'll free up with some use.

So it's all unknown at the moment. I've bought a Morgan carb tube to balance the carbs should this bike ever start again lol.

I rode her yesterday and the noise is addictive, sounds like machine gun fire on the down shift, I enjoyed riding it so much I've left my ZX-14 alone and I just play with the Nighthawk. I prefer it.

Without further waffle and ado, here are some pics, sorry there is so many. Shows you the journey I suppose.

If anyone knows anything about my choke plunger needing a pin through it and my other set don't, that would be useful. I'd love to take this out for a normal one, and not sure of it's possible?

V.tired this evening. Zzzz but I wanted to post here once I got to this stage this evening and show y'all.

I'll let you know if she starts again lol and what she performs like Dynojet stage 2 with the K&N.

[mollusc]

So, one question, and sorry if you already answered this much earlier in the process, but one of the main reasons why people say they want to go with pod filters is that they don't like the look of the airbox.  For some reason people seem to want their bike to look like it has big shoulders up front and a skinny little back end, kind of like it skipped leg day for a year.
But you're apparently keeping the lines of the 700S by retaining the side panels, which hide the airbox from view.  You can drop a K&N pod filter into the airbox with an adapter, so why the elaborate setup with the additional tubing etc.?

[ThePowster]

I don't mind the look of the airbox at all. It's a useful and integral part of the process. It houses the battery, rectifier, solenoid and indicator relay as well as other things attached to it. Removing it was never something I wanted to do.

But I started this process looking for an air filter and I could only get one in Australia, it scared me a bit as the availability is so low, especially here in the UK. Not only that the ones I did find abroad were so expensive. So that was the start of my dilemma. Then taking the airbox out, man what a total chaos and nightmare. Having to remove the wheel each time and those damn rubber inlet things are brittle and never seat right. I'd had enough messing with it so I wanted an easier solution. It was never about looks it was all about ease of maintenance and I can't wait to throw the original airbox in the bin.

I love the side panels on this bike but they also clipped into the airbox so I've got my work cut out for me on how to get these back.

I may be getting a 3D printer soon so that would allow me to design and produce a custom fit battery box which would allow me to put the side panels back and no one would know what was behind them.

I just wanna ride me. This will be my rat bike if you like, I wanna cruise around this summer on it as it is while I do a nut and bolt restoration on my Nighthawk #1 which is broken down into bits. The frame is covered in rust but I'm hoping to sandblast that myself this summer, get it all perfect and silver and paint it, same with the wheels, shaft drive and fork legs and get a rolling chassis ready to go.

My original Nighthawk has just 16k miles on it. This one has 70k on it lol.

I've no idea if this carb set up is going to work. I've a feeling I may block the jets with what media may be left behind in the passageways if there is any. But I'll drain the float bowls and see what comes out if she starts. Balancing will be interesting too.

The bike won't rev quick, it's like slow to pick up and won't rev round the clock. There is something wrong with it somewhere and I've always felt it was electrical. I know it's a process of elimination, so one problem at a time.

[mollusc]

Strange that you had so much trouble getting an air filter.  There are several different options that seem to be readily available.
Yes, you do need to take the wheel off to get the airbox out, but that has been my experience with every bike of this style and era.  Most of the time there's no need to remove the thing so I don't see that as being a big deal.

There's definitely something wrong if the engine behaves as it does.  Even with a clogged air filter it should rev hard and strong when not under load.  Not sure how electrical issues could do what you're describing.

[ThePowster]

I thought maybe coils but I've changed those and it did make an improvement but didn't fix it.

Under the tank bolted to the frame is like a CDI box or something. Mine has like black tar coming out of the box all over the connectors hence me thinking electrical problems.

[mollusc]

Yeah, that doesn't sound good.  The electronics are normally sealed inside some kind of wax to help stop corrosion and vibration breakages, and yours may be leaking out.  I found a replacement on eBay many years ago; turned out that I didn't need it and I may still have it somewhere.

[ThePowster]

Thanks for that Mollusc.

Ok so I guess final update.

Today I managed to fit the carbs on the bike. It took some doing, especially the throttle cables but I got there eventually.

I got the bike outside and went to start it for the first time.

It wouldn't fire with the choke on, or the choke off.  But with the choke on fully and throttle pinned it fired right up. That's got to tell me something.

After a minute my brother noticed fuel gushing. It was coming out of the right hand side breather between the last 2 carbs on the right. 

Now the float bowls I got in the carb rebuild kit where white and they sat smaller than the original orange ones. So it could be the float bowls or maybe one is stuck.

I couldn't see any other problem with fuel leakage.

Clearly this wants setting up now but I have other issues. My battery terminal has snapped in 2 so I need a new battery as well as I have to relocate the battery too now and house it somewhere secure with a custom made battery box which I hope to 3D print in the coming weeks.

This has been a real pleasure and education into carburettors for me. I feel like I understand them a lot more now and the terminology of the parts and process.

The whole system looks great and I'm very pleased with what I've achieved.

Will it run? Hmm time will tell. I still need battery terminals, new battery and maybe swap the float bowls and one step at a time I hope I'll get answers, twiddle a few things and have her running better than ever before.

I also remember putting a rubber washer out my rebuild kit on the mixture screws because it seemed to fit, but I'm not even sure it should have one there. It didn't when I took mine out so that could explain a few things.

It'll probably be a few more months before I've done the mods necessary and had time fettling to see if I can have her running again. But I'll enjoy the tinkering process.

[mollusc]

There should have been a rubber o-ring and a tiny washer on each mixture screw.  They can often get stuck in the hole when you pull the screw out, and must be pulled out with a pick.
Look at assembly #5:  https://www.hondaparts-direct.com/oempartfinder#/Honda_Powersports/CB700SCA_(84)_NIGHTHAWK_S%2c_JPN%2c_VIN%23_JH2RC200-EM000011_TO_JH2RC200-EM011128/CARBURETOR_(COMPONENT_PARTS)/b7b6782b-0c61-41ac-8d9f-1e6e7c12b402/cc4dfadc-d20c-4cf9-88ce-8a0aa1bee9dd/y

There's the mixture screw, and mounted on it are a spring, a washer, and an o-ring, in that order.

[ThePowster]

Thanks for that.

Ah my terminology wrong..I think I put a rubber o-ring on the slow jet which didn't have one on when I took it out. But there was a recess for it so figured it was there for a reason.

This might have something to do with why it wouldn't idle and needed full throttle with full choke to start her up?

I think that o-ring was supposed to be used for the float bowls drain screw.

I've made a list of changes I've got to do.

1. Swap float bowls over
2. Clean float valve hole to make sure it doesn't snag.
3. Check parts diagram and remove rubber o-ring from slow jet screws if they not required.

[Pete in PA]

I used a paneling nail to pull my pilot screw O-rings out.

[mollusc]

No o-ring on the slow jet (part #26 on the diagram I linked above).
There should be an o-ring on the float chamber drain screw (#4, #10).