Topic: Phaedrus: CB750 RestoMod - Update: 09/23/21 w/ new video

[Retro Rocket]

What about these,they are lots cheaper, anyone know much about them?

http://www.motorcyclecarbs.com/MIKUNI_RS_34_D21-K_CARBURETOR_P9791C702.cfm

Mick

[MCRider]

are the uni-syn tools still available? i've seen them in old car mag adverts. didn't think there was enough room to use it either. so, it works?

Yup:
http://www.minimania.com/web/Item/UNI-SYN/InvDetail.cfm

Gotta take the pods off, but Michrobis picture shows plenty of room.

Seeing as how I never synched them before, anything is better than nothing.

[MCRider]

What about these,they are lots cheaper, anyone know much about them?

http://www.motorcyclecarbs.com/MIKUNI_RS_34_D21-K_CARBURETOR_P9791C702.cfm

Mick

Those are cool too. THe difference being the TMR32s are actually shown on a CB750, which makes them WAY more valuable!      

PS: and powerful!

[michrobi]

are the uni-syn tools still available? i've seen them in old car mag adverts. didn't think there was enough room to use it either. so, it works?

Yeah it works okay. You don't want to keep the seal with the bike running any longer than you need to in order to get your reading. Gas builds up behind there quickly. I always toss a towel under the carbs when I sync them to catch the drippage. It takes some time to set the valve on the UNI to where you need it to get the right pressure needed to register a reading. Once you get it dialed in, it only takes about 2 seconds per carb to get the reading. gas is much less of an issue after the valve is setup right.

[MCRider]

are the uni-syn tools still available? i've seen them in old car mag adverts. didn't think there was enough room to use it either. so, it works?

Yeah it works okay. You don't want to keep the seal with the bike running any longer than you need to in order to get your reading. Gas builds up behind there quickly. I always toss a towel under the carbs when I sync them to catch the drippage. It takes some time to set the valve on the UNI to where you need it to get the right pressure needed to register a reading. Once you get it dialed in, it only takes about 2 seconds per carb to get the reading. gas is much less of an issue after the valve is setup right.

Thanks. My memory was I had to adjust the airscrew and main jets (112.5) and other than that they were sweet. With any luck they still are.

[Ecosse]

back when i first saw these advertised, in hand me down car mags fr: the 60's(?), i thought you had to have one for each carb.

thanks for the info all.

[MCRider]

Spent a lot of time this week on eBay trying to sell the cache of Suzuki parts from my late friend. His son and I will split the proceeds and the Phaedrus treasury can always use the help. Sales are slow, but I'll keep at it till they're all gone.

So today we concentrated on the carburettors. 29mm smoothbore Mikunis. Even though i used them for many years, I never really got into them. So we're learning a bit as we clean. First the mechanism that holds the tops of the slides is very complex. It would require the removal of several locked nuts to get the slides out to change the needle settings. I didn't need to before, so i hope not this time.


We took out all the brasses for cleaning. The float valve turned out to be a really cute piece. It has an attached screen filter, seen on the right in this out of focus picture, so no in-line filters for me.

I'm used to a main jet, screwed into an emulsion tube, a needle, a slow jet and an air bleed screw. These have an additional jet, I don't know which is which. These are the slow jets screwed in right beside the emulsion tube

Or are these  the slow jets which dip into a deep pocket in the float bowl.

The latter one resisted probing by pins, needles, electrical wires. Holes were too small. I finally found some 28 gauge steel wire at the hardware store which would go thru the small holes.
The prior jets were plugged so its good we pulled them and ran them thru with wires. The bodies were dunked in the sink with hot water to get the remaining soda out. Blow dry and I think alls well. I do have to replace one damaged float.

The carbs, the brake calipers, and the brake master cylinder are on the bench now. I'm trying to stay focused on them. Once they are complete and set aside, we'll get the engine back up on the bench.

[RAFster122s]

That looks a lot like the carbs on my CB550, those are Mikunis?

[CBJoe]

The small removable jets are the pilot jets....

http://www.allensperformance.co.uk/exp-vm29.html

Aren't the tubes in your last pictures part of the starting circuit?

Joe

[MCRider]

That looks a lot like the carbs on my CB550, those are Mikunis?

Yup, that's what they say on the sides.   

[MCRider]

The small removable jets are the pilot jets....

http://www.allensperformance.co.uk/exp-vm29.html

Aren't the tubes in your last pictures part of the starting circuit?

Joe

Thanks Joe: I'll accept that they are part of the starting circuit, as I don't know personally. Makes sense though, they are too far away from the action otherwise. The bike was always easy to start with very little choke.

That's a great diagram. I'ld like to get my hands on a manual of sorts. I've done some half hearted searches and not come up with anything.

[MCRider]

Found a manual here:  http://www.mikuni.com/pdf/vmmanual.pdf

And Z-1 has some interesting comments:

http://www.z1enterprises.com/reference/z1-carb-guide.aspx

Seems they (VM29) are good upgrades for Z1s and as they are no longer available, Z1 is interested in buying up used ones. Can't have mine. (I have 2 sets)

PS: I do understand that the newer flat slides and the CR Keihins are likely "better" carbs. I already own the VM29s and they have some provenance, so they'll do.

[Ecosse]

when you first asked about sync-ing i looked around, as i don't know about these carbs, and what little i found was virtually all on kawasaki forums and such, fwiw.

[MCRider]

when you first asked about sync-ing i looked around, as i don't know about these carbs, and what little i found was virtually all on kawasaki forums and such, fwiw.

Yes the VM29 was/is a popular upgrade for Z1s, from their stock 28mm. Not so much on CB750 as they are not AHRMA legal (I think) but for those of us who have them and the unobtanium rubber manifolds, they work well.

Actually DynoMan has the manifolds for about $160 and he's pretty proud of them. No carbs though.

[MCRider]

Bruce took the Sunday off to visit some relatives. Left to my own devices. Got up early and took the mighty FJR for a loop around I-465. About 58 miles. Gotta get my legs back under me, haven't ridden in so long. Taking a long weekend Aug20-22 to Marietta OH. On the Ohio river, borders W. VA. Do some quality riding. Should be a 1000 mile weekend, 600+ on 2 lane roads. Its an MSTA meet.  http://sporttouring.us/HOME/   I used to ride a lot with these guys. Got away from it while on the Phaedrus project. But i need to rejuvenate the spirit.

http://sporttouring.us/HOME/2010/07/mail-pouch-fly-by/

Dragging out the FJR gave me the impetus to drag them all out, and clean the cob webs literally. Blow out the debris in the shop. See Phaedrus in the daylight.




The poor neglected HawkGT:

Nearly one of a kind 5 Gal carbon Fibre tank, Corbin Seat, Ventura luggage system, F16 sport shield (not shown) gives a 250+mile range midsize sport tourer.

Futzed around with the fender. Got it to fit real nice, so that's a final for this iteration.

It may not be the FINAL fender, but for now, it fits, no interference, its sturdy and functional. On to the next thing.
Hit the brake lever with the sodablaster...nothing.

Whatever the black is on that lever it ain't coming off easily. Suggestions? I'm going for a wire brush on a drill next.
Got the replacement float and gaskets from Z1 Enterprises. Did a final once over on the carbs. Many of the jets were plugged and thick lacquer, but all clean now. They are almost back together.

eBay sales were real slow this week. Hope to get another 10-20 items on sale to build the treasury. I know I'll be needing something for the engine, though I think most parts have been bot. Maybe a 3M cam chain tensioner. I know I have new rollers, but they were bot back in 2000, so may be hard by now. Anyone know their shelf life?

Any left over money goes to the paint job.

[Ecosse]

glad to hear it ron. it's all about riding, after all.

i should follow your example.

[RAFster122s]

Brake lever is most likely anodized...to strip it an acid bath is needed...then can be clear anodized.

[MCRider]

Brake lever is most likely anodized...to strip it an acid bath is needed...then can be clear anodized.

Is that an acid that boys should play with? What? Paint stripper won't do it I take it. I've got some edges to become silver with aggressive sanding, but don't want to do that all over, really hard work.

[HondaNorway]

Try with oven cleaner foam. Let it soak in for a day. It sure removed the anodizing from the handlebar switches on my bike.

[MCRider]

Try with oven cleaner foam. Let it soak in for a day. It sure removed the anodizing from the handlebar switches on my bike.

I like it, will do!

[Terry in Australia]

Nice work Ron, it's looking good! Don't go buying any fancy new carbs either, your 29mm Mikuni smoothbores were the best carbs available "back in the day" (better than original Keihin CR's for street use) and 32 or 34mm carbs are way too big for a 750 or an 836 etc. I've got 32mm CV's on my gold K2 with it's 836cc F2 engine, but as you probably know, 32mm CV's only flow as well as a 28mm slide carb. If you want to sell your spare set of 29's, let me know, I'll use them on something, ha ha!



Here's a pic of my mocked up 1060cc engine with Mikuni 33mm smoothbores fitted, I bought these from a guy I know in the US, he had them on a Kawasaki ZRX1200, so I had an engineer friend (Ken, the original builder of my gold K2) "narrow" them to fit on my engine without the need for any fancy rubber manifolds, K8 or F2 manifolds (depending on which head you use) go straight on. I'm happy! Cheers, Terry.

[Ecosse]

god... that motor is making my trousers tight!


sorry about that, ron. 

[Terry in Australia]

Thanks Bill, I've gotta get off my arse and put that engine together, it'll be warm enough to ride my bikes again in a month or two! Cheers, Terry.

[CBJoe]

Terry,

That oil filter relocation setup is pretty freakin' slick..... I was just ogling the setup in TinTop's build thread. 

joe

[Terry in Australia]

Terry,

That oil filter relocation setup is pretty freakin' slick..... I was just ogling the setup in TinTop's build thread. 

joe

Thanks Joe!