Carb bowl drain screw ports (single or dual)

Carb bowl drain screw ports (single or dual)

So Hog fiddles and I were talking about the differences in the float bowl castings, one drain port VS dual, See the photo of the single port bowl. Anyone have details on this design change?

On the net I found a reference to the single port bowl being on a 1983 Seca 750.

Hog fiddles found a Seca from craigs list that has this single port bowl on one of the carburetors with the other three having the dual drain screw ports in the bowl castings. This oddity sparked the conversation.



FlyGp

 

It wouldn't necessarily have been Yamaha's change; Hitachi could have done it to save on production costs.

That being said, Yamaha also changed stuff a lot; and quite often never changed the part number. There are no less than THREE DIFFERENT clutch covers for the 550/600s; and the part number never changed. The shape of the cover did, noticeably, but not the part number.

And 1981 Seca 550 wheels are slightly different than 1983 Seca 550 wheels. Different enough that if you know what you're looking for you can spot it in the ad and brochure photos. Same part numbers.

If you want to really have some fun, collect a bunch of brake calipers from the same model XJs. Then compare them VERY closely. You'll find that some of them either came from different vendor subcontractors or different production facilities. Yamaha didn't make everything in-house. And it doesn't all EXACTLY match, even the "same" parts.

Fun, huh?

 

That sounds like Ford. Ford did that for years and even now.did these bikes cone in half year out quarter years.if they did that would say it all.. that will explain very little change but same p# if they really did do what I think some times you wont find out till you do a complete Vin and DCr to it (DCr date code read )

 

We've also noticed that the single-port Hitachi bowls start with the 1983 model year bikes/carbs. Have never seen an original mis-matched set of bowls on an original rack, although after 30+ years who is to know?

All of the HSC3 series (XJ750RL, XJ700's, etc.) which are 1984-later bikes come with the single-port bowls.

It may be that after original production and parts inventory of the double-port bowls was exhausted, that the single-port bowls were then sold under the same part numbers.

For most manufacturers, replacement part sales are a large profit source for them, and "it fits/works" is much more important to them rather than "it's identical to original"...........

 

Hey all.....gotta make a slight correction here--
the carb rack that I'm restoring right now was removed from my 82 xj650rj seca. All four bowls are the same as Fly showed you....my description to him got lost in my describing. This bike came with two extra racks.....and this particular rack is the 3rd rack I've done within 4 months. SO.......this bowl is the same for all 4 carbs on the bike BUT all of the other racks have the Other type of bowl.
HOpe that helps clear it up.....I think I may have just confused myself, since it's getting late.

Fly....THANKS for posting the pic for me! That didn't come out to bad considering it was a cellphone pic!

Len, I can post the numbers etched onto the bowl bottom if that would help....


Dave F

 

Hey Dave, post those numero's............!

 

Weill do that tonight when I get home!

dave F

 

Len, here's what the bowls have on them:

HSC32-1A
5V2 00
11229

casting on the flange by one of the bolt holes says "C-1"

Dave Fox

 

The 5V200 carbs are for the 1982 XJ650RJ Seca. Those carbs "should" also use the coarse-threaded version of the pilot (mixture) screw.

So I guess it's safe to say that the single-outlet version bowl was used on at least some 1982 models..............

The "HSC32-1A" obviously refers to the series/size (32) of these Hitachi (HSC) carbs. I'm unclear on what the "-1A" refers to.

5V2 00 is the model of the bike (5V2 = 1982 XJ650R Seca model), and although I'm not sure, I believe the "11229" may be some type of date code indicating the exact day/date that the carbs were assembled.

The "C-1" inside the bowl is probably a casting mold ID number, so that the castings coming out of each unique mold could be tracked for QC issues, etc. You could also see C-2, C-3, C-4, etc.


BTW, Mikuni bowls are not marked. The Mikuni carbs get a similar type of ink stamp on one of the end carbs, on the face looking "outward" (so it can be seen while the carbs are on the bike).

 

Do you have a hair dyer? Can you boil water? Get outside the box and heat those puppies up If all else fails mail them bad boys to me and I will fix em up for ya

 

My 650 Seca, which to the best of my knowledge has never had its carbs off or apart, has single-outlet bowls.

 

That's good to hear.....so I can assume that the carbs are the original carbs.

Update on the rack now is: The only things still connected to anything are the linkages. Everything else except the bodies has been cleaned, and the bodies are starting tonight. For as nasty as this rack was, it's actually cleaning up nicely and nothing has broken or been frozen except for one drain screw which has a stripped head--a drill and an easy-out got it out quickly.

Len, can you confirm for the jet sizes for me:

Current parts:

main - 110
idle- 40
airjets under diaphragm - 50 and 195
airjets in throat - both 36

Looks like I'm going to have to order a set of throttle shaft seals, fuel rail o-rings, and mixture screw o-rings, and enricher plunger rubber covers.

Do you carry replacement carb chrome covers?

Dave f