A little help from my friends

Howdy all,
Long time lurker, first time post. I've got a 1982 XJ750 (Seca) that I purchased from an uncle for $700. She's my first highway fairing bike (the twinstar capped out at 62mph.) And she only has 11xxx miles! She'd been down before (then sat for 5 years after a police auction,) but after new right hand assembly, bars, plugs, brake pedal, drum + shoes, and throttle, she's been up and running. My fantastic uncle replaced the atari, did the wiring and got her started & running. So- first ride home (~60mi) I find out that she doesn't like to idle- no problem at 2k on, but sitting at 1000-1200, she idles erratically with half open choke. I get the same results at home- starting is a bitch (compression is there- it can be heard, and she runs fine over 2k,) and she wont idle without half choke. If I don't choke her out, then I sit at the stop lights sounding like a sixteen year old with a new toy (blip, blip, blip....) The plugs look pretty fouled from the first 400 miles I've put on her. Sure enough, the ol' starting fluid on the intake manifolds while running indicates a leak on three out of four manifolds.

So, I'm home from the Bering Sea and have through the 14th of Jan to make her happy. I'm thinking start with the fuel system since she sounds half-starved. Electrical might be an issue too, but I'll cross that bridge after the fuel system. I ordered carb kits, blanking tool, synchronizer, intake manis, feeler gauges, plastic shims, yada yada (thanks Chacal!) I'm waiting for things to arrive presently, but started the teardown of the carbs (HSC32.) I've found out that someone has been in here before- the drain screws are trashed (someone tightened them with a flathead. I tried heat, PB, and an extractor in one bolted to a 1x6, only to lose the extractor; the bowls are going to a local machine shop, and I already have new drain screws ordered.) There's plenty of questionable material in the bowls, and some scoring (from a flathead?) in the airbox side of the venturis, but the diaphragms are intact, the needles passed the clink test, and all of the jets have been clear, making quick and easy cleans. I did encounter a major oddity- all of my jets are bottomed out. They're screwed into maximum depth. I've been through the church of clean, and have skimmed through several carb rebuild posts, and this doesn't seem right to me. I'm hoping for some help from you all- perhaps someone could tell me which jets I'm supposed to back off, and how far I should back them off, prior to reassembly with the kit and bench synch.
Thanks guys!

 

None of the jets get backed off; they should all be fully seated. To adjust the idle mixture you need to adjust the idle mixture screws.

The idle mixture screws are on top of the carb body, next to the choke plungers. Yours may be hidden under blanking caps, which will have to be carefully drilled and pried out. Set the idle mixture screws to 2 1/2 turns out from a softly-seated starting point. That will get you very close to where the idle mixture needs to be (so close that you may not need to do any more adjustment).





Also note that this is the correct locations of the air jets. The photo in the shop manuals are incorrect.

 

k-moe member gave you a good advice, he's very knowledgeable. As for the three pictures he posted, I just feel the need to clarify that the "Do not attempt adjustment" advice below the first picture is a general recommendation in the owner's manual and doesn't apply to your specific case.

According to what you said about how the bike is acting and to what you described, your mixture screws are bottomed "in" and you should adjust them "out" as per k-moe's advice.

 

Thanks K-moe!

Also, your seca is looking very comfortable to me- might try to do something similar with mine. I appreciate the inspiration!

And thanks quebecois59!

 

You're welcome. The comfiest thing about mine is the seat (the bars really helped too). It's a Corbin that I got used (I would not buy from Corbin otherwise). The stock seat is a butt-burner after an hour. You might look into having yours reworked to provide a wider base and more support.

 

Welcome aboard.

Gary H.

 

Roger on the corbin- will do some looking. Have an old Maxim/goldwing seat that fits her, but don't care for it much, comfort wise nor for aesthetics. My scrawny butt was doing okay after a few hours, but I'm unsure that I'd want to ride her across country for comfort reasons.

Found out that all my idle mixture screws had particularly filthy tips and were backed out to 7-9 full turns. I was regretting the money spent on the carb kit initially, but will be glad to get new needles and gaskets in there after seeing some wear.

Thanks Gary!

 

Your enricher wells are probably clogged, and the pickup tubes... And the idle circuit---- you probably have to do the throttle shaft seals, and the fuel rail o-rings, too--

 

Does anyone know the screw specs for the float bowl plugs?

 

Len Chacal ( xj4ever) carries replacements

 

Hogfiddles, just received my replacements from chacal, but outsourced my float bowls to a friend. He's extracting/tapping for me, and I was hoping for measurements that he asked for.

 

Have home soak the screws in kroil. Give a few heat/cooling cycles to the screwsto get the kroil drawn in a bit. Screw the bowls to a board or clamp them in a vise. Drill a hole into the bolt for an easy-out. Tap the easy-out in til it gets a good bite. Put the torch to the bolt wall again and keep the heat going and keep the tension on the easy-out with a socket wrench. It'll eventually give. Ive yet to have one that didnt finally come out. But, if he DOES have to drill and tap, ask Len what the thread and pitch is.... Or since you already have them, check it yourself or give one to your mechanic-----

 

Will do- already tried the PB soak/heat & cool/bolt to a board- that's how I broke the first extractor and moved to outsourcing. Thanks man.

 

Ok

 

Alright guys, time to cut losses and head back north for work (tomorrow afternoon.) If I get time before then, I'll toss up pics of stripped screws, baked on manifolds, and valves that have been running too hot for too long. Turns out that all idle mixture screws were backed out from 8-13 turns, there was plenty of varnish in the bowls, and all valves were one or two sizes out of spec. Looks like someone has been through the bike before, and done a half-assed job (black and blue gasket maker both in the valve cover? Over-torqued/stripped bolts everywhere? A hole in the crank cover? Fuuuuuuck.....)

The Seca was coming along well- carbs, intake manifolds, and shims turned into a head gasket and a valve cover gasket when two of the manifold bolts sheared off. Cleaned the carbs out, received my carb kits from Poland (was trying to save/skimp a little- $80 on ebay vs $280 from Chacal? Easy decision- too bad that the carb kits turned out to be for an 11M bike- jets of weird sizes, felt uncomfortable using main needle as labeled in a different size on the information overload hour; really just used the gaskets and scrubbed the shit out of my jets that didn't seem that bad off. Lesson learned.) Got my gasket & 0-ring/crush washer kit from Chacal, got my head back from the machine shop today and started piecing her back together.

Everything was going swimmingly- I was just about ready to slap on the timing chain tensioner when, much to my chagrin, I found that turning the crank no longer rotates the timing chain. Surely, the chain can't be broken? There's still tension on it. Did I f*** up the chain tensioner insert? I'm still having trouble believing that three weeks of work and waiting and frustration have amounted to an inoperational bike. Sure, I scraped plenty of old, torn up, baked on gasket off of many surfaces, sure the head is now clean in and out, sure I'll be able to get the bolts off next time, but a non-op bike?!

When I come back in three months, will I have to pull the whole motor to fix the timing chain? Or can I just pull the valve cover, head, and cylinder jugs to get the timing chain back on the crank? While I'm at it, am I better off fueling up with stabil and putting fogging spray into the head, or should I just store her dry with some oil coating the tank? More fun, frustrating, beautiful work for this spring.

P.S.- She's getting named "porqueria;" a term I learned in Mexico that loosely translates to "bullshit." Comes from "por que," as in why, but is used as a label for a task, usually bequeathed by another. As in, he's always busy with these tasks I can't understand. As in my girlfriend asking, "Why are you doing all of this? Why not just buy a fully-functional bike to start with? You're in as much as a decent used bike would cost."

 

It's possible that when you had everything off, your cam chain slipped off the sprocket down in the engine. It's just a matter of working it up and down, along with side to side, and turning the crank just right, to get it back on. When it's on, you'll know....

Youll have to drop the cam sprockets out of the way....probably be easier in the long run just to pull the cams back off first--- Make sure your tensioner is loose, too....

In neutral w/o plugs, you'll be able to rotate the crank by hand just by pulling on the chain.

I doubt you broke the chain... You wouldn't be able to do that by accident just working on the engine. Unless you used a chain-breaker tool to actually pull a rivet and separate the chain.....