Diaphram question

nudude53 · Posted: May 25, 2009, 11:05 pm Post subject: Diaphram question

I just rebuilt an old set of BS38 carbs for my '73 TX restore project, although it will be awhile before it will be running I need to address this problem now. After checking the diaphrams for holes (they are in excellent shape) and installing them one of the slides drops too fast when I do the drop test with my finger over the oblong pressure hole on the intake port. I put a light coat of grease in the groove where the rubber seats before I put the tops back on the carbs and it still drops too fast, the other one will hold nearly still. I do have an extra diaphram I can install but it may be something simple that I overlooked and can be fixed without tearing into the carb again. What's wrong?

xsjohn · Posted: May 25, 2009, 11:12 pm Post subject: Re: Diaphram question

My sons XJ650 did that just recently after rebuilding the carbs.......some extra fine steel wool on the slides to make sure they were smooth and a bit down in the carb bore fixed that.....the slides were slightly sticking........

xsjohn

nudude53 · Posted: May 25, 2009, 11:16 pm Post subject: Re: Diaphram question

Do you think that some air is leaking past the slide along the bore and allowing it to fall? I did put a thin film of WD-40 on it when I reassembled it but didn't think to dress the bore. I also used your Q-tip trick on the needle and seat.

xsjohn · Posted: May 25, 2009, 11:24 pm Post subject: Re: Diaphram question

Did bothof the slide rubbers feel the same.......was one maybe stiffer than the other.......cleaned a set of carbs just a couple of months ago and one was more supple than the other and it did move faster......

trya bit of steel wool lightly on the bore to maybe catch a burr and the sides of the slides.......and see if both rubbers feel the same........then run it......may not be a problem.....

and grease down in the bore could slow the slide......till it got sucked out...

xsjohn

nudude53 · Posted: May 25, 2009, 11:29 pm Post subject: Re: Diaphram question

Ok John, will do, mucho gracias.

xsjohn · Posted: May 25, 2009, 11:36 pm Post subject: Re: Diaphram question

Oh...my sons CV carbs....XJ650.....about the same as XS CV's....the thing had been setting a long time.....where the slides go in the bore there was a bit of corrosion and just a film of dried fuel......that's when the steel wool did it's thing....and again the slides had that film of dried fuel.....and the needles go into the needle jets and the thick part enters the needle jet when the slide is all the way down....any dried fuel at the opening or anywhere on the needle jet can be a problem....

xsjohn

nudude53 · Posted: May 25, 2009, 11:40 pm Post subject: Re: Diaphram question

The rubber seemed to be the same on both carbs, but the PO had rebuilt one of the carbs with the wrong kit. It had a choke gasket on it and a later model needle. There's no telling why he did that until I can fire it up and see if it syncs out right. I'll just dive back into it and try the bore cleaning trick for now and see if that works.

xsjohn · Posted: May 25, 2009, 11:43 pm Post subject: Re: Diaphram question

Most PO's should be hung and then beaten ....... Laughing

Oops are we going to be PO's someday.......... Shocked

xsjohn

nudude53 · Posted: May 25, 2009, 11:52 pm Post subject: Re: Diaphram question

Yea, this bike had sat for who knows how long too. I bought it a year ago and just now got around to working on it. There was lots of dried mystery gunk in the carbs but a good soaking in Simple Green and some aerosol carb cleaner fixed that. I run Sea Foam in my other bikes and it keeps everything pretty clean and slick, but I still had to get into the carbs on my other TX after it sat thru the winter and clean them up. It'a amazing what will grow in them when they're not running, I could have entered them as a science project, along with some of the stuff from my refrigerator!

nudude53 · Posted: May 26, 2009, 12:05 am Post subject: Re: Diaphram question

It will please me to know that someone will have something to bitch about after I shoot 7, unfortunately my brother has dibs on all my worldly toys, but that's ok, he knows how to hide a body.

xsjohn · Posted: May 26, 2009, 12:20 am Post subject: Re: Diaphram question

2012 is soon anyway.........hopefully mine will get me there........then the great unwashed can paw over my spare parts ......if my son hasn't already done that by then..... Smile

Hey Akmed ...look over here....... Shocked

xsjohn

nudude53 · Posted: May 26, 2009, 12:27 am Post subject: Re: Diaphram question

Not soon enough for me, 4 more years, geeeeeeeeez. Alamance county is running low on ammo, save your old steering neck balls and spring for a good wrist rocket. The North Koreans won't have a chance againts the good ol' boys, niether will Akmed.

xsjohn · Posted: May 26, 2009, 12:30 am Post subject: Re: Diaphram question

I stocked when Bill wandered in...........

Check some of the PDF on this site.....we may all be terrorists.......

www.firenapolitano.com/

nudude53 · Posted: May 26, 2009, 1:29 am Post subject: Re: Diaphram question

I loaded up too when Slick Willie was in charge but lost all the good stuff in a fire a few years back, all that's left is a Ruger 10-22. Turned my attention towards the TX that the roof fell in on and got hooked when I got a face full of hot, fresh buzzard crap while riding it to Asheboro a couple of years ago. Now I'm obsessed in a psychotic sort of way, not to be outdone buy the folks on those pdf. lists though. But why stop at Fat Janet, don't they all need to hang out at the Waffle House and learn about reality while they comb the want-ads looking for something they need that's not there? After all, it's their outlook on diversity that has helped us into this mess. I was too busy working for the last 44 years to pay attention to what they were doing, only to be complicated by having to try to learn Spanish for the last 20 years so that I could communicate with who ever the good folks in Human Resources shoved down my throat in their efforts to fulfill the EOE requirements. Quanity not quality is the only method now acknowledged in meeting the deadlines imposed to the lowest bidder. Keep that in the back of your mind the next time your riding across that new bridge with your wrist rocket and a pocket full of neck balls.

In the mean time I'll just worry about my carbs and keeping a full belly in my mongoose.

nudude53 · Posted: May 29, 2009, 12:21 am Post subject: Re: Diaphram question

Ok John, I cleaned up the bore with steel wool as you suggested, replaced the slide and no change, still drops faster than the other side (which barely moves at all). Then replaced it with a good spare slide that I had stashed away and still the same problem. So, could the bore be worn enough to let air sneak past the slide or should I look for another leak elsewhere? It surely won't work in sync with the other side once the bike is running.

xsjohn · Posted: May 29, 2009, 12:30 am Post subject: Re: Diaphram question

Did you swap ths slides one side to the other............also have to consider that you coud be pretty much screwed.... all in fun.... Laughing

xsjohn

nudude53 · Posted: May 29, 2009, 12:34 am Post subject: Re: Diaphram question

Nope, haven't tried that yet. Was waiting for an answer from the almighty Guru.

xsjohn · Posted: May 29, 2009, 12:40 am Post subject: Re: Diaphram question

No guru here...just have been there and done that.....and more to come for me like everyone else I'm afraid.......but god my 8-1 with the ole BS34's set right are a fricken welcome change from what I have had delt with for the last 10 years....the farther you run it now the better it runs....just the opposite from square one.......I ain't shittin........

xsjohn......

nudude53 · Posted: May 29, 2009, 12:50 am Post subject: Re: Diaphram question

Well I'm trying to stay true to the year with the carbs as well as everything else on the bike, but I do have a set of 38's from a 75 that I could put kits in try out. My brothers 75 runs smooth and sweet and starts easy when cold which I attribute to his carbs, so I bought a back-up set to have on hand. But my thinking is that switching the slides and/or replacing one would be pretty much along the same line, and by replacing one and not solving the problem leads me to believe there is an air leak somewhere. Now I just need to pinpoint it or discover what the real problem is unless you have any other suggestions on where to look next.

xsjohn · Posted: May 29, 2009, 1:01 am Post subject: Re: Diaphram question

Man try another set of carbs......all the years I have had good ones and bad ones....some I could make work and others I couldn't to please me....from me ...I would recommend staying with the conventional CV's....others might give other advice that might work too....had a set of BS34's with a bad right....and another with a bad left.......spent a lot of time on both to no avail....and the same story with the BS38's.....some things work...some don't............and don't try to make a hotrod out of it....ain't worth it....there are things these do well but that ain't one of them...at least for long run...........

If I could only explain what I have learned about these things ....but I can't....everyone has to get off the more more more thing before they could ever begin to understand.....

y personal opinin if anyone cares.....compression too high causes it to run too hot for the tiny puny cylinders to disapate the heat ...farther you ride the crappier it gets and timing too advanced....runs to cranky at lower usable rpms because of this.....total piece of crap set up factory with the low gears that scream it to death....but what would I know.....that's why they are availabe cause no one could stand to ride them and let them rot..........put them back stock and begin the crap all over again.........no bull s*** there....... Laughing

xsjohn

nudude53 · Posted: May 29, 2009, 1:27 am Post subject: Re: Diaphram question

Not to worry, no hot rod here, just a brochure picture bike if at all possible. I'll leave the sawzall work to the young bucks that are trying to build something different so that they look like everybody else. But I'll take your advice on the carbs, I like the way the CV's work and would prefer to spend the time to get them right and put the fancy carb money into something else, like a stock exhaust and good tires. Now, if I could only figure out what kind of tatoo to get....... Rolling Eyes

xsjohn · Posted: May 29, 2009, 1:29 am Post subject: Re: Diaphram question

Man I sure ain't straight out of the book.......couldn't get one exit on mine that way 11 years ago without mental collapse.......

what a fricken mess....gears compression timing and carbs being right....stock sucks ...the hotter it gets the crappier it runs..how are we going to go anywhere that way.....posted near 5000 posts to help eleviate that ....what the hell............8-1 fixed all my woes.... Laughing

xsjohn

nudude53 · Posted: May 29, 2009, 1:44 am Post subject: Re: Diaphram question

I'm not that far along with it yet John, everything is pretty much a dry fit right now while I clean, paint, polish and gather all of the stuff that I need to finish it. Then once it's road worthy I'll start the final tweeking, taller gearing is definitely on the menu along with a newer type master cylinder and improved lighting. I've got a rider that's just about the way I want it now (gallery pics), this one is the bike that I picked up for spare parts, but I just couldn't bring myself to canabilizing it so out of boredom and greed decided to restore it. It may not set the woods on fire but it will be the newest '73 in the Piedmont.

xsjohn · Posted: May 29, 2009, 2:05 am Post subject: Re: Diaphram question

Nearing 70 thousand on this one........can't think of anything I don't know about these engines after 40 years of this.... as far as chopping a bobbing I get bored fast......

xsjohn

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