carb advice?

I've been all over this site and have been through a ton of carb cleaning/rebuilding/synching threads and through the XJ 4ever catalog. There is a ton of information regarding properly straitening out your carbs, but I'm looking for a bit of a starting point.

I'm getting ready to rebuild the carbs on an 82 or 83 XJ750 maxim. What I'm wondering is what are the typical "must replace" parts that I should order? I know there will be specific parts to my set of carbs (stripped screws, broken bits, etc.), but I wanted to get a good starting point.

I've been through the catalog and pretty much every part is recommended for replacement lol. Is there a basic kit available? If not just a starting parts list would be cool.

I know this is the millionth thread regarding carbs but everything is so spread out it's tough to get your bearings. I appreciate any advice. Thanks guys.

 

good starting point is to take pics,and make notes of your carbs,proceed with disassy,making sure u use proper techniques and DONT BREAK OR STRIP SCREWS, if possible, and consider every rubber part as a must replace item. a rebuild carb kit is the internal parts of the carb bowls,and every other part is a separate item. u CANNOT replace the fuel linkage seals without breaking the carbs apart,which if u gonna do it do it right.
THEN when u get it to completely disassembled u WILL KNOW what parts need to be replaced as evidence is usually present from rusty springs to worn out screws. the carb bowl drain screws are NOT a must replace item,and neither is any hardware unless u absolutely want to do it.
THE MOST IMPORTANT PART is cleanliness of the insides and polishing the diaphragm bores. Do Not forget to replace the enrichment circuit o-rings!!

 

If you are careful and lucky, you replace nothing. This includes the needle and the bowl gasket. However, once dismantled, you can compare the various parts to each other, since there are 4 of everything. You then can buy 4 of whatever from Chacal using the XJ 4 EVER catalog.

You have to break your carbs down first to know what you need.
You have to know what you are doing before you begin.
You have to work on carbs to learn how.
It's a "catch 22"

 

It's a "catch 22"


yes it certainly is. but the brave venture where the fearful do not tread.

 

I would say that it's always worthwhile to replace the pilot screw O-rings and to put some anti-seize on the bowl drain screws.

Personally, I tend to replace most O-rings I come across, since they're generally cheap enough that it's not worth taking a chance on a leak later.

I've heard that some of the carb kit float needles are pretty bad, so buy a set from a known source. If the carbs haven't been opened in a while, you'll probably have no choice but to replace the bowl gaskets.

When I had my last set out, I also went down to Ace Hardware and got some stainless allen screws for the bowls. That made it easier to remove bowls while on the bike in case the float level needed to be adjusted.

If you're going to be disassembling all four carbs at once, definitely take a lot of pictures and use some parts bins or zip-loc bags to keep the parts separated. Make sure to identify clearly where the different jets came from because it is possible to screw an air jet into a main jet hole.

By the way, the silcone grease Chacal mentions should be available in the plumbing departement of any hardware store. Most auto parts stores won't know what it is, nor carry it.

Good luck with it.

Cheers,
Paul

 

The first thing to do, is determine if they really need rebuilt. Why are you attempting to rebuild them?

Next, is to carefully disassemble the carbs. Making note of where everything goes and keep the individual parts seperated so as to remain with their respective carb body.

Then clean and inspect everything and determine what needs replaced. There is no magic set of parts to get in advance, except for maybe float bowl gaskets.

Oh yeah, don't go replacing every rubber part unless you want to spend about $800 on your carbs. (Sorry Josh)

 

BDM the rubber o-rings IF u replaced every single one o them would cost u 60 bucks TOPS. sorry BDM maybe u should investigate and find out truth before posting. i have searched every detail associated with these carbs for 2 months BEFORE i broke mine down. my parts order list included new pilot jets (kids playin in garage knocked over my muffin tin and these DISAPPEARED) and my total cost with ALL NEW seals(o-rings,throttle shaft seals and new rebuild kits @ 30 bucks each that i already had) was 226.67. thats new o-rings for enrichment,idle mixture,fuel linkage, and throttle shaft. the rebuild kits other than anew gasket and needle seat and needle is a luxury item really may not be necessary,other than gasket. the rubber diaphragms are not a MUST HAVE unless the ones u have are damaged,and unrepairable. THAT is the only rubber item i DID NOT replace.
SORRY BDM

 

I suggest you take a chill pill and make sure of what you are posting then. You stated all the rubber parts. In addition to all the o-rings and various seals, the diaphrams are rubber and you can't buy them seperately. Those alone are over $100 a piece. Granted, it was a slight exaggeration to say it would cost $800. But you were not clear in what you were saying, and most of the advice you have given on this board has been quite shaky at best. You are like a kid that just wants to get the first word in, whether it is right or not.

I recommend you slow down and do some research, or at least know somewhat of what you are talking about before arbitrarily posting advice which either isn't accurate or doesn't pertain to the problem at hand.

I stand by my earlier post. You are the one who is lacking here.

 

this isnt a pissin contest dude. reality check. u can stick by anything u want,but i am in the middle of this project and the carbs are awaiting the new seals now. other than THAT i do know what i stated and i DO KNOW what i said......
the diaphragms piston assy's are 254 each complete assemblies. and the rubber diaphragms are replaceable ALONE.
Check your local parts supplier and see for yourself. for the sake one item u get all defensive as if i just stole your girlfriend.
REALITY CHECK,Brain function test, and a healthy dose of MANNERS are all beneficial items BEFORE YOU engage the lips.

 

Don't get mad because you post stupid advice and got called on it.

 

geez pathetic

 

I have returned from being away at my daughters wedding.

If you have a Diaphragm thats ruined ... you can get a very inexpensive set of used Carbs and take the best one.

 

then congratulations are in order,well wishes amd welcome back. we sure missed ya buddy

 

As Requested by BDM:
http://xjbikes.com/Forums/viewtopic/t=2 ... n+own.html
http://www.xjbikes.com/Forums/viewtopic/t=14692.html
http://www.drpiston.com/hitachicarbs.html
http://www.factorypro.com/tech_tuning_p ... gines.html
http://www.motorcyclecarbs.com/
http://www.xjbikes.com/Forums/viewtopic ... rt=15.html
http://www.xjbikes.com/Forums/viewtopic/t=1961.html
http://xjbikes.com/Forums/viewtopic/t=8588/
http://xjbikes.com/Forums/viewtopic/t=17449.html
http://xjbikes.com/Forums/viewtopic/t=6366.html
http://www.youtube.com/watch?v=CYgN2-96 ... re=related
http://www.youtube.com/watch?v=tR63vrfh ... re=related
http://www.timesert.com/html/bigsert.html
http://www.xjbikes.com/Forums/viewtopic ... tml#179570
http://www.xjbikes.com/Forums/viewtopic/t=1640.html
http://www.kanolabs.com/google/
http://kzrider.com/index.php?option=com ... &id=324523
http://mok.fileave.com/HitachiCarbBreakdown.pdf
that is my research project MR BDM anytime u wish just ask i will help u as well.

 

Thanks for all the great advice guys. The problem I'm having is some people are saying to wait to order parts because then I'll only order what I need and other things I've read say have as many parts you think you'll need available so things can progress forward.

While everything everyone posted is very helpful, I really was wondering from experienced carb rebuilders what are the typical problem parts/gaskets/ o-rings that absolutely MUST be replaced. I understand that until the carbs are apart there is no way of telling what needs to be done but as an example I'm a carpenter. Before I rip open a wall to fix a problem I always have the things to at least seal it up on the truck. A couple studs, a small piece of drywall, drywall screws etc are always stocked on the truck and ready to go. I suppose what I'm wondering is what are the carb rebuilding equivalent?

So far I'm gonna order a haynes manual, throttle shaft v-seals, and probably an assorted o-ring kit. I suppose I'll wait on the float bowl gaskets as someone pointed out that sometimes they aren't in bad shape. I gotta order the manual anyway to get started so I figure I'd order up whatever you guys recommend to get started.

Thanks again for all the excellent advice from everyone.

 

Do you fight with everyone, dude? Your posts are nearly illiterate and you like trolling and name calling more than answering specific questions. Nearly 300 posts in 2 months... I believe we'd all appreciate it if you would settle down, type and communicate more clearly and stop calling people pathetic.

 

I'm sure we all know exactly where you are coming from. And my earlier recommendation stands. Get a set of float bowl gaskets to be on the safe side, as they can become stuck and you may damage them getting the bowls off. Nothing else is a must replace item.

Disassemble, clean, inspect, then make a decision. I think you will find you have saved yourself a lot of money that way. The wait is going to suck if you do you need new parts, but the chances are quite good that you won't.

Also, be careful with an assorted o-ring kit. You have to make sure the o-rings are fuel resistant.

 

This is the best advice...also to consider: if you order from chacal, the parts are there in 3 days flat in most cases. You aren't going to be stuck with carbs split open for very long once you do get them open and see what you need.

I think the job of this forum isn't to write our advice like a service manual. "Replace everything" is what I'd expect to see from a Yamaha written product. It isn't what I expect to see from a forum of guys fixing up old school 80s bikes on a budget. There's a reason we all don't ride the newest and most perfect... so why act like it?

Diagnose and repair... that's what we do here. You shouldn't ever throw parts at a bike blindly. It will take everything in your wallet and more.

"If it ain't broke, don't fix it!"

 

On the O-rings, most auto parts stores stock a pretty decent variety of fuel-resistant O-rings. When I redid my BS34's recently, I just went up to the local Checker (aka Shucks, Kragen, or O'Reily) with the three sizes of O-rings I'd pulled out of them. They had all three sizes in stock, under the O-Tite brand. Ran about $4 for all of the O-rings.

Note that here I am talking about proper O-rings, not the throttle shaft seals, which are not O-rings and will almost definitely not be available from auto parts stores.

 

Thats what I like to hear lol.

 

I would suggest to use VITON O-rings. O-rings work well as soon as they are the right size but if you choose Viton they last forever. That is why Harleys have so much problem with O-orings because they use neopprene and that does not resist gas well. Yamaha and other Japanese bikes ususally use Viton that's why they last forever. I went to a specialized store where the only thing they have O-rings and they gave me all the orings for free. Otherwise I would it have to pay $1.25

My .02

 

Float Kits come with a Gasket and a Mixture Screw O-ring.
Remove Emulsion Tubes for thorough Cleaning.
Scrub or Polish Diaphragm Bores
Fuel Bowl Ports.
Flush Passages.

Go nuts.
Sonic Cleaning
Media Blasting and finishing.

 

my advice? Go to a friendly nieghborhood dealership and buy a fuel injected bike and go out and ride while the weather is still nice. I say this as i am looking at my carb rack trying to remember which jets go where- got my carb parts order from Chacal today.

 

ONLY A FEW MINUTES LATER: i just dropped my carb rack and BENT the little brass pipe coming out of the bottom of one of my carb bodies....UUUUGGGGHHHH! i screamed in a way that may lead my neighbors to believe that i am dangerous in ways that i am not. I have bent it back but now it has a hairline crack!

I stand by my previous statement about fuel-injected bikes.

 

LOL. I was a hair away from buying a brand new FZ1 myself a few weeks ago. But not as a replacement, only as a supplement to the Maxim. I wound up with a 2002 model instead. You can't beat $3100 and $98 a year in insurance for a bike that requires much less attention.

But when it comes to working on anything mechanical, you have to make sure you set aside the time, and that you have the dedicated work space to do it right. Otherwise, you are just going to wind up flustered.

 

i do not mean to steal this thread, but.....since the title is accurate i will go ahead. Now that i am putting things back together, the rubber diaphrams don't want to stay put in thier rings while i fit the carb "hats". any ideas how to make them do so?

 

well dont know what good an ASSORTMENT of o-rings will do for you but hey its your money. You need to be very specific as there are only 3 different sizes of o-rings inthe carb itself. one size for the fuel linkage rods,one size for the enrichment circuit plunger and one size for the idle mixture screw. All of these o-rings are on the site catalogue in the carb section and are very specifically sized for your needs,not a hodgepodge of MAYBE i can use these....gets extras sure they are cheap enough in to do that if u wish to. other than those items and the retaining washer inside the enrichment circuit plunger as recommended replacement the rest u can put back as cleaned used parts cause unless the springs are rusted to cr** u can reuse them,as well as all the screws but many folks recommend changing the bowl screws to allen head for ease of changing to adjust the float height afterwards. a new carb rebuild kit has a new needle,needle seat and retaining hanger with a gasket in the kit. REMEMBER i told u to get the ones with the replacement screens as your BEST OPTION at a very small diff in price. a gasket alone is an option if u wish to proceed that way,but chacal has the OEM kits with OEM needles and as noted in the aftermarket ones the needles tend to run 1 mm larger,so its your call what u wanna do.
IF you MUST have these items then get them. If your carbs are not all that dirty then get them in advance,if they are very dirty then a 3 day carb dip would be an option to help clean out the gunk. i had one carb bowl that had something in it and i soaked it 4 days and i got the enrichment hole opened up properly,no idea what was stoppin it up but something was and 1 day in the dip did NOTHING. also ANY rubber or plastic item CANNOT be dipped or it will be ruined. (o-rings,end plastic washers onthe throttle shaft,etc...)
In my humble opinion that is about all u will need for a successful rebuild. GOOD LUCK

 

SILICONE GREASE, NOT petroleum based as the petro mizture breaks down the rubber. silicone grese is available at any hardware plumbing supp;y section.dont bother your aotu parts guy unless u want silicone spray lube which will not help u.....

 

NAPA sells silicone grease. And you can use petroleum grease on your carb parts despite what many people say. I have always used regular old Vaseline and have not had to replace any of the rubber on my carbs due to breakdown. And I have had them apart for cleaning about five times since I bought the bike in 1998. It seems like every time I get a new bike, the Maxim gets neglected and I wind up having to clean it back up again.

If you think about, all the rubber on your carbs are fuel resistant, even if they are not directly immersed in fuel because they are still exposed to fuel or fuel vapors in some way. Fuel and petroleum grease come from the same place. So to say that you can't put pet on carb parts seems kind of silly.

I also worked on helicopters in the Marine Corps, and the maintenance instruction manuals also called for pet when installing seals and o-rings.

 

thats me silly me always silly from the silly farm silly as can be silly silly sillly

 

I get the Diaphragm Rubbers to stay-put by smearing the locating channel with Waterproof Synthetic Grease.
Just enough to hold it Rubber in place while the Hat goes on.

Straighten-out the Brass Siphon Tube.
Use Needle-nose to "round" the tube again.
Slip a short length of Brass Tubing you can get at a Hobby Shop ... down, over the kinked and split area ... and "Sweat" the Brass Sleeve on the broken tube.

 

Gee guess that 3 day carb dip is a GOOD IDEA THEN??? And some cheap o-rings?or better quality viton? yeah thats breakin the bank for sure.

 

The O-rings for the Pilot Mixture Screws come with the Carb Kit.
You also get a New Gasket.

If this is your first time tackling a Carb Cleaning Job, ... just Clean the Carbs and components without breaking the rack.

After you get YOUR Carbs Cleaned and ret-tuned; buy a "Parts Carbs" off eBay and PRACTICE the moves and learn the small-parts placement needed to split the rack and replace Throttle Seals.

Unless they are filthy with varnish they shouldn't NEED 3-days dipped.
Overnight in a safety dip that won't dissolve the Seals is fine.
The actual cleaning is not performed by the dip.
The dip loosens foreign matter for you to scrape or spray-off.

 

Just wanted to add that the little hole in the side needs to be solder-free, as this is an emulsion tube, and if you didn't fix it, or if the tube is blocked, then your bike would still cold-start on 3 CYL.

It's obvious that the "O" rings are fuel proof and that dime-store "O" rings are a recipe for disaster. Hey, and how about some brand new fuel line and a paper filter !

 

This is exactly what I was looking for.

 

I'm glad you found what you were looking for, but you don't "NEED" any of that stuff unless you find it bad.