xj750j carb questions

Howdy! my name is Mitchell and im new to this website although i have come across it many times while google searching stuff while restoring my 82 xj750j, thanks to ya'll for all the posts!! Now i have finally got around to registering and getting in on the action!! And hopefully contributing also!!

i have a couple of questions currently about my carbs mainly. i noticed while checking float needles and height that it changes by a couple of MM's depending on which way you face the "legs" or "fingers" on the float needle, should this face toward the air intake (airbox) end of the carbs or the fuel/air (cylinder) exhaust end? Also i should note that someone has put a rebuild kit in my carbs and so i do believe they are aftermarket floats (i read your post on the three types of floats out there in kits lol very helpfull!!)

Secondly how many jet sizes should i go up when i put on a MAC 4-1 exhaust system, iv only done jetting on dirtbikes, usually you do 2 sizes with those but thats a 2 smoker with 1 cylinder so im assuming there is a difference with an inline 4.

So to get ya'll up to speed im almost done with a moderate restoration of my bike, here is a list of everything i have done this winter. Most of it was the front end due to my steering bearing blowing up but eventually she will get a total restoration! Also ill put up a couple of pics i took during the course of the process (no particular order)

New parts

Tapered steering bearing kit (bearings blew and when i finally shut the bike down for the winter the bolt on the top of the triple clamp that threads into the steering stem had worked halfway out in other words extremely dangerous! Used threadlock when reassembled lol!

Front forks completely disassembled (cleaned, rust sanded off one of the dampers, new seals, synthetic oil)

Sealed wheel bearings, new seals also.

Both calipers overhauled (cleaned, new seal kit, BTW K&L's kit isnt the best for these bike, only gives you the piston seals and a bleeder valve cap no grommets or other random rubber seals, ordered them from partzilla, very expensive lol but i love my yamahammer so she gets only the best)

Front pads (EBC kevlar) not on yet due to im using the old rotors still, the ones i will be getting are EBC pro-lites, not enough money for those yet lol

Rear shoes (EBC kevlar)

Barnett clutch kit (awesome kit!!!, lightweight friction plates, 3 of the barnett plates weigh as much as 1 new OEM plate!)

also got a used airbox cause i put a stress-crack in it while taking it out, (damn winter and my cold shop)

All fluids changed, other little odds and ends, general maintenance, like lubing, cleaning, random gaskets and seals. New bolts here and there, applied graphite grease to bolts that need it, i.e. carb to jug intake boot bolts, had 2 of these seized up applied threadlock to bolts that need it lol.

been a mechanic for over 7 years, worked on everything! and everything. if you want to know more about me and my experiences with bikes check out the "get to know ya" (or whatever it is lol) section, ill put some stuff there also.

 

Foolber,

Welcome to the club.

Gary

 

Welcome aboard. I didn't see new brake lines in your list. The originals had a 4-year recommended lifespan; they gotta go. Take the opportunity to upgrade to stainless lines, you won't be disappointed.

I'm assuming you had the valve cover off to check your clearances.

Re: gaskets: The valve cover gasket on YICS motors is dependent on the rubber/metal composite "donuts" on the hold down bolts to seal correctly. The bolts have stop collars that prevent overtightening, and those donuts are what actually push the cover against the gasket. Once they become permanently compressed and hardened, even a new gasket will leak.

 

Yea I havent got the new lines yet. And I usually go with stainless when I do them for sure.

Yes valves are checked and Jesus. But I did not replace those rubber grommets on the bolts. Is there a kit for those so I don't have to spend 500 ordering them each seperate? Ill check around eBay but post em if ya'll know.

 

Check out the link at the top right of every forum page

XJ 4ever

 

i found a set online for $25, but for hard to find parts ill deffinetly use his catalog, any ideas about this yet..?

 

so this is odd, im double checking my carbs before i put em back on and get the bike going after a major workover on her and i find this. either my haynes manual pic is wrong or the specifications page is...

the spec page says the main air jet is an 80, and the pilot air jet is a 225. but in this pic the "main air jet" look to me like a 225 not an 80...so basically what the heck is going on here...or am i just confusing myself.

 

The AIR Jets are "Opposite" from FUEL Jets.

FUEL Jets = Main - O - Large ::: Pilot - o - Small
AIR Jets = Main - o - Small ::: Pilot - O - Large



This photograph shows the CORRECT PLACEMENT of AIR Jets.
Certain Volumes of HAYNES Manuals have this important detail listed and depicted in error.

 

I though they meckered that one up....