Throttle bogs at 55 mph...

Just got my 1994 xj600s running, changed oil and spark plugs and fixed the sidestand switch and now when i get it up to about 55 mph, it still has more throttle to go but when i pull back on it the bike starts sputtering like its overloaded. Any ideas?

 

Sounds like the fuel mixture is off. Any change to the intake or exhaust from the stock setup will cause it. If so it is time to re-jet the carbs. Is the air filter clean? Maybe time to clean the carbs also.

 

Clean carbs and New air filter sounds like a cheap, great place to start. Couple cans of carb cleaner and a few man hours and you could have a bike that runs like new

 

while working on it to get it running i had the carbs taken to a shop and cleaned and synchronized..bike idles at a nice 2k rpm..as far as I know, everything is stock. The air box wasn't correctly clamped to the top of the carbs before, and there is no air filter in the air box...still isn't....but i clamped the box correctly to the carbs along with checking to see if the new plugs had fouled and they were good too and went for another ride....bike runs and sounds good...but still bogs out in any gear at about 4-4.5 rpm and really won't go any faster than about 55 mph.

 

get an air filter it's getting to much air

 

Agreed with Bubba. That air filter "regulates" air flow going into your carbs. Get an UNI and you wont have to Re-jet your carbs. KandNs are high preformance filters, and a hassle if you dont wanna make your bike a Racer.
Your Idle shoud also be below 1500 RPM 1050 is spec i belive. 2k is idling high. Get an air filter, install, ride, and report back soldier
-SLKid

 

check you slides for free and even movement.

 

aight...thanks for the tips...i just ordered a Uni filter from bikebandit.com and it will take a couple days to get here. I will repost with results.

 

Okay, got the new Uni filter and oiled it...slid it down into the air box. Rode around a while to get her warmed up. Got on the highway, and still only goes about 60 mph at 4500 rpm. What gives?

 

You said it sputters - like not enough fuel? Could be float levels...

 

how do you check the float levels?

 

There are two methods. One, I've not done yet. Its a tube method... I cant remember the post off the top of my head.. and two is by actually pulling the carbs and removing the float bowls and measuring in MM what the levels are. While you've got the bowls off you should definatly clean your carbs if you havent done so. You'll like the results
-SLKid

http://www.xjbikes.com/Forums/viewtopic/t=15992.html
My post about float Levels. Bill guided me through it and it all made sense suddenly

 

Running the bike without a filter is no good, and will not allow you to tune correctly at ALL.

Get that idle changed... 2k is way too high.
1050RPM is spec, 1100 or 1150 is OK while you are getting it running right.

Sounds to me like something carb related, more likely than not it's the float levels or sticking slides.

Learn to do the carbs yourself, probably the most important thing to learn to do yourself on your bike.

Get the floats set right, and clean/polish your bores/slides. Clunk test them!

 

okay...I have installed filter...idle is now at about 1100 or so...i noticed today that it sputters in athe top end of all the gears....if i let off the throttle a bit it speeds up, but it bogs when at full throttle. I don't know squat bout carbs. I had sent them in to the local shop before and he cleaned the jets and snchronized them, because the carbs had been dipped before it was parked.

 

You are just a bit too far away for me to ride over and see if I can help. If you are going to be in the Dallas area any time soon except for this weekend and can trailer the bike, let me know.

One thing to do is a plug chop. Run it down the road pretty good, kill it while you are running it, and coast to a stop. Pull the plugs and keep track of what cylinder they came from. Shoot a pic and post it.

Go ahead and do a search on plug chop. It's more about patience than difficulty.

 

carbs need to be completely dismantled before dipping. otherwise it will eat your fuel tube orings, pilot screw oring, needle valve tip, bowl gasket, and throttle seals.

take the time and learn on here how to do it. its not that hard, just be patient, precise, organized and detailed.


did they have your carbs or the bike too? if just the carbs, they need to be resynced on the bike too.

 

Also- I missed when you said it sputters at the top of all gears, sounds to me like float levels are too low.

We can all walk you through the carbs.
First things first, get them off the bike.

Basically unscrew all the 8 clamps on the manifold side AND the intake boots.
Disconnect your choke/throttle linkages, and if your choke cable runs between the carbs you need to disconnect that too. Then pull your fuel line and vac line off.

Now the hard part - you need to carefully pop the intake boots (airfilter side INTO the airbox so they slide in and out of your way.
There is a groove on the edge of the boots, this needs to go into the airbox so that the skinny part of the intake boot slides into the box.

Once all 4 of those are off and your manifold clamps are loose, sit on the bike and wiggle left to right, pulling back. The rack will come off eventually!

 

Indeed! Its really really simple once you know how to do it. Its like a, "OH! Duh!" Moment. Gettin em back on is the tricky part. I like to use Silicone grease on the airbox boots (just a lil! and on the OUTSIDE of the metal on the carb, not in the boot) and my gfs hairdryer. Works like a charm.

 

This is because the government want's you to drive 55 mph. The best way to fix this problem is to play the song I CAN'T DRIVE 55 at least three times daily. See if that helps

 

SEE MY POST CLEANING YOUR CARBS !!!!!!!!!!

 

NEW UPDATE!!!

I went by to see the mechanic that worked on my carbs for me to ask him some questions. He said that there is no way that its the carbs and that it was either the fuel pump or the vacuum canister and wanted me to try riding it with the gas cap open to see if it fixed the problem. AND IT DID!!! So, if i remember correctly he said that if it did fix the problem that it means that the vacuum canister is bad....anyone know where i can get one for a 1994 XJ600S? or if it can possibly be bypassed all together?