Idle too high

Hey All,

I've got an 83 xj650 Maxim. I have done all i really know how to do to get the idle down to a normal 1000-1500rmp. i have unscrewed teh actual idle knob behind the carb all the way out, I have taken out the carbs and synced them, just to the first one. I dont have a vacuum thing to do it the whole shebang and I've replaced all the carb boots on either side with brand new ones so there's no leaks getting in or out.

When i turn it on at first, i need the choke to be on full choke otherwise it wont start since the idle is so low. as it warms up driving around town it will idle perfect, right at about 1200. if i drive it down to work, about 20 miles away on the freeway, when i get off teh free way, the idle is way up around 3000. i got it to come down to that, as it was up around 4000 before i replaced teh boots and synced the carbs. any ideas?

thanks a bunch
scott

 

Sure. You haven't really sync'ed the carbs, and you need to accurately wet-set the float levels, get the valves in spec and then DO a running vacuum sync.

Provided the carbs are properly clean.

It won't idle correctly, especially when warm, if it's out of sync and/or the float levels aren't right.

 

Gotcha. thanks for the reply
i basically followed this guys idea:
http://www.youtube.com/watch?v=AS77T2CUsjI

how complicated is wet-setting the float levels? i would assume i need some sort of vacuum sync device that lets you do that, correct? Im pretty good with this stuff, but i've never done any of it before. thx

 

Wet setting requires a remote gas tank, about 10 beers, and LOTS of patience I'll see if I can find the link to Len's write up on this.

 

here ya go

http://www.xj4ever.com/setting%20fuel%20levels.pdf

 

make sure there are no air leaks as well. use a carb cleaner and mist it over the carb and runners between the carb and engine. if the idle spikes, find the leak and fix it.

 

The "vacuum sync device" is needed to do your running vacuum sync.

AFTER the valves are in spec. (And the floats wet-set.)

Valve clearances: http://xjbikes.com/Forums/viewtopic/t=14827.html
Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

The procedures shown are the same for all aircooled XJs; however the 1100 has different EXHAUST VALVE clearances: .21mm ~ .25mm.
The intakes are .11mm ~ .15mm, same as the other aircooled XJs.

 

Max's channel is full of good stuff.

AlFrumpus has a great summary with links of what should be done to these old bikes. I think even the most finicky of us (eyeballs: Fitz) agree that his sequencing is correct.

http://xjbikes.com/Forums/viewtopic/t=43470.html

 

Thanks so much guys! really appreciate all the help. I'll give you an update after i take on this endeavor.

Scott

 

scott im havn the exact same problem,,right down to the last detail. please keep us posted on how you fixd this problem, and i will let you know as well

 

Hey Davec, I haven't yet done any work with the vacuum sync stuff. Still need to buy one, but I'll post after I do.

Scott

 

This was actually written by schmuckaholic Credit where it is due!

 

DIY sync procedure by SLKid:

http://xjbikes.com/Forums/viewtopic/t=43947.html

 

Once again, I'll reprise a contribution written back in 2006.

You don't get the jiggies being able to SEE all 4 Carbs pulling the same Vacuum simultaneously.
You DO get the Carbs Vacuum Synced.
NO Mercury
NO Fluids
NO Bottles

You COULD buy 4 Vacuum GAUGES!
But, ... the truth is:
You only need ONE!

Since this article first appeared ... there have been refinements.
The Aquarium rig is a Big Plus. No-fuss switching.
China Marker to mark the Gauge Face.
Note: Without "Restrictors" the Gauge will fluctuate so wildly no accurate reading is possible.

Journey back to the days when Rock-'n-roll was invented, was listened too on a pocket-sized, Regency TR-1, transistor radio, broadcast from AM Radio stations, and the back-cover of The Weekly Reader featured the fantastic birth of affordable wheels to move you ... The Red and White Honda-50 for a paltry $249.00

http://xjbikes.com/Forums/viewtopic/t=2 ... gauge.html

 

Excuse me, Rick. "Jiggies"??? Is that a technical term? I can't find it in the service manual.