some runability issues, but i might know why.....???

ok guys, i just need a little guidance and info on where i should go from here.

here is my story:

1982 650, traded for some quad parts sitting in my shed for years!!!

the condition i got it in was as if it were sitting in a shed for a few years as well. here is my problem i think..
the bike did not come with an airbox, the carbs were completely open. when i got it home, i wanted to know if i should work on it, or scrap it for parts, so i threw some ether in it, got it to fire up and run for about 30 seconds before shutting off. so i proceeded as follows:

remove the carbs, and COMPLETELY disassemble them, clean everything in the carbs, and cleaned the jets, then re-assemble and install back on the bike.

i had to start it with ether again, to get it running. i let it idle (high) for 15 minutes or so while watching for any leaks anywhere on the bike.

i discovered there is 2 broken header studs on the head,, on cylinder #3,

i DID have to jump start it as the battery is dead, so while i was idling it, it was running off its own power output, no battery.

today i put in a new battery on it, and got it to fire up without any ether, just messing with the choke.

after a while of idling and revving, while trying to adjust the idle, i cannot get it to idle low at all, only above ~1400-~1800 rpm's. so here is what i need to know:....

i need it to idle normal, and return to idle quickly as it should, and not "hang" around for a while before returning.

is it doing this because i do not have an airbox, and the carbs are open? or is there something else i need to look into?

the reason i am not thinking about buying an airbox YET is because they are not too cheap, i am considering building a pvc setup like some i have seen on here, and yes i can tune it for that. i am used to cv style carbs, i have them on my quads (mikuni).

i do plan on doing a bench sync before i do anything else, but i just need to know what the pros on here think about not having an airbox and the issues i am having, because,:

on my quad i have a cv carb and when i take off the intake, it does have a stumble, but will still rev "ok" and returns back to idle imideatly after i let off the throttle.

 

i should add in that when i do pull the choke in, it will race up very high, like 4k rpm's. so i have to just have it on barely when warming it up, after its warm, i shut it off and have to turn the idle up to about 1400 rpm's or else it will die, i really cant let it go below that.......yet.

 

this worked for me adleast for the application i was working on at the time take a shop rag double it up use a clamp or zip tie to hold it over the throat of the carb do all 4 i had a suzuki 850 i wanted to make sure the carbs were working right it wouldnt idle without the airbox just make sure the rag is secured well see how it idles. it just adds a little restriction to simulate an airbox

 

thanks a bunch cutlass!!!! i never thought of that!!!!! i will be sure to do it, thats exactly what i was looking for, something very easy and quick to check to see if it helps.... thanks!!!!!!!

 

you can bench sync the carbs. install and resync. OR
synce once since they are already mounted.

get your air filter setup first cuz you'll just have to resync if you do it before hand.

sync. put box on. you change the air flow dynamics and have to resync again.

 

I would keep an eye out for an air box. That shouldn't cost too much. The carb to air box boots may be harder to find. One member used fernco plumbing connectors and had good luck doing so.

MN

 

hey mn-maxims,

i can find them on e-bay for about ~$50.00 shipped, but its the box to carb boots like you said that are hard to get.

can you give me some more info on the "fernco" connectors?

 

just thinking about it too...... if i were to try anything else BUT a stock setup, it would cost more, because a darn jet kit is over 100!

 

the local dealership out here could still order them. $17 a peace though.

 

First question-- since the bike came to you with wide-open carbs, have you done a compression test to see whether or not you're spending a bunch of time and money trying to make a sour mill run? What shape is the motor actually in?

Next item; chacal (XJ4Ever, see banner upper right of this page) carries carb-to-airbox boots and I believe they will be cheaper than from Yamaha.

 

you know, i have not done a compression test yet, that is my next thing on the list to do... the weekend really flew by!

i just bid on a set of adapters on ebay, i will see if i get them, if not i will talk to chacal.

hopefully nothing will be wrong with the engine........ fingers crossed!

 

update***

i just tried that little trick said above, i took a CLEAN shop towell, and ziptied it around each carb, nice and snug. just to be sure i put two zipties per carb!

i fired it up, it started right up, completely cold, and idles good! still a little high, but it is not eratic and jumpy.

i just picked up an airbox, and am trying to get some adaptors from the airbox to the carbs, and i think i will be halfway there.

next on the list, i have to fix a broken exhaust stud.....or two on cylinder # 2. the idiots broke them, and "taped" it back together with some high temp tape.... gosh!!!

then i am going to do a compression test, and replace the spark plugs, then sync the carbs and report back on how she runs...

its already 100% better than when i got it. she was abused.... i am falling in love with this thing!!!