problem staying running

[Guest]

I finally got my 81 450 fully asswmbled. In order to get it running i have to have the chock on. The rpms will jump to about 5k and then go back down to about 2-3. As the bike runs for a few i can come off the chock a little bit but the bike will adventally stall out. Im thinkink maybe the carbs need to be synced? Any ideas

[BigD_83]

I am sure a carb synch would not hurt, but it sounds like your slow speed circuit is not performing the way it should.

Other than dying out, do the revs settle out lower than 2-3000rpm?

What work did you do on the carbs/motor when your motorcycle was apart? You have been on the forum for awhile;how far down the basic maintenance list have you gone?

[lorello]

When i bought the bike the guy was in the process of putting it back together just had the carbs engin gas tank n the speedometer on it. The electrical seems to be all hooked up.. all ive done was put the rest of the bike together.. as far as how much the rpms go down im pretty sure it doant go below 2000 unless its starting to stall

[lorello]

Anyone know how to diagnose the slow speed circuit problem..

[Agemax]

Anyone know how to diagnose the slow speed circuit problem..

yep, strip the carbs and give them a jolly good clean, soaking overnight preferably, or an ultrasonic tank, or at the very least.......some carb cleaner and blow all the jets and orifices out with an airline.

[Tamara]

Pull the carbs, take them apart and give them a good cleaning. The 450 should idle without issue between 800 & 1000 rpm.

[pete]

+1 on the cleaning... if the carbs have been sitting for that time then the fuel will definitely have gone off and you will have some varnish in there that needs to be removed with a proper clean.

Don't forget an O ring kit from cycleorings.com if you haven't done that yet either.

[lorello]

If i rember corectly my carbs seen faily clean . I dont know what the guy did to the carbs when he had them off before i bought the bike. So maybe theve been cleaned... also what should i soak them in . Would running jetted carbs with a stock airbox cause this like i said no clue whats been done to my carbs before i bought it just find it fishy that all the airbox mounts were cut off the fram

[BassCliff]

Hi,

I found these "how to" guides (PDF files) on some guy's website.

Mikuni BS(CV) Carburetor Rebuild Tutorial
(Mr. Nessism)

CV Carburetor Rebuild Guide
(Courtesy of GSR and John Bloemer)
(Click here to see the CV Carb Notes)

GS450 Carb Rebuild Guide
(Mr. Flaming Chainsaws)

Check out the complete GS maintenance lists HERE.


Thank you for your indulgence,

BassCliff

[pete]

If i rember corectly my carbs seen faily clean . I dont know what the guy did to the carbs when he had them off before i bought the bike. So maybe theve been cleaned... also what should i soak them in . Would running jetted carbs with a stock airbox cause this like i said no clue whats been done to my carbs before i bought it just find it fishy that all the airbox mounts were cut off the fram

Ok, you definitely need to go through the cleaning guides on BassCliff's site he just linked for you. The 450 one by Flaming Chainsaws should be good.

You guys in the US have access to Berrymans carb dip which I believe has a basket for all the parts etc. so go that way.

Also, make sure you get an O ring kit from the most awesome Mr Robert Barr at www.cycleorings.com (he's a member on this site).

[lorello]

alright thanks . but before i take my carbs apart i was reading up and read about the pilot screw and am gonna take a look maybe it needs to be tightened a lil... it seems like the problem my bikes having has to do with getting to much air seeing the choke has to be in a certian place for it to run. ima take a look at my carbs tomrow but anyone know the part number of the pilot screw in this diagram http://www.boulevardsuzuki.com/fiche...1980&fveh=2093

[pete]

The pilot screw will make it run leaner/richer at idle, but it definitely won't make it lean enough to have to use the choke to stay running...

Due to emission laws dictating the mixture screw be sealed, it doesn't appear on any parts diagrams I've seen unfortunately and I've never seen anyone find the part number for them or the springs...

[eil]

Yep, pilot screws have no part number because Suzuki considers them a non-serviceable part of the carb body.

Z1 sells aftermarket pilot screws, though.

[lorello]

Yea i havnt been able to find anything about them anywhere.. i was messing around with i think its the part 62 sum big aduster screw tightened it a lil and it seemed to run more stable would start with the chock barly on and the rpms wouldnt stay as high so getting better

[pete]

#62 is the idle adjustment screw, it should be set so that idle is around 1100 RPM.