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Message started by Iono on 05/25/11 at 19:08:39

Title: carb or petcock problem
Post by Iono on 05/25/11 at 19:08:39

My bike (LS400) will idle with no issues I can also drive in any gear if I keep the rpms down, but the minute I apply throttle the engine boggs down and will quit running if I don't back down and baby it.

I assumed it was a problem with the carb blocked jet dirty..., so taking off the tank in preparation for removing the carb, the only way I could drain the gas was to start the bike and with the engine running I could drain the fuel, the minute I turned it off the fuel stopped draining out..last time I drained my tank I did not have to do this... turn the petcock in any direction with the bike off and the gas would drain.

So what do you think, leave the carb alone, clean repair the petcock or is it a carb issue, can the petcock cause this problem?
Thanks in advance

Title: Re: carb or petcock problem
Post by Serowbot on 05/25/11 at 19:16:53

Stock petcock should only drain in prime position...
You got a busted vacuum diaphragm...

Replace or Raptorize...

How to check your petcock,... (http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1)

Title: Re: carb or petcock problem
Post by Iono on 05/25/11 at 19:26:15


5147504D55404D56220 wrote:
Stock petcock should only drain in prime position...
You got a busted vacuum diaphragm...

Replace or Raptorize...

How to check your petcock,... (http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1)

Dam that was fast, sounds good, thanks for the info

Title: Re: carb or petcock problem
Post by Oldfeller on 05/25/11 at 19:31:24


Best advice around here is to FIX THE PETCOCK ISSUES before trying to do anything else.  

Until the petcock is "known good" you are just beating your head against the wall as a bad petcock can mock all known carb problems, some known electrical problems and it will surely drive all your troubleshooting efforts into pure insanity if you don't make it "known good" right off the bat.

+1 on the simple mechanical Raptor from me, simplicity helps tremendously when fixing up carb related symptom chasing.  

You can repair the stock petcock, but you do know that a vac hose will crack or a diaphragm will either get stiff or rupture on you again down the road causing you to go round this same barn yet again.

Something else a stock petcock can do that drives you nuts once you start down the engine mod path is it will not flow enough gas at full speeds once the vac diaphragm gets stiff and hard.  

Motor vacuum drops off some at top RPMs and bike speed, and that is enough to give you all sorts of "wrong jet" type symptoms when the stiff vac petcock diaphragm begins to literally lightly fuel starve a modified engine at full speed runs.


Mod boys need a Raptor ...


Title: Re: carb or petcock problem
Post by verslagen1 on 05/25/11 at 19:53:55

1st understand what's going on or  you'll throw money at it till it's fixed.  I thought yogert taught you better.


4B6D6C6D020 wrote:
My bike (LS400) will idle with no issues I can also drive in any gear if I keep the rpms down, but the minute I apply throttle the engine boggs down and will quit running if I don't back down and baby it.



Quote:
I assumed it was a problem with the carb blocked jet dirty..., so taking off the tank in preparation for removing the carb, the only way I could drain the gas was to start the bike and with the engine running I could drain the fuel, the minute I turned it off the fuel stopped draining out..last time I drained my tank I did not have to do this... turn the petcock in any direction with the bike off and the gas would drain.
Yes you got a petcock problem, but not a cracked diaphragm.  Fuel used to run with lever in any position, jambed shutoff valve.  Now it'll only drain when bike is running, no longer jambed, working like it should.  It maybe that your lever doesn't do anything, it's become disengaged from the valve.


Quote:
So what do you think, leave the carb alone, clean repair the petcock or is it a carb issue, can the petcock cause this problem?
Thanks in advance

To your original problem I vote carb problem, possible that the main jet has fallen out or there's a washer under the jet that's gone missing and allowing the main jet and needle jet to be sucked up flooding the carb.

And take apart the petcock, certainly something wrong.
And BTW, it's a LS400, the guy is not in the USA.  Didn't the last guy say he couldn't get raptor parts?

Title: Re: carb or petcock problem
Post by Iono on 05/25/11 at 20:19:23


584B5C5D424F494B401F2E0 wrote:
And take apart the petcock, certainly something wrong.
And BTW, it's a LS400, the guy is not in the USA.  Didn't the last guy say he couldn't get raptor parts?


Thanks to all for the info, I will start with the petcock, I'm located in Thailand (from the U.S.) and bought the bike about six months ago, Man I love this freak'n bike, it has had small issues, but gets up and moves...I can always have parts shipped here, although expensive to ship better then paying over the top prices for motorcycle repairs...In Thailand anything 400 and over is considered a big bike and needs someone who has dealt with anything larger then a moped and there are just a few, watching them do repairs makes me feel like they are just fumbling along...so it is up to me from now on  :-/..

Title: Re: carb or petcock problem
Post by verslagen1 on 05/25/11 at 20:22:23

I got a kid's chineese atv from a 'friend', the petcock looks just like a raptor.  so, look around.

Title: Re: carb or petcock problem
Post by Iono on 05/25/11 at 23:58:41

Well I converted the petcock to manual; started the bike and same problem, apply gas slowly and as it gets in RPMs it boggs down....so I would like to rebuild the carb or replace the jets (would be my first time)...can anyone direct me to a rebuild kit...

I'm also going to purchase a new petcock as previously it was difficult to turn and is still difficult to turn on and off.

Title: Re: carb or petcock problem
Post by Routy on 05/26/11 at 06:18:03

From your post it sounds like if you baby it up there, the bike will run fine at freeway speeds. If this is so, your problem is not anything to do w/ the main fuel delivery,.....including the petcock, the screen on the petcock, any fuel filter, or a main jet.

The problem is in the carb !
This doesn't mean you don't have an issue w/ the petcock also,.....if it won't drain on "prime"

Title: Re: carb or petcock problem
Post by Iono on 05/28/11 at 04:19:18

Well would you beleive I found a new pet thingy at the store in my area, I thought I would have to drive to the big city.....any way new petcock is just on/off/reserve...with that said I also took the carb apart clean it and put it back in the bike....so all is well...

Not really not when I turn the fuel on it comes out of the bottom of the motorcycle a black hose?

Prior to this I forgot to install a hose on the carb, ok the vacuum area has been closed off, the I go from petcock to the main inlet for the gas, then there are two other nipples, forgetting what I took off from where I just looped these together....hmmm any suggestions?  I've looked at manuals and can't where the hose goes for the two nipples I assume to each other?

Title: Re: carb or petcock problem
Post by verslagen1 on 05/28/11 at 22:04:13

http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1098869040

Title: Re: carb or petcock problem
Post by Iono on 05/29/11 at 05:13:53

Thanks, I've looked at the pics previously to include printing a step by step on taking apart the carb... I must have screwed something up inside as the fuel would go in and come out of bowl vent 2 and bowel vent 1 I then connected both of these together and it shot out of the bottom of the bike, funny stuff...maybe I messed up the floats not sure...so time to take it apart again, good times. ;D

Title: Re: carb or petcock problem
Post by Routy on 05/29/11 at 19:28:03

Are you holding the carb upside down, and checking the float level measurement ? Also that the float is parallel (from R to L) w/ the carb body.....in case it got bent somehow ?
And to save the trouble of putting it back on the bike till you know its right, just hold the assembled carb upright near the petcock, connect the fuel line, and turn it on, wait a couple 3 minutes. Any sign of fuel,.....its back apart.
Oh,.....I ain't never been majorly into this carb,.....just so you know :o

Title: Re: carb or petcock problem
Post by Iono on 05/30/11 at 07:10:55


757A607B67617270787661130 wrote:
Are you holding the carb upside down, and checking the float level measurement ?


Well I broke down and took the carb to a Harley dealer about an hour from where I live...he couldn't do anything for me but suggested a guy with a small shop (whole in the wall) now this is Thailand and my Thai is so so and his English was ok, but he understood what I had done to the carb (looked to be big time carb abuse  :-[ ) he then took action....man this guy took a file and a piece of widdeled wood to my carb it took about three hours, but dam after some filing, cleaning with thinner, poked with pins and whatnot the jets and carb were sparkling, he then had a setup where he could test it and properly set the floats, after he was completed his assistant looked at me and said...he is McGuyver  ;D, the issues where bent floats, rubber grommet broken, main jet frozen on and on and on....
Thanks to all for the help and all the suggestions.

Title: Re: carb or petcock problem
Post by Iono on 05/30/11 at 20:02:48

Well I put the carb back on the bike today, it started right up no leaks, beautiful....WAIT, same F'n problem, idles great the minute I start to give it gas it boggs down, could this be as simple as a spark plug problem?  That's my next step, first I need to pick the bike back up after kicking and dragging it around my yard Mother FU@KER!!!!!!

Title: Re: carb or petcock problem
Post by verslagen1 on 05/30/11 at 20:18:06

couldn't hurt to change the plug.

how many miles on the bike?

Title: Re: carb or petcock problem
Post by Iono on 05/31/11 at 04:48:38


392A3D3C232E282A217E4F0 wrote:
couldn't hurt to change the plug.

how many miles on the bike?

Milage is 23937.1, however this could be way off as it is asia and they really don't check this stuff when I registered the bike in my name just frame/engine number......

The plug is fine, it kills me as it cranks right up no issue, but give it gas as it climbs in rpms it boggs down....I"m at a loss and may take it to the guy that did the carb for me...I hooked it up to two of my water buffalos today and dragged it around the yard and then kicked it a few times....Mother F@cker still doesn't want to work...oh well

Title: Re: carb or petcock problem
Post by Routy on 05/31/11 at 06:10:41

Curious,.....what happens when you give the choke a click or 2 ?
Does that help or hinder ?
The choke can be the best....handiest pc of test equipment you have.
If choking it helps, the prob is definently in the low speed circuit,....or fuel enrichment system ?
I don't know this carb well enough to give anything but the basics.

Title: Re: carb or petcock problem
Post by Iono on 05/31/11 at 06:43:10

I'll give that a try tomorrow as it is night here and I can't be revving it up and ticking off the neighbors....you know what is really cool...I just noticed that many of you are from the NW...I'll be dammed as I lived in Yelm, Wa for 8 years and also in Portland for a year...

Title: Re: carb or petcock problem
Post by Iono on 06/01/11 at 02:46:27

Well I took the bike to the shop same guy that cleaned the carb, it now runs, well I mean when I left the shop it took off down the road normal and within 5 minutes started acting up...deal is taking off and releasing the clutch I need to milk it a bit then I can go, when up to speed and let up on the gas and then reapplying gas it hesitates then seems to kick in...oh well I can cruise at 80/90 KPH so for now it is ride-able, but I need to workout this issue...thanks to all for the suggestions and what not.

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