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Discussion Starter #1
Hi,

I'm new here and just got my first bike...a 2003 yamaha v star 1100 custom. It has 10100 miles on it and I just got it saturday. Started and ran perfectly when I went to check it out.

But the next day It was giving me problems starting and stalling at idle. It would eventually sputter out and stall and the idle was really slow. I tried all amounts of "choke" eventually getting it to start but it kept getting worse to the point where I had to stay on the gas at stop lights to keep from stalling...also any amount of choke above 1/4 to none normally puts out black exhaust.

I checked the spark plugs and they were jet black. Put new ones in fired right up and ran great...however 50 miles later they are now black and each time I start it, it gets a little harder to start. It also seems like I don't have a lot of power on 3/4-full throttle, however all other ranges seem fine.

One last thing, before I changed the spark plugs it was running really rough and wanted to stall below 10mph in 1st and 12ish in 2nd. The new spark plugs fixed this though.

I'm thinking it is running rich and needs to be rejetted...however I don't want to dive into doing this right away if it may be something else...

thoughts? I just want to ride!!!
 

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Hi,

I'm new here and just got my first bike...a 2003 yamaha v star 1100 custom. It has 10100 miles on it and I just got it saturday. Started and ran perfectly when I went to check it out.

But the next day It was giving me problems starting and stalling at idle. It would eventually sputter out and stall and the idle was really slow. I tried all amounts of "choke" eventually getting it to start but it kept getting worse to the point where I had to stay on the gas at stop lights to keep from stalling...also any amount of choke above 1/4 to none normally puts out black exhaust.

I checked the spark plugs and they were jet black. Put new ones in fired right up and ran great...however 50 miles later they are now black and each time I start it, it gets a little harder to start. It also seems like I don't have a lot of power on 3/4-full throttle, however all other ranges seem fine.

One last thing, before I changed the spark plugs it was running really rough and wanted to stall below 10mph in 1st and 12ish in 2nd. The new spark plugs fixed this though.

I'm thinking it is running rich and needs to be rejetted...however I don't want to dive into doing this right away if it may be something else...

thoughts? I just want to ride!!!
About "re-jetting". What size pilots and mains are in there now? Without that bit of info and knowing absolutely nothing about the bikes history, we're just making wild guesses. Get yourself a Yamaha Shop Manual and start doing some diagnostics or get it into a shop and let them take a look. It really could be a dozen different things.
 

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Mick's right. You need to tell us a bit more about your bike. Was it sitting for a long time before you got it? Is the AIS still connected? What jets are installed? Lots of questions eh. It may be worth your while just to bring it at the shop and have them look at it. If not, get us the info and we'll do our best to help out.
 

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Discussion Starter #6 (Edited)
The guy I bought it from said he had it rejetted about 3 years ago. He put about 1000 miles on it a year over 4 years. I'm not sure if it was sitting for a while...I asked him how often he rode it but I can't remember what he said. Also, the pipes either aren't stock or have all the baffles completely removed. The previous owner said they were stock but I don't think they are. I'll get some pics tonight.

I'm not sure what jets are in there. Will I be able to tell if I pull them apart?

Not sure about the AIS I'll take a look at it tonight. I found a shop manual online so I'll use that. Air filter looked clean but I'll take a look at it again.

***correction*** the old owner never had it rejetted, just cleaned, although he didn't know if a previous owner did, he thought they were probably stock though.
 

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Sounds like you definitely have a carb issue. I'm guessing it way too rich for whatever reason and that's what's fouling your plugs. I will agree with everyone else here in that you need to either find out how to do it yourself and tear into it or pay someone else that does. From my experience being a newby I would suggest pay someone. I just finished chasing down a carb issue myself. Thought I knew what I was doing but turns out I didn't. Glad to know my mechanic did. :D
 

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If you take off the bowls of the carb you will be able too. It will say right on the jet, real tiny.

As for the AIS, If you still have those large silver/chrome pipes running along the outside of the bike, you probably still have it installed. Some people do a quick fix to disable it ( check here; http://www.vstar1100.com/jack_phelps/vstar/ais.htm ) so the previous owner(s) may have done that. You should be able to check by simply removing the left side cover.
 

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Discussion Starter #9
I'd like to rejet it myself if that is most likely the problem.

AIS is still on and intact.

I think the exhaust are cobra exhaust but I'm not sure. I also tried to get a picture of the inside. The guy before me installed a baffle to pass MD state inspection.

There also seemed to be a little gas coming out of the exhaust from the front. If I put my hand behind it I get little black droplets on it. The first spark plug I took out also had some gas or oil on the threads.

I'm not sure if the air filter is too dirty, Any suggestions on how to clean it w/o compressed air?

It looks like the problem is the spark p
 

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Yeah..Honestly, You're gonna have to go into the carbs to get anywhere I think. It's alot easier than you'd expect.

Wild ass guess - I think the previous owner rejetted....and now the pilot jet has loosened and fell into the bowl. ;). Ask me how i know about that one. lol. But there could be several reasons, definitely gotta check the jet sizes and PMS setting.

Filter looks alright. Exhaust looks like Cobra like you said...Maybe Hard Krome.
 

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Discussion Starter #11
Yeah I did some research and they sound and look like Hard Krome big straights.

Without knowing what exactly is in there now for jets can I just go ahead and purchase a baron or dynojet kit? I guess my question is will they come with enough options to cover the jetting I need (whatever that may be)...All I really see are generic kits.

I'd like to give it a go myself first...worst case I figure i'll end up having to bring it to a mechanic anyway. The process doesn't sound too hard and I have a service manual.
 

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I would tear the carbs down first and see. And I wouldn't recommend getting either. The dynojet kit uses different sizes than regular mikuni jets...and I think they normally go for like ~80 dollars.

You can get individual jets for like 4 dollars each, versus buying a jetting "kit", Or a 4 pack for 12-13 online.
 

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For a stock intake with pipes, you'd want 117.5 (or close) main jets in both carbs. No need to buy a "kit" as mentioned above unless you like to spend money on stuff you'll throw in the garbage can.

But as mentioned in my first post.... until you know what is in there, you're really wasting your time worrying about jets. Get the carbs off, have a look inside to make sure everything is put together correctly and that everything is clean. If you're not sure how it should look, I'd definitely consider taking it to somebody that does. It could save you a lot of heartache. These carbs are about the simplest out there, are generally very easy to fix, if you take enough time to educate yourself on their operation. If you want to take the time.....great, if not, there is nothing wrong with letting someone else do it.
 

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Discussion Starter #14
Okay, took it apart today and this is what I found:

I have a DYNA performance electronics 3000...not sure what it does.

Whoever took the carbs apart last didn't put the top cover on right and the diaphragm couldn't work right. see pic.

I'm pretty sure the o ring on the carb needs replacing.

Front:
needle clip is on 2nd space down from top
Pilot 20
Main 107.5
Pms 2 turns

Rear:
Needle same as front
Main 105
Pilot 20
Pms 2 turns

I think switching to larger main jets would solve my problem of 1/2-wot where it just gives high revs and produces little power. From what I've read it seems like I should start there and get that correct and then go from there.

Any suggestions or other thoughts?
 

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The dyna could be part of the issue. Go HERE and read. Get those settings right first. Do you know if your bike still has stock cams?

I'm hoping you can save that diaphragm....somebody really hashed that thing. If it doesn't seal perfectly, I'd get a new one.

Your mains appear to be super lean, but with so many jet manufacturers who knows what they are. If that is a stock intake, you need a couple Mikuni 112.5's or 115's. Really no need for 2 different sized jets. Make sure they are Mikuni jets. You can get them at almost any Harley dealer....I've found most Yamaha dealers just give you a blank stare when you request jets. They should be no more that $4-$5 each.

However, you said the plugs were black. The jets you have in there appear to be small and would make it lean, and they adjusted the needles to be extremely rich to compensate. That means that your drenching everything in fuel from 1/4 to 1/2 throttle...then starving it above 2/3 throttle. You said you are on the 2nd notch from the bottom...that's pretty rich for a stock set up.

Do the needles have 5 .... or 6 notches? If they have six, I'd consider throwing them away and getting some stock ones. If they have 5, put the clip in the center notch. With the jet sizes mentioned above, that should get you running where you need to be.

With the pilots being oversized (stock is 117.5), I'd leave the PMS at 2 with the possibility of turning it back to 1 3/4 or until I started to get a little bit of backfire.....then out another 1/8th turn.

As with everything else, make sure your needle holders or intact and that everything else in the carb is correct.

Just rub some light oil or waterless hand cleaner on the O rings to help clean them, then wipe it all off when you go to reinstall. Unless they are cracked or leaking, you'll probably be OK.

Also...go HERE and bookmark it. Everything you need to know about your bike is there. Almost every one of your carb tuning questions is answered there....look in the tuning section, but if the 1100 is new to you I would highly suggest carefully reading the "New Owners" section.
 

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I would try setting the DYNA at the stock timing curve too and then after the jetting gets sorted out, then playing around with the different curves.

For the factory one(Curve / ADV 1), switches 4, 5, 6 and should be down
 

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Discussion Starter #17
The dyna could be part of the issue. Go HERE and read. Get those settings right first. Do you know if your bike still has stock cams?

I'm hoping you can save that diaphragm....somebody really hashed that thing. If it doesn't seal perfectly, I'd get a new one.

Your mains appear to be super lean, but with so many jet manufacturers who knows what they are. If that is a stock intake, you need a couple Mikuni 112.5's or 115's. Really no need for 2 different sized jets. Make sure they are Mikuni jets. You can get them at almost any Harley dealer....I've found most Yamaha dealers just give you a blank stare when you request jets. They should be no more that $4-$5 each.

However, you said the plugs were black. The jets you have in there appear to be small and would make it lean, and they adjusted the needles to be extremely rich to compensate. That means that your drenching everything in fuel from 1/4 to 1/2 throttle...then starving it above 2/3 throttle. You said you are on the 2nd notch from the bottom...that's pretty rich for a stock set up.

Do the needles have 5 .... or 6 notches? If they have six, I'd consider throwing them away and getting some stock ones. If they have 5, put the clip in the center notch. With the jet sizes mentioned above, that should get you running where you need to be.

With the pilots being oversized (stock is 117.5), I'd leave the PMS at 2 with the possibility of turning it back to 1 3/4 or until I started to get a little bit of backfire.....then out another 1/8th turn.

As with everything else, make sure your needle holders or intact and that everything else in the carb is correct.

Just rub some light oil or waterless hand cleaner on the O rings to help clean them, then wipe it all off when you go to reinstall. Unless they are cracked or leaking, you'll probably be OK.

Also...go HERE and bookmark it. Everything you need to know about your bike is there. Almost every one of your carb tuning questions is answered there....look in the tuning section, but if the 1100 is new to you I would highly suggest carefully reading the "New Owners" section.
The only thing wrong about all this is that the clip on the needle is 2nd down from the top, not bottom. Sorry about not being clear. Also I think the pipes are Hard Krome big straits or maybe cobra. so not stock. so I'm guessing 115 jets as from the 1100 website?

I'll take a look at the dyna in a few days. I stripped my seat screws and gotta drill them out and get new ones.

Thanks for all the help everyone!
 

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The only thing wrong about all this is that the clip on the needle is 2nd down from the top, not bottom. Sorry about not being clear. Also I think the pipes are Hard Krome big straits or maybe cobra. so not stock. so I'm guessing 115 jets as from the 1100 website?
No guessing....with those pipes, go with 115's. It really doesn't matter where the clip on the needles is now, it's not right. 5 groove needle it goes in the middle slot....or just buy a set of stock needles, then you'll know for sure what you have.

These carbs are super simple. They just need to set up right one time and you're good to go. Don't forget to synch them when you get them back on. That's about the most important part of the process.
 

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Just curious, but why do you recommend the same main jets in f/b versus staggered?
IMO, it doesn't make that big of difference, especially when you have aftermarket pipes.

You spend 90% of your riding time on the needles and pilots anyway. It's far more important to get those right...and they come set exactly the same from the factory. I think Yamaha probably just tried to keep the bike as lean as possible for the North American market. I prefer to run my air cooled bikes a little on the rich side for cooler running.
 
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