Chasing ghosts with engine revival

[joej85a]

Hey guys, I am currently reviving my dad's 2000 roadstar 1600 and I am having an issue that I cant seem to chase down, I am hoping the collective brain here can help me see what we are missing. Quick backstory: Bike sat for about 3 years, I picked it up, new battery, removed and cleaned gas tank, new fuel petcock, new fuel filter, new fuel lines, new fuel pump. Complete carb rebuild with factory jets. New oem intake manifold and intake o-rings.

I started it up on a gas iv to set the idle, etc. With a fan on it, let it get up to temp, set base idle, air mixture screw set to stock spec, seems good with roll on throttle. At temp throttle blips bog down and lots of popping through the carb. Went through the carb again, all clean no debris, and accelerator pump is verified working.

Verified fuel is getting into the carb bowl and flowing freely. Put the tank on and went for a test ride. Bike performs normally at 1/2 throttle and down. If you blip or roll on full throttle it begins backfiring and popping. It seems like a standard blocked jet, but I have verified the jets are clean multiple times. Bike also seems to get hot quickly, not terribly, but hotter than I remember, which again makes me think lean condition. So I took it to my local mechanic that is also a Yamaha certified guy.

He went through the carb again, verified all clean and is having the same symptoms. Runs like garbage over 1/2 throttle or so. He said he thinks it is one of 2 things: valves are tight and allowing the popping back through the carb, or somehow the timing has gotten off. He said the crank rotor on roadstars dont have a key, and are only torqued onto a beveled crankshaft and they have been known to twist slightly, which changes the timing. He also called the local yamaha dealer and they verified the transmission recall has not been done on this bike. He suggested that I go ahead and have the recall done, and see if when it is reassembled back to stock specs if it fixes the issue. If not, we can dive back in. Well this started a new issue. We cant find a dealer that will do the recall. They havent said no directly, only that either they dont have a qualified mechanic to do the recall, or that it will be 3-4 months and I would have to pay for all supplies (seals gaskets, etc) to do the recall. Not sure what the real story is there, but Im not having any luck with the recall route.

So, that said, anyone run into a similar issue? It really seems like a lean condition to me but I cant find it. I tend to think about the intake boot and the orings that seal it to the head. I tried piping in some propane around the intake flanges but didnt hear much of any change to the idle speed. Should I take them off and yamabond the orings and reinstall to rule out a vacuum leak there? Thoughts?

Thanks in advance for reading all this mess and for any direction or advice!
Joe

[Shores]

Do not jump to the conclusion that the timing is off or the valves are out of adjustment. That is unlikely. If it ran well before it was parked 3 years ago then those things would not change. I suspect you either have an exhaust leak at the new header gaskets or you have the wrong Jets in the carb. You need to tell the carb gurus here what type of air intake and exhaust you have as well as what type of jets you have in the carb. We typically don't trust a lot of mechanics.

[joej85a]

Do not jump to the conclusion that the timing is off or the valves are out of adjustment. That is unlikely. If it ran well before it was parked 3 years ago then those things would not change. I suspect you either have an exhaust leak at the new header gaskets or you have the wrong Jets in the carb. You need to tell the carb gurus here what type of air intake and exhaust you have as well as what type of jets you have in the carb. We typically don't trust a lot of mechanics.

Haha, I hear you. So the intake is completely stock, with stock filter. The exhaust system is completely stock as well. I will have to verify jet sizes, but I did order factory replacement size jets. Stay tuned for the verification of jet sizes.

[Engineman]

These bikes do not like to be blipped. They will pop back through the carb if you do this. The accelerator pump comes on from start to 3/4 throttle and squirting directly straight to the throat of the carb near the needle. Make sure it’s a good flow of fuel too. Going over 1/2 throttle and runs like crap tends to be the float level not set right meaning not getting enough fuel. Hope this helps.

[joej85a]

These bikes do not like to be blipped. They will pop back through the carb if you do this. The accelerator pump comes on from start to 3/4 throttle and squirting directly straight to the throat of the carb near the needle. Make sure it’s a good flow of fuel too. Going over 1/2 throttle and runs like crap tends to be the float level not set right meaning not getting enough fuel. Hope this helps.

I did replace the needle valve in it, so the float level could possibly be an issue as well. I confess float levels were always above my pay grade. But ill see if i can find some videos. Thanks for the suggestion.

[joej85a]

Alright gang, here is my plan of attack. I have been wanting to do a fuel pump delete, so I ordered the appropriate parts as listed in the article here (updated ones). While doing that, I am going to remove and insure I have no leaks in the intake manifold. I am thinking a thin coat of yamabond on the flange surfaces. While apart for that, I will verify float level per the pump delete article, and verify jets. Parts are due the 24th. Stay tuned and thanks!

[Shores]

Unless you know your fuel pump is bad, I would hold off on going pumpless until you get it running good first and get all the carb adjustments made. Changing too many things at once can make problem solving more complicated. What I do when I bolt up the exhaust headers is to make sure that the headers are seated very well against the gaskets and tighten them part way first, working my way back and forth all the way to the mufflers. If you just bolt everything up all at once you run the risk of having a leak at the header gaskets. Torque the bolts a little bit at a time along the entire exhaust making sure that the exhaust ports get priority.

[davej]

Don't use Yamabond on the flange use permatex hylomar. Napa also caries Hylomar. Smear it across the flange and oring let it flash set and install the manifold. Also before installing the new manifold place a pc of wet/dry sandpaper on a flat surface and resurface the flange. using a figure 8 motion sand until the green coating is gone and the flange is flat. if you have an adjustable needle in the carb let us know what groove the clip is in.

[scotcher65]

did you replace the spark plugs

[scotcher65]

my bike was acting similar to yours but i replaced the spark plugs and ran a couple of treatments of seafoam fuel treatment. Sometimes when a bike is laid up it just needs a little running time to get it back on track

[Horsehammerr]

After several days of putting up with the SAME problem . I simply let mine warm up good and then took a spray can of Brake Cleaner , with the little red straw in the spray tip , and lightly sprayed each intake connection , Carb. to intake , and OH YEAH !!! , the vaccum line nipple on the top toward the rear of the Intake manifold and BAAM ! There it was , vaccum leak. Sealed that dang thing and all the Popping , Sputtering and missing is GONE !

[Horsehammerr]

Well it lasted one day . What is a good way to permanently seal the intake manifold vaccum nipple ?

[davej]

solder it closed

[joej85a]

did you replace the spark plugs

I did, sorry forgot to mention that.

[joej85a]

Don't use Yamabond on the flange use permatex hylomar. Napa also caries Hylomar. Smear it across the flange and oring let it flash set and install the manifold. Also before installing the new manifold place a pc of wet/dry sandpaper on a flat surface and resurface the flange. using a figure 8 motion sand until the green coating is gone and the flange is flat. if you have an adjustable needle in the carb let us know what groove the clip is in.

Okay I will check that out. Im hoping it is a vacuum leak somewhere in the intake. Sure seems like a lean condition to me.

Thanks for all the continued suggestions guys!

[Dr. D]

I am willing to bet that your float level is too low. During your carb rebuild, you may have bent the float tab that contacts the needle valve when you had it out. It is easy to do.

I improperly adjusted my float height too low, and experienced the same symptoms you did. Basically, under deep throttle your draining the float bowl. After a few seconds, or even while your bike is dead but still rolling, it'll fire right back up - as soon as the float bowl is filled up again.

When I went pumpless and was adjusting my float level, I was going off old/wrong information and using the float bowl mating surface on the filter side of the carb. The correct measurement is using the intake side of the float bowl mating surface (4mm or so above it). Don't make the mistake I did. I was very frustrated for a few days.

[Shores]

Well it lasted one day . What is a good way to permanently seal the intake manifold vaccum nipple ?

Solder it shut.

[roadiemort]

Solder it shut.

[Horsehammerr]

Winter Project

[brianmac]

replace it with something tuffer than chineseoprene cap. i use EFI line with a cut off galv nail as short as possible. and clamps

[joej85a]

Update gentlemen. Sorry for the long gap, but the issue has been resolved. Apparently the jet kit i used in the rebuild did not contain the correct jets/needle. I cannot recall what brand it was, but suffice it to say something was up with some or all of the parts. I put the original jets/needle back in it, cleaned the slide, as it had some pitting on the back, and bingo. All issues are gone. Thanks to everyone for the collective experience and brain power! Another one back on the road.

[Tcontrol]

In your very first post…..

”Complete carb rebuild with factory jets.”….

and now you are saying that the jets were not the factory jets…..

i would say that you have effectively misled these fine people at the clinic with incorrect information… hard to troubleshoot a problem based on incorrect or incomplete data…

at least you were honest with an update that problem was resolved and what was corrected… i wish you many years of riding the aforementioned bike because the roadstar is an a wesome and dependable machine when maintained and serviced correctly…

[joej85a]

In your very first post…..

”Complete carb rebuild with factory jets.”….

and now you are saying that the jets were not the factory jets…..

i would say that you have effectively misled these fine people at the clinic with incorrect information… hard to troubleshoot a problem based on incorrect or incomplete data…

at least you were honest with an update that problem was resolved and what was corrected… i wish you many years of riding the aforementioned bike because the roadstar is an a wesome and dependable machine when maintained and serviced correctly…

True, I should have clarified that I meant factory sized jets. Just glad its going again.