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Discussion Starter #1 (Edited)
My last cruiser bike was a Yamaha Raider. Loved the power of that bike and the fork angle but wanted something a little more comfortable. The 1300cc v4 design in this bike is great! I can rev it more than my raider, seems the gears are almost longer too. I don't miss the raider surprisingly.

Ok, now on to the question...

Bike is having a hard time idling and it seems to be due to cracked intake boots. The boots themselves have grommets or caps on the vacuum ports. Is this normal? Are they there to just test for leaks? This is my first carb'd bike. I have owned a lot of carb'd snowmobiles though. :)

Looking to replace all 4 boots and figured I would start with The Bay. Looks like I can get a set of 4 for $33 shipped... Any reason I shouldn't go with one of those sets?

Bike has vance and hines pipes, mustang seats, leather bags all around, blue in color.
 

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I have a 2000 named Ursa (she's a bear!)

the vacuum ports are there for balancing the carbs with vacuum gauges.

if the covers are cracked and leaking (or missing) you need to replace them. Should be able to find a package of something close at Advance Auto or similar parts store.

Before you run out and buy new intake boots and pull your carbs all off, use an un-lit propane torch while the bike is idling, and see if pointing the propane at the boots changes the idle speed. If there is a vacuum leak it will usually idle faster. Hold the torch with the bottle pointing up, so you get just the gas coming out, dont hold it tilted over or upside down so your get a stream of liquid propane coming out, that is too much. you can also run the test with WD40 or other volatile fluids, but it tends to make a mess.

On most Vstar bikes those rubber looking intake boots can look all cracked on the outside, and everyone sees that and freaks out. But it rare for the cracks to go all the way thru. Unless you test for vaccum leaks and are sure its the boots, dont jump on it because of the way it looks.

By far the most common problem with carbs bikes is a previous owner stopped riding one day and left the bike parked with 10% ethanol fuel in the tank, and after just a few months it breaks down and starts clogging things up. If the bike will run at all you can try putting a carb cleaner in the fuel, run the bike a hundred miles or more, and if the fuel is running thru the ports and jets at all, it might clean them out, and that is all you need. A bottle of Seafoam is $8 at walmart, and its enough for 16 gallons of gas.

The other thing: dont pay much attention to how the bike idles when you first start it - it takes several miles to warm up.

BTW, these V4s with the 4 independant exhausts sound like they are puttering when they are idling, that is normal. If its running well when you get on it, it might just be you need to get use to the sound of the engine... and maybe adjust the idle speed a bit.

Good deal on your new royal star - there are a lot of them out there, and they tend to be insanely reliable. I got mine last fall, and hardly ever see anyone here posting problems or issues, most people that have one just ride and ride and ride.

EDIT to add: here is recent thread talking about the boots, with a photo of one sliced down the middle:

https://www.starbikeforums.com/forums/14-royal-star/116308-oil-leak-new-me-99-rsv.html
 

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Discussion Starter #3
Thanks. I can't get it to idle period. It wants to start up, I crack the throttle and I can keep the bike running. But when I let off the throttle the bike wants to die. I can only get the bike to run if I have the choke all the way out. If I push the choke in and keep my hand on throttle its fine, but if I let off the throttle the bike will stall out.

I can get the bike to run for a bit using the choke but it too will eventually stall out on its own. I imagine I need to adjust the fuel/air screw. Not sure what the screw is technically called. Usually an "air" screw if on the airbox side and usually fuel screw if on opposite side. Either way, the screw is used to richen/lean out the airfuel at idle. I will start there I guess. After seeing the side cutout of that boot your right, highly doubt its cracked all the way though.


The bike has been sitting for months, I will try the additive as you suggested.
 

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KCW is correct, check for vacuum leaks before tearing apart. Another good way I check for vacuum leaks without making a mess is to spray brake cleaner around the area. It drys almost instantly and idle will increase if you have a vacuum leak. Since it's a new to you bike I'll second the suggestion of Seafoam. Keep us informed.
 

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Thanks. I can't get it to idle period. It wants to start up, I crack the throttle and I can keep the bike running. But when I let off the throttle the bike wants to die. I can only get the bike to run if I have the choke all the way out. If I push the choke in and keep my hand on throttle its fine, but if I let off the throttle the bike will stall out.

I can get the bike to run for a bit using the choke but it too will eventually stall out on its own. I imagine I need to adjust the fuel/air screw. Not sure what the screw is technically called. Usually an "air" screw if on the airbox side and usually fuel screw if on opposite side. Either way, the screw is used to richen/lean out the airfuel at idle. I will start there I guess. After seeing the side cutout of that boot your right, highly doubt its cracked all the way though.


The bike has been sitting for months, I will try the additive as you suggested.
Sounds like pilot jets are clogged. Heavy dose of seafoam and ride around neighborhood if possible to have the seafoam work. It will take a while but strongly suggest before adjusting anything. Adjusting with clogged jets usually compounds the issue.
 

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try the carb cleaner or another method to soak your carbs, and if the bike will run on the road but just idles rough, get on the road and take a 50 to 100 mile ride, and when you have the chance, like going up a hill in 4th gear, get on it hard and open up all the jets so the gas mixed with carb cleaner is blasting thru and cleaning any gunk out

do this before you start trying to adjust the PM screws or the idle speed, or to balance the carbs. I would also pull the plugs and replace them, there are 4, and they are about $2 each. It will give you a good indication if the bike has been running rich or lean... I would normally suggest replacing the air filter, but if your bike has a stock air filter its kinda of pain to replace it. I was able to change mine out without removing the air box off the carbs (like you are suppose to), by taking just the top off and kinda forcing it thru the top of the frame, but I was risking breaking the plastic.

I didnt know it at the time but the original owner of my RS put an aftermarket chrome trim kit all over the bike, and some of it was blocking access to the sides of the carbs, making it harder to get the air filter box off the bike. I have that crap mostly off the bike now, still have a few more pieces of 'flair' to remove... but if your air cleaner has not been changed recently (likely because it is hard to get to) then that will make the bike run rough too.

You normally should not need to adjust the PM screws, or the idle speed, or balance the carbs unless you are cleaning the carbs manually, or changing the jets to match a new exhaust or intake pods.

The problem with E10 gas breaking down is very very common, esp with carb'd bikes, esp in the northern states where bikes get parked for 6 months or more, and some people do not use a fuel stabilizer when they park the bike, then we get a flood of new owners every spring wondering why their bike isnt running right now, because it ran fine last September when they parked it for the winter.

Gunk in the carbs really is the most likely cause of a newly acquired bike not running well.
 

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If you want to see what Im talking about with the chrome trim/flair kit, the photo in my garage page...
<= over there
in front of the red garage door - click on the thumbnail in the garage page to see the full size photo

I took that just after I got the bike: see the triangle covers over the brake calipers, the basket over the brake light, the Venetian blind looking saucers over the beautiful chrome dome clutch and crank shaft covers? You can see the covers over the sides of the carbs just under the gas tank, there were covers over the engine mount bolts, the axle bolts... I would never add stuff to a motorbike that has no functional purpose, so all that is mostly off.

The original owner also put one of those LED engine and underframe lighting kits on the bike, and left a genuine rats nest of wires in the battery compartment - all gone now. I also took the 'eye lids' off all the lights and turn signals.

When the last of its removed I will post new photos of Ursa in my garage page.
 

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Discussion Starter #8 (Edited)
Thanks, yeah I normally put seafoam in my bikes every fall just to prevent the buildup issue. Ethanol based fuel is here a lot longer than most states due to the colder months... I drove it 10 miles home the other day and it idled fine, so hopefully the seafoam does the trick. I was cleaning up the bike and noticed the cracked boots and the bike didn't want to idle so I just made an assumption... The bike was from an estate sale, I paid very little for it and just assumed there might be some things wrong with it at that price point.

I went ahead and added roughly 2oz of seafoam to the tank. Wife takes off in a few hours, I will ride the bike for a while and see if it cures the issue.




Those mirrors are no longer on the bike. I found the original ones in a box that came with the bike and put them back on because I couldn't see out of the "deluxe" mirrors and hated the way they looked. I also need to install the saddle bags.
 

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Discussion Starter #9
Ran the tank of gas empty that had the seafoam in it. Bike runs a tad better, but still needs some work. When I was getting into it on 3rd, 4th and 5th gear I could hear the engine rev higher but the speedo wasn't going up at times... I would then let off the throttle and hammer it again and it would pull. Almost like it was running lean sometimes.

Pulled the front driver side and passenger side plugs.

Driver side is the furthest away and the passenger side is the closest plug.


 

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Discussion Starter #11
Also does anyone here have aftermarket lighting on their bike? Need to tear into this thing. Somehow every light lense cover is either cracked or missing screws. Figured I would swap to LEDs. The main headlight looks to be 7", has anyone done a 7" led swap on this bike?

My last bike I went with kuryukan integrated brake light and turn signals and chrome license plate cover. I am thinking of doing the same with this one.
 

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when I got mine last fall the previous owner was only riding it once a year to get it inspected. He said he drained the fuel out every winter, but that is still not often enough unless a stabilizer is being used.

going from 5 years on a VS650 to the Royal Star 1300 I was just cracking the throttle for most of the short test ride I took. I knew as long as the bike was sound and the engine was not knocking I could get it running well. The gas he had in the tank looked like coffee. I drained it out after riding it 5 miles to my work, and started the seafoam 1 ounce / gallon process.

When I first got it, it would bog down in 5th gear at 55mph - instead of speeding up the bike would slow down with half throttle, and the engine was struggling. It took a couple tanks of fresh gas with seafoam, new spark plugs (the old ones were only finger tight), but the bike came to life after about 150 miles. I could actually feel when the last carb blew the snot out of its jet, the bike has run great ever since.

When the bike is running well it will spool up from a stop to 55mph, going just thru 1st, 2nd and 3rd, and will be really smooth when you get on the throttle. Thing to keep in mind, there are three passages in the carbs, the idle flow, the PM screw flow, and the main jets. The main jets dont even open till you have the throttle cranked almost half way - each is progressive and additive, so if you are only puttering around you are barely engaging the PM screw fuel passage and not flowing anything thru the main jets. If you dont have the user manual or service manual, you can google the speed range in each gear - that engine will rev higher than you would think and it has a rev limiter, so dont be afraid to rev it up before you grab the next gear. It does not sound like a motorcycle when you get on it, with those 4 independent exhaust pipes it sounds more like a chevy small block V8.

If you can get your hands on a tach it would be good to check the idle speed, Im pretty sure it should be 1000 rpm. These are short throw piston engines, so they do not putt putt putt like a HD, they idle faster. Some people turn the idle down to make it sound like a HD at idle, but that will drop your oil pressure. Its possible the previous owner had that idle speed screw turned down.

I would replace those plugs, a couple have a lot of carbon, keep at it with the seafoam in the fuel till you use up the whole 16 ounce can, and then after 1000 miles pull the plugs and see how they look.
 

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one other thing that is common on royal star bikes, the way the choke cable is held out is prone to failure if someone tightens the plastic nut too much

its broken on mine - if I pull it out it pulls itself back in, so for a while I was holding it half choked while it warmed up for a minute. I have been able to hold the pieces together with a couple zip ties, and that works, but eventually I will need to replace the choke cable, because the part that holds it in place is crimped onto the assembly.

If you are having trouble with it idling when its cold, that could be part of it, the choke knob drifts back in by itself.... ?
 

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Discussion Starter #14
Idling is no longer an issue. Pretty sure it was just bad gas gumming up the carbs. After running the tank down and adding another tank it fires right up now. I did turn the screw a half turn counter clockwise to get it to idle right but it also fixed the backfire issue I was getting when downshifting and coming to a stop. Took the bike out this morning and it's running great! Just need to fix some minor cosmetic things and it should be good to go.
 

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Discussion Starter #15
Thanks again for the help and the warm welcome!

I just need to find some aftermarket front turn signals. Unfortunately the stockers don't use the pretty normal/standard 10mm threads that most aftermarket options use.


I like the look of something like this.

https://www.jpcycles.com/product/220-0521/kuryakyn-by-kellermann-chrome-bullet-atto-amber-turn-signal?mrkgcl=444&mrkgadid=3303098870&utm_source=bing&utm_medium=cpc&utm_term=Brand&utm_campaign=Bing+Shopping++Generic+-+Lights+and+License+Plates&utm_content=pla&creative=77446907763711&device=c&matchtype=e
 

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Discussion Starter #16
Went into dealer and bought new plugs. Got 3 of the 4 replaced using an 18mm socket. The rear passenger side for whatever reason was not machined the same and my socket was too thick to get in that bore to get that plug. My bike did not come with a toolkit, so I don't have the spark plug tool ; (

The dealer also had a K&S catalog and was able to find me replacement factory turn signals. So I should hopefully be able to get the thing back to normal.
 

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did you look down in the spark plug well to make sure there was nothing in there? The plugs are somewhat buried in there, and also if you get water in there it will pool at the bottom. I always start my RS up after washing it so those little puddles will evaporate out.

it is a tight squeeze to get the 18mm deep socket in and then get a torque wrench on it. I did not use a special designed spark plug socket (with the foam inserts and all that).
 

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Discussion Starter #18
I will use my air compressor and blow out that area to see if there is a small pebble in there or something. It feels like the socket is just too thick and it's hitting the walls of the bore.
 

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Discussion Starter #19 (Edited)
Also, one last thing I noticed on the bike... I can push the headlight in and out... Seems the bottom of the headlight is fixed (looking at the design it looks like it uses springs to provide pressure) the top can pivot into the housing if I press on it lightly. Shouldn't it be rock solid? I pulled the headlight out and I don't notice any missing springs/clips. There is a small notch that towards the top of the headlight housing and everything there seems good too... Looks like its some type of press fit retention blade type deal. I went ahead and used a hammer an lightly tapped it to apply more tension. It helped, but the headlight still moves about 1/4" in and out of the housing.

I assume this is just normal with this older designed bike?
 

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a really useful resource for yamaha bikes, if you dont have the factory service manual PDF

goto www.bikebandit.com click on OEM parts

then Yamaha

then select your year and model bike

then on the left side click on ELECTRICAL > OEM > HEADLIGHT

and it will show you the exploded motorcycle drawings with all the parts in that area, and under the name of each part and the price if they sell that part

you can select in to just about any part on your bike, it helps to see what is suppose to be in there (for stock parts), if you are missing something, or someone changed things

esp useful if you pull a carb apart

I would just post a link to the page for your exploded headlight drawing, but for some reason the links dont aways go all the way to the drawing page - you have to go to the website and click thru the tree

it looks like there are springs involved that are used for the headlight alignment, the screws pull it one way, and the springs push it back the other... so unless your springs are broken or frozen or missing it appears you can push on the outer headlight lens, and the whole thing will push in a bit.

look at the drawing and see if that seems right with what is on your bike.
 
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