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2004 Roadstar blowing carb off manifold
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TOPIC: 2004 Roadstar blowing carb off manifold
#1019536
Hopcycle (User)
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2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
Good morning gents! My name is David, and I own a small town bike repair shop. Been in operation 13 years. I'm new to the forum, although I have used this forum as a guest and am amazed at the amount of knowledge on here. I've come to pick some brains because I have a bike that is thoroughly whooping me. Here's some background info. bike arrived firing on one cylinder. found the expected SVS issue. Pulled both heads and did a valve job although I didn't ream the guides as that was before I was aware of the SVS problem. Replaced the piston rings since bike had 97k miles on it. Also found 3 of the 4 lifter plungers stuck. Replaced all 4 lifters. Bike has Kuryakyn Hyper charger and Vance and Hines long shot exhaust. Reassembled bike and it ran great for about 400 miles and then suddenly without warning started coughing so bad it blew the carb off the intake. Installed leakdown tester and front cylinder shows a 4% drop and rear at 3% which is well in spec. Had not previously touched carb, but went to it next. Found accelerator pump clogged and binding and corrected that. Found the vacuum slide actually melted on back slide, replaced that. Cleaned all jets and passages. Checked vacuum diagpram for holes, removed intake, inspected for cracks and reinstalled with new o-rings, removed AIS and plugged port on intake and the 2 lines to the heads. Verified idle screw was in far enough. Bike fires, idles rough for about 20 seconds and then blows carb off intake violently. any thoughts from you experienced Yamaha mechanics?? Any help is greatly appreciated!
 
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#1019537
Bofo (User)
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Gender: Male Location: TAMPICO, MEXICO Birthdate: 1958-09-26
Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  

From Tampico Mexico

Surely here you will find a lot of technical help.

 
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#1019544
smokescreens (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
did you check for a vacuum leak?
 
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#1019548
SKWEARpeg (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
smokescreens wrote:
did you check for a vacuum leak?


^^^^^^ Check and make sure the cap on the vacuum port the AIS connected to didn't blow off. Is the clamp still around the neck on the Manifold to hold the carb inplace? Doesn't the Kury silly charger have some sort of hardware that fastens it to both cylinder heads?
 
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#1019555
texasscott1 (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  


The first thing I noticed was new lifters on a 97,000 mile cam. 400 miles later and the problem starts again. Coincidence?
 
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#1019556
Hopcycle (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
yes sir and found none, but can't keep it running longer than a few seconds so can't do much checking
 
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#1019557
JEastonjr (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
When you put the plug wires back on did you put them back on according to the service manual? (it does matter)
 
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#1019558
Hopcycle (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
yes sir checked all that. and yes the hypercharger mount to the heads, but the rubber boot has enough flex to still allow carb to blow off.
 
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#1019560
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
I thought of that but cam lobes looked to be in great shape.
 
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#1019561
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
yes sir absolutely sure plug wires are on correctly.
 
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