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Re:2004 Roadstar blowing carb off manifold
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TOPIC: Re:2004 Roadstar blowing carb off manifold
#1019562
MidnightRide (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
Hopcycle wrote:
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.

Yes but the carb is STILL supposed to have a clamp to hold it onto the manifold. If the clamp's not there then surely there will be huge vacuum leaks if nothing else.

I have the hypercharger as well but it's not designed to push the carb up against the manifold, only to mount to the outward side of the carb.

Is the metal clamp (like a giant hose clamp) still there? I'm sure it is but have to ask.

Oh and FYI if you hit the gold 'Quote' button in the lower right corner, rather than 'Reply', we can see which question you are actually responding to!
 
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Last Edit: 2017/08/11 12:45 By MidnightRide.
 
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#1019568
jd750ace (User)
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Gender: Male jd750ace Location: Waxahachie Texas Birthdate: 1969-10-30
Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
Cams looked good before the 400 miles and now it will barely run? Better pull those lifters back out and have a look. BTDT. Followed all procedures for breaking in new lifters on a used cam, ate them anyway. All new, all good, over 50K miles ago. Used Sealed Power HT2011 lifters.
Started with a ticking front that would not stop. Lifter would not pump up and stay, even on the bench. Does not happen often, but does occasionally.
 
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#1019581
Hopcycle (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
MidnightRide wrote:
Hopcycle wrote:
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.

Yes but the carb is STILL supposed to have a clamp to hold it onto the manifold. If the clamp's not there then surely there will be huge vacuum leaks if nothing else.

I have the hypercharger as well but it's not designed to push the carb up against the manifold, only to mount to the outward side of the carb.

Is the metal clamp (like a giant hose clamp) still there? I'm sure it is but have to ask.

Oh and FYI if you hit the gold 'Quote' button in the lower right corner, rather than 'Reply', we can see which question you are actually responding to!


Thanks for the heads up on the quote button!! I know my replies were confusing lol Yes the clamp is on andhas been very tight every time it blew the carb off.
 
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#1019582
Hopcycle (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
jd750ace wrote:
Cams looked good before the 400 miles and now it will barely run? Better pull those lifters back out and have a look. BTDT. Followed all procedures for breaking in new lifters on a used cam, ate them anyway. All new, all good, over 50K miles ago. Used Sealed Power HT2011 lifters.
Started with a ticking front that would not stop. Lifter would not pump up and stay, even on the bench. Does not happen often, but does occasionally.



I failed to mention I went with the sealed power lifters also. No indication before this issue such as the ticking. and removing the decompression solenoid and doing a compression check sort of gives me confidence the lifters haven't failed yet. but thank you for the thoughts
 
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#1019700
texasscott1 (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
It occurs to me that the backfire could be caused either by the exhaust valves not opening properly or the intakes not closing all the way. If there's exhaust pressure left in the cylinder then there's going to be a heck of a bang when the intakes open. Same if the intakes aren't closed all the way when the plugs fire.

The cam could be at fault (probably) or not having reamed the valve guides. 400 miles is about right for new lifters to wear down an old cam.
 
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#1019720
ctkog (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
First of all from California

If you verified SVS, and mentioned not reaming the guides, and problem came back, couldn't it still be SVS causing the problem?
 
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#1019724
Questcap (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
I thought SVS was typically an exhaust valve issue, but it's sure sounding like an intake valve would be hanging up, don't it???
 
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#1019727
Curt (Moderator)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
SVS is caused by bad jetting. In my experience get rid of the hokey Hypercharger and get a real true air filter like a K&N filter. Rejet your carb to better jetting and remove the air jet that the HC calls to be installed. I had a HC long long ago and had many problems like you and I developed a SVS cure which the guys use. Got rid of the HC and rejetted my carb and all was good for many years to come. There are to many places for air leaks on the rubber boot on a HC and the air/fuel value changes to much and to be honest all they are is something to try and impress people who know nothing about bikes to start with. Just my .02 and if you need any information that used to be on my site just PM me you e-mail address here. here.
 
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#1019730
ctkog (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 2 Weeks ago  
Questcap wrote:
I thought SVS was typically an exhaust valve issue, but it's sure sounding like an intake valve would be hanging up, don't it???

You're right Questcap typically the exhaust, if too low quide clearance with heat. I agree it sounds more like would be the intake and don't know if intakes ever show SVS. I don't see why not if the clearances arent' met. And I think only early 1700s that had the problem.
 
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#1019767
Hopcycle (User)
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Re:2004 Roadstar blowing carb off manifold 6 Months, 1 Week ago  
texasscott1 wrote:
It occurs to me that the backfire could be caused either by the exhaust valves not opening properly or the intakes not closing all the way. If there's exhaust pressure left in the cylinder then there's going to be a heck of a bang when the intakes open. Same if the intakes aren't closed all the way when the plugs fire.

The cam could be at fault (probably) or not having reamed the valve guides. 400 miles is about right for new lifters to wear down an old cam.


I haven't checked for the exhaust valves opening, but the leak down test gives me some level of confidence that the intake valves are closing. I should be able to install leak down tester, and rotate til exhaust valves should be open and see if I have air blowing out the exhaust. Thanks for the idea!
 
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