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Increased backfires during rapid decelerations prompted investigation. I am a newbie and tightened the front header bolts pretty tight after discovering they were loose. Certainly more than 16.5 ft lbs. I rode the bike a few times since the tightening.

1. My question is should I borrow a torque wrench and back the bolts out to 16.5 lbs. ?

Noticing more backfires than usual but far less then before I over tightened the front header bolts it was time to FIND the rear header flange. I discovered a loose bolt and one missing. The left rear is now snug after much profanity and many different combinations of extensions and universal joint sockets to finally get it snug. Yes, I understand that these bolts are to be tightened similar to a car wheel (a little on this one, a little on that one; keeping even pressure on the part for an even tight seal) and the bike is my only usable transportation currently. OEM bolts for the rear should be here Friday FEB. 14th. Happy Valentines Day, I get to deal two of the most difficult bolts to access on the bike. But it is hard not to love her.

I have a Leo Vince SBK and read on here that the Leo's flange is thicker than stock and the stock bolts will not go in as deep. With that said I am thinking eventually studs and nuts would be a better set up.

2. Any thoughts for me switching to exhaust studs in the future? Would loctite be recommended or will these possibly need to come out at some point?

3. What studs would I use ( thread size, material, length of stud for front and length for rear)? I noticed the front and rear bolts have different part numbers; I assume different lengths.

4. What type and material of washers?

5. I saw one person suggest copper nuts for exhaust stud nuts, what material would our gurus suggest that the nuts be made of?

This is a great group and adds to the pleasures of being an SVRider.

P.S. This is on a 2004 SV650s with approx. 7,500 miles.
 

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Increased backfires during rapid decelerations prompted investigation. I am a newbie and tightened the front header bolts pretty tight after discovering they were loose. Certainly more than 16.5 ft lbs. I rode the bike a few times since the tightening.

1. My question is should I borrow a torque wrench and back the bolts out to 16.5 lbs. ?

Noticing more backfires than usual but far less then before I over tightened the front header bolts it was time to FIND the rear header flange. I discovered a loose bolt and one missing. The left rear is now snug after much profanity and many different combinations of extensions and universal joint sockets to finally get it snug. Yes, I understand that these bolts are to be tightened similar to a car wheel (a little on this one, a little on that one; keeping even pressure on the part for an even tight seal) and the bike is my only usable transportation currently. OEM bolts for the rear should be here Friday FEB. 14th. Happy Valentines Day, I get to deal two of the most difficult bolts to access on the bike. But it is hard not to love her.

I have a Leo Vince SBK and read on here that the Leo's flange is thicker than stock and the stock bolts will not go in as deep. With that said I am thinking eventually studs and nuts would be a better set up.

2. Any thoughts for me switching to exhaust studs in the future? Would loctite be recommended or will these possibly need to come out at some point?

3. What studs would I use ( thread size, material, length of stud for front and length for rear)? I noticed the front and rear bolts have different part numbers; I assume different lengths.

4. What type and material of washers?

5. I saw one person suggest copper nuts for exhaust stud nuts, what material would our gurus suggest that the nuts be made of?

This is a great group and adds to the pleasures of being an SVRider.

P.S. This is on a 2004 SV650s with approx. 7,500 miles.
I don't have experience on this specific issue, but I was an auto tech for 25 years in my previous life. Almost ALL manufacturers use copper nuts on exhaust manifolds. So I would recommend the same if you switch to studs. I would take it a step further and use copper pinch nuts so you don't have to worry about them backing out. Preferably use a flange nut so you don't need a washer, otherwise I would use a stainless washer.
Any loctite would need to be spec'd for high heat.
 

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I am an airplane mechanic, not an auto or bike tech. With my background, I recommend you borrow a torque wrench if you can. Specs are given for a reason. I wouldnt think over torquing the head bolts would cause backfiring though. Maybe that's a fuelling issue?

As for the exhaust bolts, I'd recommend pulling one out to see how far it actually goes into the threads. Unless the Leo's flange makes a difference of more than one of two threads, I wouldnt worry too much about it. Just make sure again that you torque them properly. Maybe invest in your own wrench. Doesnt have to be a super nice one, just has to get you in the ballpark. I also have a tendency to over torque things :p
 

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I am an airplane mechanic, not an auto or bike tech. With my background, I recommend you borrow a torque wrench if you can. Specs are given for a reason. I wouldnt think over torquing the head bolts would cause backfiring though. Maybe that's a fuelling issue?

As for the exhaust bolts, I'd recommend pulling one out to see how far it actually goes into the threads. Unless the Leo's flange makes a difference of more than one of two threads, I wouldnt worry too much about it. Just make sure again that you torque them properly. Maybe invest in your own wrench. Doesnt have to be a super nice one, just has to get you in the ballpark. I also have a tendency to over torque things :p
"I wouldnt think over torquing the head bolts would cause backfiring though. Maybe that's a fuelling issue?"
To clarify the backfiring was before I tightened the header flange bolts that attach the header to the head.

Fortunately for me I have a Tool Library a half mile from my home. It was started with a $100,000 grant that our zip code was awarded for recycling the most trash instead of putting items in the garbage.

The premise of the Tool Library is often homeowners will buy a tool for a project and later never use the tool again. This again helps reduce waste. A membership is $50 a year or $500 for a lifetime membership. They have everything from an autoclave to sewing machines. Yes, a personal torque wrench is likely necessary to correctly work on my bike.

Thanks for your input. I will get use to using a torque wrench.
 
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