Topic: Replace Header Studs With Allens?

[MattFreeman]

Is there any reason that I shouldn't replace my header studs with allen bolts on my CB750F1?

I would think that as long as they are proper length and torqued correctly that it should be fine but I thought I would ask.

[MCRider]

Is there any reason that I shouldn't replace my header studs with allen bolts on my CB750F1?

I would think that as long as they are proper length and torqued correctly that it should be fine but I thought I would ask.

I did. You want to catch at least 8 full turns of thread. Whatever length that is. IMO

[MattFreeman]

No negative repercussions? Bet it looks great. Do you need to check torque more often/at all?

[MCRider]

No negative repercussions? Bet it looks great. Do you need to check torque more often/at all?

Nope. Got em at ACE, black with chrome washers. Torque? What's that?  Tighten them till the crush washer gives, then a skosh more.

Its a lot easier to get the engine in and out of the frame without those header studs sticking out, not that I ever needed to do that... 

[MattFreeman]

[/quote]
Torque? What's that?  Tighten them till the crush washer gives, then a skosh more.
[/quote]

My sentiments exactly. I just wanted to sound fancy.

Glad to hear at least one component of my "vision" dosen't need altered.

[benjamin550]

What about things like float bowl screws? Mine are all stripped and Allen screws sound perfect since your working in tight spaces.

[MCRider]

What about things like float bowl screws? Mine are all stripped and Allen screws sound perfect since your working in tight spaces.

NO you absolutely cannot use Allens in an application like that, way too confusing...




JK   

[benjamin550]

MC- Thanks for the warning man, I was just about to do it too! Who knows what would've happened if I had done something CRAZY like that?!? Whole bike mighta done BLOWN UP!






But seriously, thanks.

[camelman]

The bolts should work fine, but there was a reason for the studs to be used.  Bolts typically spread their load over the first 4-6 threads with the first thread taking most of the tension load.  Each time you torque down a bolt, it will slightly yield that first thread.  Do it enough times, and the thread fails.  Not much of an issue if you aren't tightening and loosening a lot, and not much of an issue if you have plenty of other threads that can take that load as the first thread fails.
Studs are used, especially for steel into aluminum, to minimize the likelihood of stripping out the threads in that hole.  So, be careful when you tighten them down, and I wouldn't recommend it if you expect to have that exhaust off much.

Camelman

[Steve F]

Studs should be used for the exhaust-to-head fastening.  Reason being that you're trying to draw the header pipes up tight to the head and if you're using bolts, the drawing-up forces, combined with the turning of the bolts can (and have) strip out the threads in the head.  If you use a stud, the stud gets inserted to full depth BEFORE any stress and possible stripping of the threads are possible since there is no turning and pulling going on at the same time.  Bolts LOOK really cool, but the headache of fixing stripped threads in the head is just a PITA!
If you feel lucky, go ahead and use the bolts.
Steve F

[MCRider]

Can't disagree with camelman or Steve, makes perfect sense.

Gives me the opportunity to expound on one of my pets, tightening things too tight. Things that are squishables like spark plugs, oil drain bolts, oil filter bolts, tappet covers, and exhaust header bolts should not be manhandled. They should be drawn up to the point where their squishable washer becomes squished then another skosh and that's it. If it leaks, tighten it a bit more.

If someone is using the stud or the bolt (if so inclined) to leverage an exhaust header into place one is asking for problems. The exhaust header should fit into the hole or spigot nicely, then be drawn up properly with little effort. If it takes effort something isn't fitting right. When it comes to aftermarket pipes that can happen.

If the pipe fits nice, and you get 4 or more threads started before any tightening really happens, all will be well (with bolts).

When it comes to stock pipes, I've seen owners tighten the rear first then try to draw the header into the head stripping the studs. Then breaking the stud trying to get it out of the head. Yikes!

So again I agree, the stock mount is the proper mount. I'll cheat fate with the bolts. And I encourage everyone to take it easy on the squishables.

[camelman]

MCRider,

Could I interest you in a possible job assignment?  It would entail searching out all current owners of motorcycles that I might buy at some point in the future, and teaching them the lesson you just stated so that I never again have to deal with stripped out threads.  I don't have any money to pay you with, but I'm sure the satisfaction that comes from performing a public service like this would be sufficient.  ;-)

Camelman

[Terry in Australia]

Well actually.......... Suzuki and Kawasaki (and just about every car manufacturer in the world) used bolts rather than studs, so I don't think there's going to be any problems with your intention to replace your studs with bolts.

Just make sure you use stainless steel bolts and use some anti sieze "copper grease" compound. Only problem I ever had with one of my Suzuki GS1000's was I broke a bolt that had not been moved in 10 years when I changed the exhaust system. I went to buy a new bolt at the Suzuki dealer and they told me that had I warmed the engine up first, I wouldn't have had a problem.

Oh well, I've had no issues since, and the good thing about bolts rather than studs is that you won't scratch your freshly powdercoated frame when you re-install the engine........ Don't ask me how I know. 

[MCRider]

MCRider,

Could I interest you in a possible job assignment?  It would entail searching out all current owners of motorcycles that I might buy at some point in the future, and teaching them the lesson you just stated so that I never again have to deal with stripped out threads.  I don't have any money to pay you with, but I'm sure the satisfaction that comes from performing a public service like this would be sufficient.  ;-)

Camelman

Done, not a problem!   

[MCRider]

Well actually.......... Suzuki and Kawasaki (and just about every car manufacturer in the world) used bolts rather than studs, so I don't think there's going to be any problems with your intention to replace your studs with bolts.

Just make sure you use stainless steel bolts and use some anti sieze "copper grease" compound. Only problem I ever had with one of my Suzuki GS1000's was I broke a bolt that had not been moved in 10 years when I changed the exhaust system. I went to buy a new bolt at the Suzuki dealer and they told me that had I warmed the engine up first, I wouldn't have had a problem.

Oh well, I've had no issues since, and the good thing about bolts rather than studs is that you won't scratch your freshly powdercoated frame when you re-install the engine........ Don't ask me how I know. 

Interesting points about the other manufacturers. Didn't know that. Definitley do and will use anti-seize, use it on all that sort of stuff.

I mentioned the ease of getting the engine in and out as well. Those studs nick up the down tubes.

[thehammer]

I recently broke off the nub (on the cylinder head) that the rearmost and leftmost bolt that secures the valvecover to my boss' cb 650. I took off the valvecover because i didnt want to wreck my good 18mm with a grinder to change spark plugs(take a look at plugs 2 and 3 on a cb650 sometime). the bolt broke off flush in the head, so, I drilled it out. I should have used a helicoil right away but i thought maybe I could get that 6mm or so lenght of bolt out clean with an ez out extractor. Big mistake. Boy do I feel stupid.

Heed my stupidity.  DON'T . . . FORCE . . . IT!

I suppose in your case, worst case scenaro: you have to make thread repairs. But I cant seem to fix this with jb weld and the cheapest fix is to replace the head. although the valvecover still doesnt leak.

[swellguy]

I use longer than required socket head cap screws with a nut threaded way up near the head. I tighten the cap screw into the cylinder head and use a wrench to tighten down the nut so the exhaust is snug to the cylinder head.

[turboguzzi]

Well actually.......... Suzuki and Kawasaki (and just about every car manufacturer in the world) used bolts rather than studs, so I don't think there's going to be any problems with your intention to replace your studs with bolts.

Just make sure you use stainless steel bolts and use some anti sieze "copper grease" compound. Only problem I ever had with one of my Suzuki GS1000's was I broke a bolt that had not been moved in 10 years when I changed the exhaust system. I went to buy a new bolt at the Suzuki dealer and they told me that had I warmed the engine up first, I wouldn't have had a problem.

Oh well, I've had no issues since, and the good thing about bolts rather than studs is that you won't scratch your freshly powdercoated frame when you re-install the engine........ Don't ask me how I know. 

well, actually my gpz750 kawi has studs...  i am also for studs, less wear and tear on the soft threads . water cooled bikes and cars have less of a problem as the area doesnt get as hot as in air cooled

[NitroHunter]

I used polished stainless allenhead bolts for my turbo header installation, just made sure they had maximum grip length (thread engagement) and of course anti-seize. Everytime the header came off, it was re-installed with new crush gaskets. I didn't go crazy with the torque.

My old Cobra motored bike had allenhead bolts in the custom painted black-bodied CR29's with chromed float bowls and tops... but that was just too dazzeling to recommend.  

[bikerbart]

This helps.Since nobody is responding to my thread I think I will replace the bolts with studs.Granted its a lil too late now that I have to helicoil 1 hole.But when I am ready I will use studs.

[sebatje]

I have some studs with allens on the inside (don't know the name in english) those are great to use. You can put on your header and then screw them in, hold them with an allen key and just screw on the nut.

[MCRider]

I have some studs with allens on the inside (don't know the name in english) those are great to use. You can put on your header and then screw them in, hold them with an allen key and just screw on the nut.

That's a curious hybrid. Biker Bart could use that.

[MCRider]

This helps.Since nobody is responding to my thread I think I will replace the bolts with studs.Granted its a lil too late now that I have to helicoil 1 hole.But when I am ready I will use studs.

I saw your other thread and had to bite my lip in answering. Probably others did too. The problem is with the pipe. What can we say?

I like sebatje's procedure. Maybe you could use it. Get the pipe in the head as good as possible, then screw in the studs, then the nuts. Use big fat ones, hardened if possible, studs too.

Alos, maybe stack 2 exhaust gaskets in each port. That way the whole pipe doesn't have to draw down as far and the offending pipe may set easier. Finally, try setting the offending pipe first, lightly, then set the others. Who knows, sorry.

I've had aftermarket pipes in the past that weren't welded perfectly and they were a #$%*.

[Terry in Australia]

well, actually my gpz750 kawi has studs...  i am also for studs, less wear and tear on the soft threads . water cooled bikes and cars have less of a problem as the area doesnt get as hot as in air cooled

Well actually...... ( ) I wouldn't put my finger on a water cooled bike's header pipe mate, I doubt whether I'd notice the difference in temperature between it and that of an air cooled bike? I've accidentally touched the hot exhaust manifold on my water cooled car, and it blistered up just the same?

And seriously, excepting racing conditions (that 99% of us here aren't involved in) how often are you going to remove and replace your exhaust system? I've had my Suzuki GS1000S for 10 years and I've had the exhaust off maybe once or twice since then?

I think Sebatje's procedure is the winner here, use your allen bolt like a stud and tighten the exhaust with a nut, hows that for simple and smart, and when it comes time to pull the engine, no scratching the frame. Perfecto! Cheers, Terry.

   

[swellguy]

I think Sebatje's procedure is the winner here, use your allen bolt like a stud and tighten the exhaust with a nut, hows that for simple and smart, and when it comes time to pull the engine, no scratching the frame. Perfecto! Cheers, Terry.

Not to put too fine a point on this but I posted that earlier in the thread, with photos. Glad you like the idea.

[MCRider]

I think Sebatje's procedure is the winner here, use your allen bolt like a stud and tighten the exhaust with a nut, hows that for simple and smart, and when it comes time to pull the engine, no scratching the frame. Perfecto! Cheers, Terry.

Not to put too fine a point on this but I posted that earlier in the thread, with photos. Glad you like the idea.

That happens to me all the time too. Sometimes it takes repitition before something clicks. His allen heads were different from yours and had the aaah factor. But you're right both ways conceptually the same.

[Terry in Australia]

I think Sebatje's procedure is the winner here, use your allen bolt like a stud and tighten the exhaust with a nut, hows that for simple and smart, and when it comes time to pull the engine, no scratching the frame. Perfecto! Cheers, Terry.

Not to put too fine a point on this but I posted that earlier in the thread, with photos. Glad you like the idea.

Oops, sorry mate, my bad, it was your idea, and a bloody good one at that! 

[bikerbart]

yeah,its the pipe,I need to put the bike on a table and have a couple of buddies help twist and wrestle while I tighten them in place.F@#* that.For now I put the original 4-4 341's on it and I love it.the problem is the yosh replica pipes are much thinner at the head so if you dont get it just right it leaks.Until I do some headwork,I will leave it alone.

[sebatje]

I think Sebatje's procedure is the winner here, use your allen bolt like a stud and tighten the exhaust with a nut, hows that for simple and smart, and when it comes time to pull the engine, no scratching the frame. Perfecto! Cheers, Terry.

Not to put too fine a point on this but I posted that earlier in the thread, with photos. Glad you like the idea.

My bolts are without the head so you can screw them in, put on the exhaust and then screw on some nuts. Its great when you have not a lot off clearance between the pipe and the exhaust flange. We always use this on competition engines.

[Terry in Australia]

Yep, and they look cool too!

[754]

Finally read this..
 My immediate thought on how to cure this, is shown in post #20

 I truly am having a hard time believing, that so many of you are not familiar with(or even know the name of) the commom setscrew....

 We have been using them for years, fixed/ converted many an H-D head with them. I learned long ago with H-Ds to convert to setscrews if you want any kind of reliability.. have redrilled many to oversize, stock thread and oversize threads.

 Swellguy, your partsguy should have shown you the CCI or Drag kit to change these, been around for 25+ years.. if you want a clean look, use an acorn nut, or allen nut.

 Constant re & re of a bolt into aluminum is not good for thread life, worse if there is constant heating and cooling cycles.

 Maybe someonme can get a box Quantity, then resell in sets of 8 with a bit of markup..hopefully in bright plated.

[swellguy]

My first post actually showed the exhaust setup on my 54 Panhead which has an old metal gasket along with liquid gasket. It's not the cleanest look but for the period of bike that it is, I like it. I agree that a setscrew, especially with an acorn nut would not only do a great job but look much nicer.

On my cafe project, I got lucky in that I had a set of stainless metric socket head cap screws that were the perfect length for the exhaust flanges, so I'm pretty happy with this detail:

[754]

Didya mean 2nd last year of the no timken pans with  heads converted to shovel flange.. model..??

 I'd like to see that.. . I can conert them to outside oiler BTW..
 If you are ever up this way, come check out the shop...

[swellguy]

54 bottom end with STD jugs.