Needing HD Head Studs??

[wrekd]

I just put new rings in my quad because the old ones were shot and it was smoking bad. So I took it out the other day for a break in ride, and all was good. Changed the oil and then went out yesterday. We rode all day and then the last 5 minutes of the ride it sounded like I had a real bad exhaust leak. The quad lost alot of power and started smoking a little bit. So I limped it back to my buddies house, it was still idling good, but when I revved it up you could just hear the air coming right out. Looked at the engine and there was oil leaking out of the head. So Im guessing I blew a head gasket??

I gotta rip it apart yet, but I dont think it did any internal damage. It wasn't knocking or anything, just sounded like an exhaust leak.

Im definitely getting the HD stud kit. What else would you guys recommend while I have it ripped down again. I want it to be reliable. I was thinking about putting a stock jug back on, but I really like the added power of the 440 kit. So if there is any other HD parts you guys think would help, lets hear em.

Thanks

[F-16Guy]

Studs will solve your problem. Don't get rid of the 440 kit.

[mcgrath]

X2 hd studs will fix the problem

[TRXRacer1]

You know the studs aren't the problem, it's the threads in the cylinder. Get some inserts installed and keep using the studs you have. HD studs is another product that sells mainly because the majority don't understand material strengths and machining methods.

[Ryanwolfe911]

+1

[Pipeless416]

Originally posted by TRXRacer1
You know the studs aren't the problem, it's the threads in the cylinder. Get some inserts installed and keep using the studs you have. HD studs is another product that sells mainly because the majority don't understand material strengths and machining methods.

inserts? wouldn't that still require some sort of drilling and tapping? can you explain a bit further? i've really researched this a lot when i was going to fabricate my own studs, and i concluded that the stock threads are all cut and not cold formed.

edit: i understand what you're saying, that its not the actual studs, but the threads they are screwed into. i also realize that the real benefit of the hd studs is the installation process that rolls the threads instead of cutting them, not having thicker studs. I'm just interested in hearing about these inserts. sounds like a cheap alternative for many people.

[TRXRacer1]

Originally posted by Pipeless416
inserts? wouldn't that still require some sort of drilling and tapping? can you explain a bit further? i've really researched this a lot when i was going to fabricate my own studs, and i concluded that the stock threads are all cut and not cold formed. I'll keep it simple, it's all about a proper footprint. The practice of using inserts oddly has been around for a LONG time. I've built some wild 2 strokes back in the day that made enough comp to pull studs. Inserts always fixed the problem(mostly had problems with Suzuki). Why do the HD studs work, because they're taking a bigger bite on the aluminum. The bigger the bite, the stronger the hold. The 400 studs aren't stretching, so all we need to do is give them that proper hold.

An insert is still machine work but parts are a lot cheaper then HD studs. I know the HD studs aren't terrible but they are totally unnecessary. The machinist will do the same work that he would for the HD stud, drill and tap to the specified new size but instead of installing new studs he'll install an insert that you just thread your old studs right back into. Most of the time they're steel but I've even seen bronze work.

[Pipeless416]

thank you :) . exactly the explanation i was looking for.

[wrekd]

Thanks for the help guys.

I still think Im gonna go the HD stud route. You get stronger studs and a better hold. Plus they're not that expensive. Whats another $55.

[F-16Guy]

Originally posted by TRXRacer1
...Why do the HD studs work, because they're taking a bigger bite on the aluminum. The bigger the bite, the stronger the hold. The 400 studs aren't stretching, so all we need to do is give them that proper hold.

An insert is still machine work but parts are a lot cheaper then HD studs. I know the HD studs aren't terrible but they are totally unnecessary. The machinist will do the same work that he would for the HD stud, drill and tap to the specified new size but instead of installing new studs he'll install an insert that you just thread your old studs right back into. Most of the time they're steel but I've even seen bronze work.

The HD studs are more about how they are installed than their size. I agree with you to a point, but can you install Heli-Coil inserts with rolled threads? It doesn't do much good to re-thread the holes in the same manner that they were machined in the first place. The majority of the additional strength gained with the GT Thunder fix is from roll forming the threads, not the additional diameter of the studs (although that probably helps, too).

[TRXRacer1]

Originally posted by F-16Guy
The HD studs are more about how they are installed than their size. I agree with you to a point, but can you install Heli-Coil inserts with rolled threads? It doesn't do much good to re-thread the holes in the same manner that they were machined in the first place. The majority of the additional strength gained with the GT Thunder fix is from roll forming the threads, not the additional diameter of the studs (although that probably helps, too). I do not recommend heli-coils. That's just a repair where an insert is more like this:

http://images.grainger.com/B289_21/images/products/small/SMALL-THREADINSERTSELFLOCKING.JPG

[F-16Guy]

Can you roll form the cylinder threads for the insert? I agree that the studs themselves aren't the cause of the blown head gaskets, but if you don't strengthen the weakened aluminum around the stripped threads, you aren't really fixing the problem. I've read about people buying the HD studs and installing them themselves, only to have them pull out also because they used a cutting tap.

[TRXRacer1]

Originally posted by F-16Guy
Can you roll form the cylinder threads for the insert? I agree that the studs themselves aren't the cause of the blown head gaskets, but if you don't strengthen the weakened aluminum around the stripped threads, you aren't really fixing the problem. I've read about people buying the HD studs and installing them themselves, only to have them pull out also because they used a cutting tap. The overbore for the insert is all you need to clean up the damaged area, it's not a large area by anymeans. A drill and tap with proper clearances is just fine for the new threads. It's not something that I can really prove to you with a keyboard. I wish I could do better for you but the larger "footprint" is all you need assuming you have quality tools and can get the holes exactly strait like a machinist would in an end mill. Your average Joe will mess that part up and poor machining is why you've heard of even the HD studs failing. A cutting tap is not the issue.

[F-16Guy]

The problem with this engine is that the forward cylinder head stud is located right by the exaust ports. The aluminum where the stud screws into can get too hot (especially with a big bore or improper jetting) and weaken, causing the stud to pull out more easily. That's why GT Thunder uses a roll form tap. It makes the aluminum more dense and re-strengthens it. If you put an insert in with a cutting tap, you're cutting new threads into the weakened aluminum, so there's a chance that the insert will just pull out like the stud did. There's a chance that it may not, but it's not a gamble I'd like to take. The studs have a larger OD and a longer reach, and that, coupled with the formed threads, makes it pretty much bullet-proof.

[TRXRacer1]

Over engineering works but it's like acting out of fear more then logic. Honda just simply dropped the ball on this one and it's an inconsistent fit. The stock 10mm size stud, which is the largest size stud you'll find in an engine like this, would actually be perfect if the clearances were dead on but they aren't always so. Ever wonder why some studs pull and others don't? It's just sloppy mass produced garbage. This isn't the only engine out there with a stud mounted on an exhaust port.

The idea that the entire area is weekended is nothing more then a sales pitch. Overbore the hole a little and you're back in good material. Don't hack the re-thread and you're good to go. Inserts are not only bigger in diameter but usually a coarser thread taking a larger, almost double the depth bite into the aluminum.

This easily goes in the category of mass thought/internet BS. If you've ever spent time designing and machining you'll get it, if not then you're in the majority and it's easier to go with what you've heard.

[F-16Guy]

I agree with you about production quality, and properly installed inserts will probably hold, but I don't think anyone can dispute that the strength of aluminum degrades significantly when overheated (300-350 degrees). I think the reason some pull and others don't has a lot to do with production tolerances, but also with people modding the engine and not jetting properly or otherwise overheating the engine. My point is just that making the threaded area more dense would be preferable to leaving it like it is. You can call it over-engineering; I call it insurance.

[tri5ron]

here's some results of a simple web search for what it's worth...

http://www.portlandbolt.com/faqs/rolled-vs-cut-threads-bolts

http://www.ctemag.com/dynamic.articles.php?id=197

http://www.mmsonline.com/articles/rolling-threads-has-advantages.aspx

http://www.landisthreadingsystems.com/ThreadRolling/CNCThreadRoll.htm

[TRXRacer1]

Originally posted by tri5ron
here's some results of a simple web search for what it's worth...

http://www.portlandbolt.com/faqs/rolled-vs-cut-threads-bolts

http://www.ctemag.com/dynamic.articles.php?id=197

http://www.mmsonline.com/articles/rolling-threads-has-advantages.aspx

http://www.landisthreadingsystems.com/ThreadRolling/CNCThreadRoll.htm I think you've misunderstood me. I'm not claiming that cut threads are as good as formed, they're not. I'm just stating the fact that you don't need them in this case.

[katch26]

also keep in mind that gt thunder is selling you a 450 cam chain and selling it as this super heavy duty 400ex chain. Not saying theyre scam artists but being a good salesman is an art lol

[tri5ron]

Originally posted by TRXRacer1
I think you've misunderstood me. I'm not claiming that cut threads are as good as formed, they're not. I'm just stating the fact that you don't need them in this case.
Sorry if it appeared that I was arguing the debate.
It was not my intention for posting the links. I was simply trying to provide some detailed info. on rolled vs. cut threads.

with over 25 years in aircraft production and repair, I'm fairly experienced with hoop tension, cold forming, coining, and structural integrity of aluminum, and it's working processes.
Not trying to be a jerk here,... just providing some applicable info.

BTW- I like your avatar,...
You buying ???:D

[TRXRacer1]

Originally posted by tri5ron

Not trying to be a jerk here,... just providing some applicable info.

BTW- I like your avatar,...
You buying ???:D Never thought you were being a jerk, I just thought something was mis-interpreted. My bad!

I'm over by Wag-Aero so if you're ever in the area I'll definitely buy.

[wrekd]

So GT Thunder uses a roll form tap and the threads are roll formed also?? Sounds like the best bet and cheap insurance. Even if it costs a little more.

Overkill never left you stranded.

[wrekd]

Another little problem Im having is 3 or 4 of holes my valve cover bolts screw into are stripped out. I was thinking of fixing them with helicoils. Is that the best way to go?? Also does anyone know what size helicoil kit I need to get?? Sorry for all the ?'s, but my quad is at my friends house 40 mins away.

[Ryanwolfe911]

Heli-coils will work just fine for that. I've had to do the same to mine. You need 6mmx1.25 heli coil kit

[wrekd]

Cool. Thanks

[wrekd]

EDIT: <<< That say 8-5-09 on anyone elses comp??





Figured I'd bring this thread back up instead of starting a new one.

Well I just pulled her apart tonight and there is no internal damage or anything. Thank god, lol. But 2 of my head bolts were loose :confused: So Im guessing my studs are fine. They didn't seem loose or anything.

Im still gonna send it to GT Thunder to have them install the HD Stud kit just to be on the safe side.

Just wondering why the head bolts would come loose?? Do you guys use any type of threadlocker on the bolts?? I don't want them coming loose on me again.

[wrekd]

Oh yeah, another thing. Anyone ever hear of these guys: http://advmachining.com/400EX.html

Im thinking about getting my head port and polished while I have it apart also. He quoted me $429 for P&P, multi-angle valve job, Kibblewhite valves, valve guides checked, valve springs checked, new valve stem seals, and gasket surfaces prepped.

Should I even bother with the Kibblewhites?? He said that they won't make a difference, just that they're better made. My valves look fine to me, so I don't want to spend extra money if I don't have to. Especially when he said the above mods would only net me about 2.5-3 HP.

[F-16Guy]

Originally posted by wrekd
Oh yeah, another thing. Anyone ever hear of these guys: http://advmachining.com/400EX.html

Im thinking about getting my head port and polished while I have it apart also. He quoted me $429 for P&P, multi-angle valve job, Kibblewhite valves, valve guides checked, valve springs checked, new valve stem seals, and gasket surfaces prepped.

Should I even bother with the Kibblewhites?? He said that they won't make a difference, just that they're better made. My valves look fine to me, so I don't want to spend extra money if I don't have to. Especially when he said the above mods would only net me about 2.5-3 HP.

The loose head nuts are indicative of the studs pulling. I replaced my head gasket once before I got the studs done, and it went together fine and seemed to torqued down okay. Less than an hour of run time later, it blew again. The studs never felt loose in the cylinder, but the nuts would loosen up.

I would pass on the P&P unless you're going to install oversize valves and do a full race build. The stock head flows pretty well according to most engine builders, so that money would probably be better spent elsewhere. Maybe a 450r carb? That would make a big difference for under $100 used.

BTW -- is your piston the flat top Wiseco? No dome, just flat across the top with small reliefs for the valves? If so, read this:

http://www.exriders.com/vbb/showthread.php?s=&threadid=8316&highlight=decked+cylinder

Don't worry too much about retarded cam timing. Read more about deck height and achieving the proper squish/quench. If you have the Wiseco flat top 440 piston, you'll probably want to have the cylinder decked to zero deck height. Your 440 will run much better if you get the deck height correct and get the compression ratio up to where it should be.

[wrekd]

Originally posted by F-16Guy
The loose head nuts are indicative of the studs pulling. I replaced my head gasket once before I got the studs done, and it went together fine and seemed to torqued down okay. Less than an hour of run time later, it blew again. The studs never felt loose in the cylinder, but the nuts would loosen up.

I would pass on the P&P unless you're going to install oversize valves and do a full race build. The stock head flows pretty well according to most engine builders, so that money would probably be better spent elsewhere. Maybe a 450r carb? That would make a big difference for under $100 used.

BTW -- is your piston the flat top Wiseco? No dome, just flat across the top with small reliefs for the valves? If so, read this:

http://www.exriders.com/vbb/showthread.php?s=&threadid=8316&highlight=decked+cylinder

Don't worry too much about retarded cam timing. Read more about deck height and achieving the proper squish/quench. If you have the Wiseco flat top 440 piston, you'll probably want to have the cylinder decked to zero deck height. Your 440 will run much better if you get the deck height correct and get the compression ratio up to where it should be.


Thanks!!

Yeah Im gonna pass on the P&P. I'm gonna get a new exhaust and probably a 450R carb instead. My stock carb is all messed up anyway. Its broken where the throttle cable screws in, so its just kinda flopping around. I figure with those 2 mods I'll probably see around a 5 hp gain instead of the 2-3 from the P&P.

I DO have the flat top Wiseco. Its supposedly a 12.5:1 compression 440 kit. I don't want to deck it too far though. I still wanna be able to run pump gas. If i get a zero deck height, will I still be able to run 93??

This is my 1st quad since I was 17. So I've been out of the loop for almost 9 yrs now. I had a 97?? Lakota 300. So all of this is relatively new to me.

[Pipeless416]

Originally posted by wrekd
I DO have the flat top Wiseco. Its supposedly a 12.5:1 compression 440 kit. I don't want to deck it too far though. I still wanna be able to run pump gas. If i get a zero deck height, will I still be able to run 93??

not sure if you knew this, but 11:1 is as high as you can go on 93.. some people even have problems with that setup..:ermm:

[wrekd]

Originally posted by Pipeless416
not sure if you knew this, but 11:1 is as high as you can go on 93.. some people even have problems with that setup..:ermm:


Yeah, I read that in the thread above. But from what that thread says, the Wiseco 11:1 is actually about 9.5:1. So with the 12.5:1, I figure Im at about 10.5:1.

I think I'm just gonna leave everything alone except for the pipe, carb, SPAL fan, and HD studs. After all this I'm gonna focus on the looks department and fixing all the little stupid stuff that the previous owners have all messed up. This thing was a basketcase when I 1st got it, BUT, its slowly coming back together :D

[F-16Guy]

As far as I know, the piston issue was with the 11:1 flat top Wiseco. You may be correct about the 12.5:1 being lower, because I've heard several people say they've run pump fuel or a mix with the 12.5:1 kit with no issues. If it were actually 10.5 or 11:1, it would be ideal (unless, of course, you really wanted 12.5:1). If you're not having problems and you're happy with the way it runs, leave it alone. If you do deck it to get it up to 12.5, it will almost certainly need at least a 50/50 mix of race fuel. Flat top pistons are better able to cope with higher compression ratios because the combustion is distributed more evenly over the surface of the piston since there is no dome sticking up, so you don't get any hot spots. That may be what's helping you get away with a slightly higher ratio. If you really wanted to build a full race engine, that flat top piston would be a great foundation.

[wrekd]

Originally posted by F-16Guy
As far as I know, the piston issue was with the 11:1 flat top Wiseco. You may be correct about the 12.5:1 being lower, because I've heard several people say they've run pump fuel or a mix with the 12.5:1 kit with no issues.


It didn't say anything about the 12.5:1 kit, but I'm assuming Wiseco figured the compression ratio out the same way they did with the 11:1. It runs fine on 93 right now, so I really don't see the need to bump up the compression. Im gonna throw a compression tester on it when I get it back together just for the hell of it. The stock compresion ratio is at about 118psi at 9.6:1. So hopefully it comes out a little higher, like around 125-130psi (just ASSuming on that one...lol). But with the Stage 2 cam it might be around stock. IDK, we'll see. I'll post up what I find when I get it back together.


Oh yeah, should I use thread locker on the head bolts when I put it back together?? If so, what kind do you guys use??

[F-16Guy]

Sounds like you have it under control. Make sure you hold the throttle wide open during the compression test (a lot of people do that wrong).

No thread lock on any of the fasteners except the cam sprocket bolts if you had it off. Coat the cylinder bolts and head nuts/washers with a light film of clean oil before assembly. Coat the cam journals and lobes and the rockers and sub rockers with assembly lube.

[wrekd]

Originally posted by Ryanwolfe911
Heli-coils will work just fine for that. I've had to do the same to mine. You need 6mmx1.25 heli coil kit



Ok, I'm ready to buy the helicoil kit but I can't find that size. All I'm finding is M6x1x9.0mm.

http://www.handsontools.com/HeliCoil-5546-6-Coarse-Thread-Repair-Kit--M6-x-1-x-90mm_p_9194.html

^^^
Is that the right kit??

I can't find a fine thread kit either. This is a PITA!! lol


I ordered a set of Douglas .190 Red labels for the front today. Now I can finally put my Razr2's on. Also bidding on a set of front fenders and a black gas tank cover on Ebay. The PO hacked the **** out of the fenders that are on there now and they look like hell with the OMF scoops. The scoops actually stick out farther then the fenders. And my cylinder is getting shipped out to GT Thunder tomorrow. So its slowly getting there.