Damaged Head Pipe Threads PLEASE HELP!

[Mythos]

I am installing a full system exhaust and have discovered that just one of the threaded holes the header bolts thread into will not accept a bolt. The bolt threads in a couple turns and the bolt goes crooked and stops. I have not tried to force the bolt in farther. I have tried a different bolt but it seems to do the same thing. I have seen a couple chips of aluminum come out of the hole and now I do not know what to do.

Can anyone suggest some steps to take to solve this problem?

 

[Freechance]

Well i would get u a metric tap i believe its a 8mm x1.25..but maybe someone can chine in on that size..
I would slowly work the tap in until a good bolt will thread easy by hand.. And throw those bolts away especially if there damaged u dont want to risk messing up other threads..
U really got to make sure the bike is cold when u take bolts out of aluminum because it can mess the threads up..not saying u did that..or corrosion or something on the bolt...i usually try to use new bolts or clean the old ones really good..i usually find a nut and make sure it goes on the bolt easy if u reuse bolts..but sometime the threads mess up taking the bolt out...i think u will be fine with good bolts and working a tap in slow..i would not run the tap all the way in just put it in a turn or so the back out cleaning the tap each time and use some lube on the tap..until u can run the bolt in easy by hand..

 

[Mythos]

Thank you, Freechance and thanks also for posting helpful info on this thread I recently started.
https://www.hayabusa.org/forum/gen-ii-busa-information/167745-bent-header-bolts.html

That problem is now solved but it would seem I now have another problem that is directly related .

Well i would get u a metric tap i believe its a 8mm x1.25..but maybe someone can chine in on that size..

The exact bolt is m8 x 1.25 x 25mm.

U really got to make sure the bike is cold when u take bolts out of aluminum because it can mess the threads up..not saying u did that..or corrosion or something on the bolt...

LOL, I am so incredibly slow at wrenching, that engine had to be cold as a stone when I took the header bolts out!!


Actually, the bike had been sitting for at least a week so the problem could not have been that the metal was too warm. Good tip though, thanks!

i usually try to use new bolts or clean the old ones really good..i usually find a nut and make sure it goes on the bolt easy if u reuse bolts..but sometime the threads mess up taking the bolt out...

I did end up replacing 2 of the bolts because they were bent. As you mention, I prolly should have bought all new bolts just to be safe. I did run a M8 bolt over every one of the header bolts and it spun freely over all but two. I replaced those two bolts.

..but sometime the threads mess up taking the bolt out...

I am super careful when I wrench and I even removed the header bolts with the thought in mind that they could damage the soft aluminum threads in the block. They all came out easily after they were broken loose. I don't think there is much I could have done to avoid the problem I have so I feel a lot better. One of those things that might have happened and gone without mention if I had the exhaust installed for me at a shop. I guess I put more effort into starting that bolt when putting it back in. That did not help. lesson learned. Glad I did NOT go harder trying to get that bolt started.

i think u will be fine with good bolts and working a tap in slow..i would not run the tap all the way in just put it in a turn or so the back out cleaning the tap each time and use some lube on the tap..until u can run the bolt in easy by hand..

Thanks, Freechance. I feel 10x more confident now. I will pick up a new m8 x 1.25 x 26 SS bolt today at Ace Hardware and find the right sized tap to run through the bolt hole in the block. I'll post up the results on this thread///Thanks again for all of the help.

Daron

 

[Mythos]

FREECHANCE!!! YOU DA MAN!!!!!!!!

$11 got me this m8 x 1.25 tap and tap wrench. I used WD-40 and I was careful to get the tap started perpendicular to the engine. It did exert a tiny bit of slow pressure to turn it....the thing was cutting away chunks of aluminum after all.

The depth I chased the threads to is marked by the blue tape. I turned the wrench exactly two revolutions. That was what it took to get past the bad spot I guess. I cleaned the hole out with a Q-tip and WD. The new bolt went right in.

If anyone else has this problem, I would recommend a chuck style wrench like the one I got. If you get a simple vice type wrench, there will be greater control but the T handles prolly will get in the way. The one I has allows you to reach in at the bolt holes. The T handle also clicks back and forth if you want to get it out of the way while you turn.
View attachment 1560036

Thanks again for th eexpert advice, Freechance. It's not too often that I get myself into a sticky spot like this one. :duh:

 

[Freechance]

Thats great u got it fixed..
Ya i bought a cheap set of taps from autozone 3mm to 12mm i think it was but the t handle sucks..i seen a complete set with die at ruralking for under 50.00 ..
I been think about buying that set ..
Those dies would be nice since your mostly messing with aluminum parts and such..especially with some of the bolts have corrosion or locktight or what ever on them...

 

[Mythos]

I might pick up a set myself. If you see a good deal, don't wait too long....it always comes in handy down the line.

Thanks again, pal. Thanks for the great description and important details such as "don't tap the whole depth." This was very helpful to me and I hope others will benefit from this if they have the same kind of scare.