HELP!!! Pulled exhaust threads
 

One of the bolts on my brison 3.2 kept coming loose so I brought it in to clean the threads and locktite them. one of the bolts came out along with most of the threads.

Should I drill and tap? Whats the next size up from 10/32?

Suggestions please.

Thanks

RE: HELP!!! Pulled exhaust threads
 

I tapped my 3.2 and one of my 4.2s to 1/4x28.

RE: HELP!!! Pulled exhaust threads
 

the other option is go to a good autoparts store and get a heilicoil kit. in the kit is a drill and tap, and inserts that when screwed into the inlarged hole restore the original thread size. the repaired threads will be stronger than original.

RE: HELP!!! Pulled exhaust threads
 

I thought about both but was worried because there is not much meat between the bolt hole and ex. opening.
Will check parts stores in the mornin and compare the size of helicoil to a 1/4 bolt.

thanks

RE: HELP!!! Pulled exhaust threads
 

The problem is the width of the casting on the other side...A 1/4 bolt is too big, I know, I tried it, the cylinder is still here[&o]....A 5mm heli coil starts with a #7 drill, .201...Less chance of going through the side of the already narrow casting...Most of the time if the hole is stripped, no drill is necessary, just screw the tap into the hole...A heli coil kit is expensive for ony 1 heli coil, best to find a motorcycle shop that uses heli coils...The heli coil itself is cheap, about $.75.....

RE: HELP!!! Pulled exhaust threads
 

The next size up is 12-24, but I would do what Ralph said and take it to a bike shop and have it coiled to 5mm, those bolts are fairly easy to get, bolts in most 3W exhaust bolts are 5mm.

Tom

RE: HELP!!! Pulled exhaust threads
 

The ultimate fix is to install a Timersert. Unlike Helicoils which are indeed coils, Timeserts are solid and use no more space than a Helicoil. Another advantage is Timeserts roll the last thread and using the special insertion tool that comes with the kit it forces the bottom of the Timesert into the parent material so it will NEVER come out. I bought the 10mmx1.0 for spark plug holes and the 5mmx.8 kits. They run about $65 for the kit and 5 inserts. New inserts run .85 each.

www.timesert.com

RE: HELP!!! Pulled exhaust threads
 

Well i serched all over and finally found a 5mm kit. $36 ouch. for 12. Ohwell, got extra's and it is fixed. Cycle shop couldnt help.

Come to find out the original bolts are 5mm. I was comparing them to my taps and looked like 10/32 but when I went to Ace I found out different.

Thanks for all the help.

RE: HELP!!! Pulled exhaust threads
 

Don't get too excited about using 12-24's. They are usually special order. No one stocks them.

Enjoy,


Jin

RE: HELP!!! Pulled exhaust threads
 

Number 12 screws and bolts can often be found at a shop that repairs old tractors or a very old hardware store. Number 12 was a common size on forty and fifty year old tractors. No one designs with #12’s today.

Bill

RE: HELP!!! Pulled exhaust threads
 

The easiest and quickest way is to just change to a different measure. I stripped a prop lug hole on a hub. It was a 4.7mm threaded hole. By jumping to a standard thread, which is equal to a half size increase in diameter, it only required a tap without drilling a larger hole. End result was a 4.7 mm converted to a 3/16' standard. No loss of volume from a larger hole if I were to go to the next size up in metric and not nearly as large as what a helicoil requires. Joe