The thread for one of the exhaust bolts at the front of the engine on my vfr is fooked.

I know i can helicoil it but i'd rather not since I did that on my previous bike and it only worked for a short time before i was back to square one.

I think my best option is to drill and tap the hole.

Anyone done this for their exhaust bolts? If so can you advise me, what tap size should i use? What bolt should I use as well (M?) ?

Thanks.

from memory the header bolt is 6mm x1 so tap it out the next size up which is 8mm or get some liquid metal fill the bolt hole and re tap the same size

[quote="Sam"]The thread for one of the exhaust bolts at the front of the engine on my vfr is fooked.


Are you sure its not just the threads on the nut thats damaged? Try running a correct size die over the bolt that sticks out of the cyclinder block. A lot of those die sets are quiet wide, you may have to cut it a bit. So you can get it to turn on the threads. And then see if a new nut will go on. Would'ent fancy drilling into the cyclinder block if you could avoid it.

dar5150 wrote: Are you sure its not just the threads on the nut thats damaged? Try running a correct size die over the bolt that sticks out of the cyclinder block. A lot of those die sets are quiet wide, you may have to cut it a bit. So you can get it to turn on the threads. And then see if a new nut will go on. Would'ent fancy drilling into the cyclinder block if you could avoid it.

Unfortunately its not the nut, i wish it was. I dont particularly want to drill and tap especially at that angle.

mart wrote:from memory the header bolt is 6mm x1 so tap it out the next size up which is 8mm or get some liquid metal fill the bolt hole and re tap the same size

Thanks Mart.

You're saying is should drill it, then put liquid metal in and then retap it to its original size?

Will this hold or a temp fix?

helicoiling is the best option,if your not confident doing it take it to a engineer shouldnt be too expensive.

Sam wrote:The thread for one of the exhaust bolts at the front of the engine on my vfr is fooked.

I know i can helicoil it but i'd rather not since I did that on my previous bike and it only worked for a short time before i was back to square one.

I think my best option is to drill and tap the hole.

Anyone done this for their exhaust bolts? If so can you advise me, what tap size should i use? What bolt should I use as well (M?) ?

Thanks.

Was it helicoiled properly? I've never had one fail :/

Ive decided i dont want to go down the helicoil route.

Could anyone tell me definately what tap size i need?

From the options which one should i go for?

The options: 7 x 1mm, 8 x 1mm, 8 x 1.25mm.

I know im making this a bit long winded but ive never done any tap & dieing before and i dont want to screw it up.

you must first look at your options of bolt, (thread) IF,you can get a 7x1.25mm stud or bolt,it sounds like you might just be able to run a 7x1.25mm tap straight in the existing hole,i think handlebar whigt bolts are 7x1.25.