which helicoil kit to buy/fixing 250r head stud

[JasonB]

I stripped out the front stud on my 250r's head and I think im supposed to helicoil it since the retap I tried failed under use. I need to buy a helicoil kit to fix my head on the air cooled 250r. Its a bored over 1983 honda 250R. Since I know nothing about this helicoil deal, how do I use it? Do i need to re tap the hole for a different size or will I be able to just buy the 12mm kit heilicoil offers? Is helicoil just a spring 'looking' thing I insert in a drilled untapped hole, or what? I know nothing about how helicoil works so Please explain if possible :D

Im good with my hands but have never had to deal with working with helicoil. I retap normally but I dont want to drill out the cylinder head so I can use a bigger bolt to secure the top of the head. any suggestions?

my brother thinks we should resurface the head becuase the heat may have warped it from the lack of bolt to keep the head sealed down. I dont know since Im new to 2 stroke bikes lol the engine is an air cooled 83 and is bored over to my knowledge

[Rennat_2006]

Youve got to drill the hole out a little bigger most of the time then use the tap in the kit to tap the hole for the helicoil then thread the helicoil in.

If it was ridden without a bolt in alot of heat/cool down cycles i would get it resurfaced. After the fight i had/ still may be having with the head on my ktm if i had any doubt i would have it decked.

[hrc85250r]

if you buy the kit, it will come with the helicoil tool, helicoils and it will have the drill bit size and tap you need written on it...so all you need is the kit, tap and the bit it says is needed... also, if you think this is somewhat not the perfect way to fix a threaded hole, alot of drag engines have ALL of their tapped holes helicoiled before they are put together and all aircraft engine's aluminum components are helicoil'ed from the factory. helicoils are more than twice as strong as a threaded aluminum hole when installed correctly.

[Dirtcrasher]

Yep, helicoils are the way to go.

Why did you say 12MM?? Your referring to the nut size aren't you?? Those head studs should be 8mm X 1.25 pitch and and get the longest helicoil you can in there maybe 15mm long. That kit will run about 40$ but you will use it again and again. Get yourself some spare 5mm and 10mm length coils also. That drill is gonna be slightly laarger than the hole and its gonna grab real quick, so make certain you are perfectly straight - use 2 other people to watch for the drill bit to be perfectly verticle and use a variable speed cordless drill. It is best to do crucial helicoils in a milling machine....

You'll pay 25$ to resurface that head, it's aircooled so I'd simply get a 7$ headgasket and try it.

[scooterroo]

this is a good thread, i have to do the same thing to my drain plug, grrrrrr.

[jason 32]

if your kit is 40.00 like mine was - i would take it to a machene shop i did-
im not sure on the prices any more but if its high i would let a machcene shop go a head,( the price was outrageious) for a kit!! ,and be done with it

scooteroo-- you could tap it for a standard, or a bigger size i had the same prob with my kx drain-

[Dirtcrasher]

That kit will fix hundreds of holes in it's lifetime. I have 7 kits and use them all.

When doing a drain plug or other critical areas, put lots of grease on the drill to hold the chips. Flush with diesel 2 times and cheap oil a couple of times. Then your good to go!! Careful nut to jam anything into the shift cam which is usually right there.

Going up a size is a bad thing with some cases, there just isn't the same thickness all around that area on some models and it can be a crapshoot.