Author Topic: effen helicoils in spark plug holes  (Read 1281 times)

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Offline camelman

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effen helicoils in spark plug holes
« on: June 11, 2010, 09:17:55 pm »
I just got a CB500 four back together and started it up.  There were a few standard growing pains, but the oil quickly held tight, the engine revved like a turbine (4 into 4 sounds great by the way), but then I noticed a hiss when I stopped the engine.  It came from the #1 cylinder which we installed a helicoil in.  The PO had butchered the spark plug hole and left a mess.  Anyway, the plug would not seal to the remaining surface, which meant it kept leaking gasses.  I thought about using another washer, high temp epoxy, even gasket material, but those all seemed like band-aids.  Then, I found some spark plugs from my old S-10.  They were slightly larger than the 500F plugs, so I pulled off a crush washer, doubled it up, and installed.  Hissing gone.  Everything holds.  Camelman is happy.  Now, I just need to figure out why raw fuel is pouring out the #2 exhaust.

Now, on a different note, the 4-4 sounds AMAZING!!!  It is freaking phenomenal.  I thought I was in love with this bike after we finished it, but then I picked up a 1972 CB450 for a friend and got it going.  I have now jumped the fence squarely into twin land.  Yep, I am confident enough to admit that I likes twins... in any form... cylinders... you get the point.

Okay, back to the Tecate.  You all have a wonderful night.

C-man
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline Luk_E29

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Re: effen helicoils in spark plug holes
« Reply #1 on: July 10, 2010, 12:21:44 am »

Hey!! this is Luke in SF over on 8th street..
Good to here you got that 500 all done.  Still working on mine! Hard to find time with school but im almost done with the engine rebuild, it has been quite a learning experience. 

On to twins huh?  sounds cool.

Did your buddy,  umm Eric?? Cant remember  :-\  Figure out the seat mold he was thinking about? We talked a little about me possibly trying to vacuum form it at school but my shop is shut down for the summer, Academy of Art seriously neglected some fire codes hahaha, Anyway I lost his number.  If he still needs to vacuum form it, i will have access to the machines in September. and would be up for trying to help.   
If he did make a mold I may be interested in buying a seat from him for my bike.  ;D     Can you let him know im still interested in trying to make a mold or if he has already done that possibly buying a seat from him... if he's making them.   

you still have my number?  808-756-5705

Cool. Have a good weekend.

Luke

Offline Old Scrambler

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Re: effen helicoils in spark plug holes
« Reply #2 on: July 10, 2010, 09:08:58 am »
Camelman........A time-sert thread repair is best for aluminum heads............your patch has lifted the plug a small amount from the chamber and could cause it to foul and do other nasty things to the chamber over time.
Dennis in Wisconsin
'64 Triumph Cub & '74 Honda CB750 Bonneville Salt Flats AMA Record Holder (6)
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Offline crazypj

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Re: effen helicoils in spark plug holes
« Reply #3 on: July 10, 2010, 09:38:03 am »
Timesert is only 'best' when Helicoil wasn't done properly.
If plug is leaking it means Helicoil wasn't tapped straight
 For spark plug holes in alloy head you need copper plated Timeserts which are available in USA but may be a little difficult to locate (copper plated have been available in Europe for over 30 yrs)
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