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Old 03-15-2011, 09:17 AM   #1
CurlyMike OP
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TIME-SERT® on GSPD head bolt

OK, long story made real short. I have been after a deal for 9 months that finally went through over the weekend. My new daily rider. Its a 91 R100GSPD. The PO, an inmate here, dies and his wife was selling all of the bikes. Legal battle in family, bla, bla. So I got it home. Carbs off, OK, looks like he was going to put Mikunis on it. Just had the heads dual-plugged. Battery was dead. Tried an old battery and it tried but no go. Noticed a small puddle of oil from the left side under the valve cover. Decided to check the torque specs because of all of the new thing. The valve cover nut was just hand tight and no small 8mm nuts.

So when I checked the head bolts that hold the rocker I discovered a huge issue. The bottom intake will not tighten and is pulling the head bolt out. The others were at 45 pound which I know are way too much. I go to 30 and stop. So I am going to have to put a Time-Sert in it. I dont want to do the helicoil. I can pay a local shop to do it for $30 buck or do it myself with a friends set. Does anyone know the correct size, specially the depth that I will need? By the way, this was the short version...
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Old 03-15-2011, 10:45 AM   #2
Wirespokes
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Nice looking bike!

Now you'll have to double check all the fasteners on the whole bike! What was he thinking???

The timesert kit is about $60 as I recall. And it may be wise to purchase the kit considering how over-torqued that side was. They may be holding now, but who knows if they'll pull out in the future. At least it's a lower one and you won't have to worry about the oil galley.

I'd measure how deep the stud went, then get that length timesert. That would be a pretty easy measurement to make.

$30 doesn't sound like a bad price to have the time sert installed - just the insert itself costs six or seven dollars.
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Old 03-15-2011, 11:00 AM   #3
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First off, you can't see how tight something is by seeing how many ftlbs it takes to move it for static friction. A lot of people call it "stiction". At least when it is applied to forks. The force it takes to start something moving is ALWAYS at least a little more than what it took to get it there.

Checking the nuts thusly sounds like a perfect way to pull more studs.

Every manufacturer I know of including BMW uses Helicoils to strengthen threads versus timeserts. Your engine already has a least a couple coil inserts (the generic name for the brand name Helicoil) installed at the factory because they work better than Timeserts but they are harder to install correctly and there are numerous ways to install one incorrectly. It's a one time repair, I would have it done right with a coil insert.
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Old 03-15-2011, 11:32 AM   #4
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I've got a couple of helicoils holding studs in and they are working fine. Just have to make sure to do them properly, as SS said. Like everything else on the bike- can only cheap out so far. You will probably use 12point coils, the longer ones, as I recall. I think regular ones have 7 coils or thereabouts and arent deep enough.
I have a fear of going over 22 or 23 pounds on those head studs. They dont need it.

Still and all, the first time I blew one out i took the bike to the machinist and he charged me $20 for doing the work on the bike on the trailer. I brought him the helicoils, he had everything else. Talk about a good deal to get back on the critical path in a hurry, that was well worth it.
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Old 03-15-2011, 12:14 PM   #5
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Quote:
Originally Posted by supershaft View Post
First off, you can't see how tight something is by seeing how many ftlbs it takes to move it for static friction. A lot of people call it "stiction". At least when it is applied to forks. The force it takes to start something moving is ALWAYS at least a little more than what it took to get it there.

Checking the nuts thusly sounds like a perfect way to pull more studs.

Every manufacturer I know of including BMW uses Helicoils to strengthen threads versus timeserts. Your engine already has a least a couple coil inserts (the generic name for the brand name Helicoil) installed at the factory because they work better than Timeserts but they are harder to install correctly and there are numerous ways to install one incorrectly. It's a one time repair, I would have it done right with a coil insert.

GM allowed time serts for repairs in their engine remanufacturing program but not coil inserts due to better hold up in their durability testing.
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Old 03-15-2011, 12:28 PM   #6
CurlyMike OP
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Stagehand, where did I say I was trying to do this the cheapest way? I want it done right and done right the first time, that is all. I think this debate could go on and on about Helicoil versus insert. Like tube or no tubes on tires or oil and tire preference, Coke or Pepsi...

Right or wrong I am going with the Time-Sert. The PO on my last daily rider used a coil to fix the center stud on the valve cover and Paul Sturgis had to fix it with an insert after he pulled that out as well. My main question was about the depth, like Terry was saying.

I always error on less force. Most important tool in the box for be before and after this is a good torque wrench and trust in manuals...

I just need to know what size insert I need to make sure this cycle shop has one. He is an older fellow that has worked on bikes for 50 years and he just wants to make sure he has the right one if I am going to bring him the bike.
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Old 03-15-2011, 12:51 PM   #7
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Quote:
Originally Posted by Big John Sny View Post
GM allowed time serts for repairs in their engine remanufacturing program but not coil inserts due to better hold up in their durability testing.
GM? I don't know about GM. Motorcycles are another story. Look at any thread strengthening on any motorcycle and I believe you will find coil inserts. Airheads have them installed at the factory in some of the transmission and front cover threads. They are better IMO. BMW's too.
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Old 03-15-2011, 01:00 PM   #8
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No offense, meant, Mike. I must have been drunk. I just looked at the specs for time serts and I think you are looking for the 9 or 11mm depth, not deeper. I still seem to remember the 12 point being a solid fit, (and what with an M10bolt probably doing 1.5mm pitch; that being a 9mm case thickness I guess) and the 14 that comes with the kit might work for being that its not one of the oilers so I guess I'll just watch and learn from here.

Nice bike by the way, congrats and the red and white ones are the coolest.
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Old 03-15-2011, 01:21 PM   #9
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Quote:
Originally Posted by supershaft View Post
GM? I don't know about GM. Motorcycles are another story. Look at any thread strengthening on any motorcycle and I believe you will find coil inserts. Airheads have them installed at the factory in some of the transmission and front cover threads. They are better IMO. BMW's too.
I use both, never had any failure of either. I believe both are a significant improvement over the original parent material if done properly. Gm only let us use those for repairs because they (time serts anyways) showed improved strength even over the original cast iron block material for even critical (head bolt/main bolt). I had no failures on PPAP test engines and they do some pretty extreme testing on engines. I dont think he has any worries whichever route he chooses.

BTW: My Gixxer had inserts in the aluminum frame from Suzuki. As has been mentioned, 10 different people will have ten different opinions if you listen long enough.
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Old 03-15-2011, 01:23 PM   #10
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Thanks SS, I might be a bit sensitive about it as well. I have waited 9 months to ride it and now have to wait some more. Its better than riding it for several weeks and finding out it has issues.

Thanks for the info, thats what I was hoping for. I am going to order both so that we dont have to wait for the right one...
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Old 03-15-2011, 02:27 PM   #11
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timeserts are simply a newer iteration of the old threaded insert (helicoil is a brand name) technology.
There are many flavors of them. alot are solid inserts instead of threaded coils.

the keys to making it work in this application are (off the top of my head):
  1. correct material to suitably match the parent material
  2. machining work done perfectly normal to the flange surface
  3. correct depth of insertion of the insert or else properly sized (# of threads) insert
  4. if it has a flange on it, machining or blending it off or cutting a relief in the case
  5. depending on the stud, ensuring that the oil feed hole is not blocked as a result of the repair
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Old 03-15-2011, 03:22 PM   #12
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one more thing that might be helpful if you aren't planning to remove the case.
I had planned on making one of these and like everything, progress keeps slipping.

Anyway, I knew they sold repops of these but I didn't know you could rent them!

RENT LINK

I used one of these tools (borrowed from Anton at the time) when I did this repair a few years back.
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Old 03-15-2011, 03:37 PM   #13
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Thanks for that, I am planning on using an old cylinder that has some bad pitting to put off and make as the jig...
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Old 03-15-2011, 04:18 PM   #14
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Quote:
Originally Posted by CurlyMike View Post
Thanks for that, I am planning on using an old cylinder that has some bad pitting to put off and make as the jig...
Please take some pics of it. I have a cylinder from Stagehand (the circlip incident) that he was kind enough to give me and I had planned on doing the same thing. Again... someday. But any tips/pics would be greatly appreciated.

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Old 03-15-2011, 04:49 PM   #15
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The cut off bottom of an old cyklinder makes a perfect jig for drillig a straight hole.

BMW sells a longer version of the time cert specifically for this application..already impregnated with sticky stuff so it won't come out.

All the studs should measure the same distance from the case. exactly 10" if I remember right.

Check to see if the bottom holes go all the way into the case..not in front of an engine right now. I know the top ones don't but seem to remember the bottom ones do so you have to watch for shavings from drilling and tapping.

Easy fix with the right size drill and tap.
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