Best method for mounting the engine / manifold bolts?

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East82

New Member
Oct 17, 2011
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SoCal
After reading thru some threads and being directed to a search by decoherence I wanna run this past you all and see if it makes sense and if there might be a better way.

The mounts, top and bottom, along with the intake manifold are studs. The outtake manifold is bolted on. My idea is to tap the mounts and cylinder @ 1/4 - 20 and use quality bolts, longer ones for the mounts and around 1" length for the manifolds. This will do away with all the studs.

Is this a good way to go about it or is there a better way? I'm looking to secure the engine to the frame the best way and to prevent stripping all the way around.

Thanks
 

leadfarmer

New Member
Sep 30, 2011
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VA
I guess it would make a good project, but why not leave the studs alone until they cause a problem? Also, you are tapping into (probably cheap) aluminum. How much stonger are bolts going to be.
I am not trying to shoot down your solution, but just asking if it is worth the trouble.
 

GearNut

Active Member
Aug 19, 2009
5,104
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San Diego, Kaliforgnia
You can improve the strength of the mounts by carefully tapping them out to maximum depth. The factory does not cut the threads to the full depth of the hole. Use longer studs to take advantage of the now deeper threads. The more threads you have engaged between the soft metal that the cases are made of and the threads of the stud the more reliable the mount becomes.
Studs are recommended as well as Loc-Tite blue to keep them from vibrating loose over time.
The reasoning for studs is you install them before mounting, when you are twisting them in there is no load on the soft threads of the cases. Later on when you tighten the nuts onto them during engine mounting you are not tightening against the soft threads while twisting a bolt into them, risking stripping out the soft threads. The pre-installed stud all ready has maximum thread engagement and maximum strength.

There are certain mounting situations where a stud is not possible. My Atlas is one of them. In that situation I started out with bolts that were too long and cut the bolts to thread in as far as possible, taking advantage of the new threads that I tapped into the cases. Still plenty strong enough and I do not plan on ever removing the bolts as I used a custom frame adapter. I have no worries of stripping the soft threads. Any hardware that needs servicing in the future is on the adapter, not the engine.
 

decoherence

New Member
Aug 23, 2010
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sebring,fl
i went with 1/4-20.
i used that instead of metric because 1/4-20 is a super common size.
most hardware stores have a whole isle of standard & only 1-2 trays of metric.
also my father has a ton sae tools & i have only a couple of metric in each size.

i used the tap handle to hold the drill bit & did it by hand.
it was easy & no chance of reaming out the hole.
tap all the stud holes @ once. they all have the same fault.
also having matching bolts makes it easier to know what wrench to reach for or carry.
tap slowly. back it out @ least once.
proper use it to use "cutting oil". don't have any worries to pick it up for 8 bolts.
wipe a little 2-stroke or car oil on the tap.
after i tapped, i took my dremel & ground down most of the tapper on the tap & re ran it in each hole to get threads as deep as possible.
if you can find a "bottom tap" there is no taper & it will made threads to the bottom.
you might want to pick up bolts in several sizes or you may find yourself having to return to the store. or but threaded rod & cut off what you need.
i know you were thinking of shimming the engine to get chain tension & that is why you might end up changing bolt length depending on your mounting needs.
being that the chain is a loop a 1/4 inch shim will affect the chain about half an inch.
be prepared to have some some time to get it done right.
if you get some chain stretch later, you can either ad a thin shim or loosen both mounts & see if a little tilt forward or back may fix that.
before each ride for the first few times might need a little adjustment while everything gets settled.
don't worry if your carb is level. just take of your filter to see if the carb is leaking gas into the engine.(there is an answer if that happens)

everything above is the un-proper/down & dirty way to do it.
like most will advise only using grade 5 or 8 bolts, keep carb level, blah blah.
we don't live in an ideal world & i rather you be able to enjoy your bike than worry about things that will most likely not be a problem.
there are many other threads for ideal info if you like.


if you take that extra time to get it mounted well & both chains taught, you will have little to no problems in the future.

ps. pick up a half link @ the bike shop for the peddle side in case you might need it.
pss. i appreciate your final response in the other thread. it takes a man to admit error. :thumbs up:
 

Al.Fisherman

New Member
Sep 9, 2009
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Calera, Alabama
After reading thru some threads and being directed to a search by decoherence I wanna run this past you all and see if it makes sense and if there might be a better way.

The mounts, top and bottom, along with the intake manifold are studs. The outtake manifold is bolted on. My idea is to tap the mounts and cylinder @ 1/4 - 20 and use quality bolts, longer ones for the mounts and around 1" length for the manifolds. This will do away with all the studs.

Is this a good way to go about it or is there a better way? I'm looking to secure the engine to the frame the best way and to prevent stripping all the way around.

Thanks
I don't believe in bolts for the head, intake or exhaust in these engines. I have studs since 2009 and they are as sound today as the day I installed them.

Now what I do is. Tap holes to ensure the threads are bottomed out (I use a bottom tap, but have both). Replace all studs with Metric 8.8 hardware, lock tite ( I use red, and if needed to be removed, heat is needed) them in and use a locking nut. If you enlarge the hole and tap then you have no room to do it later should you need to do it.. Torgue on 6mm is between 50 to 75 INCH pounds.
All around, a bad idea.
 
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East82

New Member
Oct 17, 2011
33
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SoCal
Here is where I stand today - tapped out the engine mounts as far as I could. I originally got Kobalt tools from Lowes, but the wrench (tried two) just would not hold the bit. Went to HD and got an Irwin wrench and that works peachy.

I am awaiting for a cylinder head to arrive and once it does I'll tap the manifold holes as well. I picked up some 3" rods of 1/4" - 20 and lock nuts (the kind with nylon on the inside). I'm also going to pick up a few 4" rods as spares.

I can cut the rods to length. I like them a bit longer than the stock hardware. Decided to go with studs vs. bolts, because they will go all the way in the holes and locktite blue should hold them and prevent stripping due to vibration.

At the end of this hack, I'll have 1/4" - 20 studs in my engine mounts and in/out manifold with flat and lock washers, and lock nuts on each.

Thanks guys

brnot
 

decoherence

New Member
Aug 23, 2010
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sebring,fl
since you went with studs, you can use double nuts to get them secure.
first tighten the first nut like normal. then add a second. hold the first nut then tighten the second nut against it. they keep from loosening that way. it also is a way to install & take out the studs.
 

rohmell

Active Member
Jun 2, 2010
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New York
I picked up some 3" rods of 1/4" - 20 and lock nuts (the kind with nylon on the inside). I'm also going to pick up a few 4" rods as spares.
What is the temperature rating on the nylon? I would think that it would get soft or deteriorate from the heat, at least on the exhaust side.
 

East82

New Member
Oct 17, 2011
33
0
0
SoCal
@ Rohmell - The nylon nuts are for the engine mounts. Taking Decorence's advice and using doubles on both manifolds.