Engine to Frame Bolts Size Weirdness

[Cutter]

So I was checking out some titanium engine mounting bolts on ebay from Rich at RLA Developments, and comparing then to the price of some hardened aftermarket ones in the US on the TPO site. RLA ebay advert said his 12mm bolts fit all monsters. The TPO site said their bolts only fit post 2002. I queried this with Rich cos both can't be right. He said that as far as he knew they come in 10mm x 235 mm and 12mm x 258mm, and to check which I have and he could supply.
Here's the wierd bit, my old bolts (which seem to be made out of the same monkey metal as every other bolt on the Monnie) are 10mm x 262.5 and 10mm x 251! Plus each of them has a different length of threaded section.
I mentioned that I would ask on the forum and Rich at RLA said he would be very interested to know, as he doesn't want to mislead anyone... Anyone got the knowledge on the dimensions for engine/frame mounting bolts?? :scratch:

[slob]

Not sure if this will help or just add to the confusion

http://cgi.ebay.co.uk/DUCATI-748-916-ST-SS-ST-TITANIUM-ENGINE-BOLTS-NUTS-/330462189510?pt=UK_Motorcycle_Parts

Would make sense to me. since
<2001 Monsters are more or less SS Motor in 888 Chassis
>2002 air-cooled Monsters are essentially SS in ST chassis.

As for water-cooled
I have a nagging memory that someone told me that 748 and 9xx required different length engine bolts, which I only remember because it really surprised me at the time.

[Capo]

I have the high tensile bolts from TPO, made by ARP they are precision items and will not flex like the OEM ones. I torque them tighter than OEM to increase stiffness at this critical joint.
Its the length of the unthreaded part that is important, the plain part must pass through the frame lug each side, the diameter of the thread is slightly smaller and can allow more movement (and the std ones will move) this movement beats down the crests of the thread increasing the clearance further. Also the thread offers a lower contact area.

With the bolt centred in the frame, the ARP items have the thread terminated about 1mm clear of the frame lug, a hardened washer is provided to take this up.

When installing, measure the amount the bolt protrudes from each size and equalise it. Grease the thrust face of the nut.

Monsters do not have a direct load path from the swing arm to the frame, it travels via the engine and these two bolts. Any movement here will be detremental to the handling. The torque should be checked periodicaly.

[Cutter]

Slob and Capo many thanks for your responses. I am still a bit confused though. My problem is that my 96 M900 has two bolts of different total lengths, and diffferent threaded portion lenghts too. Plus I seem to remember from disassembly (a while ago now) that one of them threaded into the frame and one didn't, That seemed borne out by offering them up the other night (I didn't tighten the one that appeared to thread in the frame lug in case i got it wrong and stripped something.) Has my M900 got the wrong bolts?:scratch:

I would like to get the RLA ones (and TPO doesn't list for my model anyway) but his measurements don't seem right for my model (measurements in first post of thread).

Rich from RLA would like to know too so as not to mislead anyone. To put it simply please does anyone know how long and how wide 1996 m900 bolts should be, how long the threaded portion should be on each, and whether the two bolts are different from one another? The RLA ad for "all Monsters" is here:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330455542942&ssPageName=STRK:MEWAX:IT

[Cutter]

Capo - realise the importance of the bolts which is why I want to upgrade. Can you explain what you mean by equalising the length that protrudes each side? Does this involve extra washers or something or do the ARP ones have a nut at each end of threaded rod rather than bolt and nut? Also does't greasing the thrust face (ooh err missus) mess with the torque values? Sorry if I am being thick I am in no way an engineer... :)

[Pomp1]

Not sure if this will help or just add to the confusion

http://cgi.ebay.co.uk/DUCATI-748-916-ST-SS-ST-TITANIUM-ENGINE-BOLTS-NUTS-/330462189510?pt=UK_Motorcycle_Parts

Would make sense to me. since
<2001 Monsters are more or less SS Motor in 888 Chassis
>2002 air-cooled Monsters are essentially SS in ST chassis.

As for water-cooled
I have a nagging memory that someone told me that 748 and 9xx required different length engine bolts, which I only remember because it really surprised me at the time.

That was me Slob, bolts are about 8mm longer in a 748 frame compared to a 996

[Pomp1]

Here's the wierd bit, my old bolts (which seem to be made out of the same monkey metal as every other bolt on the Monnie) are 10mm x 262.5 and 10mm x 251! Plus each of them has a different length of threaded section.


one is front and one is rear, they're indeed different. You should also have one that is a nut+ bolt and one that is a rod with 2 bolts if my memory serves me right

[Capo]

My reference is to the S*R series, it seems that yours is a different system that I have no experience with, I defer to those that do.

Ducati recommends the application of lubricant to fasteners, the specified torque value will be based on this.

The torque value is calculated to achieve the required clamping force to prevent movement between them. The material and size of the bolt is selected to provide that force without exceeding its modulus of elasticity. Value engineering dictates that little or no reserve will be available. The ARP studs ( stud is threaded at both ends where as a bolt has a hex on one end the thread on the other) being made of high tensile material can withstand much higher torque values. Increasing the clamping force stiffens the joint.

The stud needs to be positioned centrally, slide it in from one side and observe the protrudance on the other side make the protrudance equal on both sides. Then fit the washers and nuts.

[Cutter]

Thanks chaps. Capo - thanks that clarifies it nicely.
Pomp - That sounds nearer to what I have except that both of mine are bolts (hex heads) and one seems to thread into frame lug rather than just pass through....

[Pomp1]

Thanks chaps. Capo - thanks that clarifies it nicely.
Pomp - That sounds nearer to what I have except that both of mine are bolts (hex heads) and one seems to thread into frame lug rather than just pass through....

yep, sounds about right, except I now think to remember one being an allen, but I may just be a bit confused..

[Cutter]

Sorry I meant they are both Allens - I am losing the plot here:spin:
So maybe I need to try and re fit mine (although I knackered a nut getting them off), to remind myself how they fit, and then send them to RLA and see if they will make them up, as he did say he could produce to fit requirement.

[Capo]

These guys make a conversion for 10 to 12mm
http://motorcycle.nicholsmfg.com/index.php?option=com_virtuemart&Itemid=53

This is what is involved

Thank you for purchasing our bolts. You will find they are considerably stronger and tougher than the stock bolts. Nichols bolts have proven without failure for the past four racing seasons. Five AMA Superbike riders and several AFM and WERA riders have used these motor mount bolts. More than two hundred riders in twenty states are currently using them. Lap times have been reduced as a result of the increased chassis rigidity. Installation requires less than an hour and can be accomplished with simple hand tools. Below is detailed instructions, Loctite, and torque specifications:

INSTALLATION:

We recommend you replace the front bolt first on applications requiring two bolts. It is beneficial to place the bike on a swingarm-stand to perform the installation. The rear bolt is more of a challenge due to the fact that the rear suspension places a load on it.

With the bike placed on a swingarm-stand, remove most of the suspension load when you remove the rear bolt and install the new one. This can be accomplished by having someone lift up on the rear of the bike while removing the stock bolt and installing the new one.

When drilling the frame, we recommend that you only back out the stock bolt enough to drill thru the frame plus a .25 of an inch (6mm) for 1992 or earlier models. On later models you need to drill thru the frame plus 1.25 inches (30mm). The reason this is necessary is because the holes in the engine case are not straight. These holes are cast. The stock bolt is soft enough to conform to the miss-aligned holes -- but ours will not.

Once you have done the drilling and cleaned ALL the chips form the hole, you may use the new bolt to drive the stock one out. This should be done with a soft hammer (plastic or lead) but NOT with ball-peen or a carpenters hammer. Please do not forget to use the Loctite and torque the bolts properly. The studs and nuts are shipped with some lube on them. We suggest that you remove this only after you have centered the stud and nut assembly. If you decide not to use the Loctite, do not assemble the nuts and stud without some type of lubricant or anti-seize. If the nuts and stud are assembled dry they will almost certainly gall together and you will not separate them without causing severe damage!

You will need to drill the threaded end of the frame with a .406 dia (13/32) drill. We recommend the use of a slow rpm drill motor (approx. 600rpm). The drill will most likely cut a little oversize (.002 to .005) this will give you the necessary clearance for the bolt. It is a good idea to use some cutting oil when you do this (WD-40 works well). Please make sure that your drill follows the threaded hole. If your drilled hole is not reasonably straight, the bolt may bind when you install it. Prior to installing the bolt, make sure ALL the chips are removed form the frame and engine.

After you insert the bolts through the frame and before you apply the Loctite or tighten them, please make sure you center the nuts on the bolt. Both nuts should have equal engagement on the bolt. You can do this by measuring the depth form the outside edge of the nut to the end of the bolt. Remember to install the short nut on the battery side of an 851, 888, or 916.

IT IS CRITICAL THAT THE NUTS ARE CENTERED WITHIN 1/16 OF AN INCH (1.5mm). TORQUE TO 45-50 POUND-FEET (6.2-7.0 Km).

[Cutter]

Thanks for that. Slighty concerned as the Nichols bolts appear on the famous m900 blog of an ex-UKMOC member and seem to have been a nightmare to fit.... See here:
http://m900.blogspot.com/2007/02/frame.html