Subframe Bolt Upgrade How-To

[Daggy]

Hey all,

I upgraded my subframe bolts recently and thought I'd post a simple write-up to show just how easy it is. I didn't see a photo write-up on this site. I've seen the post, and it looks a little overwhelming. It really is a pretty simple job.

To start, here's the bike with the fuel tank/seat/panels removed:

For those who can't get this far, maybe some professional help would be in order. Note: I had the carb off to do the $carb shimming. Keep yours on until all drilling is done to avoid getting filings in intake(s).

Take a look at that picture again. Those four bolts hold not only the subframe and seat including you and passenger (important), but the airbox, exhaust, rear fender/light, rear cargo plate + cargo, and if you have panniers (loaded too), all that adds up to a lot of weight! Wise choice to upgrade the bolts!

The subframe is shown here by the black hash marks, with the upper bolt mount by the red circle/arrow, and the lower bolt(s) by the green circle/arrow:


When I bought my bike, the previous owner gave me a Dual Star kit to go with it that he never put on. I'm not endorsing Dual Star; this is what I used, and know about.

The kit includes (3) drill bits (two the same size), (1) alignment sleeve, (1) long upper bolt/nut combo, (2) lower subframe bolts (with 1 washer), and detailed instructions with pictures:





The last pic doesn't show the lower subframe bolts (in the next pic) but shows the OEM upper bolts as indicated by the red arrows next to the long bolt which is the upgraded top subframe bolt. (yes, that would be an upgrade!) The alignment sleeve is shown by the green arrow. The tape around one of the narrower drill bits is used as a depth gauge, as according to the instructions.

Contrary to the instructions, I replaced the lower frame bolts first. Here's why:
When you pull all 4 bolts out, the frame is free to fall back and hard to line up to drill the upper. Hint: replace the lower ones first, tighten them up (with lock-tite of course) and the frame will basically stay in place, making the top easier to drill.
Here's an old and a new lower bolt side by side. They look identical (the new is higher grade), even in a blurry pic:

They give you one washer (not shown in that pic) to use under the left lower bolt so the threads don't stick too far in and allow the chain to hit it. I told you this stuff was simple!

Here's the OEM upper bolt out:

It is kinda small in comparison to the frame strength:

The red line shows where you need to drill through. That welded cross is solid steel, not just a steel tube. (It is partially drilled/tapped for the OEM bolts)
The two upper bolts are replaced by the upgrade long bolt:


The drilling is the most difficult part of this job. I used a Milwaukee 120v hammer drill (not on hammer-mode of course!) Start first with the taped (to indicate depth) drill bit and drill through one side until you get to the tape:



Note: my photos were taken after the job was done. I didn't drill with the carb off!
It does get a little tough going, as the bits will want to grab, twist, and bind. Just go slow and steady, making sure to keep the drill lined up straight.
Another hint: as soon as you reach solid steel, pull it out and use a smaller pilot drill bit (or two) to go through. It will make drilling with the larger bits that much easier. Remember to drill straight.
It will produce a lot of drill shavings. I didn't use any drill lube/cooling spray, as I took it slow and gentle, but did use my vacuum to suck up most of the shavings cleaned up while I was drilling:

It may help to grow a third arm here.

They give you two smaller bits so you can use one as an alignment bit on the first drilled side while you drill the other side:


Let me rephrase: Drill one side to the taped depth, install the other bit to keep it aligned, then drill completely through from the other side. Not rocket science here folks!

Keep the alignment bit in, and once you're completely through, you use the alignment sleeve (which fits right inside the frame tube) and the larger drill bit to finish drilling through:



That bit wants to grab and bind too.

Once you're all done drilling, you install the upper bolt and nut and tighten it up. The nut is a special "Fuji"-style locknut:

So it is. I put some antiseize on the shaft of the bolt and a little lock-tite on the threads just to be secure .... I'm not sure what the torque specs are - somewhere between snug and tight.

That's all there is to it. It is easy to pull the carb off when the subframe is loose and can be pulled back, if you need to do some carb work ... mods, etc. (hint, hint)

I hope this makes it easier for some to understand. Now go upgrade!

Dave

[michaeln]

Great write-up, Daggy. I have already done the upgrade to mine (using Eagle Mike's drill through kit), but this will be very helpful to others.

I used cutting oil and a 1/2" drive variable speed drill motor with a right angle handle, slow speed, and it was still a difficult process to drill it. That's a big chunka steel you have to get through there.

It takes enough pressure to keep the drill cutting that the bike wants to fall over away from you. I eventually figured out that standing on the left side of the bike while drilling from the right side allowed me to pull the drill toward me and press the bike against my thighs.

[tyfi]

wow great write up thank you for the good clear description I got the kit with mine but no instructions or I lost them somewhere you have cleared that up for me thank you thank you that looks easy I will do mine right away now that I know how

[jeepinbanditrider]

I wonder how much extra strength you could gain without drilling but by adding grade 8 hardware everywhere?

[michaeln]

Originally Posted by tyfi

that looks easy

The procedure isn't complicated, but the job isn't easy either.

[michaeln]

Originally Posted by jeepinbanditrider

I wonder how much extra strength you could gain without drilling but by adding grade 8 hardware everywhere?

The $5.00 kit just has 4 12.9 (hardened) M8 bolts to replace the stockers. The $24 kit has 2 12.9 M8 bolts and one long M10 12.9 bolt with locknut, and you have to drill for that one. I am a heavy guy and like to load a buncha stuff on the back and go camping, so I opted for the drillthrough kit.

I think the Dual Star version is a ripoff. They get $49 for the same thing that sells for $24. The kits are from our own Eagle Mike.

[Daggy]

Originally Posted by jeepinbanditrider

I wonder how much extra strength you could gain without drilling but by adding grade 8 hardware everywhere?

I think a lot of guys are a little put off by the drilling method. It isn't really that hard. The biggest problem is keeping the drill/bit straight and true. If allowed to angle or wobble, the bit will bind and grab. Start from the right side to put pressure against the sidestand. Starting one of the smaller bits from the kit, it will drill reasonably fast through the OEM drilled/threaded sections. You'll know when you hit solid steel; the drilling will get a lot slower and solid. Switch to a smaller bit (1/8' e.g.) that will go through much easier. You needn't worry about it centering, as the bit will find the bottom of the drilled galley. Here's a little drawing showing the subframe on the top of the picture and the view is from the top looking down (the squiggly lines are the welded areas):


(Ok, so my picture-taking skills are better than my drawing skills)

Just remember to take it slow & gentle. Let the drill do the cutting. Nice new sharp bits help tremendously. Be patient. It'll go through. Oh, yeah, did I mention to keep it straight?

Dave

[keithm]

"I've seen the post, and it looks a little overwhelming"

I read that post and found it very informative. The author of that post is "brillent" if you ask me. It felt as if I was looking over his shoulder (or even looking thru his eyes!) as he was performing this mod. There is another detailed walk thru on removed in the HOW (hall of wisdom) section.

[threadkiller]

Originally Posted by keithm

"I've seen the post, and it looks a little overwhelming"

I read that post and found it very informative. The author of that post is "brillent" if you ask me. There is another detailed walk thru on removed in the HOW (hall of wisdom) section.

It appears to me that you are the author of the write-up. It's no wonder you find it informative and "brillent"...

[Daggy]

Originally Posted by threadkiller

It appears to me that you are the author of the write-up. It's no wonder you find it informative and "brillent"...

I have to admit that keithm's write-up was thorough - very thorough ...

Now do we have DIY tutorials on all our sites? So there's no excuse for anyone to be in the dark about the bolt upgrade!

Happy drilling!

[rider33]

'nice job and thanks for taking the time to write it up for us all.

[SWriverstone]

One other tip: when I drilled mine, I cable-tied the open end of the hose from my big shop-vac so it was sitting right there by the drill bit. This enabled me to focus on the drilling without having to hold the vacuum tube.

Of course, you could just skip the vacuum altogether...but you'll have a big nasty mess of metal shavings to clean up afterward (and I didn't want any of those getting on my bike).

Another tip: use one of those telescoping magnet-wands inside the hole to get any remaining metal bits out of there---works great! (and you'd be surprised at how much it'll come out with!)

Finally, I didn't have any specialized drilling oil (didn't even know what that is!)...but I occasionally sprayed the bit with WD-40, and it worked fine.

Scott

[johntripwire]

Daggy got the kit with the bike for free, along with other goodies. He ain't no dummy!

[hojo]

Why do you need this mod, is it for those that want to jump school buses, or is the frame bolts that weak?

[johntripwire]

Not that the frame bolts are substandard, but perhaps an engineering error on stress factors. (like my fat ass) The people at Kawi are clueless on how we treat these bikes.

John