Jump to content
Sign in to follow this  

Okay to drill swingarm for chain guard bracket?

Recommended Posts

I'm going to be putting a chain guard back on my bike as no chain guard worries me with a passenger. Anyway, the front tab that is on the swingarm is missing. Must have been broken off by previous owner. I do not want to weld a new one on and risk messing up the temper of the aluminum. I thought of jb welding one in, but think it wouldn't last. So, my final thought was to drill and tap a small hole on top the swing arm and bolt a little "L" bracket on that would then allow the gaurd to bolt to it. Do you guys see any issues with this as far as strength of the swingarm...I don't think a little hole is going to weaken it.....can't be any worse than the deep gouge it has now from the kickstand grinding on it when the suspension cycles. (I fixed the kick stand just as soon as I bought the bike)

Thanks guys, I'm eagerly awaiting your opinions.

Jerry

Share this post


Link to post
Share on other sites

I guess nobody wants to touch this with a 10 foot pole! :cry:

I understand. The more I think about it the more I'm leaning towards and epoxy.

Jerry

Share this post


Link to post
Share on other sites

I work for a fabrication shop and the shop guys that tig weld ss and alum. don't want to touch it for fear of weakening the arm, even though the heat would be minimal and localized. The shop forman used to ride a lot and is leary of doing it. I wish I knew if these swing arms were heat treated or some weird alloy etc. I think the epoxy is the only safe way without knowing.

Jerry

Share this post


Link to post
Share on other sites

Thanks guys. Pop riveting would be better since I don't have any tiny taps anyway.

I live in Virginia. Unfortunately, I'm in Northern Virginia now, with all the traffic and yuppies! (I grew up further down Virginia away from all this)

Jerry

Share this post


Link to post
Share on other sites

There's no way TIG welding is going to weaken the swingarm. I doubt very much that any sort of post-fabrication annealing or heat-treatment was done at the factory. And even if it was, letting the arm air cool after the welding would be just fine. But drilling two small holes for rivets won't hurt anything either if you're more comfortable with that.

Share this post


Link to post
Share on other sites

OK,, well too far for me to help out then. :cry:

I personally would not breach the integrity of a boxed section of a structural member with out having the engineering data to back up such a mod.

On the other hand,, I do it all the time when I fab, build, and modify stuff in my shop.. So,, don’t listen to me :cry: You'll probable be just fine.. but if not, and the swing arm falls apart,,,, keep in mind I said not to do it :cry:

Share this post


Link to post
Share on other sites

I think I'm gonna drill and rivet. I "think" the swingarm is clearcoated anyway, so the tig would screw that up (in a small area anyway) I'd love to fix the gouge in the arm, but I know it would be nasty looking when the clear burns off! Now if someone tells me it isn't clear coated I may be tempted. I had a MX friend look at the gouge and he says he has worse on his bike and he jumps it HIGH every weekend, but I still think about it when I'm jump'n!

Thanks guys for the info and I appreciate/value it a lot!

Jerry

Share this post


Link to post
Share on other sites

If you have to weld something on your bike, either remove it from the bike, or disconnect the battery and CDI. Otherwise, you may be buying new ones after. :cry:

Share this post


Link to post
Share on other sites

I’m not sure if the swingarm is clear coated. You could get a razorblade and test scrape an inconspicuous area to be sure. Personally, I’d prefer the look of a repaired gouge w/ some burnt clear coat over the look of a broken swingarm

Share this post


Link to post
Share on other sites

Weld or small threaded holes are no problem. The swing arm is anodized and that must be removed in the area before it can be welded. I did exactly what you are saying. I drilled 3 small holes and threaded 5mm, 0.8 to attach a chain guard bracket. If you are concerned about the holes, take a look at the right side. Suzuki already did it there. 5mm screws hold the brake hose retainers in place. I do not recommend pop rivets. Not that strong and harder to remove than screws. Buy a tap. They are inexpensive. Use metric 5mm, 0.8 or US 10-32. Good point about the CDI box. I always disconnect electronics if I can. Should not be as problem except with hi-freq but I do it for all welding.

Share this post


Link to post
Share on other sites

just make a band clamp to go all the way around it. like an old bendix bike brake. drilling a hole is a good way to get a crack started. welding shouldnt be a problem if u do one side of your bracket let it cool then do the other.

Share this post


Link to post
Share on other sites

I’m not sure if the swingarm is clear coated. You could get a razorblade and test scrape an inconspicuous area to be sure. Personally, I’d prefer the look of a repaired gouge w/ some burnt clear coat over the look of a broken swingarm

I agree, but the gouge really isn't that deep so I'm not too worried about it. Thanks everyone for the advice and suggestions. I'll let you guys know what I finally do.

Thanks again,

Jerry

Share this post


Link to post
Share on other sites

Just drill a hole and tap it, or rivet, its all good. A little hole the size needed for a small tap isn't going to affect the structural ridigity for it in the least. The swingarm on my Honda RS250 GP framed supermono racer has a hole drilled in it half way down for a brake line retainer. All box section alloy frames for road bikes have holes drilled in them for fairing mounts etc. Hell, my supermono frame has large chunks cut out of it and re-welded, new braces made up to replace ones cut out, etc etc. Think about the holes drilled into the swingarm already for the grease nipples.

I don't think a hole will promote a crack. Holes are normally drilled on the start and end points of an existing crack to stop it. Same as with a windscreen repair right?

Share this post


Link to post
Share on other sites

I put a chain guard on my Gixxer1000 using the drill and rivet technique. No problems there and that thing is under some mighty forces at times.

Share this post


Link to post
Share on other sites

Boy you guys get worked up over a little weld that the factory put there in the first place. Your shop guys must be pretty anal if they would not weld that back on for you. Have them boys TIG it back on the way it is supposed be! Either that or tell your girl friend to keep her feet on the pegs, If she does this then you don't need the chain guard. I broke both of those brackets off and grinded the welds down and haul my girlfriend all the time. Not much concern about her sticking her foot in a chain that is going to push her foot forward. The bottom side is what you need to watch out for. That and the wheel sucking a foot in! If this happens don't think that plastic guard was gonna help ya anyway. :cry:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×