Topic: Frame bracing

[shouse76cb]

Hello all,

I'm stripping my '76 750k down to the frame for blasting and painting and am wondering if it would be a good idea to add frame gussets while I'm at it. It's strictly street driven. Would adding them give a noticeable improvement to a bike that's not raced? If so, where would I add them? From reading here I understand that one connecting the front tube of the triangle to the tube under the seat is one place to put one. Thanks in advance for any advice.

[MCRider]

First i would say i do't know any way you'd ever be able to tell the difference on the street. Having said that, I gusseted my streetbike.    Simply because its trick, i always wanted to do it and my bike is a "bucket list" project bike.

The 2 most common are in front of the head where the ignition switch would go (so it intereferes and must be moved. Follow that tube back behind the carbs and put in one.

Next is in the "V" right above the swingarm pivot bolt.

Next would be to weld the pressfit of the steering head into the downtube. This is the 2 downtubes in front of the engine.

Looks trick and gives you bragging rights at the Dairy Queen.

Pics if needed.

[shouse76cb]

Thanks for the reply MCrider...i understand the areas you are decribing. Pics would be great too! Just so I can see the size of the gusset and everything. Yeah I figure why not...they do look trick. We have too many Dairy Queens here in Texas to not have the frame gusseted lol

[Really?]

Tagging along.

[MCRider]

Thanks for the reply MCrider...i understand the areas you are decribing. Pics would be great too! Just so I can see the size of the gusset and everything. Yeah I figure why not...they do look trick. We have too many Dairy Queens here in Texas to not have the frame gusseted lol

Gotta run. I'll post some this evening.

[Dyrden]

I'm in.

[lucky]

Better know what you are doing when you weld on a 33 year old frame and it is only 1/16 (.062 thousandths thickness).

You need to know which way the weld goes how to keep the heat to a minimum or you can make the frame weaker than it was originally. Too much welding and the frame  and it can get distorted and out of alignment. You can LOWER its value.

If I saw a frame welded by a unexperienced person with a MIG welder I would just walk away.

It should be TIG welded and by a motorcycle expert, not a structural ironworker. No offense but it is a specialized welding problem.

My advice is do not do it if you are not very experienced.

I am a certified welder and a certified welding inspector with many years of motorcycle experience. I also have welded aircraft parts and parts for the marine industry.

[Old Scrambler]

Two trick areas for low cost improvements in addition to the MC recommendations.......double the thickness of the triangular motor-mount on the right side at the front....could be made from billet......and add a 1-inch curved-tube brace to the inside of the swingarm just in front of the tire.

[shouse76cb]

I'll be taking it to a shop that specializes in welding motorcycle frames here in town. Im definitely not a welder. Thanks for the suggestion lucky.
Old Scrambler- do you have a picture of the tube on the swing arm? Thanks guys

[Old Scrambler]

Take a close look at the Cycle-X race bike on his web page.  It sets about 1-inch of clearance back from the inner edge of the swingarm and follows the profile of the tire.

[MCRider]

here's the spots I had tacked off. Waste of $$ on a street bike. Wished i'd had it done on my racer, so I'm doing it now:
headstock gusset to downtube, note, do not close off the bottom of the upsidedown U:

Removable gusset for my old sytyle APE frame kit:

HD front mount, douybled up with the case guard bracket:

All motormounts were increased in size and bored to fit bolts tighter, bolts made to fit, mostly from stainllss stock. Rear top rail gusset (slightly too big)

double sided rear motor mount made by Rob Voxonda

swingarm gusset (too small)

other welding included moved and permanent rear pegs, fork dampener mount, pad on base of sidestand.



Removed and replaced swiingarm bosses (long story)


I took my cues on the frame stuff from racers here and from Tony Foale frame guru. He says often with old Jap bikes the frame is more important to shore up than the swingarm.