350X and cracked frames

[FlyingW]

It has become apparent to me through many hours of reading that the frame of the 350X is prone to cracking in the areas of the swing arm mount. Has any of you guys encountered this problem and if so, what did you do to remedy the defect? I can slap a weld bead on it but it's just going to come back. What shoudl I do? :bash:

[350xhilaration]

Replace the frame is the only remedy I can see being a complete fix. Mine popped in the same place on the high side. It's been welded and hasnt cracked again...yet.

http://www.350xriders.com/crack1.jpg
http://www.350xriders.com/crack2.jpg
http://www.350xriders.com/crack3.jpg

[Black Sheep]

this is all too very common on 85's and the first production run of 86's. on the second run of 86's Honda added some material to the back side to reinforce the frame.

myself i'd have to say out of the hundred or so 85 and early 86 frames i've seen over 75% were cracked in the same spot.

the problem stems from the frame flexing to much and using the motor as a intragal part of the frame. you'll notice that the motor mount right above the crack is a "hanging" mount on the other side that leads to a lot of motor flex thus causing the frame to crack.

i've repaired them in many differant ways and the best sollution i found was to reweld the entire frame and gusset the problem area.

[FlyingW]

Thanks Mr ATC for the insite in to the problem. I have shown a picture of the problem to a couple of mechanical engineers at work and they came up with the same conclusion. This is a milestone for the bookworm engineers to apply some practical theory to a real problem and come up with a viable solution validated by a guy who lives in the real world. Anyway, I went and saw a welder today and he is going to fix me up. One question, are there any other areas that need to be beefed up while I have my trike at the welders? :fire:

[FlyingW]

One more question Mr ATC. Is the other side of the frame opposite the cracking on the left prone to cracking in the same way? I realize that welding a gusset on the right side of the frame poses a problem due to the utilities that run through or mount in that area. Suggestions????:doh:

[FlyingW]

One thing that bothers me about this problem is this, if the engine mounts are transfering the force to the frame causing it to crack then wouldn't it be consistant to see more cracked or broken engine mounts on the case? Surely, the steel frame is stronger than the the aluminum cases.

[NOS_350X]

Well right now i have a 350x thats torn appart because of a cracked case and cracked frame. Does that answer your question?

I have yet to see the frame crack in the lower spot. I would just throw a weld around it, grind it down and get a piece of pipe that slips over it, cut the pipe in half and weld it on. Now its twice as strong. The frames you cant get a good weld on because the metal is so thin.

The other part of the frame that cracks is on the left side tube that goes from the grab bar area down to common problem area. It normaly brakes about 1-3 inches away from where it comes together by the grab bar.

[Black Sheep]

"One question, are there any other areas that need to be beefed up while I have my trike at the welders? "

YES, have every weld rewelded and close up the gaps. once you look at the factory welds you'll notice that Honda did not weld all the seems all the way around. on most bikes/trikes/quads this allows some needed frame flex, however the 350X being a cross between a backbone frame and perimeter frame changes everything. It actually has too much flex.

also, have the swingarm pivot area doubled up (use steel washers welded to outside of frame) this area is known to eggshape after a while.

and, the subframe. gusset that as well if you tried you could bend it with a good kick.

when welding the frame make sure you have a expert welder do the job. the frame is made from cheap mild steel and is thin walled. MIG welding usually burns a hole before you can get a good weld. my frames are all welded useing TIG.

as far as engine cases' the stock motor mounts are designed to bend "before" the cases crack however i have seen two broken cases before but one was due to the front downtube being pushed in to far as the result of a head on colision with a U.P.S. truck

[Black Sheep]

here is one of my frames I reinforced

[Black Sheep]

here is one of my frames I reinforced

[Mr. Richard]

BILL,,,you got a pm! :D

[FlyingW]

Mr ATC,

Based on the pictures you posted, is it safe to assume that all the gussets you welded in are all in the sub-frame as well as the steel washers to beef up the swing arm pivot? Also, if its not too much trouble, could you post a picture of the left side of the frame. The welder won't get to mine until next week and I want him to see what the suggested solution is. Thanks very much for all your help with this.

[350xhilaration]

I went to look at a local 350X for sale yesterday (The guy had 3) one was cracked in the same spot. He never knew it til I pulled the rear plastic off. We checked his other two and they werent cracked.

Get some pics after you get it back. I'd like to see it.

There is a member on my site (3ww and maybe here too) "fyi" that was questioning whether there would be a "market" for an all aluminum custom 350X frame to help with the weaknessses of the OEM frame. I said it's a great idea, but I would think only the hardest core of 350X owners would put up the cash to buy one.

Any takers?

[NOS_350X]

Originally posted by 350xhilaration


There is a member on my site (3ww and maybe here too) "fyi" that was questioning whether there would be a "market" for an all aluminum custom 350X frame to help with the weaknessses of the OEM frame. I said it's a great idea, but I would think only the hardest core of 350X owners would put up the cash to buy one.

Any takers?

If its cheep enough (under $400)and after i see it hold up for a while then i would be VERY intrested. hell one would be mine

[350xhilaration]

Hop over to my site or 3ww and pm the guy. He's the dude that was running the NOS and doing dyno pulls on the 350X. Seems like a nice guy that's not full o chit.

[jenndnn3]

We as well finally lost our frame last year. But we caught ours at surface cracking. Just starting out. So we kinda got lucky I suppose.

Mr.Atc, welcome back! Brian like your fix better then what I had done. Which was just a reinforcement of the area rather then useing both parts of the frame. Ours showed up aprox same area as 350xhilirations. I told the old man quit jumping,:doh: (yeah right!:chuckle: )

[Black Sheep]

Originally posted by FlyingW
Mr ATC,

Based on the pictures you posted, is it safe to assume that all the gussets you welded in are all in the sub-frame as well as the steel washers to beef up the swing arm pivot? Also, if its not too much trouble, could you post a picture of the left side of the frame. The welder won't get to mine until next week and I want him to see what the suggested solution is. Thanks very much for all your help with this.

your assumptions are correct. however that is not all I do. if you look at all the welds were frame pieces join you'll notice the welds are not complete. by this i mean the seam or joint may be 3inces long but the weld is only 1 1/2inces long. I finish up all these welds to completly close up ALL seams. Normally on a normal frame this would not be desireable because it would become to stiff by reducing frame flex, however as i have stated before, the 350X being half single backbone and half perimeter frame already flexes too much.

sorry i do not have more photos. this was taken back in 2000 before my divorce

[FlyingW]

Mr ATC,

I got my trike back from the welder and this is how he did it. I know it's more desireable to weld the gusset inside of the frame but in this case, he put the gusset on the outside. I will have the welder put gussets on the inside of the frame in the other areas this winter. Thanks for all you help.

[FlyingW]

Here's a better pic.

[ridetrikes250R]

well, yes mayb to the eye it would look better to be beaded on the inside, more showy, but i can tell you have have picked up the trade of welding in the last few months, and that weld bead and backing plate, looks to be very strong, i think your problem is taken care of. if you really want to have a smoother look, you could take a grinder with a sand paper wheel, and smooth out the weld alittle more, but it seems to look smooth and sleek with the paint.... i think its a good job, i hope you have lots of fun on your atc
Adam

[FlyingW]

Hey Adam. I did go some grinding on the welds but I didn't dwell on it too much because this winter I will tear down my trike and take it back to the welder to add some gussets added in some other places. This one gusset was mearly an emergency repair. The plate the welder added is only welded on one side because he couldn't get to the inside of the plate. I will sandblast the frame and cut out the gussets myself to ensure I get what I want. I should take a welding class. I have welders at work but I weld like old people screw, not very good lol....... :shocked:

[ridetrikes250R]

you weld with viagra???.... whatever works best for yah.....Does it make your hands stiff so you dont shake ??? LOL jk jk ,,,,,, anyways, yah it will look nice wen yah redo it... they always do, it looks sharp for a emergency fix.... GOOD LUCK!! ride hard!!
Adam