View Full Version : 350X frame crack, case crack

07-11-2010, 07:57 PM
First off, great site. I had been a viewer for some time now but only recently registered. This is my first post so, if there are any issues with format etc. just let me know.

In an attempt to make this the shortest story possible - Picked up a 350 for a good price - $500 since some of you may be wondering. The guy i bought it from was 83 and getting out of riding due to his riding partner (wife) passing . The bike looked to be in great shape except for a small crack in typical 85' frame area (left side). Got home began basic checkthrough / maintenance. Oil, filter, plug, air filter, lube / bearing check etc. I knew i had to weld the crack and wanted to add gussets (thanks for that post by the way) but I needed to go for one ride right? So, I go for a small ride no plans to do anything crazy. End up hitting a drop off that I didnt see coming and must have tweaked the frame / engine. Crack got larger and case cracked by rear motor mount.
I kicked myself real hard for riding in the first place and started thinking that the 350 was like my "elsinore" - gone in 60 sec reference for those still reading this long story. Anyway, said maybe i should tear it down and part it out. Slept on it woke up checked the ol' C.L and found a frame and complete bottom end for a good price. fate? Me thinks so....or at least that is a good way to reason to oneself for buying more junk. So, I pick both up but still thinking should I tear down and rebuild or move on?
Where I need input from the readers of this site.

1. Difficulty in tearing down a 350 motor and fixing as needed? Yes i have the manual. No i have not had to do a bottom end before. Yes, i have done a fair amount of mechanical work but am more of a step up from shadetree.
- fyi - i cannot simply swap bottom ends as the one I purchased was left open for some time e.g. dirt may have entered block.

2. Have motors torn down and rebuilt professionally? Cost? - on average... I have seen a lot of #'s in past threads...just figured i would ask in case anyone had the work done recently.

3. I see some complete motors posted. I have an option to pick a complete motor up for around $650. Not one of those sitting 25yr crate motors on ebay either. This one was pulled from a 350 where the other parts were kept and motor was not needed.

4. If I go the tear down what i have and rebuild route any other mods that should be done at that time? I dont really mean a big bore kit or anything like that. I mean checking out / replacing any weak internal motor parts such as oil pump etc. For performance I plan simply to do the 400ex carb / 450r exhaust upgrade.

I have pics too. Thanks all for the help.

07-11-2010, 08:55 PM
Wow you long winded ain't ya but no problem at least you won't get 50 million diff ques. so how much are you willing to spend to get her back up that will help with these guys answers and advice

I will be the first to say welcome to the site

07-11-2010, 10:40 PM
First off, damn that sucks.

It's hard to have something and not ride it!

Even when you know you shouldn't.

Aight, so you are into the trike for $500 and the cost of a new frame.

I'm guessing you got the new frame and bottom end for less than $150, but I don't know.

If that is the case though you are still in good shape.

Let's see some pictures and go from there.

Welcome to the site!

07-11-2010, 11:47 PM
what would I do, (not always the right thing) I would weld the frame where it broke and get a new good bottom end>>> and rebuild the top when i changed over. But pics would help... You broke the motor mount in the rear that connects through the case?? If so man was that a Cliff you went off? If you could get some pics up If would be great.

07-13-2010, 11:11 PM
Ok first time posting pics too so lets see how this goes. http://www.honda350x.com/forum/picture.php?albumid=53&pictureid=430

crack left side...


Leak area - motor / frame mount


Another image of leak area - seems to be small crack left side case where bolt runs through block / frame


07-13-2010, 11:51 PM
Yeah i agree with gary was it a cliff you went off of

07-14-2010, 12:38 AM
Well, I thought it was a casual ride. Still trying to figure out how it happened myself. I know many have commented on the 350x suspension and I did find it lacking a bit.

I know I went rambling on with my first post but it was to show the options I thought of. At first I was saying should I rebuild or not? I go in the garage and look at the X and say, I gotta rebuild.
So, at this point - Just trying to figure out best option for rebuild? i listed the options I had thought of in the begiining of the post. By the way since Dom asked, the replacement bottom end was $100. So, total cost $500 bike, $100 bottom end. $50 for extra frame. Let's say I have 1K to put into it. The question is how best to spend the $.

Thanks guys.

07-14-2010, 01:29 AM
Welcome to the site JP.

Congrats on your purchase. Sorry to hear about the issues. I think an engine skidplate would have saved your bottom end. Should of, could of, would of, but didn't. The past is the past. Time for damage control.

Professionally built should be out of the question. I bought a 86X as a backup bike and it turned out to be a project bike. Long story short...the whole engine ended up needing rebuilding except for the tranny. I got all the parts for approx $900 on eBay (I found some great deals). I went down to my local Honda shop to see what they would charge because I didn't have time to do the rebuild because I was rebuilding my 85's rear and needed to get it finished for an ATV event. I also bought my first and last quad earlier that year which also became a major project bike. Anyway, Honda quoted me approx $1600 for the rebuild. That included all the little parts and pieces I didn't have (I had the major parts but its the little ones that kills the wallet). So, that would have been $2500 to get it back in running shape. Don't forget, I paid $1600 for the bike!!! Total cost for the bike and repairs...$4100. F:censored:k that!!! The Pro option was not an option for me. I was in the same boat as you JP. Should I part it out and hopefully break even or should I rebuild? There was a part of me that needed to make sure another X was out there running in the world. Plus, I didn't want to go through all the BS parting it out. So my dad and I rebuilt the motor. Actually, my dad did most of it because he couldn't stay away from the bike until I got down to his house on the weekends.

Don't worry about the length of your posts. Some of us have deep lungs and strong fingers!!! ;)

07-14-2010, 03:03 AM
I say Weld the brake, ya it will not be pretty but some welding will hold for some time, may even be stronger. Get a good new Bottom end, or a whole new motor. When or if you change the top rebuild it. First thing first how do the exhaust head bolts look??? If you can get the exhaust off the motor you you are off to a good rebuild... Those motors with the manual and a little know how are not really that hard to rebuild. The hardest thing is going to be doing it with out braking bolts off.

You may consider this http://cgi.ebay.com/ebaymotors/honda-350x-motor-engine-bottom-end-_W0QQcmdZViewItemQQhashZitem3a5cbb686bQQitemZ25066 3889003QQptZMotorsQ5fATVQ5fPartsQ5fAccessories

then choose your rebuild, Id get the head Valves done at your local machine shop, It should be around 50 bucks... Figure your bore go up or stay with a nice hone and new rings... They should also be able to to bore and hone.

You may even consider this


Good luck.

07-14-2010, 11:58 AM
That rebuild kit that gary showed is nice but when i rebuilt my top end i consider this kit but got to looking at the cylinder and it was still in good shape and didn't look very worn so i just bought this std piston with 12:1 comp http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=&store=Main&catId=&productId=p4396M08100&leafCatId=&mmyId=10270
This gave mine lots of power and then i order this gasket kit http://www.denniskirk.com/jsp/product_catalog/Product.jsp?skuId=&store=Main&catId=&productId=p26582&leafCatId=&mmyId=10270 but it is Whitch ever is easyest for you the two rebuild optoin gary and i gave you are about the same in price

07-14-2010, 12:38 PM
I say Weld the brake, ya it will not be pretty but some welding will hold for some time, may even be stronger.

Just welding the crack will not work and actually make it weaker.

While the suspension is partially to blame it is not the entire cause. There are quite a few "new" guys out there trying ti fix these frames. The problem is they are either basing their assessment off of quad experiences or by copying my ideas. Yet none of them know the real reason for the break.

The main reason these frames flex is the side to side twisting of the frame due to the frame design itself and they way the engine is mounted.

I have a gusset kit I developed from over 20 years of 350x ownership. 65.00 plus S&H. The kit will stop the frame flex, reinforce the seat area, and cure the dreaded frame crack.

If you have the Honda service manual swapping lower ends is not a big deal. Just pay attention to how it all came apart and what order the gears and washers are in. If your unsure of doing it I can do it for 300. Parts and shipping not included.

I also recommend progressive suspension springs in the front with 15wt fork oil and a works "guts" kit for the rear shock. About 450.

07-14-2010, 12:42 PM
Yeah if his bill gets to steep i would recomend him just save up to buy a TPC or atleast thats what i would do.:salute:

07-14-2010, 08:12 PM
We have two x's with welds, One i know has been there for 10 plus years. (red frame) My uncle welded this one up... the blue frame we have had for a while now, the guy said it was welded when we got it... Im not a welder or do I know how to repair or build frames... I was just thanking if he was going to scrap this bike or frame he should try to get some one to weld it for him,,,
To me it's worth a shot welding it up.. who knows maybe it will last 10 years.

The weld job is the thicker part of the frame there in the pics, You can really tell in the red because the paint don't match.

the last pic is a frame we have that is broke beyond repair,, it is also broke on the other side as well..

07-15-2010, 01:24 AM
UMMMMM, I do believe these boys covered it all! The gusset kit is frigging awesome and striping the X is a smart idea, cause they get beat on, power coat is around 125 plus the 65 plus the 500 plus the 100 and then the 50 your still doing OK!! Break both bottom ends down and find the best parts and clean um up!! 12.1 comp GREAT PLAN..very healthy upgrade, I my self went HUGE and built a 385 with the 12.1 and had the gears undercut, for around 600!! But its what ya got to work with and things will come together!! P.S I through numbers out there but I aint gonna try to add them up!! ROFL!!