300EX engine in a 350X?

[ATC King]

Is it a bolt-in swap?

With all the talk of Goki starters recently, if the 300EX engine is a direct swap, BAM, OEM e-start and be done with it.

[wild200x]

I have heard this is true. Also that you could put the 350x top end on? Not sure. Just what I have heard.

[oldskool83]

350x top ends wont work on 300ex. you can use a 350x head but its a bad idea as they dont flow as much oil. Use 300ex motor, all of it and spend the money to get the motor some good HP. it can be done. I am doing a 300ex motor in a 350x right now. I have a 11.5:1 CP piston in my motor, head will get a cam and porting with a 5 angle valve grind....a nice exhaust and it will move just like a 350x.

[ATC King]

Thanks.

I've got a line on a 300EX that is about to be junked. I don't have a use for it at the moment, but don't want to see it just tossed.

If I could find a 350X roller at a bargain price, the e-start and reverse 300EX engine would be bee's knees.

[Eric250R]

Other than the top engine mount and finding a spot for your battery ( I just use the battery box from the 300ex) it's a direct bolt in.

[oldskool83]

here 9s mine for those who need to see pics. Ive know about this swap 15 years but still never saw one.

[patriot1]

Oldskool83:

Were you also able to use the 300EX swingarm? axle?

[oldskool83]

300ex swinger is 3/4 "shorter in length and wider in the width between frame. It also does not have a rear shock mount like the 350x does. I am using a 350x swinger and 350x axle. You want to use 1986 350x swing arm as it has the gussets and rear brake stay pin. If not you can use 1985 but it needs to be gusseted and have the pin added. Not a big deal either way.

The chain won't line up as 300ex drive sprocket is in different location than 350x sprocket. I put an order in for a laser cut adaptor to line everything up. It's not a really big deal

I have both year swingers. You also use 86 350x / 300ex carriers with are 100% the same. You will not use 1985 carrier, they are junk with the finned adjustment tabs.

I had a 300ex swing arm a cut at work cut in half with a band saw. I didn't ask him to do it but he miss understood me. I had a bad 1985 swinger with a carrier someone cut in half I spend the next few days grinding apart the 300ex swinger for its carrier and added it to the 350x. my 1985 swinger is about 1/8" longer then factory now. Nothing to brag about.

Next i had the chain guide mounts cut off and 300ex ones welded on since you can not get new 350x guides. There was a guy selling them for $90 JR trike sports but he stopped also. I had a TM design one and figured I'd just use it. 300ex stuff should be around another decade at least.

[sledcrazyinCT]

I've got a line on a 300EX that is about to be junked. I don't have a use for it at the moment, but don't want to see it just tossed.

Did you end up with the EX as a start to future project?

[ATC King]

I just need to go get it.

I had put it out there for someone else to use, but I'm going to keep it for myself and make a long term project out of it. Long term, because I'm not throwing mad money at it, so I'll have to wait until that right 350X donor trike comes my way.

[oldskool83]

I bought all my 350x parts independently from people just wanting to blow stuff out. Then I sold off what I didn't need. My 350x has cost me nearly nothing. Not paying these 4K prices for clamped out machines needing full overhauls. Until I'm done I might have a 1990's used prices into my machine.

[ATC King]

Finding a good frame is going to be the hardest part.

I don't want some rust bucket that'll need major repairs, or anything with more cracks than solid tube. Without a jig, keeping everything true during major repairs is questionable, and without a good and straight frame to start with, building a proper jig would be virtually impossible, unless Honda has a 350X frame jig squirreled away somewhere. I couldn't afford it anyway.

No hurry either, because I've got to make space for the project before I can really get it going. I've got to get ride of a couple rides to do that, no way around it.

[oldskool83]

My frame was all broken up..they will be if used good. Your going to need to gusset the heck out of certain area anyway. I paid $180 or so for my frame shipped. Bought a gusset kit and new foot peg plugs. Welded it up.

Working now on the horrible seat latch area. You wont find a frame not needling work. Plus there are item's not needed on the 350x frame to run 300ex motor and you'll need to weld stuff onto it also I'm sure.

You want a frame needing work as your going to make it better, nothing build in 1985is going to be like todays designs. All we have done is make things stronger to last.

I titled my frame too. Ill make a build thread one day how to do the 300ex swap.

However I do feel people need to think to build what they want, no one has told me tricks. I've figured it out myself with out asking a single question.

[ATC King]

I'm setting the frame goal high, so I have wiggle room. :beer


Gussets were already on the list and a battery box and such bits; already considered. I don't think I'll be able to slide in to a frame for that $180 range unless luck is on my side. It's a virtual trike desert around here, and any of the good stuff is hidden away, collecting dust in some geriatric's garage.


"nothing build in 1985is going to be like todays designs"

For sure. Even the welds look ten times better nowadays.

[oldskool83]

I just finished my new seat latch area for the frame. That's one area nearly all frames split. I may offer kits as a fix. Depends how busy my job keeps me and another issue i have at hand. Each day i do somthing, atv atv or home rekated... btw i got my frame and triple tree off a facebook group. I noticed people in groups really want to sell the paets vs the clowns on your local marketplace who just are day dreaming.

[ATC King]

I picked up the square today.

This is how it looked insitu:

267409

Don't anyone hold their breath. This thing is in bad shape. It sat with the spark plug out. It does roll though, and go through the gears. The clutch also works. I'm going to literally fill the engine with a diesel/oil mix, all the way to the very top. It'll leak out though, 'cause the case has chain damage. Doing what I can to get the current moisture out and protect anything that isn't already FUBARd.

That's the most I'll do to it until this winter, and possibly longer. I won't be able to touch it, because I'll be away.

Cost so far - $0

[oldskool83]

I don't understand why people throw their money away..not you just the person who owned it.

You can part the rest out you dont need qhich is about everything.

I buy them all the time to rob parts. Id take your seat and rear shock if you desire to part.

Last few i bought were mixed with 350x parts.

[patriot1]

Good score King. If nothing else for the back rims and hubs. I also saw where a guy figured out how to use the back fenders on a 350x.

[ATC King]

I don't understand why people throw their money away..not you just the person who owned it.



Some people are just like that. I've seen those who've spent their own hard earned money, and just destroy and neglect things. I'd never have anything if I was like that.

[ATC King]

Good score King. If nothing else for the back rims and hubs.

That's a negative, Ghostrider.

267415


It's not even the worst part either. I drained mostly water out of the engine, through the stripped drain plug hole. Done what I can and poured about two gallons of diesel through it.

I'm not excited about it at all, but with the starting price, there's some wiggle room. Now I just need a similar condition and price 350X to complete the set.:)

[oldskool83]

300ex hubs wont fit on 350x axle anyway. like i said you wont use much from the 300ex but the motor and wire harness. even the carb is about worthless, needs 400ex carb at least grab some go. you can get them hubs off, ive done it. it takes a lot of time to slightly grind weld down. But when things are free time is ok to spend on them.

I'll make a build 300x build thread one of these days. Might just be some pictures. I did order a new engine mount kit and some other laser cut items I needed make. There will be things you just can't find anymore and its cheaper to just make new items. I had to do that for my seat.

[jasong_10]

Now I just need a similar condition and price 350X to complete the set.:)

This thread has me very interested in one of these builds, I've got to find both though, lol.