GS300L engine swap with GS450

[tyson916]

Hello everyone,

I am glad I've stumbled onto this forum site as there seems to be a wealth of info here. Apologies in advance if this has been posted before but I could not find any answers in the search here or google.

Last year I did the unimaginable (to my friends, relatives and most sane people I've run into) and rode my 1982 GS300L to Winnipeg from Vancouver; a fantastic 2200 km ride (1375 miles to the unmetric) over 3 days.


Suzi kept up relatively well blowing a fork seal and stretching her chain along the way (that's what that clanking sound was!) but called it quits in Winnipeg a 100 km shy of our destination due to some electrical failure. So there she remains for the time being almost forgotten until I stumbled onto a local craigslist posting for a 1980 GS450:

http://vancouver.en.craigslist.ca/pm...737260462.html

So my question is how different are the electrics on my bike vs this GS450? If modifications are required, what would I be getting myself into?

A thought that creeps into my mind is swapping the motor and everything into my 300 frame. A call to my local shop says it's not possible or worth it but I thought I'd post it here just in case anyone has experience with this.

I see someone else was considering the same swap here but hasn't followed up

http://www.thegsresources.com/_forum...35#post1555635


Thanks for any help!

[olddaddy]

Well, anything is possible depending on how much time and effort you are willing to spend. If it were me, I'd either be happy with the 300, fix it's problems and ride.....OR build up the 450 and do the same.

When I bought my GS 450 I considered building either a 500cc engine, or swapping in a 650 Tempter engine. I'd heard it could be done and the challenge was tempting (pun intended) However, cooler heads prevailed and I just focused on riding the GS450.

The 650 Tempter engine is still with me and is currently waiting it's turn in line to be installed into a GS550 frame. That way I still ride the always faithful 450 and work on the 650 when time and money allow.

Lot's of options for you to consider. Riding is always the best option. Building is a close second though.............

[Wyldesoul]

I've swapped a 450 motor into a 250 frame, and it's... Not fun. You'll need to modify the engine mounts to do so. I know this is relevant to you because it was perfect bolt-in to change the 250 to a 300.

The only mount that lined up was the very bottom one. I had to make new brackets for the front mount (the 450 has dual tube frame up front, the 300 (and 250) has a single tube). The lower rear bracket fit with modification, and the upper rear bracket had to be removed completely. The engine didn't fit into the frame with it.

I had to severely modify the front sprocket cover (cutting off about the back half).

You'll also need the wheel and sprocket from the 450. I would be willing to say you will have to use pod filters and rejet, as the 300 airbox won't fit the 450 carbs, and the 450 airbox won't fit the 300 frame.


It can be done, it just takes a bit of frame modification. The electrics, however, work perfectly, no modification needed there.

But no, it is NOT a bolt in. A 250 motor, however, is a perfect fit. Same HP, just in higher revs, and a 6 speed, not 5.

For the easy way, get a hold of a 250 or 300 motor. The 450 is very hard to do. Trust me, I know from experience.

[oldrookie]

Why not fix the electrical problem? Plenty of info here to walk you through it.

Probably cheaper and quicker.

[tyson916]

Thanks for the replies everyone. I'm working on getting the 300 shipped home and will definitely do an investigative search into the electrical gremlins.

There's a 250 that's for sale locally that a buddy might pick up as a starter bike and sell to me once he's ready to upgrade so it looks like I'll have a better parts bike than the 450.

Happy new year!

[tyson916]

For the easy way, get a hold of a 250 or 300 motor. The 450 is very hard to do. Trust me, I know from experience.

Thanks Wyld. I was hoping someone on here has done this swap and it does sound out of my league for the moment as I have zero experience with fabrication. I hope my buddy picks up a 250 that's for sale and I'll grab that off of him after.

Cheers,

[Wyldesoul]

I might recommend just riding the 250, and using the 300 as the parts bike, unless you really like the cruiser style position the 300 gives you.

There's a few goodies that the 250 has that the 300 doesn't, and it'll be a bit difficult to swap those all onto the 300.

Mostly the front brakes. the 250 has disc fronts, and the 300 has drum. To swap the brakes over, you need to swap the whole front end over, quite the challenge.

That and the 250 has a nice tach in the gauge cluster.

Personally? I would say don't worry about swapping anything, just ride your 300 until your buddy gets bored of it, and get his 250 off him. A better optioned and nicer little bike all around.

And I will suggest that you don't ever sell it... When you upgrade to a much bigger bike, you'll be surprised by how fun it is to hop back on a little one.

That's why I'm getting a new TU250 this year.