Will CB350 fit in 175 vertical frame?

Whitey80

You're all idiots.
There's a solid '72 CB350 engine/case on my local craigslist for $50. have a '71 CB175. will this motor fit in my frame easily?
 
Sure. Just not clean. I have no doubt that with a hacksaw, a drill, some files and such you could piece together engine plates to hang that 350 from your 175 frame. I think the frame will flex unless you brace it up, but yeah I'd imagine it could be done.

...just because you can, doesn't mean you should.....
 
I agree with Swagger on this one. Physically, the dimensions between the 2 are very similar. But all it takes is one area to be the "wrong" size and you start looking a huge frame mods.

And it would take a good bit of bracing to get the frame sturdy again.
 
i said no way because OP sounded inexperienced and was looking for an easy swap...

OP should just buy a cb350 if they want the power, although i do have to say, i like motors as stressed members as much as the next guy
 
Actually, the 71 CB175's arent stressed members - only the 68's.

As far as power gains go, you just cant beat a small 2-stroke motor. But that's a whole other fitment.
 
alread have the 2 stroke done with my 72 dt250 street tracker.

Big Rich, thanks for a straight-forward answer.

Rocan, as far as putting the 350 in, the "why" is because i am able to, the weight difference is negligable, would be hands down, the cheapest power adding mod, and considering i got this bike for free, a 350 would be alot nicer (not that I'm not apreciative of the fella that gave it to me). the power increase isnt as such as would be overstressing the frame. am more than experienced enough mechanically....thought it just be easier to ask on dimensions than to head out and measure 20 times over, but you proved me wrong. thanks.
 
If you are REALLY considering it, i have a tore down 350 in the garage. I can measure the width of all the mounting points and compare them to a 175. Just saying.....

I think if anything, the height of the motor is what will get you.
 
Big Rich said:
If you are REALLY considering it, i have a tore down 350 in the garage. I can measure the width of all the mounting points and compare them to a 175. Just saying.....

I think if anything, the height of the motor is what will get you.

Rich, I would more than appreciate that! Thank you very much sir.

Sorry for the little tirade, I assure it was not directed at you. Just becomes irritating by those assuming that because you are new to one particular group that you don't know your asshole from your elbow.
 
Not a problem at all.

But try to think of it this way - we know nothing about you and for safety sake have to assume that you really dont know anything. Nothing personal - just better safe than sorry!
 
Whitey80 said:
Rich, I would more than appreciate that! Thank you very much sir.

Sorry for the little tirade, I assure it was not directed at you. Just becomes irritating by those assuming that because you are new to one particular group that you don't know your asshole from your elbow.

Whitey, the question does tend to suggest that. A 175 has barely enough brakes for its 15HP and tiny forks. A 350 motor makes about twice as much power and we'd tend to expect that to exceed the design parameters of the complete chassis.

As Rich already said, people here have no idea who you are and you didn't tell us much. Given that lack of info about you, it seems like a reasonable assumption. And we have to remember that 90% of people who arrive here have just bought their first bike and don't know what they don't know.

It's a new poster's responsibility to provide a forum with enough information to form an opinion. In the ansense of that, the assumption is as you suggested. Hope that clears the air a little.
 
Fair enough.
Had bikes for the last 25 years, starting with a Zuki RM80X then graduated to Flat Track at 15 with a Harley Sprint 350 (living in Oklahoma, that's about all there was to do). Lived in the country, so I also took it out on the roads to get around, and occassionally to town (avoid the local authorites when possible, run like hell when not, even though they knew who I was). Jumped up to CBR900RR at 17, then 929RR (because fuel injection is rad) they made great stunt platforms because they were really well balanced on one wheel, and were cheap to repair. Finished my sport bike stint on the 954RR after a long series of more than painful crashes. Left bikes for a while after that, but couldn't stay away. Picked up a '05 GSXR1000 in '07, then started building that DT250 that you see in my new member thread. Then that 175 came along as a "tip" from a long standing client.

Mechanically, started as a shop helper at a landscape company in the service garage at 15. Helping repair and overhaul trucks, UNI's, tractors and trailers. That lead to a small automotive business in town where I expanded my ASE's to suspension/steering sytems, chassis ground/electrical, manual driveline and axle, a/c systems and finally engine performance. Ended my auto career at Pro Chrysler/Jeep in Northglenn, CO as a driveability tech, where I became completely burned out on the industry and switched careers to tattooing.

Phew.....hope that helps with my introduction!!

(and no, I don't know everything about motorcycles. mostly, just enough to get by probably. That's why I'm asking questions. As far as the rest of the bikes ability to handle the new motor, those concerns have popped into my little brain, but I believe it would still be cheaper, and more fun to convert this bike to a 350 than to just go buy one that already came that way! that's why I have these old junkers....fun projects.)
 
I think if you did it 'right' it would be good fopr bragging rights at a minimum.
It wouldn't take much to create a brace from the head to the backbone/steering stem area. As long as your plates are burly enough it's hold. You'd definitely need to upgrade the suspension and brakes, but if you're considering the swap you[='ve likely already thought of this as well.
 
Swagger said:
I think if you did it 'right' it would be good fopr bragging rights at a minimum.
It wouldn't take much to create a brace from the head to the backbone/steering stem area. As long as your plates are burly enough it's hold. You'd definitely need to upgrade the suspension and brakes, but if you're considering the swap you[='ve likely already thought of this as well.

I think you are thinking off the wrong frame, after '68 they stopped doing the stressed member frames of the sloper engine and switched to the "vertical" 175, which has a full frame (downtube).
thank you much for the inpot though
 
Ya, Swagger knows - just suggesting some brace locations.

I forgot to throw a tape across that 350 motor this morning - Ill try to get it tomorrow morning. Sorry bud!
 
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