Moving tires from big bike to little

So I bought a used 701E which came with a new 140/80-18 MotoZ Tractionator. This tire is very noisy on the highway and much more aggressive than I need for that bike. But my FE350 has a worn factory tire, 120/90-18 and I want to change to more aggressive tires on that bike. So I’m thinking of moving the MotoZ to the FE350. Based on physical size the MotoZ will “fit” on the 350 although it is larger. I understand I’ll loose some power because of the larger diameter and may bottom out the tire on the fender, but are there any other significant problems I’m not seeing?

Check and see how much clearance you have with the swing arm and chain.

what he said. knobs will hit the chain first. possibly the underside of the fender & frame when you bottom out. otherwise... go for it

I've got plenty of room and I don't ride that aggressively to be bottoming out. Thx

Heavy tires add to unsprung weight and make suspension more harsh.

Wide tires make the bike harder to turn.

There is not much harm in giving it a try and seeing if you notice these things.

Thanks, that's the kind of information I am after. Thanks for the input.

I just hate to take it off and not use it. Especially since I need new tires on the 350.

Too much traction may make the motor feel underpowered to you.

Swap a 120 with someone that needs a 140??

I usually run a 110 tire to keep the bike more lively. Suspension, turning and motor pep.

Depends. Sizes can be very different based on the DOT vs Non-DOT. DOT tires are sized based on the actual outside with of the tread. NON-DOT tires are based on the size of the body, not including the side knobs. If the 140 is a DOT and the 120 is a Non-DOT, then they will probably be pretty close to the same size.

As for aspect ratio, the DOT and non-DOT effect stated above also holds true.

Finally I feel that aspect ratio or height has much less of a difference with regards to motorcycle tires in general.