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View Full Version : how the 110 and the 125m differ



westsideriderz1
10-16-2016, 07:31 PM
Hi all,
this is a general thread to list the differences between the 84-85 110 and the 84-85 125m as a general reference for anyone looking to do an upgrade. I bought a 125m motor to upgrade my trike a bit and ran across quite a few differences. I assumed the bike just used a stroked version of the 110.


You can modify the intake from the 110 to accept the 125m bolt pattern. Even though they look the same they are slightly off. Regardless, the modification is useless as the intake will not fit back into the 110 frame. This leads me to believe that either the jug sits at a different angle, or the intake on the head is located in a different location. the 125m also uses the same engine mounts in the rear and a different front engine mount. Note: Although the front engine mount is a different part number, my 125m motor bolted into the 110 engine mounts with no changes.
the 1984 125m is a downshift model. the 1985 110 is an upshift model. 4 gears for both
the carburetor appears to be the same for the exception of the jets. A carb rebuild kit for the 125m will upgrade the 110 carb.
The 1984 125m has a different rectifier than the 1985 125m. One has 4 wires, other has 4+1 wires.
The forks are the same build except for a small tab to locate the front brake drum on the 125m.
The electronics vary a bit. I believe they both use the same CDI and perhaps the same ignition coil.
The 1984 125m head only has a valve seal on the exhaust side. I believe this was corrected in 1985. I believe the intake valve may not have needed on since it doesnt "sit" in oil
The 125m has a handlebar mounted choke cable. The start button on the handlebars can be added to the 110 assembly.
The 125m runs the exhaust down the side of the bike as where the 110 ran up through the frame.
The 125m uses different sub transmission only available on 84-85 125m.
The trx125 uses many of the same parts. Partzilla and Babbittsonline both have cross reference options to see what parts may fit other bikes.



Please feel free to add to this list.

Big G
10-18-2016, 12:48 PM
Good info - thanks for sharing! Any idea if the rear axle assembly can be interchanged?

oscarmayer
10-18-2016, 04:06 PM
125m has a longer stroke and carb sits different angle. thus intake is different. what are you trying to accomplish? a 125 into a 110 frame? not much advantage there. unless you have spare both.
they make adapters that bolt to the head and the intake will bolt to it, but it allows you to adjust the intake to different angles so it fits easier. I used to run these on my son's race 4-stroke and turned the car sideways out the let side so it got most air but not in the way. worked awesome.

Ol Deuce
10-18-2016, 10:02 PM
Thats good quick info Thanks for the info!!!

westsideriderz1
10-24-2016, 12:04 PM
I havent seen any difference in the rear axle area. Can anyone shed light on info for this?

westsideriderz1
10-24-2016, 12:05 PM
I really wanted the electric start. When i first start, I was going to see what changes needed to be made to the left side case to accomplish this but i found a good deal on craigslist for a 125m motor.

keister
10-24-2016, 12:48 PM
Good info!
Reminds me of a thread I started looong ago.

http://www.3wheelerworld.com/showthread.php/86337-110-amp-125-Buyers-Guide?highlight=110+125+buyers+guide

The wife is gone, but I still have the 110 and 125.

redsox
06-19-2018, 09:07 AM
Just searching here. I have a spare 1984 125m engine and wiring harness. Will it bolt right into a 1984 110 frame? What surprises should I expect?

Bob39666
08-03-2021, 04:16 PM
Redsox - just curious. Did you ever make this swap. I’m interested in doing the same thing.

sledcrazyinCT
08-05-2021, 11:43 AM
Redsox - just curious. Did you ever make this swap. I’m interested in doing the same thing.

Good you found this thread was gonna copy and paste in yours