ChinaRiders Forums - View Single Post - BD125-8 ZS190 swap and EFI conversion

glavey · 01-20-2019, 08:46 PM

With some juggling of engine support bolts, trolley jacks, and a hammer I managed to get the 125 engine out. Looking at the 125 and the 190 side-by-side I'd guess the 190 is... about 20% bigger externally; the longer stroke, 6-plate clutch, 5th gear, and overall increased beefiness are probably the reasons why.

I drilled out the 190 mounts and the mounting tabs on the bike to 3/8 in. If I, or anyone else wanted to, they might be able to drill out the mounts even larger if it turns out that this engine shears bolts as well. Although if you look at the location of the crankcase breather nipple and the angle it goes into the case, it seems to be very close to the top mounting hole.

I'm hearing a creak from around the swing arm pivot when moving the bike, so I figure this is the best time to check that out and make sure nothing is broken or about to break around there.

I tested the microsquirt as much as you can with only power and a serial connection - some readings fluctuated a bit since their input pins were left floating, everything I looked at and tested seemed to work.

I got an update from the seller on aliexpress - the order has now shipped and should be at my door in 5-8 days with a refund in it doesn't show up in 21 days. When it arrives I get the arduous task of wiring the 190 into the 125's wiring harness and combining the harnesses from the microsquirt and the aliexpress seller.
I think I'm going to keep all of the EFI-related wiring in its own separate loom and harness - if for some reason the EFI doesn't work out It'll be much easier to just disconnect the EFI harness and remove it than taking apart the entire wiring harness to take out just the EFI-related wires.

The exhaust I bought does seem to fit the 190, but it is very close to the starter motor, and I'm worried about all the heat that will be going into it. Exhaust wrapping may be in my future.

Apologies for the lack of pictures and video; a build thread without pictures is quite lackluster, but I am doing all of this in my bedroom and I'm afraid if I take a picture, I'll have a prescription bottle or a butt plug in the background. Not to mention I don't have a very high standard for household cleanliness.

01-20-2019, 08:46 PM	#3
glavey Join Date: Oct 2018 Posts: 74	With some juggling of engine support bolts, trolley jacks, and a hammer I managed to get the 125 engine out. Looking at the 125 and the 190 side-by-side I'd guess the 190 is... about 20% bigger externally; the longer stroke, 6-plate clutch, 5th gear, and overall increased beefiness are probably the reasons why. I drilled out the 190 mounts and the mounting tabs on the bike to 3/8 in. If I, or anyone else wanted to, they might be able to drill out the mounts even larger if it turns out that this engine shears bolts as well. Although if you look at the location of the crankcase breather nipple and the angle it goes into the case, it seems to be very close to the top mounting hole. I'm hearing a creak from around the swing arm pivot when moving the bike, so I figure this is the best time to check that out and make sure nothing is broken or about to break around there. I tested the microsquirt as much as you can with only power and a serial connection - some readings fluctuated a bit since their input pins were left floating, everything I looked at and tested seemed to work. I got an update from the seller on aliexpress - the order has now shipped and should be at my door in 5-8 days with a refund in it doesn't show up in 21 days. When it arrives I get the arduous task of wiring the 190 into the 125's wiring harness and combining the harnesses from the microsquirt and the aliexpress seller. I think I'm going to keep all of the EFI-related wiring in its own separate loom and harness - if for some reason the EFI doesn't work out It'll be much easier to just disconnect the EFI harness and remove it than taking apart the entire wiring harness to take out just the EFI-related wires. The exhaust I bought does seem to fit the 190, but it is very close to the starter motor, and I'm worried about all the heat that will be going into it. Exhaust wrapping may be in my future. Apologies for the lack of pictures and video; a build thread without pictures is quite lackluster, but I am doing all of this in my bedroom and I'm afraid if I take a picture, I'll have a prescription bottle or a butt plug in the background. Not to mention I don't have a very high standard for household cleanliness.
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