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Having just wrapped the Koito installation and seeing as my fuse panel replacement is next, I thought I'd take some time to try and add the smallest amount of tech to the group about wire terminals. I'd messaged a few folks early on who provided some good tips and feedback on different brands, thank you @mattressking! I also ordered up numerous terminal types and sizes, multiple crimpers, and have some thoughts.
First, vendors. I know that many of the full-service vendors in the mud community sell loose terminals, this isn't a knock on them (I've received some with new switches and plugs I've ordered from a few great folks on here) and of course Coolerman has been providing these services for years. The barrier I found was in a solid source of part numbers/specific information of what is best where. Not a lot of detail is posted past the "crimp on some new terminals and you're golden". We more electrical work coming, I wanted to build out a kit of parts that worked well, and worked for me.
I scoured the websites of the non-LC specific vendors often referred to on this site and realized there were so many more options than 'simply buying some terminals' would imply. Brand, size, type, insulated/non-insulated, finish, for connector bodies vs. loose, sleeves, and then so much nuance variation in terminal tension design and keeping ability. I made some orders and figured I'd learn by doing. Terminals are cheap!
I ended up ordering from:
www.corsa-technic.com
www.cycleterminal.com
For the Koito swap, if you want to shorten the harness in all the right spots, you'll need .187 and .250 female spade terminals for both of the relays, M8 ring terminals for the power feeds if you adjust them, and H4 female flag terminals for the driver headlight socket. Sounds easy enough, right?
Harness .250 terminal (Yazaki) on the left (tin), failed Furukawa attempts with cheap crimper. Crimper was side-loading the terminal and pushing it out of the jaws.
Harness .187 terminal (Yazaki) on the left and Furukawa on the right. Crimp was improving, but not fully capturing the wire. You can see how much longer the terminal is. It wouldn't catch the retention clip in the relay base.
After finally getting it right, here's one of the relay bases terminated (Yazaki and AMP) before putting it all back together. Note the tap on the ground wire, this is exactly how the H4 harness comes from Toyota, just buried in the vinyl jacket and some heat shrink. I applied the same after this photo.
Both relays buttoned up tidy. This portion of the harness is now ~8" long, vs 2-3' as delivered. No excess to coil.
First, vendors. I know that many of the full-service vendors in the mud community sell loose terminals, this isn't a knock on them (I've received some with new switches and plugs I've ordered from a few great folks on here) and of course Coolerman has been providing these services for years. The barrier I found was in a solid source of part numbers/specific information of what is best where. Not a lot of detail is posted past the "crimp on some new terminals and you're golden". We more electrical work coming, I wanted to build out a kit of parts that worked well, and worked for me.
I scoured the websites of the non-LC specific vendors often referred to on this site and realized there were so many more options than 'simply buying some terminals' would imply. Brand, size, type, insulated/non-insulated, finish, for connector bodies vs. loose, sleeves, and then so much nuance variation in terminal tension design and keeping ability. I made some orders and figured I'd learn by doing. Terminals are cheap!
I ended up ordering from:
Corsa Technic
Motorsport electrical products: OEM and hard to find terminals and connector kits, wiring, harness supplies, tooling, and sensors for modern and vintage motorcycle, automotive applications. Easy online shopping, low cost shipping options, to expedited around the world. We accept Paypal and...
www.corsa-technic.com
Motorcycle Terminals, Connectors, and Wiring Accessories
Cycle Terminal - We have Your wiring Needs. OEM Style Japanese Motorcycle Wiring Terminals and Connectors for Yamaha, Kawasaki, Suzuki and Honda Motorcycles, from the 60’s to the 90’s. Motorcycle electric products and accessories, Motorcycle Fuse Box's, Bullet Terminals, Spade Terminals and...
For the Koito swap, if you want to shorten the harness in all the right spots, you'll need .187 and .250 female spade terminals for both of the relays, M8 ring terminals for the power feeds if you adjust them, and H4 female flag terminals for the driver headlight socket. Sounds easy enough, right?
- For my harness modification, I needed (4) .187, (4) .250, (1) M8 ring terminal, and (3) H4 flag terminals.
- The original terminals on the Toyota 81110-60P70 harness are Yazaki brand, but despite all my efforts, I could not find that specific terminal on Yazaki's website or elsewhere online. Many of the alternate terminals and the generic stuff are longer with different head shape, or have a thicker/thinner/longer insulation retention crimp making the whole terminal 20% longer.
- The Furukawa terminals I first ordered (from Corsa-Technic) were too thick, and shifted/crushed in the crimpers vs the ears rolling into a crimp. All the Yazaki and Sumitomo and AMP connectors (in these flavors and other sizes) were slightly thinner, maybe more flexible, and all crimped well after some practice.
- The best-crimping and most-similar terminals I found to fit in the Koito relay housing and the H4 plug were:
- .187 female: AMP 187-1620 N1 from Motorcycle Spade Terminals - https://www.cycleterminal.com/spade-terminals.html. These are AMP vs the original Yazaki, and have a slightly different head design. But overall dimensions are perfect, they crimped easily and fit/retain in the relay bases very well.
- .250 female: Yazaki / Sumitomo FST 1418N on Motorcycle Spade Terminals - https://www.cycleterminal.com/spade-terminals.html. These are brass, vs the original tin plated, but the geometry and size are spot on and they fit/retain in the relay bases perfectly.
- H4 Flag: Unsure on brand, FT312 from Motorcycle Flag Terminals - https://www.cycleterminal.com/flag-terminals.html. These are tricky. The orientation of the flag means that a normal crimper will crush the female spade portion during crimping. I ended up using two crimpers to do these. My normal one oriented backwards to crimp just the insulation retainer, then a single wire crimper offset to crimp the wire portion of the crimp. It was jank, but worked.
- Random M8 ring terminals in a larger assortment from Amazon. I kept the original + lead, and shortened the -. As delivered by Mr. T, the - lead is the perfect length, but after shortening other parts of the harness, I pulled about 2' of extra ground wire back toward the battery and wanted to remove the excess there vs cutting/splicing in the middle of the loom. What is odd, the power feeds from Toyota are too small to fit on M8 studs, looked to be M6 sized. Very small for most battery terminals. I opened up the hole on the + feed end with a step drill and the good ole' hand clamp.
- As far as crimpers, I tried a few.
- I had a cheap Amazon crimper kit that I'd originally bought for small lugs. It had a half dozen jaw sets. The terminal jaws just crushed the connectors. I think the issue here was bad tolerances and rough finish on the jaws that caught the brass and didn't allow it to slip. They work great for other things, just not for this. https://www.amazon.com/dp/B0BJVH4J6Q?tag=ihco-20
- Had a good tip here for this model and it made a few good crimps. I ended up not enjoying the grit in the mechanism and overall crimp feeling: it just felt like a lot of drag was keeping the pressure from making it to the crimp itself. https://www.amazon.com/dp/B0F4CLFZ3J?tag=ihco-20
- Also tried the high $$ option, which was where I landed. Subsidized by a birthday gift card and after making some of my best crimps yet, I kept them. They'll earn their keep after these next few projects. https://www.amazon.com/dp/B005EXP43Q?tag=ihco-20
Harness .250 terminal (Yazaki) on the left (tin), failed Furukawa attempts with cheap crimper. Crimper was side-loading the terminal and pushing it out of the jaws.
Harness .187 terminal (Yazaki) on the left and Furukawa on the right. Crimp was improving, but not fully capturing the wire. You can see how much longer the terminal is. It wouldn't catch the retention clip in the relay base.
After finally getting it right, here's one of the relay bases terminated (Yazaki and AMP) before putting it all back together. Note the tap on the ground wire, this is exactly how the H4 harness comes from Toyota, just buried in the vinyl jacket and some heat shrink. I applied the same after this photo.
Both relays buttoned up tidy. This portion of the harness is now ~8" long, vs 2-3' as delivered. No excess to coil.
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