Kona Hei Hei 29 Bafang 250W 36V Build Thread

[dan3572]

So thanks again for everyone who helped with all my pre conversion questions. Apart from tweaking the firmware, I finished the build on Saturday and took it for a test ride.

This is a thread in case it helps anyone else attempting a similar conversion.

1. The biggest challenge was battery placement. I might have since found a better option (sod's law, just after finishing) but I went for a 19.2Ah battery in a bag supplied by Custom Built eBikes in the UK, who I ended up buying the motor kit off too. I could've saved a bit by importing from China but would have had to wait a long time for the battery and the savings would be subject to the customs and duty lottery and I would not have had the support from Custom Built eBikes which has been very good. These were me offering it up to check it should fit before doing anything more in case I had to return it.





2. Bottom bracket removed, and a bit of a clean up. I didn't perform a full strip down as it's hardly been used since I last did so. The shock was sent off to TF Tuned as it needed a service and an o-ring near the pro-pedal/adjuster ring had failed.



3. Offering up the supplied 46T chain ring which I was pretty sure wouldn't fit. I ordered the 44T version being fairly certain that wouldn't fit but although the box was labelled 44T it seems the wrong chainring had been put in the box at the factory. A replacement was offered (without the need to return the 46T).



4. I checked the chain line with the supplied chainring. The cassette is an SRAM PG990 11-34T. Looked good to me.



5. I decided to go a bit mad with the Lekki parts. I needed a smaller chain ring. Although I could see the potential benefit of going even smaller I thought the 40T would be a good bet so I ordered the kit with the replacement cover along with an extra spacer (you get one with it), the 5mm motor bracket spacer and the Buzz Bar V3 170mm cranks with offset adjustment, all from Brighton Ebikes.

I added extra grease to the the gears and replaced the cover, making use of some black stainless steel bolts I had already. In fact I replaced all the motor housing bolts with stainless steel.

 

[dan3572]

6. Cockpit initial setup.



A bit of neoprene added to protect the Scandium frame a bit. It is also helitaped. I don't know if this was a good idea or not.

7. I now moved onto the brake sensors. I ended up cutting some pieces off joinery spacers and sticking with 3M tape and placing on some rubber next to the bars, all held on with a cable tie. Once on, the shape of the brakes meant that the cable ties don't pull vertically so I later added some more pieces which although not all that pretty, seems to work well.

I attached the magnets to the reach adjustment dials with 3M tape and heat shrink, being careful to minimise the heat applied.

 

[dan3572]

8. The gear cable normally runs under the top tube with an exposed central section then down the top tube of the rear triangle. The cable length was a little short to place at the rear and I felt the sensor would be better protected under the top tube so I added a gear cable outer and a couple of extra stick on cable guides (changing the adhesive tape to the better 3M tape I had).




9. I decided I'd prefer the speed sensor to be on the left of the bike to avoid damage if the chain came off. There was insufficient clearance for the supplied magnet so I replaced it with one from Cateye. I then covered the sensor and wiring with a neoprene sleeve.



10. I wasn't sure whether to use the supplied light but thought I might as well. The bracket didn't suit this bike so I fabricated a piece out of aluminium and added to another handle bar bracket I already had.



11. Now the battery. The battery and bag are a tight fit in the frame which is actually quite good in terms of keeping it steady. The bag is ok but a hole needs to be cut for the wires.

I opted to route the wires into the right side pocket so the terminal and charging terminal can be accessed without opening the main compartments and there's more protection.

This is what I came up with to prevent it sliding into the shock.

 

[dan3572]

12. Then all that was left was to attach the chain ring, chain, cranks, and pedals. The chain turned out to be the correct size without any adjustment. I had so slightly longer Ti bolts around that I used, longer ones being required as I added two 2mm spacers before the chain ring.

I was glad I bought the Buzz Bars. They even out the q factor and look great.

 

[dan3572]

 

[dan3572]

All went great on the test ride. There were a few more challenges than I expected but the end result is great fun. Trouble is I want one now too.

Now to find out/work out the best firmware adjustments to make for this style of bike and get out and enjoy it.

 

[peter.c]

Well done a nice build ,my only thought might be the two raised heads on the bottle cage mounts could rub through . And after learning the hard way a couple of luggage straps on the outside of the bag around the frame as the bags can rip

 

[dan3572]

Thanks, I'll watch out for that but hopefully the velcro will prevent it or a could add a couple of patches of the opposite velcro. It's more solid than I expected. The zip on the bag broke but a replacement is coming.

 

[dan3572]

So my wife tried it today and, apart from learning when to change gear , it went well.

I've just tried accessing the firmware and decided to set most of the settings in line with the Karl's Special Sauce profile. The battery cut-off was set to 31V already which seemed fine to me so I left it. I also left the start current at 20%.

Regarding the throttle settings, I'm guessing there have been firmware updates since that was written as we had the ability to set the throttle speed with the display/controller from 1 to 9 so I left it set to 'By Display's Command'.

What I wasn't sure of was whether the speed setting should be changed from the default?

The only other thing I changed was the wheel diameter to 29" although I wasn't sure whether this was necessary as I had changed it in the display settings. Any thoughts on this?

I'll give it a test ride later but any thoughts/advice would be welcome.