CNW e start conversion, sprag failures

Café au Lait · 2026-06-24T18:07:53-0600

My bike #101 was built 2013 and I bought in 2024 with just over 10k miles. It now has 22k. However the bike only had the E start kit fitted in 2021 and I’ve no idea what the mileage was at that point.

However I reckon it likely the owner put most of the miles on in the early days and then reduced to the point of moving it on.

Matt may well know and I’ll ask next time I contact him but my guestimate would be 8k.

I always kick the bike over from home and only use the E at petrol stations and pubs/cafés etc or anytime I need to start it whilst astride it so not a heavy user but if the wear is mileage dependent then roughly 12k ish

Hutchison hemi · 2026-06-24T20:08:52-0600

CNW starter installed spring of 2019 at 5,500 miles.
First sprague failure 6,300 miles later @ 11,800 miles CNW replacement installed.
Second sprague failure 6,700 miles later @ 18,500 miles (Chinese) sprague installed.
Two bearings in the kilt failed 4,100 miles later @ 22,600 miles. Heat related I believe. The grease in the bearings was black and crystallized and bearings partially seized. Installed new bearings and changed sprague with another new (Chinese) sprague because it was already disassembled. The first Chinese sprague was still working properly.
4,000 miles later @ 26,000 miles everything is fine. First two spragues installed lubricated as received. Chinese spragues had atf for lube.
My bike probably has very few starts compared to some as I ride it between 100 and 200 miles every time I take it out, usually only stopping for fuel.

gortnipper · 2026-06-24T20:49:57-0600

Sounds like every 6k mi for your riding. You have 2k mi to go.

dobba99 · 2026-06-25T03:32:23-0600

Hutchison hemi said:
CNW starter installed spring of 2019 at 5,500 miles.
First sprague failure 6,300 miles later @ 11,800 miles CNW replacement installed.
Second sprague failure 6,700 miles later @ 18,500 miles (Chinese) sprague installed.
Two bearings in the kilt failed 4,100 miles later @ 22,600 miles. Heat related I believe. The grease in the bearings was black and crystallized and bearings partially seized. Installed new bearings and changed sprague with another new (Chinese) sprague because it was already disassembled. The first Chinese sprague was still working properly.
4,000 miles later @ 26,000 miles everything is fine. First two spragues installed lubricated as received. Chinese spragues had atf for lube.
My bike probably has very few starts compared to some as I ride it between 100 and 200 miles every time I take it out, usually only stopping for fuel.

Thanks for the information, Question, which bearings failed?

Hutchison hemi · 2026-06-25T05:04:33-0600

dobba99 said:
Thanks for the information, Question, which bearings failed?

The bearings that failed were about 2 inches in diameter and about 1/4 inches wide from memory. There is also a very small diameter bearing which was ok.

dobba99 · 2026-06-25T06:17:29-0600

Hutchison hemi said:
The bearings that failed were about 2 inches in diameter and about 1/4 inches wide from memory. There is also a very small diameter bearing which was ok.

Ok, the two bearings either side of the sprag. Apart from replacing the sprag as a service item another thing to do, when your in there replacing the sprag, is to remove one of the rubber shields from these two bearings, clean out the old grease, repack with a high temperature grease and replace the rubber shield.

Starvingphotog · 2026-06-25T06:55:03-0600

So, I recently installed my cNw starter kit this spring at 8929 on the odometer. I'll see how many miles I get out of it before any of this happens to me. Seems like I should expect it too around 15k on my odometer. I use the start each time I ride, and generally ride on the weekends for about 100 miles. So, it will take me a while to get to 15k. My kit would have the latest bearings that Matt uses which I believe is different than what was used before 2020 when most of you guys seem to have had your kit installed. We'll see how it goes. I have the Shorai LFM21 w/315 cold cranking amps so lots of juice to spin the starter well enough.

Bummer that this is a complication of electric start mechanics, but knowing that this is an issue and serviceable easily enough, makes me think to get spare parts on hand for when it happens and do a refresh of the kit bearings each 5k miles or so. Probably overkill but what isn't on our bikes....

ebyker · 2026-06-25T08:32:34-0600

Starvingphotog said:
So, I recently installed my cNw starter kit this spring at 8929 on the odometer. I'll see how many miles I get out of it before any of this happens to me. Seems like I should expect it too around 15k on my odometer. I use the start each time I ride, and generally ride on the weekends for about 100 miles. So, it will take me a while to get to 15k. My kit would have the latest bearings that Matt uses which I believe is different than what was used before 2020 when most of you guys seem to have had your kit installed. We'll see how it goes. I have the Shorai LFM21 w/315 cold cranking amps so lots of juice to spin the starter well enough.

Bummer that this is a complication of electric start mechanics, but knowing that this is an issue and serviceable easily enough, makes me think to get spare parts on hand for when it happens and do a refresh of the kit bearings each 5k miles or so. Probably overkill but what isn't on our bikes....

I see all this talk abought the CNW E start I have an earley kit the only problems that I had where a sprag lock up after a kickback after 2 failures from a kickback Matt sugested that I replace my Pason ing with a sparks ing no more kickback and no sprag lockup [ lock up means all dogbones jamed and not able to engage ] the other problem that I have and have not seen any one talk about is failure of the adjustable detents they ware out and will not stop the gears from spinning cause a iritating wine noise Matt sent me several updated sets with hardened ends they siill wore out and stoped working I find it hard to beleve that I am the only one to have that problem I have modified the start motor [ relocated the spring ] so that the gear stays ingaged and removed the detents the gears now stop as soon as te bike starts sorry the italics falt of my computer

CNW e start conversion, sprag failures

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