2003 CRF150F Electric Start Modification

7 replies to this topic
  • AnimalDan

Posted April 27, 2009 - 10:06 AM


So here is my little story on adding electric start to my 2003 CRF150F. Why would I do this? The rational is a long story but in a nutshell, I found a California legally plated 2003 CRF150F. After 2004/5 you cannot legally do a CA plate conversion (well you can but it’s a special construction or a tricky story). This is the perfect bike for my girlfriend (with it lowered) except for the lack of electric start. She can kick start it in the parking lot but the 150 does not kick over as easy as the XR100 or her TTR125 and her lack of height makes it tough to kick on the uneven trail or after it’s been on its side and slightly flooded.

My thanks to coeshow :banghead: for giving me the correct info, otherwise I got a lot of well intentioned but incorrect advice.

The 2006-up CRF150f has electric start but is a different engine and different frame than the 2003. The 2003 CRF230f is the same frame and externally similar engine. So I spent time comparing schematics between the CRF230f (e-start) and the 2003 CRF150f. It was like reading a Highlights magazine at the dentist, trying to find the differences between the similar pictures. I was generally unsuccessful in finding used 230 parts, and the parts I did find were as expensive as the new part.
Since it already had a Baja Designs kit, I didn’t have to worry about the stator or reg/rec. Here are the basic steps, I don’t cover the details. I figure anyone nutty enough to do this is smart enough to not need them.
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Pulled the left side crankcase cover and flywheel. The flywheel uses a 16mmX1.5 RH MP puller (thanks ThumperTalk). Mounted the starter clutch to the flywheel making sure it was installed in the right direction.
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Re-installed the flywheel, added the starter gears and shafts. Verified that it already had a fully wound stator. I couldn’t figure out how to install the neutral switch. I don’t think it would fit my stator, it’s a rewound 03 CRF150F stator or an aftermarket. Replaced the left side crankcase cover and installed with the starter gears and starter motor.
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Mounting holes for everything are already there. Here was the only real problem I ran into. The carb bowl bottom nut hits the tall starter bolt.
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If this were a typical carb I could just rotate the carb a little but this carb won’t spin. So I had to just stretch the carb-to-cylinder fitting. There is a lot of pressure here now so I hope it doesn’t lead to problems later. Any suggestions are welcomed. Installed the battery box, battery, cables, starter solenoid, and cover.
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Mounting tabs for the box are already there on the frame. I didn’t order a 230 wire harness because I figured the BD dual sport kit modified it anyway. I figured out what wiring I would need, skipped the neutral and clutch safety cutouts. Added the starter switch to the handlebars.

I rate this project a medium difficulty, if you can pull a flywheel or replace a stator, you can do this. No drilling, grinding, welding or cutting required.

Parts needed are on the following pages; Battery (box and electrical), Left Side Cover, Left Crankcase Cover, Generator, Starter, Wire Harness and a starter switch. Probably cost me about $600 (no stator or reg/rect cost since I already had a street legal dual sport kit installed). The girlfriend now has a street legal 2003 CRF150F with kick and e-start.:banghead: Thanks for humoring me.

  • heybuddy1901

Posted April 27, 2009 - 10:22 AM


kick and e-start! NICE!

:banghead: for ingenuity (which i cant spell right now)

  • coeshow

Posted April 27, 2009 - 06:35 PM



Nice job! You have done what I contemplated some time ago. I may still perform this someday to my 150/230 bike. The late model XR200 manifold is a bit longer, will bolt on and would allow improved carb fitment if you choose to look into it.

You could also purchase a couple of gaskets and fabricate a spacer (between head and manifold) long enough to allow proper fitment along with added length screws.

  • AnimalDan

Posted April 28, 2009 - 09:26 AM


Thanks for the ideas. The fiche for the XR200 makes the manifold look like it has a different orientation than the 150 but I'm going to give it a try. The gasket is another great idea, thanks.

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  • Towlieee

Posted April 28, 2009 - 09:48 AM


What about just saving the starter bolt or the carbs bolt?

I forgot if that bolt on the bottom is hollow or solid on the carb? If it's solid I'd just take a grinder to it personally

  • AnimalDan

Posted April 28, 2009 - 12:51 PM


What about just saving the starter bolt or the carbs bolt?

I forgot if that bolt on the bottom is hollow or solid on the carb? If it's solid I'd just take a grinder to it personally

Starter bolt; there'd be nothing left of the starter bolt head. Carb bolt; pretty sure I would have to take off too much of the carb "bolt" and it would break through but I will check it out. I thought about grinding down the starter housing and using a shorter bolt but figured there was a reason they made the two starter bolts different sizes. I didn't look inside the starter to see how thick that shoulder is so it is still an option to check out but it would mean dismantling the starter.

  • Chuck.

Posted April 29, 2009 - 06:45 PM


Replace the starter bolt with a button head bolt, available from commercial fastener suppy stores. Here are two pics of some metric stainless steel button heads used to solve the interference problem on a fork conversion:

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  • Towlieee

Posted April 29, 2009 - 08:24 PM



:banghead: :banghead: :banghead: :banghead: :banghead:

Even if that wasn't enough, could maybe even trim a little off the carb also :foul:

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