SC24 engine in SC21 ?

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09-04-2013, 02:18 AM

Ronfaren

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SC24 engine in SC21 ?

Hello !

After searching the forum for a similiar topic, i now start my own.

I have a damaged SC21, which needs a replacement engine and fork. Regarding the engine i am guite lost. What do i have to consider when/if doing this swap, and is it even possible ? I have a great offer on a SC24 engine, but if other engines are an easier switch, please tell

I realise that some engine mounts has to be replaced, but will it indeed fit the frame ? Can i use the SC21 wiring/switches etc ?

I hope someone kan provide som help.

Thank you !

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09-04-2013, 05:57 AM

Sebastionbear1

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Welcome the CBR Forum!

Well David put an SC21 engine into a SC24 frame so it must be able to be done.

Just read the following thread and reverse everything!!

https://cbrforum.com/forum/cbr-1000f...-frame-147180/

Be aware of the differences in the spark pulse/igniter between the two motors. You will have to use some of the wiring and electrikery from the donor motor bike

Cheers, SB

Last edited by Sebastionbear1; 09-04-2013 at 05:59 AM.

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09-04-2013, 02:49 PM

David Van Onselen

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I can summarize the basics for you. Firstly the engine will bolt straight in. No changes there. The wiring difference is the pulse generator (left hand side of crank) You will need to remove the single coil version from the SC24 and fit the double coil from the SC21. Change the rotor as well to the SC21 type. That'll make the engine exactly the same electrically and you don't have to change anything on the bike. Carbs are different so use your SC21 carbs. The other snag is the waterpipes on the head. Either swop the SC21 head onto the SC24 engine, make sure to use the SC21 head gasket as well. Alternatively you will need to use the SC24 pipe connectors on the side of the head and make up piping from there to the thermostat housing under the tank. That should sort you out. Any hassles give me a shout and I'll talk you through it.

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09-05-2013, 01:31 AM

Ronfaren

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WOW, thanks for fast and very usable replys. I noticed the SC21 into SC24 swap, but was afraid to conclude anything from this. Of course the only thing broken on my sc21 engine, is the pulse generator :/ Anyways, this shouldnt be that expensive as a replacement part. Ill swap the head and carbs, thank you so much for the help - never messed with a cbr before.

Regards

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