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Old 11-01-2010, 12:52 PM   #1
m6rk
 
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honda cub c90 tuning help / links

Hi there,

I've just bought a honda c90 cub. It's gonna be a birthday present so am stripping it down and rebuilding it. It's going to be road legal so nothing offroad!

I'd like to give the engine a little more poke. Either by doing a complete engine swap or a 110 head conversion or similar.

I was wondering if someone could point me to the threads where this has been discussed? or could recommend a carb/head combo for the c90 or a complete new engine that isn't too expensive that would fit. ( I can weld, but would prefer an easy transplant as possible)

The bike needs to stay a semi auto.. so no clutch lever!

Any advice appreciated!!!

Many thanks
Mark
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Old 11-01-2010, 12:54 PM   #2
jakeyy
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Re: honda cub c90 tuning help / links

Great bikes they are, indutructable
http://www.pitbikeclub.co.uk/showthread.php?t=36728
Theres a tune up guide mate
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Old 11-01-2010, 01:01 PM   #3
m6rk
 
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Re: honda cub c90 tuning help / links

many thanks to the welcome. i'm used to working on 600cc race bikes so this should be fun!

That guide seems more of a service manual. Just wondering if there are any guides on fitting bigger heads / what size carb is recommended, exhaust systems etc?
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Old 11-01-2010, 01:02 PM   #4
jakeyy
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Re: honda cub c90 tuning help / links

Quote:
Originally Posted by m6rk View Post
many thanks to the welcome. i'm used to working on 600cc race bikes so this should be fun!

That guide seems more of a service manual. Just wondering if there are any guides on fitting bigger heads / what size carb is recommended, exhaust systems etc?
Oh, right.
You will have to ask some of the more experianced members on this site, as i am sure they will know.
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Old 11-01-2010, 03:28 PM   #5
dervdub
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Re: honda cub c90 tuning help / links

Depends alot on the engine, there are more than 1 type fitted to C90's.

If you're lucky you could change the barrel and piston for a 110/125 (same bore size 52.4mm) and a head from the same (23mm inlet, 21mm exhaust)

You can get cams for these heads but they are relatively pricey, best option would be to get an E22 head from a 72cc chinese clone, same valve sizes, slightly smaller combustion chamber and a very revvy cam.

Port the head and fit a VM22 carb, jet to suit and you should laughing with around 9-10hp.

There was a guy on ebay called pedshed selling flat top 52.4mm pistons and fast road cams very cheap but I think they were end of stock stuff, I've fitted both to a chinese 125 and ported the head/VM22 and it flies.

Hope that helps
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Old 12-01-2010, 06:46 AM   #6
Despise
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Re: honda cub c90 tuning help / links

Quote:
Originally Posted by dervdub View Post
You can get cams for these heads but they are relatively pricey, best option would be to get an E22 head from a 72cc chinese clone, same valve sizes, slightly smaller combustion chamber and a very revvy cam.
funny enough I think ooracing sell the E22 and it aint too dear either
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