1989 honda c90e tec help/advice

[kirky1298]

evening all , just looking for a little help from all you petrol heads out there
i've bought a honda c90e to do a charity run round scotland later in the year.
problem is , i took it out for a test ride today and it's doing 25mph flat out at a push unladen , i'm 18 stone ( cue the tosser jokes ) anyway , having done some research it seems that the 16mm carb is too small , so , i have bought a 26mm carb kit designed for a 125 cc and above monkey bike . the kit includes an inlet manifold and foam air filter ...what i want to know is , with the propper jetting will this carb still be too big or will it make a wee difference to the bike ??
i pulled the cylinder head off the c90 tonight and polished and ported it . the valves look fine ,the exhaust port was excessively carboned up . i plan on fitting a racing cdi and fast road cam also , but basically what i want to know is , will the carb be ok ????
thanks in advance

 

[DrFarkoff]

Kirky How long is a bit o string ????

Try it and see

BUT If the exhaust port was badly carboned up what will the exhaust be like inside????????????

I had a bike a few year back that no one could sort I finally got a clue when I started it without the expansion pipe the part between the silencer adn the spanny pipe was carboned up so there was only 8 mm of a 20 mm pipe usuable

Result Speed increase from 30kmh to 85 ish with a 20 stone tosser on it

Check yer pipe Kirky

evening all , just looking for a little help from all you petrol heads out there
i've bought a honda c90e to do a charity run round scotland later in the year.
problem is , i took it out for a test ride today and it's doing 25mph flat out at a push unladen , i'm 18 stone ( cue the tosser jokes ) anyway , having done some research it seems that the 16mm carb is too small , so , i have bought a 26mm carb kit designed for a 125 cc and above monkey bike . the kit includes an inlet manifold and foam air filter ...what i want to know is , with the propper jetting will this carb still be too big or will it make a wee difference to the bike ??
i pulled the cylinder head off the c90 tonight and polished and ported it . the valves look fine ,the exhaust port was excessively carboned up . i plan on fitting a racing cdi and fast road cam also , but basically what i want to know is , will the carb be ok ????
thanks in advance

 

[MarkShelley]

It is usually 2 strokes that get carboned up pipes but I guess it wouldn`t hurt to give it a clean out. I used to do my 2 stroke pipes by putting a bung in the engine end and filling it with a caustic soda solution and leaving overnight. Read the instructions though, it is dangerous stuff!!
There must be loads of better forums than this for cub engine queries, being the most sold bike ever in the history of biking!

 

[bustupbiker]

Did the C90(e) not have a smaller exhaust front pipe a bit like thay do with 50cc mopeds...another tube down the front pipe...worth a check.
I bought one too for the same reason but it looks like my trip will not happen now, i even bought a new Lifan 125cc motor to fit for the trip Nice little bike with 9000 on the clock.
Lyn.

 

[kirky1298]

JUST A WEE UPDATE , RED ONE WAS A HONDAC90 ECONOMY AND WAS FITTED WITH A 16MM CARB AND MANIFOLD AS STANDARD ,, PURE PISH AND WAS DOING 25MPH AT A PUSH WITH AN 18.5 STONE TOSSER ONBOARD ... SO ... I REMOVED THE HEAD , POLISHED AND PORTED IT AND FITTED A 26MM CARB AND BIG BORE MANIFOLD . I HAVE STILL TO FIT A RACING CDI AND FAST ROAD CAM , BUT CHECK THIS BABY OUT SO FAR .... REVS OUT SWEET AS A NUT .... AND PULLING 30MPH OVER 150YDS ... HOW FAR CAN I TAKE IT ??? THATS THE QUESTION ???

EXCUSE THE HEAVY BREATHING AND PANTING BTW , I FELL OFF THE GS 2 DAYS AGO AND I'M STILL PRETTY SORE

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[D6]

mustv been summat wrong with the original carb, as all mine have very easily done at least 45mph standard?
ps, 110cc barrels can be had for these if you look around,
the lifan engines aint bad, (you can even go to around 20bhp with the 145cc un)
but the honda is a more reliable engine, weak points are burnd exaust valves,water tracking on the supressor cap, and people lettin em run outa oil,
the non electric start ones seem to run longer, dunno why?
that was a nice gentle start up on the vid
if it smokes like that on a gentle start or when its warm, id throw a set of rings in if your off round jockland, they only hold a litre of oil, and rings are cheap and only an hours job,
that air filter looks like itl be fun in the wet too, id, guard it a bit,