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37mm to 41mm bored out FCR carb

Joined Nov 2001
17K Posts | 773+
Ely, England
here is one i hope dale will help me with:

bored out 'scoots' 37mm carb to 41mm and it went ok after i decided to use araldite to bond the two lower chambers.

i test rode my FE400e bike and to cut a long story short; the bike wanted to go leaner on the MJ. fine except i went through 150 main and ended up using my smallest which was a 148MJ.

i'm 90% sure this was right and indeed i could have gone leaner. i'll be looking at a 145MJ or even a 142MJ.

is this right?

EFP c2.

whacky, whacky!!!!

this is where i earn my corn!

regards

Taffy
 
Cheers Taffy for doing this work on my dinky fcr. Took it for another quick blast when i got home, seat of the pants test i'm sure its now kicking out more bottom end. Wheel is out and the wet is off, will put on the road legal tyre next weekend and then i'll be able to give it some beans without the fear of major tankslappers.

Thanks again for a quality service :D
 
Taffy said:
here is one i hope dale will help me with:

bored out 'scoots' 37mm carb to 41mm and it went ok after i decided to use araldite to bond the two lower chambers.

i test rode my FE400e bike and to cut a long story short; the bike wanted to go leaner on the MJ. fine except i went through 150 main and ended up using my smallest which was a 148MJ.

i'm 90% sure this was right and indeed i could have gone leaner. i'll be looking at a 145MJ or even a 142MJ.

is this right?

EFP c2.

whacky, whacky!!!!

this is where i earn my corn!

regards

Taffy

Hi Taffy,
From personal experience and is often the case with such an undertaking the inlet bell / Venturi aspect ratio has been altered with a consequent reduction in flow efficiency. Such a reduction in efficiency increases the venturi signal strength @ and / or near WOT by means of acting as a smaller Venturi than it actually is.

You may attempt to address such an issue by hand dressing the inlet bell.


Hope this helps.

Sincerely,
Dale
 
got that dale and understand it. i trust it may have to be extended slightly and taper in more slowly?

i see all these cute keihin belmouths in blue and wonder aloud whether anything can be done with these 'homemade' ones that are fitted to huseys. the blues i trust can't be made to fit.

me thinks i need to make some clay ones on the wheel and try them!

you need many skills to tune a bike but now being a pottery master is another!

just jestin! :lol: :lol: :lol:

on saturday i noticed that my rear trials tyre had worn a hole in the rear mudflap (infront of the rear wheel). saturday evening i noticed that it was rubbing so hard that it had rubbed a groove in the rear shock lower mounting point!

now the only time it would have done that is in top gear and flat out! so i will have to reconsider all tests. it was all right with the old chain. now i have a new one on; it has brought the rear wheel forward.

man o man o man :( :( :(

thanks again!

Taffy
 
FCR41.sized.jpg

Lineaweaver FCR 41 / Circa 2000

VS.jpg

Business End :D

Please visit my Gallery:
http://www.husaberg.org/modules.php?set ... _album.php

Note:
Velocity stack slips inside of large K&N air filter.


Kind Regards,
Dale
 
The float bowl drain valve is a nice touch. I don't think it would clear the starter as it is a tight enough squeeze as it is.
 
nice work dale!

was that a baked bean tin or tomato soup? :lol: :lol:

just jestin!!!

i trust there is a little trough/ditch in the belmouth for air to send a signal through the PAJ and MAJ?

you may have read above that my trials tyre had grown by over an inch and has even worn a groove in the lower shock. it even managed to touch the rear spring. the two are over an inch apart in the workshop!

thanks.

Taffy
 

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