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Vfr400 nc30 uk carbs

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Romney1

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Vfr400 nc30 uk carbs

PostMon Dec 04, 2017 6:14 pm

Have recently purchased a vfr400 uk 1990 model the engine has been replaced at some point to a jap spec engine from a 1992 the carbs remain uk spec with metal slidders all 4 jets are 118 mains 35 .
My question is does this seem right and what needles go where front and back
Carb needles at the moment J1GA front J1GB rear .
I have read as much as i can online and alot of people when stripped uk carbs have the needels this way but then people say b to front . Im not sure if this is being mistaken from the non uk carbs .

Can anyone shed some light on what way round for sure should the uk needles be -
Cheers steve
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Neosophist

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Re: Vfr400 nc30 uk carbs

PostTue Dec 05, 2017 9:45 pm

there is a pinned thread on carbs.. its quite long but i seem to remmeber some discussion about uk cabrs going on in there and a definate answer being reached
xivlia wrote:i dont go fast on this bike so really do not need a rear brake.. /


vic-vtrvfr wrote:Ask xivlia for help, he's tackled just about every problem u could think of...
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Romney1

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Re: Vfr400 nc30 uk carbs

PostTue Dec 05, 2017 10:39 pm

Can you explain how to find these ? Iv done a search by typing uk carbs in but doesnt come up with a couple of things
Really appreciate your help
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RickOliver

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Re: Vfr400 nc30 uk carbs

PostWed Dec 06, 2017 12:46 am

UK carb spec -

Needles - J1GA front, J1GB rear

Emulsion tubes - 4 + 1 hole front, 3 + 1 hole rear

Main jets - 122 front, 120 rear

Pilot jets - 35 all round

Rick
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Romney1

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Re: Vfr400 nc30 uk carbs

PostWed Dec 06, 2017 1:00 am

Cheers Rick

After finding out the engine is non uk and actually from jap import should the jetting need changing to jap spec or put to uk then jets atm are all one size 118 the exhaust is standard also iv not rode the bike yet as its a project but had the carbs vapor blasted and ultrasonic cleaned and starts first flick but the rev seemed slower than expected to increase . But iv never had a 400 before only 600’ so might be normal cheers steve
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Re: Vfr400 nc30 uk carbs

PostThu Dec 07, 2017 11:08 am

Romney1 wrote:Cheers Rick

After finding out the engine is non uk and actually from jap import should the jetting need changing to jap spec or put to uk then jets atm are all one size 118 the exhaust is standard also iv not rode the bike yet as its a project but had the carbs vapor blasted and ultrasonic cleaned and starts first flick but the rev seemed slower than expected to increase . But iv never had a 400 before only 600’ so might be normal cheers steve


its an old carbed cv bike.. the revs will rise slowly compared to say a modern 600, especially something with fi.

stock uk or stock Japanese exhaust? they have different part numbers... ive never had the chance to cut up a uk exhaust to see whats in it but i suspect it might be freer flowing.

Since you already have jets why not get it running first...

A dyno run wiht a/f graph will show you what power its making where and what rpm its doing... best way to go i think as youll be able to see the overall health of the motor and where any mixture can do with a fettle.

oh and the carb thread is a sticky.. its the first thread in the workshop at the top.
xivlia wrote:i dont go fast on this bike so really do not need a rear brake.. /


vic-vtrvfr wrote:Ask xivlia for help, he's tackled just about every problem u could think of...
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Romney1

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Re: Vfr400 nc30 uk carbs

PostThu Dec 07, 2017 2:09 pm

Well its a project bike and has no mot been stood since 2000 so i removed the basics and cleaned to get it running .now its completely stripped the frame has been chromed and everything else powdercoated its now being put back together .I was unaware about the exhaust part number difference as the silencer was dented so i purchased a replacement stock exhaust off ebay . I hope this will not effect the running ? . I will check them when i get a min. Im just trying to Work out why it is running 118 all round, tbh from the information off rick the needle and tubes where wrong anyway so ill swap them to what he stated . . I have would like to upload pictures of the build but i cant seem to find how to add pictures.

Cheers
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Romney1

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Re: Vfr400 nc30 uk carbs

PostFri Dec 08, 2017 9:58 pm

The part numbers of exhausts i have 1 x HM MR 8E1 and 1x HM MR 8K1 can anyone identify the uk and import
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Re: Vfr400 nc30 uk carbs

PostSat Dec 09, 2017 8:59 am

Japanese bikes have 8K1 on them.
xivlia wrote:i dont go fast on this bike so really do not need a rear brake.. /


vic-vtrvfr wrote:Ask xivlia for help, he's tackled just about every problem u could think of...

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