Bigger carb xr400

[cu5hty]

my mate has a xr 400 with the front end off a husky 610 fitted and moto wheels, with the rest of the husky in bits all over his garage we decided to fit the carb from it to his xr, not sure what model but its a mikuni pumper carb and it fit strait on. took it for a test run and there is allot more power, throttle is more sharp all he needs to do now is 440 it and a new exhaust and i think he will have a nice all round bike, fingers crossed he passes his bike test next monday or he will spend more time staring at it than riding it. ill find out what model it is and put it up with some pics.

[jasonbc]

my mate has a xr 400 with the front end off a husky 610 fitted and moto wheels, with the rest of the husky in bits all over his garage we decided to fit the carb from it to his xr, not sure what model but its a mikuni pumper carb and it fit strait on. took it for a test run and there is allot more power, throttle is more sharp all he needs to do now is 440 it and a new exhaust and i think he will have a nice all round bike, fingers crossed he passes his bike test next monday or he will spend more time staring at it than riding it. ill find out what model it is and put it up with some pics.

Don't dother the bike can't handle it and it will end in tears it's common for theses bike to **** there load when the 440 kit is fitted my came with one and some other bits like weisco 12.5:1 piston see below











Which leads to this---------------









Hope that convinces you to not bother big bore kits are not worth it and remember this IS common

[cu5hty]

i got my old xr400 done into a 440 i bought a 440 kit including a new barrel and like you say it ended in tears so after some time spent repairing it a mate of mine said to get a new barrel 440 of course and he got hold of a piston and rings, the rings and piston were allot different to the 440 kit originals the piston was longer and the rings where slightly thinner, he took the lot to his shop put it all together tested it and gave it back its done over 2000 miles since and i sold it on and still see it about. i can get hold of the info on the piston used and rings etc if anyone is interested i agree the kits are a bit poo but with a different piston it seems to work fine

[jasonbc]

i got my old xr400 done into a 440 i bought a 440 kit including a new barrel and like you say it ended in tears so after some time spent repairing it a mate of mine said to get a new barrel 440 of course and he got hold of a piston and rings, the rings and piston were allot different to the 440 kit originals the piston was longer and the rings where slightly thinner, he took the lot to his shop put it all together tested it and gave it back its done over 2000 miles since and i sold it on and still see it about. i can get hold of the info on the piston used and rings etc if anyone is interested i agree the kits are a bit poo but with a different piston it seems to work fine

The taller piston means its high compression,as for the barrel you don't need a new one you have 2 options bore out the old one or press a new liner in it. Got to say i disagree with you 2k miles isn't enough to run in properly may be working fine now but see how long it lasts, you may be lucky

[dazzerrtw]

The thing to remember with Honda XR400 is

The Standered bike is almost perfect at what it does,it only needs a few basic mods to sort it.

Everyone I know that started fitting big bore kits ..carbs and tuning,
all had problems with their bikes.

If your looking for more speed it may be better to change to a crf.

Standered XR's will last and just keep running without to much bother.

[cu5hty]

The thing to remember with Honda XR400 is

The Standered bike is almost perfect at what it does,it only needs a few basic mods to sort it.

Everyone I know that started fitting big bore kits ..carbs and tuning,
all had problems with their bikes.

If your looking for more speed it may be better to change to a crf.

Standered XR's will last and just keep running without to much bother.

true thats why i changed to the 650 xr. i might tell him just to stick with the carb and leave the 440 kit alone see how it goes im sure he will get board and change for a bigger bike soon. dont we all at some point