Author Topic: White Brothers DR400T  (Read 67668 times)

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Offline oldmxracer

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Re: White Brothers DR400T
« Reply #195 on: February 05, 2015, 08:14:12 am »
Well done! I like it....

Offline Curtis

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Re: White Brothers DR400T
« Reply #196 on: February 05, 2015, 08:28:48 am »
Hell yes! Love it. Strange that it pops when you wind out the mixture screw? Maybe try a slightly larger pilot jet, see what happens.

Offline FourstrokeForever

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Re: White Brothers DR400T
« Reply #197 on: February 05, 2015, 09:21:00 am »
I agree with Curtis. With you saying the header gets hot very quick that would indicate a lean mixture to me. Also, the fact that the problem (popping) gets worse when you wind out the mixture screw also indicates a lean mixture. Remember, the more air you put in by opening the venturi size, you will also need more fuel  8) I would enlarge both the pilot and main jets as a start.
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Offline mick25

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Re: White Brothers DR400T
« Reply #198 on: February 05, 2015, 09:38:19 am »
Also check the header pipe is sealed good , take it off and look at the header pipe gasket and make sure the gasket is crushed all the way round so there's no air getting sucked in when backing off on the gas , if it's leaking it can make it pop to .

Offline Momus

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Re: White Brothers DR400T
« Reply #199 on: February 05, 2015, 08:27:37 pm »
Check the ignition timing. It could be retarded if the pipe heats quickly.
If you love it, lube it.

oldfart

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Re: White Brothers DR400T
« Reply #200 on: February 05, 2015, 08:44:23 pm »
Come up one on the pilot   (Std  is # 15 )   ;)

Offline pmc57

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Re: White Brothers DR400T
« Reply #201 on: February 05, 2015, 09:25:10 pm »

From my understanding most 4 stroke carbs have their air (fuel screw) screw located  somewhere between the carb body and the cylinder. The further out it's turned the more fuel it allows hence making a richer low end fuel/air mix. This is opposed to a typical two stroke carb like a Mikuni where the airscrew is at the rear of the carb body and that by turning the screw out allows more air and a leaner mix.

Make sure you know which way to turn the air/fuel screw to make a richer or leaner mix.

Air screws at the back of carbs: turning the screw out = more air and a lean mix
Air/fuels at front of carbs: turning the screw out = more fuel and a rich mix