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blbills

Help revive YZ400...

8 posts in this topic

Hello all,

I have been away from riding for the past 6 months and I need some assistance. I took my YZ400 for a spin for the first time in a while and I noticed a sivere bog when I am agressive on the throttle that wasn't there before. I'm planning on going on a huge ride on monday, so I really only have saturday to address this problem and I would love some suggestions as to how to go about it.

I imagine a full carb rebuild is in order due to the gas sitting in the carb that long. I was wondering if there was a quick fix that you may suggest. The bog may also be due to the cold weather. I usually ride in the summer when the temp is much warmer. Could that be causing the bog?

Anyway any suggestions would be greatly appreciated.

Thanks,

Brian

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Clean out the carb, clean out the air filter and throw in some fresh gas. Rejet for current conditions since you may be a little lean with your summer jetting. Also don't forget to change the oil since the bike has been sitting. Hope that gets ya going.

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Hey thank for the tips. I'm not too familiar with the re-jetting. You say that I may need to richen it up. Which jet would that be and how big of a change do you think is in order?

Thanks

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Budget trick.

Try and run a little injector cleaner through your carb. Put a little in the tank with a full tank of gas. Sometimes it will clean any buildup/varnish out of the carbs. Made a difference on my Bike.

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Well I did a complete carb rebuild with no luck. It still bogs like crazy. I was hoping that cleaning the acc pump real well would do the trick, but I didn't notice any change. I did notice that the main jet is a 170 (stock is a 175) that may be too lean for the winter time. I know nothing about proper jetting. Would buying a new main jet around a 175 fix this bog? Also what about the pilot screw? Would adjusting this have any effect on the bog. I also made a big oppse while taking the carb apart, I disconnected the tps sensor from the body of the carb. I put it back as close as possible to its original location; so I'm not sure if this is contributing to my problem aswell.

Any help would be greatly appreciated,

Brian

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Budget trick.

Try and run a little injector cleaner through your carb. Put a little in the tank with a full tank of gas. Sometimes it will clean any buildup/varnish out of the carbs. Made a difference on my Bike.

Ha that is what I do.. lol..

I keep the carb and injector cleaner handy and pop some in from time to time so I won't have to open the carb. Really don't want to do that as I have 2 left thumbs.. Wish I could help you blbills...

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Hey all, I solved the bog problem!!! I broke down and bought a JD power kit for the carb and it completely fixed the problem. My bike has never run better! I just wish that I would have done this 3 years ago. Thanks for all your help.

Brian

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Hey all, I solved the bog problem!!! I broke down and bought a JD power kit for the carb and it completely fixed the problem. My bike has never run better! I just wish that I would have done this 3 years ago. Thanks for all your help.

Brian

good choice, well worth it IMO :banghead: jetting can and will make a huge difference

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