Here is the story. (2000 Scrambler 400 4x4)

I installed a HPD trail pipe, Roller Clutch, New clutch springs and weights. I also installed a RCR air box mod and rejeted with a 270 Main jet with a 30 pilot jet. Set needle to position 3 and used washer that HPD supplied with kit. All standard stuff and installation went well. Finished and took it for a 5-8 minute ride and parked it due to rain. Ran fine and I was amazed with my new machine. Today I come home early from work to go for a ride and fire it up and head for the woods. I get about 3 houses down the street (less than 1/4 mile) and the machine dies. Set there for a while trying to start it and it wont. Finally get it started and keep heading for the woods and it dies again. I give up and get it started and go back to the house. I tore the carb apart and it looks ok. I have checked the spark plug and it looks like it is running a little lean. I put in a 280 main jet and start it up and it sounds OK. I take off and it seems fine then I get about a 1/4 mile and it dies (just like it has run out of gas). One thing one of the people I have had look at it noticed was that my 270 main jet isnt. It is clearly mislabled. It is visibly smaller as compared to my 250, 260, 280 (guess it might be 220 that looks like 270 on the stamp). I can not believe that even with a smaller jet I could have hurt my engine in that small amount of time. There has been no signs of metal or anyting bad on the spark plug (except it does appear to be running lean).

I have checked that i am getting gas. I have checked that nothing is clogged in the carb. I have changed the spark plug 2 times.

What have I done to my machine or what have I forgot to do too my machine. Any help or advise would be greatly appreciated.

And on top of this I had a water pipe break today flooding my basement (water recovery people are here as I type). WHAT A DAY!!!!

Thank you for your time and help
KD

 

Is the vent hose pluged on the carb?

 

Dazed

Cant say that I checked that but I will.

Thank you for your advise.

Anybody else have any ideas?

KD

 

We'll start from the ground.........put in a new plug and run her. If that doesnt do the trick, write back. I plug can be royally screwed and still look good. Check it out.

EC

 

Kevin i would check ALL VENT TUBES same thing happened to my 400 SC I took it back to the dealer and the first thing he did was pull the gas vent tube off sure enough it was burnt shut causing a vapor lock

 

One more thing to check, if the others listed above fail;

Make sure that there is a flat washer between the main jet and the needle jet. The needle jet is held down in place by the main jet which is screwed into the bottom of it. If the washer is not between the two, it will allow the needle jet to rotate to where the cut out side of the needle jet(as seen from above the carb through the slide hole) blocks the flow of fuel through the carburetor. I had it happen to me once, and the results were just as you described.

 

Gordo
You win the prize.....

At the same time I did the above mods I also installed a HDP steering bushing. During this process you have to undo the the bottom and top mounts for the steering shaft. When I hooked the top mount back up I pinched the gas tank vent tube. It a good thing I have some smart neighbors and friends (both real and virtual) to help me find these problems as I might have never found it by myself with out taking it to a dealer and spending money. Also the 270 jet turned out to be correct. Just one other note. When I did the above mods I discovered that the machine had a 240 main jet (instead of documented stock of 230) also pilot jet of 25 (instead of documented stock setting of 35). Also clip was set on 4 (intead of documented stock setting of 3). Is this common for dealers to make changes to stock settings without making customers aware of those settings? I believe these are more conservative settings (rich) that would be done to perhaps deminish engine (waranty) problems. Anybody have any experiances like this?

Thank you for everyones help.

KD