pilot jet

[teirboss]

I read on the posts here that to cure rough starting in cold weather to increase your pilot jet size. I picked up a 42 pilot from my local honda shop and tried to install it and it was a different design. The threads were wrong and the diamiter was to thin. I brought it back and the kid working parts was at a loss to explain it. The only size pilot he had that looked right was a 45. I havent tried to put it in yet, but am wondering before I go rippin stuff off is this going to be to large of a jet to run. And if not will there be a problem with flooding in the summer months.

[cbrown400ex]

some people on here have used a 45. And I haven't heard anything negative about it. I installed a 42 and it works great, but I haven't tried it in the summer yet. Although it still runs and starts fine after it s hot from riding. Much like it would be in the summer. FYI the series you need is a 21.

I had the same problem when trying to go up to a 40 pilot. I am going to take it back tommorow. What do you mean when you say series 21? Are there different kinds of keihen jets?

[cbrown400ex]

yes there are at least two different styles of jets. I think the other is a series 22 and looks totally different than the 21. I think keihen makes several different carbs.

[Leo]

honda p/n for a 42 pilot jet;

99103-4200420

;)

Leo

[PsychoDave]

I have a 45 pilot and it runs great.... I was told by my local honda shop that they run 45's all year 'round. In winter it starts a lot better!!! Go for it!

Hmm...I was going to come on here and praise my 40Pilot, but now I'm thinking 42 or 45 might be the better way to go. Although better than stock, the 40 doesnt seem to be quite enough during the really cold days...

I think I am going to try the 42 first, as I would think the 45 might be a bit much in the summer months...

Any expert opinions on this? (I am not an expert on carbs by any means)

[kc 300EX]

Does any one know the stock pilot jet size for a 300EX? I would definetly like to go up a couple sizes, feels like it needs it from what I understand, thanx

[JB's 400ex]

The stock for a pilot is 38. I just went up to a 40 because the local shop was out of 42. I was switching to improve my cold starting after listening to all the posts about upping to a 42. When buying the jet the guy at the parts counter told me that when using the choke you bypass the jets so he says upping the jet shouldn't affect cold starts. Has anyone ever heard of this. Going up to 40 didn't seem to really help all that much. It did start good but I think the 42 is the way to go. I am going to wait til summer and see how it goes since it is averaging around the 15-35 degree range right now it may affect my readings.

[tprender]

I had a 42 with the stock pipe and with the WB E4 I had to use the 45. With the bigger piloet I find that I don't have to use the chock very much. I don't know what series it is 21 or 22 but it is the one that has the threads on the large part of the barrel. That is the piolet that you need to get for the 400 and the 300. I was told that you don't need to worry about the length, stock is short than the after market Keihen ones. Have the longer one both my 400 and the 440.