85 Honda ATC 250r Jetting Help!!!

[Eraginal]

Hey guys, so recently had my cylinder bored to 66mm, I just got a PJ 38mm carb, threw everything together the jets are a 162main and 52slow needle is 2nd clip, it idles fine right now but loaded up when giving gas to the point it fouls the plug, I have Boysen power reads right now that are going bad, I have a rad valve on the way, just looking for pointers on jetting as I fought this problem with my 34mm stock carb as well. Pipe is fmf fatty, silencer is a fmf power core 2, direct air because of new carb, took spark plug out and it is black so assuming running to rich. I live in California weather is about 80-99 degrees, any advice is good advice thanks for looking!

[yaegerb]

Hey guys, so recently had my cylinder bored to 66mm, I just got a PJ 38mm carb, threw everything together the jets are a 162main and 52slow needle is 2nd clip, it idles fine right now but loaded up when giving gas to the point it fouls the plug, I have Boysen power reads right now that are going bad, I have a rad valve on the way, just looking for pointers on jetting as I fought this problem with my 34mm stock carb as well. Pipe is fmf fatty, silencer is a fmf power core 2, direct air because of new carb, took spark plug out and it is black so assuming running to rich. I live in California weather is about 80-99 degrees, any advice is good advice thanks for looking!

Move pilot to 48 and clip 3rd from top. Leave main the same and run your air box with an oiled uni filter.

[Eraginal]

Thanks will give that a try I can’t use the stock air box or boot right now because of the bigger carb so I was thinking about getting a filter I can connect straight to the carburetor. Also know of a good place to get jets eBay jets come from China and I don’t want to wait a couple months to get them? Thanks

[Red Rider]

...I can’t use the stock air box or boot right now because of the bigger carb...Sure you can. You just have to stretch out the stock boot to accept the bigger carburetor. Try soaking the boot in hot (practically boiling) water, or setting it out in the sun on a hot day to make it pliable, then lube up, and slip in a beer bottle to stretch out the boot. Let it cool down, with the beer bottle in place, and then remove the bottle, and massage it over the new carburetor. Not all beer bottles are the same size, so find the right size (hopefully your favorite brand works), and go to town.

[Eraginal]

Sure you can. You just have to stretch out the stock boot to accept the bigger carburetor. Try soaking the boot in hot (practically boiling) water, or setting it out in the sun on a hot day to make it pliable, then lube up, and slip in a beer bottle to stretch out the boot. Let it cool down, with the beer bottle in place, and then remove the bottle, and massage it over the new carburetor. Not all beer bottles are the same size, so find the right size (hopefully your favorite brand works), and go to town.

Lol I like this I better use an 805 rather then the usual corona hahah

[Doug8765]

Your current elevation matters ALOT


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