LiftdT4R Posted August 13, 2006 Report Share Posted August 13, 2006 (edited) Just was wondering if I should plan on changing my jetting when I throw in my lightened flywheel, and stator timing plate. I was going to bump up to +4 on the timing, sems to be the general consensus. These mods wouldnt actually put more fuel or air into each stroke(as far as I know), so I'm guessing I would not have to change the jetting. But just wanted to make sure , I'm still a rookie when it comes to this, and I don't want to run the thing out lean until I blow it. Also, was wondering what size mains I should be running? I think I put in 290s, and the plug chop looks perfect, everything idles fine, and seems to run smooth, but just wanted to double check. Altitude is aprox. 150 ft., mods are in my sig, and the airbox still has the lid on it. And one last thing, I have been running Super gas, 93 octane, should I stick with this when I do my timing advance. I have like 110psi now. Thanks! Edited August 13, 2006 by LiftdT4R Quote Link to comment Share on other sites More sharing options...
J-Madd Posted August 13, 2006 Report Share Posted August 13, 2006 (edited) Assuming your jetting is perfect now, I'm pretty sure you need to go up a size on the mains when you advance the timing. The fly wheel has no effect...................and 93 octane is fine. Edited August 13, 2006 by J-Madd Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 13, 2006 Report Share Posted August 13, 2006 Assuming your jetting is perfect now, I'm pretty sure you need to go up a size on the mains when you advance the timing. The fly wheel has no effect...................and 93 octane is fine. Timing and compression normally doesn't effect jetting. Plug chop it to be sure... I didn't have to change my jetting at all when I went to +4 and a lightened flywheel... Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 13, 2006 Author Report Share Posted August 13, 2006 (edited) Timing and compression normally doesn't effect jetting. Plug chop it to be sure... I didn't have to change my jetting at all when I went to +4 and a lightened flywheel... Thanks, that's what I thought, I will plug chop it just to be on the safe side, but the flywheel and timing arent puting anymore fuel or air into each stroke if I understand it correctly. Any idea of what size main I should be running. All my info is in my sig and the first post. Like I said, I beleive I have a 290 main, but I can't remember. Thanks, Edited August 13, 2006 by LiftdT4R Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 13, 2006 Report Share Posted August 13, 2006 Thanks, that's what I thought, I will plug chop it just to be on the safe side, but the flywheel and timing arent puting anymore fuel or air into each stroke if I understand it correctly. True...more fuel actually cools the motor a tad, so...advancing timing may make it run a little hotter. As said, you might have to...not always. Any idea of what size main I should be running. All my info is in my sig and the first post. Like I said, I beleive I have a 290 main, but I can't remember. Thanks, I see pipes and filters. What elevation, Temps and do you have an airbox, lid, clamp on filter??? Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 13, 2006 Author Report Share Posted August 13, 2006 True...more fuel actually cools the motor a tad, so...advancing timing may make it run a little hotter. As said, you might have to...not always. Any idea of what size main I should be running. All my info is in my sig and the first post. Like I said, I beleive I have a 290 main, but I can't remember. Thanks, I see pipes and filters. What elevation, Temps and do you have an airbox, lid, clamp on filter??? Posted all the info in my first post except temp. I am at about 150ft, aprox 70*, fliter is a uni, in stock airbox, with lid. Thanks man, appreciate all the help, I'm trying to pick up a 2nd set of carbs, so I can fawk with those, while leaving my setup that I have no untouched, that way I can always drop the orignals back in, when I fawk up the jetting. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 13, 2006 Report Share Posted August 13, 2006 What...you expect me to actually work on a Sunday and scroll up? Sheesh... Sorry...didn't re-read that. I think 290 is a bit rich if you're running with a lid, normally close to sea level and average temps like that, 260 or so is the norm, but...each bike is different. I would say you're pretty safe with that for a flywheel and timing bump. Just check the plugs to be 100% sure... Have fun, you're gonna notice a whole new feel about your bike when you do these two minor things!! Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 13, 2006 Author Report Share Posted August 13, 2006 What...you expect me to actually work on a Sunday and scroll up? Sheesh... Sorry...didn't re-read that. I think 290 is a bit rich if you're running with a lid, normally close to sea level and average temps like that, 260 or so is the norm, but...each bike is different. I would say you're pretty safe with that for a flywheel and timing bump. Just check the plugs to be 100% sure... Have fun, you're gonna notice a whole new feel about your bike when you do these two minor things!! I know, I know, I didnt even expect anyone to answer on sunday, so I guess I can't bitch. I am not sure if I put in a 290 or not, it might have been a 260, but the plugs looked perfect. I really hope I notice at least somewhat of a difference with the flywheel and tiing, I just want to be able to beat my buddies 400ex with a pipe and filter by 4 instead of 3 bike lengths. If I do ditch the air box lid, what would you say to go up to, I was thinking 280, I heard that dumps a lot more air into the mix. Thanks man! Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 14, 2006 Report Share Posted August 14, 2006 Depending on the length of the race, weight and skill of the riders, you should be KILLING that 400EX. I'd say you're on the right track. If you take the lid off, you need a pro flow adapter so the filter seals correctly against the airbox. Or...you could just cut out the top of the lid, leaving the front piece there to seal it...but, what happens if you ever want to put it back on??? 280 or 290 will be good without a lid... I don't think it'll be worth a bike length, the timing and flywheel should, though... Those little 400EXs are good off the line, but that's it. Quote Link to comment Share on other sites More sharing options...
LiftdT4R Posted August 14, 2006 Author Report Share Posted August 14, 2006 Depending on the length of the race, weight and skill of the riders, you should be KILLING that 400EX. I'd say you're on the right track. If you take the lid off, you need a pro flow adapter so the filter seals correctly against the airbox. Or...you could just cut out the top of the lid, leaving the front piece there to seal it...but, what happens if you ever want to put it back on??? 280 or 290 will be good without a lid... I don't think it'll be worth a bike length, the timing and flywheel should, though... Those little 400EXs are good off the line, but that's it. Yeah, both of us have been riding for years,we started out with zook 230s, so we both have about equal skill, I usually take him by 3 bike lengths or so in about 1/8th, I do have the pro-flo adapter, I just run the lid on, cause I see some water on the trails. Thanks for the info man, you guys are super helpful! Quote Link to comment Share on other sites More sharing options...
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