hops Posted April 1, 2004 Report Share Posted April 1, 2004 Just rebuilt my engine, and as much as I hate to question "professional builders", I am still concerned with the jetting he gave me. (BTW, my engine is still in a box, F'n 12hr grave shifts) 4mm crank "play/race" port job custom cut cool head domes (cut for pump gas) timing advance +4 v-force stock carbs bored to 28mm clamp on dual K/N's CPI inframes He gave me 27.5 pilots (which were already installed) and 320 mains. Does this seem right? I know its not set up for screamin top end, but this is around what I had with just the clamp on's and CPI's. Am I missing something? Quote Link to comment Share on other sites More sharing options...
erbilabuc Posted April 1, 2004 Report Share Posted April 1, 2004 sounds about right Quote Link to comment Share on other sites More sharing options...
fixitrod Posted April 1, 2004 Report Share Posted April 1, 2004 What's your altitude? Quote Link to comment Share on other sites More sharing options...
Ducman Posted April 1, 2004 Report Share Posted April 1, 2004 Hops, I don't know much when it comes to larger diameter carbs than stock, but I'm wth you, sounds really lean to me. 320's with the stock jug and clamp-on k&N carb setup you had before sounds almost a slight bit lean, now with the bigger carbs, stroked, ported, seems like it should be in the higher 300's more like 380 or so? I don't think I would trust the 320's unless you are at a really high elevation, I'd go bigger at first to start with to be safe and if it bogs from being too rich you can always jet back down. Quote Link to comment Share on other sites More sharing options...
hops Posted April 2, 2004 Author Report Share Posted April 2, 2004 I'm right around see level, Oregon coast/Portland. I'm just not sure how much the boring will affect jet size. Almost forgot, it seems the builder set the timing to near +7. I just bolted her in today. This doesn't sound correct either. I just hate questioning those who supposedly know what they are doin, but there are some circumstances that have me wonderin. Quote Link to comment Share on other sites More sharing options...
SyNtAxx Posted April 2, 2004 Report Share Posted April 2, 2004 Hey, am jetted at 30 on the pilots and 360 on the mains with my mods listed in sig.... Maybee I am way rich ? My altitude is varied from....850-1700 feet. What you think......my plugs look good...so you sound lean in my meager opinion.. Besides you can always jet leaner if your rich....but if your lean you may nnot get the chance to jet up if you catch my drift..... Trust your gut....and go rich and work your way down... More than likely those jets may have been just a starting point..... Nick Quote Link to comment Share on other sites More sharing options...
Banchetta Posted April 3, 2004 Report Share Posted April 3, 2004 You never know, I ran 162 mains in my 34mm carbs w/ the stock cylinders, but now I have a 4mil stroker and run smaller jets in the 28mm carbs....When I did the dyno testing last year, I had 300 mains in the stock carbs and 330 mains in the ported stock carbs......It doesn't sound right, but you have a totally different motor that doesn't rev as high either, its built on torque not hp......I'm dynoing tomorrow w/ my stock carbs and 4mil stroker as well as some 30mm keihins so I'll know more tomorow... Quote Link to comment Share on other sites More sharing options...
hops Posted April 3, 2004 Author Report Share Posted April 3, 2004 Talked to the builder today, after a I gave the carbs a good cleanin. He said about the same thing as banchetta. Cause the 4mm has farther to go, "there is a weaker pulse action on the carbs, but higher crankcase pressure" or something like that. I should get her started tommorow or Sunday, crossin my fingers. Man, guess I need to read up more on 2-strokes Quote Link to comment Share on other sites More sharing options...
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