rivaz73 Posted August 3, 2009 Share Posted August 3, 2009 Hello everyone, I need help running tripple mikuni carbs on my s30 I have an L-28 N-42 block w/N42 head mild cam dont know the numbers but its mild noting aggresive. My problem is the every time cars cools down overnight it wont start only after the tempature outside reaches 80 degrees I never had this problem but I also never had mikunis I all always had webers 40"s plase help Im in L.A can names of shops that I can take the car to or tips on what to do to fix the problem. Currently running Carter fuel pump that runs 3 to 6 psi but dont know the exact psi ring at this point thanks guys. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 3, 2009 Share Posted August 3, 2009 Mikunis are usually very easy to start in cold weather. 2 pumps on the pedal and turn the key and it should fire right up, pump the gas a little once it starts until it warms up a bit and you're there. I never bothered with the chokes in SoCal or Seattle. As far as shops to take a car to for Mikunis in the LA area, that's a tough one. The only one I can think of is Top End Performance in the valley, but their rep is a little shaky. Do you know how to work on the carbs at all? Might check things like synch and idle screw position. Seems to me like something would have to be pretty screwed up to get the problem you're describing. Quote Link to comment Share on other sites More sharing options...
rivaz73 Posted August 3, 2009 Author Share Posted August 3, 2009 Im going to buy the Mikini service manual I'll get under the hood but I consider myself a novice. I know its strage I never had this problem but I also never had Mikuni's from what I hear they are really sensative and a pain in the ass to tune but I took a chance since I got the set for $800 and they were 44's other people I talk to say their to big for a stock motor but all I need this ♥♥♥♥♥♥ to do is run daily for since its the only ride I have I have heard to Top End but are knoun more for Webers thanks for your advice:burnout:I might just get them rebuild but and see where I go from there but the cost of rebuilding them.. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 3, 2009 Share Posted August 3, 2009 You should have no problem at all with 44's on a basically stock engine. Mikunis are EASY compared to Webers as they have a lot fewer adjustments and seem to hold a tune better. According to most they are a lot less finicky. I'd suggest you pick up "How to Modify Your Nissan/Datsun OHC Engine" by Honzowetz. It has good info on Mikunis. You can also download the manual from the Downloads section here: http://forums.hybridz.org/showthread.php?t=122217. At least you'll know what jet affects what. I'd focus on pilot screw setting first because it will take you 5 minutes and should make a noticeable difference. Turn them all in till they stop (might be interesting to count the turns here). Don't crank on the screw against the stop, just turn them until they touch the stop. Then back them out 1.5 turns. Don't mess with the screws again. If it's too rich at idle, get leaner pilots. If it's too lean at idle, get richer pilots. Most Mikunis I've seen have pilots that are way too lean. Aftermarket Mikunis are race carbs and come jetted small because race engines have large cams, so there is more intake stroke time to pull gas into the cylinder. Running them with a stock or mild cam necessitates larger jets. You can get jets through Todd @ Wolf Creek Racing, he's a good guy and I always got the right part the first time. Quote Link to comment Share on other sites More sharing options...
rivaz73 Posted August 4, 2009 Author Share Posted August 4, 2009 Thank u for the information I do have the book you mention and I will give it a shot trying to see if I can fix this. I also did find a local shop SunriseZ in glendale,CA if all fails will take it there thanks again. Quote Link to comment Share on other sites More sharing options...
Icehound Posted September 24, 2009 Share Posted September 24, 2009 Hey Jon, do you know of anyone in the Seattle area that rebuilds Mikuni 44s? Thanks Dave Quote Link to comment Share on other sites More sharing options...
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