Mikuni Side-draft Tuning

ThunderCougarFalconGoat · 03-08-2009, 05:40 PM

Hello guys, new poster here. I was wondering if anybody had any experience playing with Mikuni side-draft carbs?

Its on an gold '82 junkyard special with a 12a that I picked up last july. I'm a carb virgin, and nobody I know wants to touch a side-draft, so any help would be appreciated.

Thanks in advance.

TheDriver216 · 03-08-2009, 07:16 PM

What info you need? I have a Weber sidedraft.. whats going on with it?

ThunderCougarFalconGoat · 03-08-2009, 07:33 PM

Well is seems to be low on power, even for a rotory. I'm really just looking for general tuning tips and procedures, as I've never messed with carbs at all before.

TheDriver216 · 03-08-2009, 08:02 PM

What size is the carb? Choke size? jet and venturi sizes? air bleeds?

ThunderCougarFalconGoat · 03-08-2009, 09:34 PM

I have no idea how to tell these things. It was already installed on the car when I got it.

TheDriver216 · 03-08-2009, 10:55 PM

did you do all the basic tune up stuff first?

ThunderCougarFalconGoat · 03-09-2009, 01:37 AM

New plugs, wires, belts, filters, oil, cleaned air filter (could use some more cleaning though). Unless rotaries need other stuff too?

I'd like a wide-band to see whether its lean or not, but my budget for this car doesn't really support that. Plus, even knowing that, I still need to be able to do something about it. Plus, I'd like to know more about carb tuning just for my own insatiable thirst for knowledge and power.

TheDriver216 · 03-09-2009, 02:11 AM

Well you need to pull it apart and find out exactly what you have in the carb... Plus you could be down on power from just tired motor... You should do a compression test to find out if that is part of the problem as well. Dump a can of Sea Foam in your gas tank and put in a 1/4 tank of gas. and run it down to remove some carbon. Lots of little things... Have you changed the fuel filter as well?

And another thing... carbs are very testy to weather, it can run awesome in the summer but if you dont rejet or fiddle you might not run well in colder weather

ThunderCougarFalconGoat · 03-09-2009, 08:31 PM

So then how would one fiddle with the side-draft? How comparable is it to a regular carb? I've found some online resources for regular style carbs, I'm hoping its the same?

I would also assume that the rejetting would involve purchasing new jets? Know any where that sells jets for Mikunis?

PercentSevenC · 03-09-2009, 11:33 PM

I can basically only echo what TheDriver216 has said, since I, too, have only had experience with DCOEs. Run a can of Seafoam through it (even if it doesn't actually solve the problem, it always helps), and then pull apart the carb and document everything. Jet sizes, emulsion tubes, air correctors, venturis, etc.

If it's like a DCOE (and Mikunis are very similar from what I've heard), there should be idle mixture screws you can adjust, but that's about all you can do without swapping jets and so forth. I'm afraid I couldn't tell you where you can get Mikuni tuning parts anymore, though.

ThunderCougarFalconGoat · 03-11-2009, 01:22 AM

Ok, thanks for your help. Do the jets and stuff have size markings on them? I'm going to guess that tuning would be very limited without being able to get other sizes? Guess I'll have to keep my eye open on evil-bay.

TheDriver216 · 03-11-2009, 02:27 AM

yeah most of teh time they are very easily marked... pull it apart and write it down... what color are your spark plugs? you can get a general area of how its running from plug color

rotaryracer · 12-28-2009, 11:00 AM

Nissan z-cars have Mikunis stock. I also am looking for help. I'll keep looking.When I find info, I'll post what I find.

glassman · 12-28-2009, 08:48 PM

I might know where you can get some jets etc but it's been a long time since I talked to them. The place is Overseas Distributing in B.C. 800-665-5031 or 604-879-6288 ask for Jim.

I have 4 - 44PHH Mikuni's if anyone is interested, 2 are BRAND NEW plus various jets and e tubes.

I also have 2 - 45 DCOE webers and 1 - 50 DCOE weber with 4 port 13B intake. Also have one of the star mazda intakes for 12A made by Pearce??

striegels6 · 02-12-2010, 09:22 PM

Wolf Creek Racing. Owner has excellent advise and services. Stocks about everything for the Mikuni and webers. Rotary familiar.

03-08-2009, 05:40 PM	#1
ThunderCougarFalconGoat The Newbie Join Date: Jul 2008 Location: Bellingham, WA Posts: 8 Rep Power: 0	Mikuni Side-draft Tuning Hello guys, new poster here. I was wondering if anybody had any experience playing with Mikuni side-draft carbs? Its on an gold '82 junkyard special with a 12a that I picked up last july. I'm a carb virgin, and nobody I know wants to touch a side-draft, so any help would be appreciated. Thanks in advance.

03-09-2009, 02:11 AM	#8
TheDriver216 Rotary Fanatic Join Date: Feb 2008 Location: Cleveland, Ohio Posts: 159 Rep Power: 18	Well you need to pull it apart and find out exactly what you have in the carb... Plus you could be down on power from just tired motor... You should do a compression test to find out if that is part of the problem as well. Dump a can of Sea Foam in your gas tank and put in a 1/4 tank of gas. and run it down to remove some carbon. Lots of little things... Have you changed the fuel filter as well? And another thing... carbs are very testy to weather, it can run awesome in the summer but if you dont rejet or fiddle you might not run well in colder weather Last edited by TheDriver216; 03-09-2009 at 02:30 AM.

12-28-2009, 08:48 PM	#14
glassman Premium Vendor Join Date: Apr 2008 Location: Canada Posts: 173 Rep Power: 18	I might know where you can get some jets etc but it's been a long time since I talked to them. The place is Overseas Distributing in B.C. 800-665-5031 or 604-879-6288 ask for Jim. I have 4 - 44PHH Mikuni's if anyone is interested, 2 are BRAND NEW plus various jets and e tubes. I also have 2 - 45 DCOE webers and 1 - 50 DCOE weber with 4 port 13B intake. Also have one of the star mazda intakes for 12A made by Pearce?? __________________ Mild to wild, street to strip, when you want to go fast and you want your engine to last, NRS Ceramics is the only way to go. NRS Rotorsports nrsrotorsports@shaw.ca www.nrsrotorsports.com

02-12-2010, 09:22 PM	#15
striegels6 The Newbie Join Date: Feb 2010 Location: Iowa Posts: 6 Rep Power: 0	Sidedraft Help Wolf Creek Racing. Owner has excellent advise and services. Stocks about everything for the Mikuni and webers. Rotary familiar.

03-08-2009, 07:16 PM	#2
TheDriver216 Rotary Fanatic Join Date: Feb 2008 Location: Cleveland, Ohio Posts: 159 Rep Power: 18	What info you need? I have a Weber sidedraft.. whats going on with it?

03-08-2009, 07:33 PM	#3
ThunderCougarFalconGoat The Newbie Join Date: Jul 2008 Location: Bellingham, WA Posts: 8 Rep Power: 0	Well is seems to be low on power, even for a rotory. I'm really just looking for general tuning tips and procedures, as I've never messed with carbs at all before.

03-08-2009, 08:02 PM	#4
TheDriver216 Rotary Fanatic Join Date: Feb 2008 Location: Cleveland, Ohio Posts: 159 Rep Power: 18	What size is the carb? Choke size? jet and venturi sizes? air bleeds?

03-08-2009, 09:34 PM	#5
ThunderCougarFalconGoat The Newbie Join Date: Jul 2008 Location: Bellingham, WA Posts: 8 Rep Power: 0	I have no idea how to tell these things. It was already installed on the car when I got it.

03-08-2009, 10:55 PM	#6
TheDriver216 Rotary Fanatic Join Date: Feb 2008 Location: Cleveland, Ohio Posts: 159 Rep Power: 18	did you do all the basic tune up stuff first?

03-09-2009, 01:37 AM	#7
ThunderCougarFalconGoat The Newbie Join Date: Jul 2008 Location: Bellingham, WA Posts: 8 Rep Power: 0	New plugs, wires, belts, filters, oil, cleaned air filter (could use some more cleaning though). Unless rotaries need other stuff too? I'd like a wide-band to see whether its lean or not, but my budget for this car doesn't really support that. Plus, even knowing that, I still need to be able to do something about it. Plus, I'd like to know more about carb tuning just for my own insatiable thirst for knowledge and power.

03-09-2009, 08:31 PM	#9
ThunderCougarFalconGoat The Newbie Join Date: Jul 2008 Location: Bellingham, WA Posts: 8 Rep Power: 0	So then how would one fiddle with the side-draft? How comparable is it to a regular carb? I've found some online resources for regular style carbs, I'm hoping its the same? I would also assume that the rejetting would involve purchasing new jets? Know any where that sells jets for Mikunis?

03-11-2009, 01:22 AM	#11
ThunderCougarFalconGoat The Newbie Join Date: Jul 2008 Location: Bellingham, WA Posts: 8 Rep Power: 0	Ok, thanks for your help. Do the jets and stuff have size markings on them? I'm going to guess that tuning would be very limited without being able to get other sizes? Guess I'll have to keep my eye open on evil-bay.

03-11-2009, 02:27 AM	#12
TheDriver216 Rotary Fanatic Join Date: Feb 2008 Location: Cleveland, Ohio Posts: 159 Rep Power: 18	yeah most of teh time they are very easily marked... pull it apart and write it down... what color are your spark plugs? you can get a general area of how its running from plug color

12-28-2009, 11:00 AM	#13
rotaryracer The Newbie Join Date: Dec 2009 Location: Tulsa,Ok. Posts: 20 Rep Power: 0	Nissan z-cars have Mikunis stock. I also am looking for help. I'll keep looking.When I find info, I'll post what I find.