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Mikuni carb issue

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Old 11-20-13, 10:48 AM
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Doritos & Dual Sports

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Mikuni carb issue

Got a mikuni for my 85 base model 5spd. Anyone know where I can go get a manual for it? I'm confused on the four oil looking lines coming from the bottom of it and on the intake mani I got with it, the two coolant looking ports on the outside of it. Any help appreciated(:
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Old 11-20-13, 02:28 PM
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79 w 13B4port

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The two outlets on the accelerator pump housing,(thats the squareish looking thing on the bottom of the carb with the lever hanging out of it centered between the two barrells) are for the fuel return going back to the tank. It uses the returning fuel to cool the carb to prevent any vapor lock or problems caused by heat soak. It's use is optional. I never used it and never had any issues. The other two ports, (one of which in your pic has a short L shaped fuel line) is for the omp injection. Hook these up to your oil metering pump, unless you plan to premix, them just block them off. You can find manuals for this carb on E-bay for cheap, search Mikuni PPH. Also Wolf Racing has always been a good source of parts, they would probably have them as well. Which cooling ports are you speaking of? The cooling ports are on the engine and I would reccomend installing freeze plugs sealed with sillicone to block them off, they are not used with this manifold.
Old 11-20-13, 02:33 PM
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79 w 13B4port

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I'm sorry, thats WolfCreekRacing, hers a link:

Mikuni Carb Parts
Old 11-20-13, 02:37 PM
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79 w 13B4port

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The manual for this carb is OK, but if your not well versed in carb theory, especaially in webber style carbs you sould also invest in a good webber book that includes info on the DCOE style carbs, you will learn alot about how this carb works and how to go about tuning, It is very simple but it WILL HAVE TO BE TUNED. (especially the acelerator pump circuit) it will be the cause of the off idle stumble you will find when you get it running.
Old 11-21-13, 07:26 AM
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The two holes come off the intake mani. The one has a fitting already in it, the other does not. I greatly appreciate the help, but still unsure what these are for
Old 11-21-13, 07:27 AM
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And if I read correctly, I can just block off all 4 lines and find a good pre-mix to run? After getting the carb tuned properly of course
Old 11-21-13, 07:37 AM
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79 w 13B4port

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That is correct. You should do some research about premix before you decide. Their is a lot of info on here about it, pros and cons, check it out before you decide.

I feel the best setup is an adapter that keeps the omp but injects 2 cycle oil from a tank rather than the 4 cycle that the stock setup does. The only drawback to that setup is cost.

The other holes in the manifold are vacuum ports. The big one is likely the vacuum for the brake booster and the other one can be used for whatever you need or blocked off.
Old 11-21-13, 10:06 AM
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Brake booster? Would have to look up info on that... Searching ebay now for a carb manual


That's unfortunate...
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Old 11-21-13, 04:32 PM
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79 w 13B4port

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I was surprised to find that E-bay was a dead end for the manual, check with Wolf Creek Racing, It is listed on their website for ten bucks.
Old 12-03-13, 06:58 AM
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On this page
http://www.wolfcreekracing.com/index...d=30&Itemid=51

Do I have an s4, s5 or type q PHH mikuni? Just want to make sure I order the correct diagram/parts
Old 12-03-13, 12:34 PM
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79 w 13B4port

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Phh S5 I believe.
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