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Post by boaron on Aug 15, 2015 15:11:34 GMT -5
I am switching from the General board to here. My 72 H2 has stock Mikuni carb bodiies. It also has Wirges chambers (LOUD 90db at idle). I have had several rebuilds on the carburators by 'mechanics' over the years. My first question is what are other guys running for main jets with (Wirges) chambers? I have 105's in it now. Also, i had purchased a stock Sudco rebuild kit which comes with 100 main jets. Are the stock Jet needles interchangeable using the 105 mains? The bike runs good except off the line it has issues up to about 1200 rpm. Here is another question for ya. When you change out the mains do you need to also change out the air jet. In other words are they a matched set. I saw some links to a Mikuni site that i have not explored fully yet and I wanted to get some input prior to ordering jets etc. I am reading that for every 3000 feet in elevation the the jet size should be reduced by 5%. I live at 5280 feet. TIA
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Post by Curtis on Aug 15, 2015 16:01:18 GMT -5
Issues up to 1200? What do you run for an idle speed?
I generally set my idle between 900-1000 rpm
If your boggy off the line your in your pilot circuit, you may need to increase it
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Post by mraxl on Aug 15, 2015 16:03:47 GMT -5
I am switching from the General board to here. My 72 H2 has stock Mikuni carb bodiies. It also has Wirges chambers (LOUD 90db at idle). I have had several rebuilds on the carburators by 'mechanics' over the years. My first question is what are other guys running for main jets with (Wirges) chambers? I have 105's in it now. Also, i had purchased a stock Sudco rebuild kit which comes with 100 main jets. Are the stock Jet needles interchangeable using the 105 mains? The bike runs good except off the line it has issues up to about 1200 rpm. Here is another question for ya. When you change out the mains do you need to also change out the air jet. In other words are they a matched set. I saw some links to a Mikuni site that i have not explored fully yet and I wanted to get some input prior to ordering jets etc. I am reading that for every 3000 feet in elevation the the jet size should be reduced by 5%. I live at 5280 feet. TIA There are a few things you need to know.... -Wirges, late style with internal baffles are junk and will cause problems with clogging up. Early style is ok without much performance add. Stinger type works well. -Carb kits do NOT have genuine Mikuni needles or jets and will not work well... serious tuning problems. Check for Mikuni stamps/logo on all jets. -There are no air jets on stock Kaw carbs. -Your altitude makes you unique for jetting.... makes little difference what anyone else is using for jet size. Air filter types are also a big factor. -The altitude advice is probably correct.... not just for main jet. -"It has issues up to about 1200 rpm"... that is idle... what issues could there be? -H2's have an inherent problem with surging at small throttle openings. The best fix is to order a jet kit from Ivan- www.ivansperformanceproducts.com/index.htm That will also fix any non Mikuni jet/needle issues you may have. www.3cyl.com/mraxl/manuals/carbtune/carbtune.htm |
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Post by boaron on Aug 15, 2015 16:29:32 GMT -5
Originally, I had Bassani chambers until I flattened them in a fall (Worked well though). Switched to wirgis because at the time that was all I found. (Years ago) Not sure if they are early or late. I thought I saw on this forum someone who makes chambers? I have the K&N type filters on it currently. Air jet I confused it with pilot. Idle speed is 1100 rpm. OK so I am dylexic or its my age it is flat off the line up to 2100 rpm and starts to pull well around 3500 rpm. Thanks for the URL's! I will check them out.
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Post by mraxl on Aug 15, 2015 16:53:52 GMT -5
Originally, I had Bassani chambers until I flattened them in a fall (Worked well though). Switched to wirgis because at the time that was all I found. (Years ago) Not sure if they are early or late. I thought I saw on this forum someone who makes chambers? I have the K&N type filters on it currently. Air jet I confused it with pilot. Idle speed is 1100 rpm. OK so I am dylexic or its my age it is flat off the line up to 2100 rpm and starts to pull well around 3500 rpm. Thanks for the URL's! I will check them out. Start by setting timing. Then set float level. Use #35 pilot jets. Sync carbs. Adjust air screw per manual. Then find best needle clip position. Then find best main jet... 105 Mikuni may be a little rich at your altitude. K&N's with metal backing plate are not the best filters to use. Forget about rpms for diagnosing jetting problems... it's throttle position that is important. Be aware that it is not a four stroke and low rpm/small throttle position will not produce much torque.... gearing is a factor there. WTF chambers by Walms are hard to beat! |
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Post by boaron on Aug 15, 2015 17:36:31 GMT -5
Timing: Plugs set to .035
Do you use the timing instructions in the manual using a dial indicator or just go for it with a timing light? If a timing light do you set the rpm at 4K when testing? (I have a dial indicator but find it impossible to get into the center cyl.)
Pilots: Can't read marking if any on them.Unknown (Thinking of getting a kit from Ivan known)
Carbs Synced.
Air screw 1.5 turns out.
Needle clip 3rd knotch from bottom moved from 2nd knotch runs better here, have not tried any other setting yet.
Main jet: Ya, thought about the 105's and the altitude hopefully I can get this ironed out with Ivan.
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Post by mraxl on Aug 15, 2015 21:13:38 GMT -5
Timing: Plugs set to .035 Do you use the timing instructions in the manual using a dial indicator or just go for it with a timing light? If a timing light do you set the rpm at 4K when testing? (I have a dial indicator but find it impossible to get into the center cyl.) Pilots: Can't read marking if any on them.Unknown (Thinking of getting a kit from Ivan known) Carbs Synced. Air screw 1.5 turns out. Needle clip 3rd knotch from bottom moved from 2nd knotch runs better here, have not tried any other setting yet. Main jet: Ya, thought about the 105's and the altitude hopefully I can get this ironed out with Ivan. Read my original post about sequence for tuning. Dial indicator is used to set the timing marker.... then use a light on each cyl to set timing @4000 rpm. If you can't read markings on pilot, needles, mains... chances are they are not Mikuni... get Ivan's kit. The airscrew needs to be set as described in manual. It is not to be set x turns out, especially at your altitude. And if it isn't set right then needle can't be set right or will need to be reset after pilot circuit is tuned properly. |
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Post by boaron on Aug 16, 2015 13:34:32 GMT -5
Will do. Ivan's shop is closed until late August so I sent an email. That should give a me a good baseline as far as what I am actually working with. Which manaual?
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Post by mraxl on Aug 16, 2015 13:40:17 GMT -5
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Post by boaron on Aug 16, 2015 19:16:11 GMT -5
OMG fantastic,way helpful! My manuals bite. Much appreciated.  |
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Post by boaron on Aug 29, 2015 18:24:09 GMT -5
Got the kit from Ivan. Super happy with it. Runs great. Now for the chambers and paint.Thanks for all the help!
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