Jetting reference?

[gearyoliver]

Is there a document somewhere that members have posted jetting info? Ie: engine specifics, altitude, intended use etc.
If not would members be interested in contributing successful setups? I would be willing to combine results into a spreadsheet and keep it updated and available.


All comments welcomed!

[dirty_rat]

I put together a list of some of the carb and jetting specs that others have posted over the years, but it doesn't list very many. It aso list the standard carbs and jetting that came on most of the 100's and 125's. I'll have to look for it, but I can send it to you once I find it.

[gearyoliver]

Great!
If there isn't one out there already I'm gonna work up a template for pertinent information ie;

Engine model
Ignition type
Air filter type
Intake modifications
Cylinder/head modfications
Exhaust type
Carb make and size
Carb modifications
Jetting specs
Main
Pilot
Air
Needle jet
Jet needle
Clip position

Injection or premix
Fuel type
Oil
Mixture ratio

What have I missed?

[matt glascock]

If you are looking to build a one-stop shopping data spread sheet for all models (which would be totally sweet), you might consider including some other frequently accessed data such as spark plug and gap, gear oil capacity, engine/frame tightening torque specs, timing/points adjustment, and such. I'd blow it up into a poster and hang it on the wall in my shop!

[viclioce]

I’d love to see this as well! I’m at 7,000 ft. in elevation. I don’t get much more than 10-12 ft. in altitude tho. Jumping higher than that scares me now! Victor

[Bullfrog]

You have a good start on the information needed to attempt some sort of jetting guidance, but a few additional pieces of information are critical (in my opinion)
- compression
- Piston port or reed valve
- stock porting or modified
- throttle valve cut-away (slide cut-away)
- pilot air screw adjustment (turns out)
- Needle clip position (#1 is top groove)
- normal operating elevation
- normal operating location (provides hints regarding normal humidity and temperature)

Interesting project.
Ed

[Bruce Young]

Hello, Gary, that idea for a chart would be wonderful to have for each model, when you start your charts there should be one for each, not just what bikes you have in your garage or working on at the time. Also concerning jetting, be very careful to mention type of use of where and how the bike is going to ridden, and what altitudes. Lots of variables there. That is what if one looks at each models Official manual lots of the info you are going to put on your chart, will be there. So in conclusion, I would suggest that we in the Hodaka World now push to get new owners to first get a manual, to follow, and do their own home work, they will learn quicker, just like we had to over the years, it seems lots of people out there want everything, IE info handed to them. Look it up and do your own research, and go to Hodaka official web sites IE Hodaka-parts inc, in Missouri, and read what is already available. Its going to be a big project. I support your efforts and if I can assist in anyway let me know. Bruce Young

[taber hodaka]

The scary thing to me is tuning on the edge, according to the tuner. One might be on the edge of melting down rich on top and lean in the middle, depending on how you ride it could be a catastrophe. Some folks change jets for elevation others not, I do not but I am running reeds? Harry could jet and tune any carburetor and get the max out of it and I would almost call that science. To me the ace 90 book that covers tuning is has almost the perfect recipe. But a chart that gets one started would be great. ----------------- Clarence

[gearyoliver]

These are all good suggestions. My thinking in this is creating a template in such a way to incorporate the information in as linear a fashion as possible. A contributor would fill out the info they wished to share and it would be added to a folder. Probably use Dropbox or Google drive to host the folder. I'll try to post a draft form soon.

[thrownchain]

You also have to figure in how it will be ridden and the size of the rider. Ballpark is as close as you're gonna get, final tuning will still have to be done.

[gearyoliver]

Thrownchain, you are absolutely correct in that the ballpark is where you want to be. No spreadsheet can can tell someone how to set up their own bike. But it might be a useful tool to see what has been successful for someone else.

[dirty_rat]

Here are the jetting specs I have acquired over the years. Most are the factory specs, just put into one table. On the Wombat (model 94 and 94A) it has two sets, one for the early carb and the second set for the later good carb. On the Super Combat it list the standard settings, some later optional setting put out by Pabatco and some settings on some modified bikes. It also list some setting for modified Super Combats using 34mm and 36mm carbs.

Hope this helps and gets this project going.



Ace 100 (92) Mikuni VM20-SH10
Main Jet: 95
Needle Jet: N-6
Jet Needle: 4F6
Pilot Jet: 25
Slide: 2.0

Super Rat (93) Mikuni VM 24-SH
Main Jet: 220
Needle Jet: N-8
Jet Needle: 4E1
Pilot Jet: 30
Slide: 2.0

Super Rat (98) Mikuni VM 28
Main Jet: 250
Needle Jet: N-8
Jet Needle: 5F3-3
Pilot Jet: 60
Slide: 2.5

Road Toad (02) Mikuni VM 26-SC-131
Main Jet: 160
Needle Jet: O-2
Jet Needle: 5EL9
Pilot Jet: 30 (40)
Slide: 1.5

Wombat (94&94a) Mikuni VM 24 SH-83 (A or B)

Main Jet: 180 ( 140-160 )
Needle Jet: O-4 ( N-8 )
Jet Needle: 4J6 ( 4E1 )
Pilot Jet: 15 ( 25 )
Slide: 1.5 ( 2.5 )

Wombat (03) Mikuni VM 26
Main Jet: 180
Needle Jet: O-2
Jet Needle: 5F21
Pilot Jet: 50
Slide: 2.0

Combat Wombat Mikuni VM 28 SH
Std. (Opt.)
Main Jet: 190
Needle Jet: O-4
Jet Needle: 5EJ13 (5D5)
Pilot Jet: 25 (35)
Slide: 2.5 (3.0)

Super Combat Mikuni VM 32
Std. (Opt.) [Paul Stanard ]( Tom Carpenter ) [ New ]
Main Jet: 410 (290) [ 360 ] ( 400 ) [ ? ]
Needle Jet: R-9 (Q-6) [ ? ] ( ? ) [ Q--6 ]
Jet Needle: 6L1-4 (6F9) [ 6L1 ] ( 6L1 ) [ 6DP17 ]
Pilot Jet: 35 [ 30 ] ( 35 ) [ 35 ]
Slide: 3.0 [3.0 ] ( 3.0 ) [ 3.0 ]

Super Combat Mikuni VM 34 Mikuni VM 36
Main Jet: 260 460
Needle Jet: Q-6 R-9
Jet Needle: ? 6F9
Pilot Jet: 35 60
Slide: 3.5 4.5

250 ED Mikuni VM 36
Main Jet: 260
Needle Jet: Q-5
Jet Needle: 6F5
Pilot Jet: 45
Slide: 3.5

[gearyoliver]

dirty_rat
Thank you! I will add this info this evening to the list!
Here is the first attempt at a shareable document. If it seems to work I will spiff it up and make it more user friendly.

I have a shareable link through my google drive. If permissible I would like to place the link in a members only accessible location but if you email me I can send it to you for testing. If this is successful possibly a more permanent hosting solution can be arranged.

Also I know some folks are reluctant to share personal info. If you wish to contribute only put info you are comfortable sharing.

[gearyoliver]

Here is a current pdf file of the project.
You have to open in a new tab to get it to work.
comments appreciated.

https://drive.google.com/file/d/1P-Npea ... sp=sharing

[Bruce Young]

Gary, great idea, and good info sheets but be careful, when you get so many categories, it gets hard to read, Maybe break up into two sheets. Also don,t forget all models from ACE 90 on. Don,t lump groups or models together, it will confuse everyone whom follow,s lets say what is on Terry Larsons, site . I am working on a 30mm fork info sheet and measurements and such to help ID forks but with only 5 or 6 diff models of the 30mm forks it still gets a bit long, we are going to break it up into two publishing,s Great idea you have and go for it, its been need for too long. Yes its in manuals and Hodaka advertising, but never put all together as extensive as you have. Also might mention you might put a disclaimer clause because of altitudes and racing or riding machines use. Those will make endless adjustments and you don,t want someone to burn one down, while going on you recommendations, can create complications. Bruce Young

[gearyoliver]

Thanks Bruce,
The final? Lol, template should be a searchable document. I hope to be able to build up a table of contents. Possibly individual pages by specific models. The entire spreadsheet will probably be hidden. Categories are what was asked for in the above posts as close as possible as related to running setups. Information listed will be what is posted. I am not recommending any setup. Just aggregating what has been successful for others. Over time this could be a valuable tool. Time will tell.

[Bruce Young]

Gary, I personally would recommend it only as a guide, there are too many variables, when you reach out the general population some of which have no former mechanical knowledge. I can see a 16years old person with little mechanical knowledge beyond only twisting the throttle, wanting to go faster, make changes that might lead to a burnt down engine. Again to me, it should be used only as a guide or starting point. And I must also point out that it is not always the 16year olds whom seem to ask the most uninformed questions, and forge ahead without caution. But one has to start somewhere, to gain the experiences of life. Go get it done Gary, and I hope all info given will be taken as a guide. Always read the manuals. And if you don,t know ask, last but not least try to understand the way a two stroke machine works. Bruce