22mm Carb kit for Ace 100

Hodiak · Post by **Hodiak** » Wed May 31, 2017 5:39 pm

Hi,
Does anyone out there have any experience with the 22mm Mikuni replacement carb and manifold for the Ace 100 available from Strictly Hodaka? I'm not having much luck with my original 20mm which can't take any increase in throttle and gets flooded then won't start for days. It just seems to be time for an all new carb. Any thoughts on this would be greatly appreciated.

dirty_rat · Post by **dirty_rat** » Thu Jun 01, 2017 3:45 am

I don't have any experience with the new 22mm carb, but did your present problem come on suddenly or has it been getting that way for a long time? If it is a sudden change, it's probably just a matter of cleaning and adjusting the present carb.

matt glascock · Post by **matt glascock** » Thu Jun 01, 2017 9:11 am

I agree with Dirty. Mikunis are great carburetors and unless there is corrosive or structural damage, a complete dismantling followed by a thorough physical and chemical cleaning of all components, inspection, and replacement of any out of spec components should leave you with a properly functioning and tuneable instrument. What you are describing maybe reversible with a simple replacement of the needle valve and seat and confirmation that your floats actually float.

Bullfrog · Post by **Bullfrog** » Thu Jun 01, 2017 1:31 pm

It is as nifty as heck that the option of a new 22mm carb and the hardware to mount it is available . . . and there is no question in my mind that it will work well. But I'd bet that some TLC for the innards of your existing carb will get it working properly. From the description, it sounds like the float valve system for controlling the fuel level in the carb is not working . . . and that might be as easy to fix as doing a simple internal cleaning and installing a new in-line fuel filter. Of course, it might take more than that . . .
Ed

Hydraulic Jack · Post by **Hydraulic Jack** » Thu Jun 01, 2017 4:47 pm

The replacement system is engineered to work on your machine. If you have questions about how it works or if it is pre-jetted to a stock Ace, send your email to Paul at Strictly Hodaka. All of his other carbs are jetted to order so I assume this one is also.

Frankly I never was impressed with the stock 20mm working right or otherwise. Too small. Old school thinking. The 22 is better. I have used a 24 with much success, but other things were also modified to maximize the larger carb. The 22 is more like what the Ace should have come with.

Hodiak · Post by **Hodiak** » Thu Jun 01, 2017 5:52 pm

Thank you all for the ideas. I guess more info on my part would have helped.

The carb was thoroughly cleaned 10 years ago and left apart in a sealed container before I recently restored the rest of the machine. It has a new rubber tipped float valve. The floats are perfect, however I adjusted them to turn off the valve slightly sooner. I had a bad leak which I fixed with a new gasket but I thought the "higher" float might also help. It still seems to be flooding with the wet plug and the easy starting after I have let the engine dry out for a couple days.
I might give it one more teardown and soaking but it is 49 years old and if a new one will work good and last a while it might be a good investment.
I am also wondering if the 4.5 oz./gal (28:1) I am breaking it in with is too rich a mixture.

Thanks again for your help
Mike

Bullfrog · Post by **Bullfrog** » Fri Jun 02, 2017 5:06 am

A couple of diagnostics suggestions: If you turn on the fuel with the tank petcock and walk away, then return an hour or two later - do you have a puddle of fuel under the bike? If so, the float valve system is not working.

If flooding happens ONLY when you are trying to start the engine, then a check to assure that all parts have been re-installed in the carb might be in order. A missing pilot jet would cause extreme richness. If the little brass washer isn't in place between the main jet and the needle jet, richness will result. Is there a sealing washer under the float valve seat? Are ALL carb passages clean?

Note that messing about with float level to attempt to address some other problem is not recommended. Set the float level per the specifications . . . and fix the other problem

.
Ed

Hydraulic Jack · Post by **Hydraulic Jack** » Fri Jun 02, 2017 7:31 am

28:1 is not "too rich" a mixture whether broken in or not. It's fine to use from now on. 28:1 will have a bit more oil in the mix than, say, 32:1 so there will be less gasoline per measure of mix than with 32:1. Whether this is seen as being "rich" or "lean" depends on frame of reference. It will be more oil rich but less fuel rich. 28 parts gas to 1 part oil. 32 parts gas to 1 part oil, and so on. Choose your favorite frame of reference and go from there, but with a two stroke, saying something is richer or leaner needs a context.

Jetting to accommodate the mix ratio may or may not be needed. Carburation by nature is not a precision process and there is a range of tolerance. If you think it is running funky, check jetting. Otherwise don't worry about it.

I am also curious by what you mean when you say the bike "...can't take any increase in throttle and gets flooded..." Do you mean it idles but won't take any throttle change, or it runs fine up to mid range but won't take more than that, or just what? Be more specific about where and when it won't take a throttle increase, and this will help with remote control diagnostics. Ed has pointed out that changing float levels or leaving out tiny parts in the carb can cause bogging and flooding during running, and improper float levels can cause overflow while parked with the gas turned on. The more detail you can provide, the more focused the diagnosis.

As far as replacing the carb to cure an issue, that's up to you. There is no absolute guarantee that a new carb, even if purchased from a Hodaka parts distributor, will be perfectly jetted for your bike, so you may be needing a jetting adjustment even with a new carb. Perhaps not, but just so you know that no two engines are ever exactly the same, and location matters. As in altitude, humidity, and temperature can and do affect jetting. So unless your carb is actually broken or beyond repair, my first impulse would be to fix the one you have because the VM20 worked on the Ace for a very long time and still will. You might just need a tiny washer in the needle jet/main jet assembly, which is a lot cheaper than a new carb. On the other hand, if you don't like messing with dinky carb parts, a new carb is going to be a lot closer to good to go than what you have now.

Hodiak · Post by **Hodiak** » Sat Jun 03, 2017 4:16 am

Thanks again for the help.
To Bullfrog: I'm going to do as you said. I've disassembled the carb and will dunk it in fresh carb cleaner and will set the float to specs since the new float valve is working and no puddles were forming after my second re-build. all the washers etc. are accounted for. Hopefully this third try will work. If not, I think I'll try the new 22mm.
To Hydraulic Jack: It idles fine but will not rev when I twist the throttle. I'm going to do the above mentioned cleaning and float re adjustment and hope for the best. Thanks for the info on my fuel ratio...I'll keep it the same for now.

Bullfrog · Post by **Bullfrog** » Sat Jun 03, 2017 4:29 am

Allow me to suggest that simple soaks are not adequate to assure that all the passages in the carb body are cleared of gunk. Wear eye protection and squirt carb cleaner through ALL passages/jets to be sure the passages are clear.

Ed
PS: A light smear of grease on the starter circuit plunger will help assure that it seals properly in its bore. The bottom face of the plunger is a slightly compliant material meant to seal an opening when the plunger is bottomed. Is that sealing face in good condition?

Hodiak · Post by **Hodiak** » Sat Jun 03, 2017 3:42 pm

To all:
I have just about finished re-building this vm-20 for the third time.
1) I dunked it in new carb cleaner, washed it, dried it in the Sun after air blowing the passages.
2) Cut out another new bowl gasket out of 1/32" gasket material from Pep Boys. It's a lot easier the 2nd time.
3) Coated said gasket with Yamabond over both surfaces using my fingers (works best)
4) New rubber tip float valve and float set to specs.
5) New starting plunger.
6) Put back the #90 main jet instead of the new #95
7) Set needle valve back on the third groove instead of the fourth where I had moved it to.
After rebuilding this for the third time, it has become a lot easier. I know every part now and the carb looks really good for 49 years old. A nice cadmium plating, if this is possible on a zinc casting, would make it look brand new. This thing should work. If not, I can't see much more to do other than the replacement 22mm.
Thanks again to all for your comments and I'll let you know how this progresses.

taber hodaka · Post by **taber hodaka** » Sat Jun 03, 2017 5:00 pm

I never put sealant on a carb gasket in my life just a film of grease. Also I would just use a new gasket.------Clarence

Bullfrog · Post by **Bullfrog** » Sun Jun 04, 2017 5:01 am

I'm with you Clarence - grease the gasket (no "stick-em"). Hodiak, were (are) the screw "ears" of the float bowl bent "up" such that the ears come up tight before the rest of the sealing face of the float bowl? If so, a gentle, craftsman-like "truing up" of the those ears will go a looooonnnng way toward eliminating float bowl leaks.
Ed

Hodiak · Post by **Hodiak** » Sun Jun 04, 2017 6:47 am

I flattened the bowl sealing surface with a file because the ears were bent upward for years of tightening. With my handmade gasket and sealant there is no leakage from the bowl at all. The first gasket I bought for the princely sum of $25 leaked like a sieve. It was made out of very hard material that is shiny on one side.
The situation with getting my engine to run is still the same or worse now. Sometimes it putts a few times but won't keep running. Removing the plug shows a totally wet plug.
I feel that I have no option now except to try the new 22mm carb. I thought that by now I would be taking evening cruises around the neighborhood, so now I'm very disappointed.
Thanks to all for your valued input.

Al Harpster · Post by **Al Harpster** » Sun Jun 04, 2017 9:35 am

I put a VM-22-133 on my ace B+ when I did the modifications for reed valve.

The VM-20 does not fit the reed intake manifold.

The VM-22-133 did with just very slight adjustment to the mounting holes.

I believe the jetting etc. was: Main Jet : 100. Pilot Jet : 30. Needle Jet : N-8 (257). Throttle Valve : 2.0. Jet Needle : 4D20. Air Jet : 2.5. Needle Valve : 2.0

At that time I don't believe Strictly Hodaka offered a VM-22. They did have a 24mm version of the VM-22. I later bought one of those too.

I found the VM-22 to be OK. No complaints.

I bought the 24mm version because I've been buying and trying cylinders, pipe, pistons, gears and more for years.

The VM-22 wont fit the standard ace intake manifold. A manifold is the key to mounting the VM-22 to the two bolt intake on the Ace cylinder.

Ace air cleaner would not work either. I used a UniFilter foam filter. I believe the inside diameter for the Uni is 44mm. The 100mm length is right for the job.

OR

You could contact somebody like Hodaka Dave and see if he could repair your carb. Saves the manifold replacement and the air cleaner change.

Might be the low cost solution to your problem.

Al Harpster

Hodiak · Post by **Hodiak** » Sun Jun 04, 2017 10:59 am

Thanks Al,
I had something weird just happen when I went out to try starting it again. The spark plug blew out of the cylinder head. The engine was running roughly then bang. I thought it was some kind of backfire but when I looked down the plug must have hit the tank to make that sound. Cylinder head threads are shot. It should be able to be fixed with an insert. I don't understand this because I'm always very careful when threading the plug in remembering my Dad's admonishments not to strip the threads. Recently, I had noticed the plug was not threading in smoothly as I ran it down by hand.
So now I think it may not be the carb. I think the head may have given out when I first tried to start it back on May 12. It was running great but the carb was a leaking mess and, as I mentioned so many times, would not rev when twisting the throttle. As it was running it started bogging down and then cut out and never ran right since then. So now I must give the cylinder head my attention and take it to have an insert put in. I'm actually kind of glad about this latest development since I think my carb is O.K. and not leaking although now I also noticed a pattern of fresh gas that has been blowing past the cylinder head gasket even though I torqued it to 100 in. lbs. I have heard that you should paint the aluminum gasket with aluminum paint for a better seal so I might also try that.
Thanks all

Al Harpster · Post by **Al Harpster** » Sun Jun 04, 2017 12:37 pm

I'd suggest you get the shop manual if you dont have one. Read it real good. Strictly hodaka's got them. Others may too. Possibly ebay.

Your Head bolt torque at 100 in. pounds is about right. Book says 105.

You can likely buy a USED head for less than the labor to correct the one you have. Strictly hodaka, Hodaka_Parts.com and Hodaka Parts.com IDAHO are sources for used parts. So's ebay if you like.

if your head gasket is suspect buy a new one. In fact, buy the whole engine gasket kit.

If you don't want to do that, a copper infused spray head gasket sealant is available at your auto parts store for $10. Spray the one you have, let it dry, put it back in.

Me, I'd buy the gasket set. You're likely to use most of it.

I'd suggest you pressure test as outlined on this forum and, if you like, I believe the old hodaka pressure test procedure is on Strictly's site under technical tips. The pressure test will show leaks in the head gasket and a lot of other places. All leaks are bad.

A cheap pressure/vacuum guage is available from harbor freight. Yes, it's a drag to work up the stuff you need to put together a pressure test. And it's not free. But it's worth it.

You can check your ignition by taking off the shifter cover, turn ignition on, lay a plug on the head and twist the flywheel back and forth by hand. If you get a spark you're probably OK for starters.

If that looks OK you are gonna want to take a close look at point gap setting. Check it and check it again. It's a REAL pain to get just right. Be sure you are close.

What I found was that if you follow the shop manual and keep throwing money at the parts that can wear out it'll run fine.

Finding exactly which parts are worn out & causing you problems takes time and patience. And money.

Al Harpster

Hydraulic Jack · Post by **Hydraulic Jack** » Sun Jun 04, 2017 5:17 pm

It doesn't take a machinist to repair a stripped spark plug. Just make sure you get the right metric thread pitch heli-coil insert kit, and if you haven't done one before, read the instructions and/or search YouTube for a video. Don't do it with the head on the bike.

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