Need help with carb on California Motors Minarelli!?

GoldenMotor.com

Solarsyst

Member
Jan 17, 2024
30
33
18
37

So i recently bought a Minarelli Hybrid and unforntuately i haven't been able to get it to run after several attempts and test. First I thought it may be an issue with the cdi and magneto and they both read proper voltages with a meter. Tried new spark plugs, Z4C and NGK B6HS, both gapped. .24. California Motorbikes offer the chinese C20 and Mikuni VM20 OUT of stock. I have tried contacting the seller with info on the proper jetting on the carb with no response to it or luck. So I found out Smolik preformance mentioning that the main jet on a Mikuni VM20 main jet needs to be changed between 240-280 depending on your region. All videos on YouTube suggest the same when evaluating their builds. I bought the VM20 knock off and couldn't order or find the proper jets on Amazon. I couldn't find any jet kits past 190 and they sent me the wrong ones! It was a rabbit hole and huge nightmare! So now I returned the VM20 knock off and now I'm trying a NIBBI PE19 and ordered extra jets and pilots for the carb and the bike doesn't even start from stock settings. fuel/ oil ratio is 20:1 for break in as suggested from CaliforniaMotorbikes.com and 32:1 after 400KM. I can't even get this motor to run! Tried two different cdis and other sparkplugs just to the check.

Last motor I ran from California Motors recently didnt even last the third tank after break-in on 40:1 mix ratio. First the oil seal on the is the cheapest with the chinese markings blew at high throttle, so i replaced it immediatly from another graveyard motor. Then after a long drive and run full throttle! Boom. Cylinders piston exploded topping full throttle at atleast 45-50 on a Schwinn Stingray OCC Chopper. Yes I am no expert and am new to this so any suggestions would strongly help and be appreciated!

In order to make the NIBBI pe19mm to fit I had to use a slanted intake manifold from a VM22 kit i returned.... The adapter plate for the VM20 that comes with california motor bikes kit is specifically designed for the VM20 as they claim but the holes diameter is much smaller than 20mm intake. It reads about 19.5mm. Now I'm waiting on a Phantom 85 v3 and a replacement to the Wildcat PRO Racing Engine 80cc (Ported) 5HP i just blew up!!!!! I forgot to mention that their case bearings have NO gaskets on EITHER SIDE!!!! IS THIS BAD???? I read that VITON seals stop all issues so I ordered but I may have to crackt he whole lower half to properly install them! Many forums suggest ordering better bearings and oil seals for crank and magneto side. Major flaw at the price range of 200. If I would've known I would've just paid Smolik to DO EVERYTHING. I am no expert and learning as I go along.

I may just give up on the Minarelli! Seriously I ported the top cylinder, properly torqued 12ft lbs on the head, used an aftermarket CNC head as shown on Youtube from DLH preformance. GL ordering their clutches from them!! I tried, card fraud alert!! Their out of stock too. I tried contacting them no response. Not sure if he's still alive!!
 
  • Like
Reactions: fasteddy

Wevil Kenevil

Well-Known Member
Mar 4, 2022
292
262
63
47
Sack a tomatoes California
Sounds to me like you having no seals on your main bearings would be the main problem.

From what I can tell you didnt mention a windowed piston that you need to make a reeded carb function proper. I think you are changing to many parts all at once.

Peel it back to where you can get it to run and then add one part at a time, get it dialed in and then add another part.

Are you running a stock exhaust pipe? You need an mz 65 exhaust at least...


All these parts youve added need to be tuned in not just thrown together. It wont ever run doing it like this bro.

Do yourself a favor and when you get the new motor, just run it and leave it like it is. It will last a lot longer.
 
Last edited:
  • Like
Reactions: fasteddy

Solarsyst

Member
Jan 17, 2024
30
33
18
37
it has a Yamaha stock jug exhaust cut and welded to fit a felt faker. The Minarelli has a Reed stuffed with a vm 20 adapter. Read the product description I wasn't asking for discouragement. I just meant to get it running. the seller suggests the bearings with no seal is to transfer to oil. but from my research. suggests.. it's meant to fail. apparently. after a third tank of gas and the oil seal busting on the magneto side of the the magneto casing. too much compression. that was just their wildcat gtz reed valve motor. both bottom ends have the same issue! wildcat pro ported and minarelli.
 
  • Like
Reactions: Wevil Kenevil

Solarsyst

Member
Jan 17, 2024
30
33
18
37
Cooler Master Tempest GP27U
Samsung Odyssey Neo G7 43
VM 18 carburetor
Jet size 22.5 - 25 pilot 85 - 90-95 main jet

Wevil to be exact and short about it. I blew up a cylinder piston on California Motorbikes
Wildcat PRO Racing Engine 80cc (Ported) 5HP. https://www.californiamotorbikes.com/product-page/wildcat-pro-racing-engine-80cc-ported-5hp

The oil seal on the magneto busted, I replaced it and then followed the cylinder due to running mixture @ ratio 40:1. To rich. This was later confirmed by checking the spark plug and piston.

As for the minarelli if you you look on their website. The entire engine only kit comes with everything including the reed valve and windowed piston.https://www.californiamotorbikes.com/product-page/wildcat-ultra-minarelli-6hp-race-engine

Everything was installed correctly on this motor.
I am aware that the Minarelli cylinder is a from a Yamaha and this is the OEM specific exhuast i had to cut, weld and install. https://www.amazon.com/Performance-...&sprefix=minarelli+jug+exhuast,aps,108&sr=8-1


The only other reason i could suspect it not starting at this point is perhaps the reed valve stuffing plate was installed backwards. I will check today...

I couldn't find the proper main jets as suggested from Smolik Preformance. 240-280. So I went with Nibbi PE19. Their is a death kid on Youtube that used one. Others are Using Minarelli VM-20's, VM 22's, Generic Chinese PZ19s, PZ20's, PZ30's etc.

Sorry I guess it helps if i submit some pictures of the build. so here you go.....
 
  • Like
Reactions: Wevil Kenevil

Solarsyst

Member
Jan 17, 2024
30
33
18
37
Quote from

@BuildBreakFix
hey do this! Your new to those carbs right? DO NOT USE THE THROTTLE! just factory default your carb! Main Screw screw it all the way in! turn it 3 full turns out! Your air mix screw! turn it all the way in softly when you do both of them! The air mix screw you want to turn out 2.5 turns out! now your at factory defaults! Use the jets that came with your nibbi! I'm about to use the same setup on my new one in my video i just released actually LOL use the factory jets! came in your nibbi! Pull your choke when you go to start it! DO NOT USE THE THROTTLE AT ALL! or it wont start! seriously it's like most common issue people have lol they get use to NT carbs. When choke is on never use the throttle or you flood your engine! Leave the choke on! ride the bike drop the clutch few times if it's flooded. it will start right up and after it does you can baby it a few times with the throttle to get her running! turn choke off right away!
Show less
 
  • Like
Reactions: Wevil Kenevil

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,250
1,767
113
Los Angeles, CA.
I don't have any experience with the Nibbi carbs, but I'm guessing they have a idle/fuel adjustment screw like most other carbs?

The idle/fuel screw is what meters the amount of fuel going into the pilot jet (& the choke/starting circut)... So installing a larger pilot jet won't do anything unless you also open the idle/fuel screw!
(keep in mind that it is different from the idle/air screw).
 

Solarsyst

Member
Jan 17, 2024
30
33
18
37
Still no luck. Tried exactly as he suggested. Checked voltage on two cdis and magneto all read clearly? I also tried both cdis ignitons, two spark plugs, NGK BR8HS and B5HS. No spark it seems. Magneto and magnet have been aligned by a piece of paper folded in x4. So there's equal distance between them both. Tried adjusting the carb numerous ways with no luck. I also asked Break Build or fix it to demonstrate a video of his carb working. Specifically the Nibbi pe19mm.
 
  • Like
Reactions: Wevil Kenevil

Solarsyst

Member
Jan 17, 2024
30
33
18
37
Checked torque compression of head. Gaskets flush. One bolt came out taking out the nut. I flushed the bolts all the way to the bottom of the crankcase previously before install. Noticed the head wasn't seated fully recently. Removed the head checked the surface and gasket both fine. Only other thing I can think of doing is leaving the gasket on the stove for 5 minutes then placing it on and tightening it
 
  • Like
Reactions: Wevil Kenevil

Solarsyst

Member
Jan 17, 2024
30
33
18
37
Tries stock minarelli head. Changed magneto after checking spark. Engine hesitates to turn magneto without power drill. Got spark on Another magneto. Compression was OK, torque 12ft lbs with torque wrench. Tried stock minarelli head. No difference in starting.
 
  • Like
Reactions: Wevil Kenevil