Mikuni carburetor

[xboxrox]

BACKGROUND HERE: http://www.mightyram50.net/vbulletin...Working-OR-Not

This thread is about me & (you my helpers) trying to fix my 1986 Dodge Power Ram50 (32-35DID TF207 7Z08 Mikuni carburetor, California emissions)... It got broke trying to replace a leaking accelerator pump diaphram (cracked off a "L" shaped sliver chunk of the phenolic resin mixing body machined surface under the accelerator pump cover... It now leaks gas big time..! Truck sits...

I discovered today that my carburetor is original & never rebuilt, photos coming soon... I also know that the 1985 carburetor from PicknPull is all same as mine (except it's from a RAM50 RWD not 4X4)... From now on, I'll refer to this carb from PicknPull as "1985" & my original as "1986"

Today, got photos of the HOLE in the phenolic resin mixing body on 1986 and unlike the melted edge looking HOLE on 1985 there is at least a HOLE on both carburetors... 1986 looks as though there is a brass shaft in the hole & 1985 looks like a ball bearing deeper in the hole... At least I now know that 1985 is not trash coz of it having the HOLE in the mixing body... When I first looked at 1985, I thought "oh crap, a nipple or something is busted off"

1985 has a slight sticking spot about half way through the throttle travel & 1986 throttle movement is smooth throughout full travel...

PLAN ??? as of today --

1) Spray carburetor cleaner 'n oil on 1985 and install it on the truck, cross fingers & hope to get toilet tissue as needed..?
2) Investigate possibility of machining 1986 mixing body and installing a spacer under the accelerator pump cover..?
3) Rebuilding 1986..?
4) Locate & purchase a non trashed phenolic resin mixing body..? good luck
5) Order an Ultrasonic Cleaner from Amazon (Jeff needs more CORONA$$BUCKS) and Aliexpress cancelled my order..!
6) Leave 1985 alone 'n keep it as an example how to reassemble 1986..?

CARBURETOR REBUILDING BASICS Part 1: https://www.youtube.com/watch?v=85nszLpbbXY
CARBURETOR REBUILDING BASICS Part 2: https://www.youtube.com/watch?v=dprLQcQrAqE

At least not having wheels is helping me & wifey to remain isolated & quarantined at home, damned COVID-19

Your thoughts guys & gals..?
Much Aloha --
George

[geezer101]

I don't know if you've explained this in another thread/post but is there a reason why you're sticking to the Cali emissions carb? You can break these carbs down to 3 basic components without having to strip every screw, linkage and shaft out of them. The only thing you need to do to get there is disconnect a connector linkage or 2 from the throttle/butterfly body to separate them. Give the JY carb a good blasting with carb cleaner and then give the moving linkages and shafts a shot of WD40 and install it. I would use the leaking carb as the 'guinea pig' and attempt the basic breakdown. Once you have familiarised yourself with the fuel float and ball check valves etc reassemble it and break it down again so you know where linkages etc have to go. I wouldn't even attempt to fix the accelerator pump body as the plastic resin wasn't machined in the first place and there are too many things that can go wrong milling such a small area.

Tips - get a nice fresh screwdriver to take the carb apart and before trying to remove the top cover screws, give every screw a light tap with a hammer with the screwdriver as it will help free frozen threads (these carbs are notorious for getting the screw heads chewed out trying to disassemble them) Keep it upright while taking the top cover off and take note of the galleries in the proximity of the accelerator pump as this is where the check ball and brass float is located - disastrous if you lose them. And keep away from crowds/avoid spending non critical time out of your home. Stay safe George!

[xboxrox]

Give the JY carb a good blasting with carb cleaner and then give the moving linkages and shafts a shot of WD40 and install it. I would use the leaking carb as the 'guinea pig' and attempt the basic breakdown. I wouldn't even attempt to fix the accelerator pump body as the plastic resin wasn't machined in the first place and there are too many things that can go wrong milling such a small area. And keep away from crowds/avoid spending non critical time out of your home. Stay safe George!

geezer-man thanks so much for sharing these thoughts of wisdom... I was kinda thinking the same, just get the truck able to run for groceries asap... Here are photos of my 1986 carby & the J/Y 1985 carby (showing that weird hole ~ what is it for & what does it do..?)

California emissions WHY? Just because I suppose, the more changes, the more costs & I am happy having it original as possible... Thanks again for the well wishes, it goes for us all here no doubt...

CarbPnP2.jpgthe HOLE.jpgthe HOLE2.jpg

[geezer101]

I honestly think it's not worth holding onto a carb just for factory originalities' sake. This is one of those moments where owning an old vehicle can grief you from lack of parts (especially brake parts for a Gen 1 - rear brake shoes and front rotors are not easy to get...) The federal emissions carb will bolt up and function in an identical fashion to the Cali choker. I have a feeling a fed will be easier to fully strip down as IIRC some of the screws holding the Cali together are tamper proof - meaning they have to either be drilled out or ground off to work on it. You may inadvertedly find some power too by changing the carb...

[xboxrox]

I honestly think it's not worth holding onto a carb just for factory originalities' sake. This is one of those moments where owning an old vehicle can grief you from lack of parts (especially brake parts for a Gen 1 - rear brake shoes and front rotors are not easy to get...) The federal emissions carb will bolt up and function in an identical fashion to the Cali choker. I have a feeling a fed will be easier to fully strip down as IIRC some of the screws holding the Cali together are tamper proof - meaning they have to either be drilled out or ground off to work on it. You may inadvertedly find some power too by changing the carb...

geezer, the knowledge you just shared will help me a lot... Federal rebuilt carburetors are still available at local auto parts stores like O'Reilly's... Gosh, hope I ever need to fix the brake shoes; my truck already has a NAPA brand new brake master cylinder... I want my truck to be the last vehicle I need to own or at least last until another small mini truck or cheap 4X4 vehicle is being sold in USA... Preferably something Made-in-Anywhere but USA with a ten year or 100,000 mile bumper to bumper warranty and CVVT gas mileage... I don't want much, just the smallest & cheapest truck or Jeep type vehicle sold but not made in USA...

Wifey and me both came to the same decision today about how best to get the truck running again... Assuming the J/Y carburetor can bolt on and operate safely without gas leaks or engine acting up too badly -- we will hire Vernon again to do the install... He has been loyal to us even if he does break stuff sometimes...

Happy for getting your thoughts braddah

[xboxrox]

Texted Vernon 'n asked him if he would install & he said: "OK, cool..." O'Reilly's will have the mounting gasket tomorrow morning...

[geezer101]

Remember it might not be your intention to modify your truck, but Gen 2 stuff will swap over onto it without mods and will make maintenance and parts more accessible. If that's what it takes to keep 'er on the road. I got my fingers crossed (what's left of them anyway...) that the JY carb will be a win for you.

[xboxrox]

Gen2 fits? Including the electrical & sensor connectors? WOW
X'd fingers will Help

[geezer101]

^addendum - some resin body carbs have the EGR valve integrated into the carb and some don't. I've also seen carbs with 3 electric control solenoids installed into them + the fuel bowl vent/fuel cut solenoid (I rebuilt one and it was hell). They all share the same bolt pattern so you could in a pinch swap parts between carbs to build a hybrid of different control/EGR options. These bloody Mikunis have that many different combos of control mechanisms you could write a whole book on them Some people hated the early alloy body Mikuni Solex for some reason but I found them to be not only forgiving to work on but tweakable as far as performance was concerned.

[WarStryker13]

If that '85 carb has issues I can clean up my '87 carb and send it to you, it didn't seem to have any major issues that I could sense from the short amount of time I had it on my truck.

I wasn't going to say anything in case there was a difference between gen 1 and gen 2 that I didn't know about, but it seems like you've got quite a few options open to you now, and even if it's only good for parts it should be helpful to you.

[FMS88]

Don’t mean to burst bubbles, but a Gen2 carb is not a direct fit on a Gen1. Between the Gen1 and 2 there are differences in the intake manifold, ECM, engine and ECM harnesses, vacuum lines and the vacuum control box. These would have to be changed or modified to ensure the Gen2 carb performs properly. Seems like a lot more work and expense than getting the ‘85 carb to work.

[xboxrox]

THANKS everyone..! Vernon (a local guy who will work on cars) will install, inspect & adjust the 1985 Mikuni today once I pick-up the mounting gasket at O'Reilly's Kailua store... Automotive Mikuni manuals & info are obscure but motorcycle Mikuni is everywhere... I would consider a TBI conversion if available and not super expensive... I have a dream to rebuild my 1986 carby but 7 of 9 planets need to be in alignment for that to begin...

[xboxrox]

Mission Complete J/Y OEM Mikuni is installed & road tested: RUNS GREAT 'n more response, no lag @ WOT

Opps Virus, after sitting 10 minutes with heat soaked engine it would not start but started on 2nd try... Then missed a few times getting out of the grocery store parking lot... Wife says, don't worry, the truck is just getting used to it's heart transplant

Thank you all for your help & prayers -- God is watching over us... How else would PicknPull have a decent Mikuni carby NEVER..! As well as parts puller Allen there to nab & send it & Vernon here to install it..! Carb $125.00 shipped & $75.00 install with free engine shine
Aloha -- George

[geezer101]

Who is that masked man? Hopefully the start glitches will iron themselves out, but it's not dumping fuel everywhere and it's running well once it chooses to start so that is promising.

[xboxrox]

Who is that masked man? Hopefully the start glitches will iron themselves out, but it's not dumping fuel everywhere and it's running well once it chooses to start so that is promising.

YEP YEP NO gas leaks & it runs That masked man is me co-avoiding the corona BUT I did HiFive Vernon when the truck fired up..! Wife says I don't need an ultrasonic cleaner now; yeah, I need a rebuilt steering gear now

[xboxrox]

UPDATE April 1st (No Fooling) Took photos of both the 1985 & 1986 Mikuni carburetors; looking the sameOh sameOh... They both have 3 HOLES plugged with what looks like two part epoxy... Not sure what the glue is meant to hold back or plug off: Gasoline, vacuum or close off the phenolic mixing body's casting vent holes..? Maybe I could use the same epoxy glue to fix the crack in my 1986 Mikuni (see carby2 photo)..?

Truck ran perfect today although still had a little rough running the first minute while choked BUT it's much less rough less duration & no black smoke or rich gas smell like before... Starts quicker too & has more umph to do 80MPH in an area previously limited to 60MPH by the truck's performance...

NO FOOLING HERE R PHOTOS:
CARBY.jpgCARBY2.jpgCARBY3.jpgCARBY5.jpgCARBY7.jpgCARBY4.jpg

[geezer101]

When they build carbs they have to cross drill galleries sometimes to get them to route in the direction they need to operate various vacuum circuits. They use pressed in brass plugs on cast alloy carbs to seal off the externally drilled holes and that wouldn't work on a resin bodied carb, so they use an epoxy instead.

[claych]

???
Apologies,I have not seen brass plugs on any Thermoquad .
???

[geezer101]

Webers use alloy plugs. Nearly every every bike carb used pressed in brass that I'm aware of. All alloy Mikunis use brass as well and there is at least one exposed brass plug on the top cover of resin body Mikunis.

[xboxrox]

MIKUNI INFO LINKS:

https://www.autozone.com/repairguide...00c15280054793

Edited July 31st 2020: added TOMCO Mikuni Parts PDF doc

[claych]

^^^-
Moderators the above should be a sticky

[xboxrox]

HEY Ya'll POSSIBLE CARBURETOR FIX

My original 1986 Mikuni has a healthy sized "chunk" broke off at the mounting surface for the accelerator pump cover & 1st try fix with super glue did not work, leaked gasoline right away...

Today, saw & read this from my little parts/tools box --
20200707_130914.jpg20200707_130856.jpg

[85Ram50]

Cool.

[geezer101]

Meh, nothing to lose

[85Ram50]

How did it work out xbox?