Worn out carburetor

Forum rules
Please do not start new topics here, but here: New Panhead and Flathead topics
Post Reply
mbskeam
Posts: 1006
Joined: Tue Mar 16, 2004 5:52 am
Location: Sultan, WASH
Been thanked: 2 times
Contact:

Worn out carburetor

#1

Post by mbskeam » Tue Jul 11, 2006 10:30 am

well as some of you know I run a 38mm mikuni. has anybody ever seen a carb just get worn out from use, like the slide, fuel nozzle, fuel needle...etc???

Cotten.........
will a m74 do a 88"

mbskeam



Gearbox
Posts: 38
Joined: Sat Jul 14, 2007 3:08 pm

Re: Worn out carb

#2

Post by Gearbox » Tue Jul 11, 2006 11:29 am

Every thing mechanical has a service life , so your carb may be to that point . We both know that more fuel and air will make horse power , to a point, isn't that why you stroked it? I know this isn't a good comparison to a Pan motor, but what MM are the Twinkie's running in the carb? They be 88ci , right.

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois
Has thanked: 100 times
Been thanked: 268 times

Re: Worn out carb

#3

Post by Cotten » Tue Jul 11, 2006 12:36 pm

A big motor can run with a tiny carb, and a tiny motor can run with a big carb.
In other words, pick a size that is appropriate for your riding habits. Smaller bores accent torque and efficiency, whereas larger bores accent flow and peak horsepower.
Consider whether your payload is a light or heavy one, whether passing accelleration is more important than pulling power, and whether fuel prices mean anything to you.
The Factory always stayed conservative on bore size until Pans came along, when they opened them up dramatically with the M74B.
(This coincided roughly with Eisenhower's Interstate initiative.)
It is nearly as large as Pan ports can ever use.

My 86" did great with its M74B, even when harnessed to a hack.
(Come to think of it, I wore out a 38mm MickeyRooney back in the '70s, but it was tired when I got it. It was a fine carb, but too modern for my personal tastes.)

....Cotten

mbskeam
Posts: 1006
Joined: Tue Mar 16, 2004 5:52 am
Location: Sultan, WASH
Been thanked: 2 times
Contact:

Re: Worn out carb

#4

Post by mbskeam » Tue Aug 01, 2006 5:27 am

well I picked up a replacement 38 (least amount of work)
well the old carb was shot, let me tell you.
I put the jets that had been runnin in the 88", and they both where way to small, in the new carb. it must have been so loose and opened up that gas just flowed like it was free......
now I have to play the ride and rejet, ride and rejet till I get the plugs to read correct.
I don't like white plugs, this is a bad thing.ran real smooth but to lean for me. got some new jets at the yammy dealer and now its time to tinker some more.....
as if I ever will stop....LOL

mbskeam

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois
Has thanked: 100 times
Been thanked: 268 times

Re: Worn out carb

#5

Post by Cotten » Tue Aug 01, 2006 11:05 am

Mbskeam!

Most modern fuels do not make 'color' upon sparkplugs like the good ol' days. It now takes many many miles just to get a grey color, making plug reading a poor diagnostic of fuel mixture.
It is a real problem.

....Cotten

mbskeam
Posts: 1006
Joined: Tue Mar 16, 2004 5:52 am
Location: Sultan, WASH
Been thanked: 2 times
Contact:

Re: Worn out carb

#6

Post by mbskeam » Wed Aug 02, 2006 3:11 am

hhmmm. the gas here in the NW does color the plugs, is it that p4 gas that you keep talkin about, with all it wonderful propertys...LOL
put on about 40 this afternoon, got back and the plugs are a dark/med brown. now to fiddle with the main a bit and it should be good to go.

mbskeam

Cotten
Posts: 6911
Joined: Mon Aug 26, 2002 9:09 am
Location: Central Illinois
Has thanked: 100 times
Been thanked: 268 times

Re: Worn out carb

#7

Post by Cotten » Wed Aug 02, 2006 11:07 am

The fuels that don't color the same have "anti-deposit" additives as well as "injector cleaners" , such as Shell and BP pump gases.
And yes, they are certainly P4gas here in the Midwest!
The qwickymart generics are fine if they don't have ethanol blended into them, but they are low octane.

....Cotten

Post Reply

Return to “Carburetor/Fuel system”