Yamaha Triples
Search Forums | Statistics | User Listing Forums | Calendar | Albums | Chat | Skins | Language
You are logged in as a guest. ( logon | register )

Corroded Carbs
Moderators: Moderators

View previous thread :: View next thread
   Maintenance and Repair -> CarburetorsMessage format
Posted 2018-07-09 2:47 PM (#153910)
Subject: Corroded Carbs


Posts: 457
Location: Brighton, MI
Wake up everyone! There's a new thread!

One of my Triples has a carb issue.

I was tooling along on one of my SFs a week ago. I came to place where the speed limit increases to 55 MPH on a wide-open, 2 lane road. I opened it up all the way, and "cough, cough, sputter, etc...."

After that, it would idle OK, but as soon as I gave it some gas, it would shut down to two cylinders.

I didn't believe it was the problem, but I had been knowing I should rewire the fusebox; so I did that to make sure everything had the necessary juice. I knew it wasn't the problem, but I felt better that I finally fixed the weak fusebox.

Then I did what I knew I had to do. I pulled the carbs. The pictures show what I found.

The #2 main jet ingested a big clump of debris and it was blocked. The #3 pilot wasn't spotless either, although that wasn't the main problem. (Get it, Main problem)

I didn't find any appreciable rust when I drained the bowls, although there was excessive debris in the bowls. The carbs float needle screens were spotless. It seems the debris is from corrosion inside the carbs. The blue accumulation suggests the copper from the brass has formed some kind of compound on the aluminum. Seems galvanic in nature.

We all pine about the evils of ethanol. This seems to be a case in point. FYI, these carbs were rebuilt about 7-8 years ago. During the first few years, I drained the bowls in the winter. After I acquired more bikes, I began to leave the fuel in the winter and try to run them all ASAP when opportunity permitted.

The whole irony is that this my second Triple. I have owned the other Triple since it was almost new. I rebuilt the carbs in my first Triple after about 30 years, and they were spotless inside. I never drained the bowls in those carbs.

Embarrassing moments during this carb rebuild:

(a) I stripped one of the pilot jets, and then broke off the Easy-out in it. Game over for that carb body. I know better. Some of you have been there too.

(b) On the replacement carb, I broke off the screw that holds the carb body onto the angle-iron bracket. I was not able to the get it out with an Easy-out. I stopped before I broke another Easy-out. Tried to drill it progressively bigger and work it out. No luck. So, I drilled and tapped all the holes on all carbs from 6mm -> 7mm. Then I realize 7mm is not-so-standard. Eventually I found suitable 7MM bolts.

I wonder why these carbs have so much corrosion.

I might put paper filters on the gas lines to make me feel better.

Not a big story, but nothing else going on here.


(Carb 1 small.jpg)

(Carb 4 small.jpg)

Attachments Carb 1 small.jpg (96KB - 30 downloads)
Attachments Carb 4 small.jpg (99KB - 33 downloads)
Top of the page Bottom of the page

Jump to forum :
Search this forum
Printer friendly version
E-mail a link to this thread


Running MegaBBS ASP Forum Software
© 2002-2019 PD9 Software
(Delete all cookies set by this site)