TDM900 : Cold start trouble
Part II by E.T.


For a little while the fast idle hadn't been working properly, so at long last I decided to do something about it. I hope the following will help others. Incidentally the fast idle unit can't be bought as a separate unit, you can only buy it as part of the complete throttle body assembly, list price about £1300...yes thirteen hundred!!!

Symptoms

Originally the symptom was one of no high idle on start up on a cold engine, making it difficult to start and keep running. After a service, and I can't remember the exact circumstances here...it was months ago...the symptoms changed to having a fast idle at start up, but then remaining fast.

What is the problem

The fast idle plunger is a little unit screwed onto the front of the throttle body. It has two pipes off the radiator which heat a wax stat. As the wax stat heats it expands, pushing a plunger side ways. This pushes against a slider arrangement (which is sprung loaded) and adjusts the throttle setting (independently to the twist throttle).

All of this is exposed to the elements and the water and spray tends to work into the plunger and seize it up. Hence it can get stuck in one position.

What to do about it

The repair is simple in theory. The fast idle assembly is held onto the throttle body by two screws. Remove these and remove the two radiator hoses and take it off the bike. The whole thing comes apart with two screws. Free it up, lubricate and replace on the bike.
Easy eh!?

Except...getting to the bugger!

(image)Prop up the fuel tank. I've made myself a holder-upper. Consists of a bit of aluminium shower curtain rail, flattened either end. An 8mm hole drilled in either end at 400mm centers. Use the tank bolt and a nut bolt of suitable type and prop the tank up so... it's nice and secure and great for lots of those under tank jobs.

(image)Once the tank is up you need to remove the air filter box. I didn't remove this altogether, I just disconnected the hoses, undid the jubilee clips on the air intakes, and the securing bolt at the very front, then lifted it to one side.

(you'll notice from the picture 1, that I placed a clean sandwich bag over the air inlets to the engine to keep any potential dirt/dropped screws etc out)

(image)Now you can easily see the Fast Idle plunger. This is on the right hand side of the bike at the top of the throttle body (its the cleanest looking bit in the photo, at about "7pm").

(image)Disconnect the two pipes, having something suitable to plug the ends (to save draining the coolant down)...BUT see below before you look for plugs. I ended up using a couple of 6.5mm twist drills (blunt end in, of course)

Now you will notice that you have just two screw to take out. Except...you will also notice that there is a radiator pipe in front of the screws. I got a ratchet with a 6.5mm socket and a screwdriver bit (Philips), but it was far too tight to undo - I was beginning to damage the head. The only real way to get that out was confront it head on!

Drain down the coolant (don't bother with the plug screw on the water pump) just drain using the screw on the front of the cylinder block, this will get the coolant level low enough. Don't forget to catch the coolant in a clean container, ready to stick back in later.

(image)Remove the offending pipe. Now wouldn't you think that would be easy. Two Jubilee clips and a bit of tug...but oh no! If you look here, you will see Mr Yamaha has carefully placed the jubilee clip facing downward, meaning no way to get a screw driver on it to undo. This was a careful shuffle with a small spanner...6mm (I think...I can't remember. sorry), moving it 2 degrees at a time.

Remove all the bolts that hold the radiator (no need to disconnect the rad altogether - removing these bolts the rad can just be dropped enough)

(image)Now you can get to the screws from the front - here's how I did it...

(image)

(image)And finally off comes the fast idle assembly...

(image)Undoing the two screws reveals the inside of the assembly.
...and the offending part is this stainless steel pin.

(image)It was pretty solid, but lightly tapping it back and forth freed it up until I could push it out of the body (you need to take it out from the inside). This was then cleaned, and I used copper-slip grease on the pin (I wondered whether it was genuinely road grome, or some electrolytic corrosion between the aluminium and the stainless that caused the partial seizure..??)

Sticking it all back together is pretty much the reverse of the above. I like to stick copper-slip on everything as I replace to make next time easier. When you replace the radiator hoses, and bolt it all together, do remember to do up the jubilee clip otherwise coolant pisses out every where......then you have to take the tank off again, and the air filter box.

One other point was I found it difficult to get the air box located onto the throttle body air intakes. In the end I split the box took out the air-filter so I could guide the rubbers over the intakes - lot easier.


Text & pics in this page are from E.T. / Carpe-TDM Forum.

Sign-in×

Please enter your account details


OkCancel
Lost account details×

Enter your e-mail to receive your account details

E-mail

OkCancel
Sign-up×

Why sign-up ?

  • It's free but you can make a donation.
  • You gain access to fonctionalities otherwise not available.
  • It will boost your sex-appeal and allow you to time-travel.

How to sign-up ?

UsernameRequired - 3 to 20 letters or digits
PasswordRequired - 6 to 20 letters or digits
E-mailRequired - enter a valid E-mail address
Country

OkCancel
My account×
PasswordE-mailDelete

Modify my password

Current password

New password
Confirm new password

Modify my E-mail

Current E-mail

New E-mail
Confirm new E-mail

Delete my account

Current password

OkCancel
Add commentEdit / delete message×
  • Your comments, feedback and suggestions are welcome !
  • Please use forums for any questions requiring a quick answer.
  • Your questions should relate to the TDM / XTZ / TRX only.
  • No links, ads, sales, doc requests. Thanx.
  • Edit your message then click the 'Ok' button.
  • Click the 'Delete' button to remove the message.
  • An empty message will be deleted.
NameRequired - 3 to 20 letters or digits
E-mailOptional - will be encrypted
CountryOptional
Message

OkCancelDelete

OkCancel
Terms of Service and Privacy Policy×

Collection & use of your personal information

When registering to the site, you will be asked personnal informations such as your e-mail address, your country of origin, etc. This site will not provide or sell your personal information to a third party without your consent.

The site may collect information about your visit in order to operate and improve the site and the service it delivers. This includes the pages you view, the links you click and other actions taken in connection with the site. It also collect certain standard information that your browser sends to every website you visit, such as your IP address, browser type and language, access times and referring Web site addresses. Theses data is collected only for statistical usage and will not be used for any other purpose. This data is periodicaly erased (max 3 months).

Use of cookies

This site uses cookies to memorize your display language option and your session data. No personnal information is stored into the cookies. If your browser does not accept cookies, you will not be able to change language or open session.

Use of e-mail address

This site will not sell, lease or rent the e-mail you provide while registering or posting messages. E-mail addresses will not be used for any purpose other than sending you service e-mails : registering confirmation, updating your data or requiring a new password.

Rules

This site does not allow any messages containing :

  • Spam : repeated (commercial) messages.
  • Referral Programmes or Pyramid Schemes (links to websites through which you have a personal gain).
  • Rude and disrespectful behaviour, whether it is to members of this site or the staff of this site.
  • Language that is obscene, vulgar, sexually orientated, hateful, threatening or violate any laws.
  • Offerings of products (tangible or intangible) and services that you do not have legal disposition over.

This site reserves the right to edit or delete reactions and to ban any user violating the rules without notice. Freedom of speech is a right, however this does not mean we are obliged to publish your opinion.

This policy is subject to change without prior notice.


Ok

Ok

Ok

Ok
Send SMS×
NameRequired - 3 to 20 letters or digits
Message

OkCancel