Hi all,

New to this site and just bought a mc18 so it felt appropriate to join a nsr forum.

I'm in the middle of trying to sort out the rc servo motor and have since bought a second one from ebay. The first servo didnt do anything although there is more resistance when trying to turn the servo with the ignition on.
Just fitted the second one and when I turn the ignition on the servo moves to the "lo" position, but when I start it and rev it the servo is trying to turn passed the stop in a anti-clockwise direction which is oppsite to to the "hi" position.
Not wanting to damage this servo i removed the servo roller which the cables wrap onto so there is just the shaft popping out the servo box, when I rev it now the servo continually spins anti-clockwise which is the wrong way!

Would it be possible that the cdi is faulty?

Where the cdi is on my seat unit there is another unit on the opposite side, any ideas as to what it is?? I tried deristricting the bike by disconecting the single black wire next to the red plug but the servo didnt work at all?

Getting quite frustrated now and any help will be much appreciated!

thanks nelly.

Mod edit: TXT speak etc.
FY

Hello and welcome, please read the rules and don't post TXT talk or near unreadable streams of lower case letters, I'll edit this ONE post for you but others may receive Andy's somewhat less conservative moderation


Whatever your problem is it's doesn't sound good, but I'd be tempted to check all the wiring for shorts and bad connections before I considered anything else.

However, I'm no early mc18 expert so someone else may know better.
_________________
Please do not PM me technical questions, if you can't find it on the Forum start a thread


Last edited by fontyyy on Tue Apr 13, 2010 11:03 pm; edited 2 times in total

welcome
one box is the cdi and the other is the servo control unit.
sounds like the servo contoller is buggered.
sure some one who knows more than me will correct me if i'm wrong!

On the 1988 MC18 (first year MC18 model) there are three control units.
1. CDI Control Unit - This is the larger unit on the left side of the sub frame.
2. Sub Control Unit - This is the smaller unit on the right side of the sub frame.
3. RC Valve Control Unit - This is in the center of the rear sub frame.

When turning on the ignition and increasing the engine RPM to around 2K the servo pulley should move to the HI position. Increasng the engine RPM to around 3K, the servo pulley should move to LO.

The MC16/18/21 service manual goes into further trouble shooting details like checking the servo motor as well as inspecting the wiring harness.