facebook1 youtube1 twitter1 instagram linkedin1 pinterest1

NOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community! REGISTER AND MAKE THIS BOX DISAPPEAR!

Question 1977 GTMX 80D choke lever/plunger spring

  • ARoseto
  • ARoseto's Avatar Topic Author
  • Offline
  • Junior Member
  • Junior Member
  • Posts: 24
  • Likes received: 2
Good afternoon, 
The choke lever on my mx80 is prone to gravity. If I want it to run and idle properly I have to hold the lever up with my left hand while riding.

Would this be indicative of an old and weak choke/starter plunger spring?

If so would anyone have any resources as where to acquire the plunger spring? I've done a preliminary search and it is not an easy part to locate availability on.

Thank you
04 Dec 2021 14:12 #1

Please Log in or Create an account to join the conversation.

  • Posts: 3528
  • Likes received: 1389

Replied by Gr8uncleal on topic 1977 GTMX 80D choke lever/plunger spring

If it is a Mikuni carb, then most parts are still available from a Mikuni specialist dealer (here in the UK we have Motocarb). 
05 Dec 2021 01:04 #2

Please Log in or Create an account to join the conversation.

  • Posts: 7040
  • Likes received: 2628

Replied by RT325 on topic 1977 GTMX 80D choke lever/plunger spring

Springs never give up on those type of chokes 'unless got water in' & rusted & collapsed the spring. But also important is the spring steel strip that the lever operates on to hold the lever down in the .on position.. But i guess it also holds it in the off position too when lifted up although 'still relies on the spring' to hold the plunger fully down to seal the jet closed. #31 in the link. The way its drawn is slightly confusing as it fits in the gap on top of #30 but under the moving part of the lever & can 'just' see a lump under the lever that bumps over the other lump on the spring strip. Gotta stop writing essays haha, sorry about that [& telling you what ya already new].
www.partzilla.com/catalog/yamaha/motorcy...976/gtmxc/carburetor
But wait there's more lol. That spring strip often moves to one side while tightening the plunger nut & misses the arm so no springy strip to hold it in the operating position--lever down. Easy fix just tweak it under the arm or might have to crack the nut free by one flat or so.
The following user(s) Liked this Post: Schu
Last edit: 05 Dec 2021 01:53 by RT325.
05 Dec 2021 01:48 #3

Please Log in or Create an account to join the conversation.

  • Posts: 11199
  • Likes received: 6584

Replied by MarkT on topic 1977 GTMX 80D choke lever/plunger spring

Yes, what RT325 said. 

This image is hidden for guests.
Please log in or register to see it.



Probably don't need parts but if the "stopper" is missing, there are a couple on ebay if you search for the 367-14377.flat spring "stopper" that should hold the lever up or down.

Post photos of your choke lever area if this doesn't make sense and we can try to help you figure it out. 
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
The following user(s) Liked this Post: RT325
05 Dec 2021 03:03 #4

Please Log in or Create an account to join the conversation.

  • ARoseto
  • ARoseto's Avatar Topic Author
  • Offline
  • Junior Member
  • Junior Member
  • Posts: 24
  • Likes received: 2

Replied by ARoseto on topic 1977 GTMX 80D choke lever/plunger spring

First thank you for your advice and expertise..

Good to know the choke plunger spring does not normally wear or need replacing. 

So the tab on the spring steel stopper that is below the choke lever can be adjusted or needs to be adjust so it shifts under the lever to keep it in its position to operator optimally?

Much appreciated! 

I guess I will have to play around with it.

 
05 Dec 2021 10:23 #5

This message has an attachment image.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 11199
  • Likes received: 6584

Replied by MarkT on topic 1977 GTMX 80D choke lever/plunger spring

Yes, hard to see in your picture but looks like spring stopper shifted over and isn't under "bump" on lever. 
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
05 Dec 2021 10:32 #6

Please Log in or Create an account to join the conversation.

  • Posts: 3528
  • Likes received: 1389

Replied by Gr8uncleal on topic 1977 GTMX 80D choke lever/plunger spring

As I appear to have seven carbs dotted around my office at the moment 

This image is hidden for guests.
Please log in or register to see it.

This image is hidden for guests.
Please log in or register to see it.

, I've taken a couple of pictures of the correct arrangement for you.

If yours is out of alignment, undo the 13mm headed "plunger cap" a smidge, locate the "starter lever plate" correctly and then hold this in place when you tighten up the "plunger cap".

 
 
05 Dec 2021 13:01 #7

This message has attachments images.
Please log in or register to see it.

Please Log in or Create an account to join the conversation.

  • Posts: 282
  • Likes received: 108

Replied by Sneezles61 on topic 1977 GTMX 80D choke lever/plunger spring

The second picture shows the best..
Sneezles61
The following user(s) Liked this Post: MarkT, RT325, Ht1kid, adguy2112
05 Dec 2021 13:11 #8

Please Log in or Create an account to join the conversation.

  • Posts: 7040
  • Likes received: 2628

Replied by RT325 on topic 1977 GTMX 80D choke lever/plunger spring

Probably a good idea to check the spring condition--just because. Only have to be 'just' off the seat to go rich. easy 'as' to undo the 12 or 13mm hex nut & lift the lot out.
05 Dec 2021 14:10 #9

Please Log in or Create an account to join the conversation.

Moderators: yamadminEnduronutMakotosunDEETVinnieDevinJames Hart