Author Topic: T 100 68 carb/starting problem  (Read 2804 times)

Offline dynamic

  • Advanced Member
  • ***
  • Posts: 84
  • Karma: +0/-0
    • View Profile
    • Email
T 100 68 carb/starting problem
« on: November 28, 2021, 10:39:26 AM »
I have just fitted a new concetric 626R 300 carb to my machine & it has become a very reluctent starter taking 10+ kicks to start

I have a 108 pilot jet & 200 main jet needle is on bottom notch , I do prime the engine ie. tickle throttle fully open then 3 kicks ignition off

a choke is fitted but makes no diffrence at all at any position

I do get cylinders firing but it just does not chime in

 
taking the plugs out they are barey wet , fuel flow is perfect I have both taps on to start ignition (Pazon) is spot on

once initially started hot starting is no problem the only thing not checked is float height I have not touched this from receiving the carb

all input gratefully received "worn out of North Wales "

 

Offline iansoady

  • Advanced Member
  • ***
  • Posts: 721
  • Karma: +6/-1
    • View Profile
    • Email
Re: T 100 68 carb/starting problem
« Reply #1 on: November 28, 2021, 11:03:02 AM »
Does this have a "proper" pilot jet or merely a bushing? If the latter, make sure that all drillings are clear. Where did you buy it as apparently some on the market are not too good.
Ian
1952 Norton ES2
1986 Honda XBR500
1958-ish Tre-Greeves

Offline L.A.B.

  • Advanced Member
  • ***
  • Posts: 1529
  • Karma: +32/-4
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #2 on: November 28, 2021, 11:16:32 AM »
A 626/300 (non-Premier) has the standard fixed pilot bush.
http://amalcarb.co.uk/rh-26mm-4-stroke-mk-i-carburettor.html

Do you mean 108 needle jet? The original '68 T100(C?) carb (626/8?) and generic 626/300 would have a 106 needle jet? 
L.A.B.

Offline dynamic

  • Advanced Member
  • ***
  • Posts: 84
  • Karma: +0/-0
    • View Profile
    • Email
Re: T 100 68 carb/starting problem
« Reply #3 on: November 28, 2021, 04:32:31 PM »
my carb has  an actual pilot jet came with the 108 size purchased from a store I have used for many years with no problems

maybe I have a "dud" ? at the moment soaking it in carb cleaner before poking/blowing the pilot circuit through

will post results

Offline L.A.B.

  • Advanced Member
  • ***
  • Posts: 1529
  • Karma: +32/-4
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #4 on: November 28, 2021, 04:41:36 PM »
my carb has  an actual pilot jet came with the 108 size purchased from a store I have used for many years with no problems

The 626/300 (non-Premier Mk1) has a pilot bush, therefore, does not require a screw-in pilot jet?

http://amalcarb.co.uk/rh-26mm-4-stroke-mk-i-carburettor.html
"
Details for RH 26mm 4 Stroke MK I Carburettor

This carburettor is built to a standard specification which provides approximate settings for this bore size and carburettor type. Ideal for anyone who wants to tune their machine themselves.

Comes fitted as standard with:

3 Cutaway Slide

160 Main Jet

106 Needle Jet

Pilot Bush

"
http://amalcarb.co.uk/rebuilding-mark-1-concentric-carburetter
 "
Pilot Circuit

Mark 1 Concentrics are equipped with two types of pilot jets. '2 Strokes' use a removable pilot jet which should be replaced if it is damaged or shows signs of oxidisation. '4 Strokes' generally use a pressed in bush pilot jet in the gallery behind the pilot air screw.

"

« Last Edit: November 28, 2021, 04:51:53 PM by L.A.B. »
L.A.B.

Offline dynamic

  • Advanced Member
  • ***
  • Posts: 84
  • Karma: +0/-0
    • View Profile
    • Email
Re: T 100 68 carb/starting problem
« Reply #5 on: November 29, 2021, 08:53:28 AM »
looks like im naming the pilot jet in error so I have a 108 needle jet screws in above the main jet

Offline Rex

  • Advanced Member
  • ***
  • Posts: 1509
  • Karma: +11/-69
  • I love YaBB 1G - SP1!
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #6 on: November 29, 2021, 05:45:10 PM »
Should be below the main jet ;) and normally a 106.

Offline L.A.B.

  • Advanced Member
  • ***
  • Posts: 1529
  • Karma: +32/-4
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #7 on: November 29, 2021, 06:13:25 PM »
Should be below the main jet ;) and normally a 106.

The needle jet is above the main jet.
L.A.B.

Offline Rex

  • Advanced Member
  • ***
  • Posts: 1509
  • Karma: +11/-69
  • I love YaBB 1G - SP1!
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #8 on: November 29, 2021, 09:24:48 PM »
I was being ironic, hence the  ;)

Offline L.A.B.

  • Advanced Member
  • ***
  • Posts: 1529
  • Karma: +32/-4
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #9 on: November 29, 2021, 09:33:46 PM »
I was being ironic, hence the  ;)

Glad you said so as it made no sense to me, ironic or otherwise.
L.A.B.

Offline dynamic

  • Advanced Member
  • ***
  • Posts: 84
  • Karma: +0/-0
    • View Profile
    • Email
Re: T 100 68 carb/starting problem
« Reply #10 on: November 30, 2021, 10:00:20 AM »
after soaking my carb body in carb cleaner overnight( sealed over with clingfilm) and probing/blowing the pilot airways through re fitting carb to my machine
it started a very healthy  third kick along with a nice "purring" tickover at last
I think maybe just a small amount of debris was restricting the airways even though this is a new carb
thanks to all members input  "I am now educated"

Offline L.A.B.

  • Advanced Member
  • ***
  • Posts: 1529
  • Karma: +32/-4
    • View Profile
Re: T 100 68 carb/starting problem
« Reply #11 on: November 30, 2021, 10:19:29 AM »
I think maybe just a small amount of debris was restricting the airways even though this is a new carb

It's not unknown for a new carb to still have some debris in it, however, modern fuel also blocks the pilot bush if the bike isn't started for a couple of weeks when fuel has been left in the carbs so I occasionally have to clear a pilot bush (see Bushman's link, below).

http://www.bmoc.ca/Tech%20Info/Bushmans%20Carb%20Tuning%20Update%202015.pdf
 
« Last Edit: November 30, 2021, 10:21:47 AM by L.A.B. »
L.A.B.

Offline dynamic

  • Advanced Member
  • ***
  • Posts: 84
  • Karma: +0/-0
    • View Profile
    • Email
Re: T 100 68 carb/starting problem
« Reply #12 on: November 30, 2021, 12:05:44 PM »
thanks for the info LAB intresting read    4*here will ride till I cannot feel my feet