Author Topic: RD125 Teikie TK18 carb overhaul  (Read 719 times)

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Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #30 on: May 30, 2018, 09:21:10 PM »


  ust a quick update,not had time to work on the carbs,but I have been researching the interweb,

maybe I should change the carbs for modern ones ?

 well by using Yamaha CT1 manifolds ( 314-13565-00)  still a stock item at CMSNL.com.it is possible to mount
Mikun VM20-273,but these only are adjustable with MJ and Pilot jets,and maybe 4 needles,no new slides .

 but was reccomended Dellortos ,PHBG 20AS,ref R2527,these are cheaper to buy,with much more adjustments ,only issue
is the mounting,it uses a stub,I am going to inquire further if it can be used using rubber hose to fit to manifold,a local engineering company already told me,do some basic drawings and they will fabricate 2 new manifolds .

hope to get to work on the carbs friday PM,

 will let you know whats happening,
lifelong rider,laterly with Honda,now a little RD as well

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Offline 5port

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Re: RD125 Teikie TK18 carb overhaul
« Reply #31 on: May 31, 2018, 09:13:43 AM »
Well, Niche cycle showing the VM20 for $85, with 2.0 Slide.  It is possible to cut slides larger so, 2.0, 2.5, 3.0 etc could be made from the 2.0.   :)  As for Needles and Needle jets, Allens performance listing quite a few with stock level above 2.  Only real issue, I do understand you here, if the range available is incomplete you can bet the one you want is unavailable!   :'(
However, if you think the available options cover your needs, it might work well!  :)

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Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #32 on: June 01, 2018, 05:00:03 PM »


  back to the original subject,stripped both carbs ,squirted carb cleaner trough all holes,cleaned all jets ,re-assembled ,
and started the motor,
runs better,even with aircleaners fitted ,R/H plug dark nut brown,L/H still dark grey.but it seems an ignition issue on the
L/H side,missing underload above 6.5K.
 new plugs ordered ,and plug caps ,points checked ,no sparking at the points so I assume the capacitors are OK,

  maybe next job is swop the leads to the coils,and see if the problem switches

 so,maybe the carbs are better than I thought

 let you know what happens after I get new plugs etc  fitted
lifelong rider,laterly with Honda,now a little RD as well

  1355

Offline 5port

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Re: RD125 Teikie TK18 carb overhaul
« Reply #33 on: June 01, 2018, 07:31:59 PM »
Good to hear.  :)

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Offline tony2stroke

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Re: RD125 Teikie TK18 carb overhaul
« Reply #34 on: June 02, 2018, 12:22:55 AM »
Great news  :)

Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #35 on: June 10, 2018, 07:49:07 PM »
latest update ,

 after checking carbs and cleaning ,testing ignition coils ,one was as low as 3.5ohm,so I replaced both,new plugs ,fitted Y64 needles ,
the RD is now revving up to 9.5K

 plugs are not reading the same ,R/H side is perfect,clean and with a pale center electrode,L/H still grey,but clean grey,
I seem to be having points issue,the heel is wearing minutely ,so closing the gap and retading he timing,not sure if
I should let the heel bed in,or replace with a new set .



  it really sounds great going up through the gears and changing at 9.5K !!


lifelong rider,laterly with Honda,now a little RD as well

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Offline tony2stroke

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Re: RD125 Teikie TK18 carb overhaul
« Reply #36 on: June 10, 2018, 08:34:21 PM »
Its harder to tell with new plugs, put the old ones back in just to double check, Grey is worrying, you are looking for a nice brick brown colour,.

Check your cam wheel on auto advance retard for any roughness, should be smooth as, are they old points.

Offline 5port

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Re: RD125 Teikie TK18 carb overhaul
« Reply #37 on: June 10, 2018, 08:35:08 PM »
Very good to hear you have it running well!  Cheers

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Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #38 on: June 10, 2018, 08:39:32 PM »
Its harder to tell with new plugs, put the old ones back in just to double check, Grey is worrying, you are looking for a nice brick brown colour,.

Check your cam wheel on auto advance retard for any roughness, should be smooth as, are they old points.

  the timing is fixed on this engine,and the cam is a remanufactured item,the R/H side points seem to have bedded in ok,

it is now running with airbox,filters and full inlet ducting in place
lifelong rider,laterly with Honda,now a little RD as well

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Offline tony2stroke

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Re: RD125 Teikie TK18 carb overhaul
« Reply #39 on: June 10, 2018, 10:30:02 PM »
Glad your getting somewhere with it now  :)

forgot 125 is fixed

Offline Barnett

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Re: RD125 Teikie TK18 carb overhaul
« Reply #40 on: June 11, 2018, 08:23:48 PM »
you got the little felt cam lube pad in there John? pump oil into it!
great its now revving out.
running mine in at the moment, engine very tight.
Yamaha 1974 RD125 (AS3) nearly finished!
Kawasaki 1977 z650 B1 being ridden
Yamaha 1972/3 U.S. early RD350 in bits

Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #41 on: June 11, 2018, 08:28:40 PM »
you got the little felt cam lube pad in there John? pump oil into it!
great its now revving out.
running mine in at the moment, engine very tight.

I have been using High melting point grease ,but I can use engine oil on the pad,thanks
lifelong rider,laterly with Honda,now a little RD as well

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Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #42 on: June 14, 2018, 05:05:15 PM »
  interesting developement,

  all carb settings as normal,including filters ,
 

 after running last time ,the RH pot was perfect,LH was grey.


 so I checked timing,turns out the RH was slightly more advanced than reccomened ,but it ran beautifully,
so I set the lh pot the same ,not using a dial gauge,but the marks on the stator ,,it worked out about 4mm before the indicator ,checked using a bulb ,

 result,it runs and screams out the revs ,as I remember ,revs hard,even seems to pull lower down,


 I am taking care not to get detination,and piston burning,if I feel its getting to hot,I may try B9hs plugs ,

 but I am cautiously happy ,its a rev hungry nut twin,just as I remember

 more news as it comes

  another thought,is modern petrol different from early 70's stuff,?  does it have a slower burn rate ? I know Spa MC in Cheltenham say they mod the motors for modern fuels ,
 do we have a chemist? or petro-chemical engineer on the site that can explain ?



  after asking Mr Google,I found a U S A based article ,that seems to explain about tuning older motors using modern fuel,
 check this link,and comment please

   https://www.hemmings.com/magazine/hcc/2012/04/Give-it-the-gas-/3711201.html
« Last Edit: June 14, 2018, 05:28:02 PM by Johncb500 »
lifelong rider,laterly with Honda,now a little RD as well

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Offline 5port

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Re: RD125 Teikie TK18 carb overhaul
« Reply #43 on: June 14, 2018, 05:30:53 PM »

  interesting developement,

  all carb settings as normal,including filters ,
 

 after running last time ,the RH pot was perfect,LH was grey.


 so I checked timing,turns out the RH was slightly more advanced than reccomened ,but it ran beautifully,
so I set the lh pot the same ,not using a dial gauge,but the marks on the stator ,,it worked out about 4mm before the indicator ,checked using a bulb ,

 result,it runs and screams out the revs ,as I remember ,revs hard,even seems to pull lower down,


 I am taking care not to get detination,and piston burning,if I feel its getting to hot,I may try B9hs plugs ,

 but I am cautiously happy ,its a rev hungry nut twin,just as I remember

 more news as it comes

  another thought,is modern petrol different from early 70's stuff,?  does it have a slower burn rate ? I know Spa MC in Cheltenham say they mod the motors for modern fuels ,
 do we have a chemist? or petro-chemical engineer on the site that can explain ?

Great.  As far as running 9's, why not? They are a colder running plug and that is safe.  The worst that can happen is they oil up.
As far as fuel goes,...It is all different and always has been!  It is always a mix that just conforms to the standards set, which is Octane level, ie resistance to detonation.  More recently, there are limits on lead, sulphur, water and Ethanol etc.  I set my bikes to original spec but, I am careful not to run any advance beyond the stock figure and, I stick to Premium unleaded.
BTW, not claiming special knowledge on this.  ;)

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Online Johncb500

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Re: RD125 Teikie TK18 carb overhaul
« Reply #44 on: June 15, 2018, 04:23:19 PM »



  went for a run today,after a quick run,and plug chop,plugs not to bad the LH pot still running cooler ,

 then a run on various twisty roads ,running between 5 and 9,5 K rpm the motor seemed to feel better ,

 ever passed a few cars ,screaming in 3rd,4th and top ,

 then a nice BLAST down a slight slope ,holding 9.5K in top at over 70mph indicated ,maybe clearing out the old pipes .

 quick check when I got back,the LH points may have closed slightly,so opened them to match the RH set.

 plug pic,the RH plug is on the left !!!!
lifelong rider,laterly with Honda,now a little RD as well

  1355