Norton Motorcycle Tech Talk

Home

Printer-friendly copy
Online Resources
Norton Manuals / Dyno Dave / MotoCycles.com / Daytona Bike Week
Top Norton Motorcycle Tech Talk Forum Topic #1435   Previous topic | Next topic   
captainSun Apr-03-05 10:28 PM

  
"need carb adjusting screws help"


  

          

Can someone out there advise me on how many turns out ( counterclockwise) the pilot air screws and the throttle adjustment screws should be, in order to get my 750 combat to fire for the first time in 7 years ? I am believing that all other parts and systems are ready. thanks in advance. I am hoping that with this info I will get it running and not need additional advice. thanks again, captain ps it has two 32 mm amals

  

Alert Printer-friendly copy | Reply | Reply with quote | Top
andersonMon Apr-04-05 12:40 AM

  
#1. "RE: need carb adjusting screws help"
In response to Reply # 0


  

          

Look at

http://www.hitchcocksmotorcycles.com/amal/index.php

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

MichaelBMon Apr-04-05 11:50 AM
Member since Mar 18th 2009
174 posts
Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#2. "RE: need carb adjusting screws help"
In response to Reply # 1


  

          

I always count in 1/2 turns. I use (3) 1/2 turns on the pilot, or 1 1/2 full turns.
Regarding the idle, after synchronizing the slides, I set the throttle screws to the bottom of the slide and screw in (1) 1/2 turn, or 1/2 full turn.
Good Luck, let use know.

Mike

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captTue Apr-05-05 10:11 PM

  
#3. "RE: need carb adjusting screws help"
In response to Reply # 2


  

          

Michaelb, how does one set the throttle screws to the bottom of the slide??? capt

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

MichaelBWed Apr-06-05 07:32 PM
Member since Mar 18th 2009
174 posts
Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#4. "RE: need carb adjusting screws help"
In response to Reply # 3


  

          

Remove the air cleaner. You can watch the slide raise and lower as you adjust the screw. Back it off till slide bottoms. Then in 1/2 turn.

Mike

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

MichaelBFri Apr-22-05 09:57 AM
Member since Mar 18th 2009
174 posts
Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#5. "RE: need carb adjusting screws help"
In response to Reply # 4


  

          

Hey Captain, you ever get that thing running?

Mike

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captainSun May-01-05 06:49 AM

  
#6. "RE: need carb adjusting screws help"
In response to Reply # 5


  

          

I stopped trying to get my 73 combat running because the kick pedal broke. However, I am about to resume working on it within the next 3 to 5 days. I have new float needles. I cleaned and blew out( with compressed air) the carbs. I will check compression with gauge. I have new wires to go from and to the points.( the white/black yellow/black wires).I will adjust the valves again, then I will set the points again.And then I will use special washer to hold cam in place as I turn flywheel to tdc and TRY to set the ignition timing. I am not CERTAIN that the above is the correct sequence to follow and I am a bit unclear as to the static timing procedure. I forgot to mention I will try to initially set the carbs as you all have been advising me on this forum. If, you or anyone else reading this has any advice or corrections regarding what I have said here please let me know. I will post my progress and or requests for advice. Thank you all for being so helpful and patient. You've all been an encouragement, even when reading posts to others not just to me. , captain

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

dynodaveyMon May-02-05 08:38 AM

  
#7. "RE: need carb adjusting screws help"
In response to Reply # 6


  

          

I would be locking the AA unit in the full advanced position and setting the crank to 28º rather than TDC....
then get the points to just open

HTH

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captainMon May-02-05 09:09 AM

  
#8. "RE: need carb adjusting screws help"
In response to Reply # 7


  

          

I will do that, dave, thanks, capt

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

MichaelBMon May-02-05 08:32 PM
Member since Mar 18th 2009
174 posts
Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#9. "RE: need carb adjusting screws help"
In response to Reply # 8


  

          

Synchronize and adjust your throttle and choke cables. I mentioned 1/2 turn for the throttle stop on previous post. I like to use this number because I usually am not using a choke and like to have the slide in a lower position to act as a choke. I am also experienced in starting Nortons.

It probably won't idle at 1/2 turn. The real number is probably around 1 1/2 turns. I just did a set on a good running 850 and it's about 1 1/4 on the air screw, with the idle set about 1 1/4 also.

Good luck, let us know.

Mike

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captTue May-03-05 06:06 PM

  
#10. "RE: need carb adjusting screws help"
In response to Reply # 9


  

          

thanx mike, capt

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captainFri May-06-05 06:23 AM

  
#11. "RE: need carb adjusting screws help"
In response to Reply # 10


  

          

Help! I HOPE I just need to properly adjust valves on 72 combat is that possible??? I have no compression... What next????? I'll try not to panic , what say ye?????? the captain

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

dynodaveyFri May-06-05 06:55 AM

  
#12. "RE: need carb adjusting screws help"
In response to Reply # 11


  

          

If you turn the engine over by hand....
When the RH valve is down(open), do you have clearance on the LH valve, and vica versa. both for intake and exhaust...?

If you have not adjusted them yet...are the valve clearances extra large (stuck open/bent valves)?

you may only get 100-120psi(kicking) on a combat due to the hotter cam overlap, in theory dynamic is closer to 190psi.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

MichaelBFri May-06-05 09:03 AM
Member since Mar 18th 2009
174 posts
Click to send private message to this authorClick to view this author's profileClick to add this author to your buddy list
#13. "RE: need carb adjusting screws help"
In response to Reply # 12


  

          

No compression??? As in zero, zip, nada??? Or do you mean very low compression?
Is the crank turning? Are the valves operating? If so, Dave's advise of course is right on. If there is movement in the rockers, obviously the vales are closing. If they are tight, go ahead adjust to 8 & 10.
Still no compression?? You've got trouble.

Mike

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captainFri May-06-05 05:29 PM

  
#14. "RE: need carb adjusting screws help"
In response to Reply # 13


  

          

I will take the valve covers off and see what's happening. Thanks for the advice. I will post my findings.

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

CAPTAINSat May-07-05 10:30 AM

  
#15. "RE: need carb adjusting screws help"
In response to Reply # 14


  

          

No compression after setting valves. I put a teaspoon of 30 Wt oil in each cylinder (would 90 Wt after soaking make a difference)? I guess I can try that, but am I facing a valve job? or????? I will await advice before proceding with 90 wt oil into spark plug holes, or any further action. What do you advise/ is there still hope short of engine overhaul?? capt

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

ahSat May-07-05 09:29 PM

  
#16. "RE: need carb adjusting screws help"
In response to Reply # 15


  

          

It's difficult from your posts to understand whats been done to your motor. Has it been taken apart and put back together? Was the timing chain replaced? You should be able to cycle the motor manually with the plugs out, the valve covers off and watch the four strokes and the valves operate. You can see the pistons move with a flashlight. And / or you can carefully , I repeat carefully probe the pistons position with somthing like a plastic straw.

alan

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captainSun May-08-05 09:42 AM

  
#17. "RE: need carb adjusting screws help"
In response to Reply # 16


  

          

Hi alan, I never personally have had this bike started. I did have exhaust threads repaired and replaced head gasket at that time. I also replaced timing chain bexcause old one was stretched. I replaced coils , points, condensors, cleaned stuck clutch and dirty carbs, replaced plug wires and plugs and bad auto advance. I feel that I was careful and followed manuel as these steps were taken. But...??? I'd be relieved if I just need to go back in and say perhaps adjust timing chain or something more simple and less involved than an engine rebuild. capt

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

AHSun May-08-05 10:33 PM

  
#18. "RE: need carb adjusting screws help"
In response to Reply # 17


  

          

Again I think you need to pull the plugs and valve covers off , than using the kickstart lever turn the engine and watch the 4 strokes making sure the valves are opened and closed when they are supposed to be.

alan

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

captainMon May-09-05 08:00 AM

  
#19. "RE: need carb adjusting screws help"
In response to Reply # 18


  

          

Hi Alan, I am going to do what you suggest. Should I use kick lever for turn over or is turning rear wheel okay? I usually turn rear wheel by hand. Would you please explain clearly to me just when are the valves to open and close? What an I to look for or hope to see?? The last time I had valve covers off I did not even look at inpection hole with 28 degree mark. I turned rear wheel by hand with bike in 4th gear. I watched left inlet rocker go down to what appeared to be it's bottom out point and set rt inlet at 0.008. Then I disd same with rt side inlet before doing left then rt exhgaust settings at 0.10 inches. ( something that might be of importance though, I recall that with the exhaust rockers when I was setting it to 0.10 that it would have "play" in it if I nudged it with my index finger. In other words it would be set @0.10 with gravity but @ a wider gap with a tiny touch , maybe as much as to measure 0.12ish or so?? Is this abnormal?? ) I want to start all over with a fresh start from scratch to check points gaps , valve adjustment, compression etc but I don't know where to begin to start from beginning !Help me please, I want to ride this bike. capt

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

AHMon May-09-05 10:22 AM

  
#20. "RE: need carb adjusting screws help"
In response to Reply # 19


  

          

I'm just guessing, but I think your cam timing is off, Probably by 180 degrees. You discribe the propper proceedure for setting the valve lash, But I would set for gap so it just nips the feeler gauge.

You can turn the motor either way. As the pistons move to the top of the stroke One cylinder is getting ready to fire, intake valve open and the other is pushing out exhaust gas, exhaust valve open. You need to determine that the valves are opening and closing properly to make this happen. You want the motor to fire , points open at 28 degrees. Follow dynodave's proceedure. I would urge you to buy a manual, and parts list.
alan



  

Alert Printer-friendly copy | Reply | Reply with quote | Top

AhMon May-09-05 11:06 PM

  
#21. "RE: need carb adjusting screws help"
In response to Reply # 20


  

          

Sorry to all for my poor erronious description of the 4 stroke internal combustion engine.
alan

  

Alert Printer-friendly copy | Reply | Reply with quote | Top

Top Norton Motorcycle Tech Talk Forum Topic #1435 Previous topic | Next topic





Norton Commando Oil Change