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TR7 Idle RPM Adjustment

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TR7 Idle RPM Adjustment
#1
  This topic is about my 1980 Triumph TR7 Drophead
PZ01100 Michael Bogatay
Kennesaw, GA, USA   USA
My '80 TR-7 is idling at just over 1,000 RPM even after being warmed-up and that seems high to me.
1. What should the idle RPM be at initial start-up and after being warmed-up?
2. How is the idle RPM adjusted?
3. Being a neophyte at this, where are the carb adjustments physically located?

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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR7 Drophead "The Great Pumpkin"
1980 Triumph TR8 "Wedgie"
In reply to # 1450936 by PZ01100 My '80 TR-7 is idling at just over 1,000 RPM even after being warmed-up and that seems high to me.
1. What should the idle RPM be at initial start-up and after being warmed-up?
2. How is the idle RPM adjusted?
3. Being a neophyte at this, where are the carb adjustments physically located?

Michael:

Here is the factory carburetor training manual. It covers all the various carburetor settings. I hope yours is carbureted, and not injected, or this will be of no help whatsoever. tongue sticking out smiley

Vance



1980 Platinum Metallic TR8, frame off restoration, complete.
1980 Vermilion TR7 Sprint replica, in progress.

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ozkippy Michael Kip
Emerald, Victoria, Australia   AUS
1976 Triumph Stag "Staglet"
1978 Triumph TR7 "Yellow Wedge"
1979 Triumph TR7
Vance,
I don't think I have that manual so thanks for sending the link and I shall save to the library. smiling smiley


I started reading the manual knowing that I know all of this but it will be interesting till by page whatever I was ready to slash wrists with the complexity that was required by the times. OH Dear I do feel sorry for the guys who had to work on these things at the time and do it again and again as invariably stuff fail in use.
I am spoiled by modern cars and sort of amazed that we all still play with these old simple things that , to be compliant of regulation, are really complex. Oh dear!!!!!!!!

Michael

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dhuddleson Avatar
dhuddleson David Huddleson
Manotick, ON, Canada   CAN
For a Stromberg TR7 in USA or Canada, the idle speed should be around 800rpm. If the idle hangs up above 1000rpm, the first thing to investigate is the vacuum retard to the distributor. Stock TR7 in North America have a retard for emission purposes, and there is vacuum at idle speeds. If the vacuum is present in the line/hose, then connecting to the capsule on the distributor should result in an immediate drop in engine speed. Does that happen? That's where I would start if you still have a mostly "stock" configuration for your TR7.

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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR7 Drophead "The Great Pumpkin"
1980 Triumph TR8 "Wedgie"
In reply to # 1451113 by ozkippy Vance,
I don't think I have that manual so thanks for sending the link and I shall save to the library. smiling smiley


I started reading the manual knowing that I know all of this but it will be interesting till by page whatever I was ready to slash wrists with the complexity that was required by the times. OH Dear I do feel sorry for the guys who had to work on these things at the time and do it again and again as invariably stuff fail in use.
I am spoiled by modern cars and sort of amazed that we all still play with these old simple things that , to be compliant of regulation, are really complex. Oh dear!!!!!!!!

Michael

Simply stated, there are four adjustments for idle speed;

1. Idle speed adjustment on the carb. Well, duh! A simple screw driver adjustment if you know which screw to twist. tongue sticking out smiley If that won't dial it in low enough then...
2. The choke. Your car will have a FASD (Fully automatic starting device). Put your thumb over the FASD air inlet after the car is warmed up and idling (inside the air filter housing, between the carburetors). Does the idle speed drop? Then your FASD is sticking in the on position. Some carburetor cleaner usually gets them working again.
3. Deceleration bypass valves. These go out of adjustment when the carbs get old. Check the manual, but this is very often the source of high idle speed, or sometimes a very reluctant drop in idle speed as you come to a stop. The engine GRADUALY slows down, taking up to 10 seconds to drop to idle. Both carbs will need to be adjusted separately. The rear carb is all but impossible to adjust unless you have hands the size of a baby's. I hope you have small children that you can press into service for this task.
4. Ignition timing. Use a timing light and disconnect the vacuum capsule on the dizzy. Set timing to 10BTDC, adjust the idle to 800. The manual says to leave the vacuum connected to the dizzy, but by now many (most?) of the vacuum capsules have died which affects the timing. Disconnecting the vacuum eliminates that as a source of difficulties and confusion when setting the timing. Reconnect the vacuum when finished, and readjust the idle speed if necessary.

This is why you bought the car, yes? To discover, learn, bark a few knuckles and occasionally drive. At least that is why I like owning a British car....

Vance



1980 Platinum Metallic TR8, frame off restoration, complete.
1980 Vermilion TR7 Sprint replica, in progress.

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bcbennett Avatar
bcbennett Gold Member Brad B
Abilene, TX, USA   USA
Vance, I wish to publicly state that you are VERY helpful. Your posts on so many of these boards help me so much. Thank you.

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AroostookTR7 Avatar
AroostookTR7 Keith Brown
Washburn, ME, USA   USA
1980 Triumph TR7 Drophead "Geraldine"
Thank you for posing this question.

I too have a 1980 TR7 drophead, and it is also idling too fast. I plan on tackling the issue this weekend.
I am curious to know if you solved your problem.

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sliproc Avatar
sliproc Kevin Quistberg E
Long Beach, CA, USA   USA
From time to time over the years I had the high idle problem, as stated above around 800rpm is the sweet spot, what usually fixes the problem for me is to remove, disassemble, and clean the deceleration bypass valves. It's the easiest fix and usually solves the problem. Ironically right now my idle is running low (500 to 600rpm) I just haven't gotten around to messing with it.

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AroostookTR7 Avatar
AroostookTR7 Keith Brown
Washburn, ME, USA   USA
1980 Triumph TR7 Drophead "Geraldine"
Thank you for your advice regarding cleaning the bypass valves ! This seems to have corrected my problem. What a battle getting at the back unit, however.

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sliproc Avatar
sliproc Kevin Quistberg E
Long Beach, CA, USA   USA
Keith,

If you wanted easy you should have gotten a Prius.

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AroostookTR7 Avatar
AroostookTR7 Keith Brown
Washburn, ME, USA   USA
1980 Triumph TR7 Drophead "Geraldine"
And miss all this fun ? No way.
Taking on the engine temp gauge and turn signals next.

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Pine City, NY, USA   USA
Let us know how you get the wire reattached to the censure

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