Club Triumph

Hello Willows,

I agree about the timing as regards to getting an optimum setting.
However, as this discussion is about idle speed it seemed to me that you were suggesting it as a way of controlling the idle?

Alec

Willows
critic not intended , just trying to get  the basics identified before going deeper
there, s lots of suggestions

we cant have dave changing a cam when its something simple

pete

On Friday I will be :-

Fitting a new rocker cover with a good fitting oil filler cap
If no change
Blocking off the end of the servo pipe to eliminate possible servo leak.
If no change
Blocking off both carb - rocker pipes to eliminate any air leak there
If no change
Adjust the timing to 8 before instead of 12
If no change
Remove carbs and check both butterflies are shutting properly
If no change
Fit a 25d dizzy instead of the current 45d and set it as per book
If no change
Say Bollocks and go for a curry


Spoke to Andrew turner today and he said there's only one size diameter of jet and needles for HS6 carbs, different profiles of needles obviously but only one base diameter of jet
I also need to check that I have the correct float bowl chambers
He also mumbled on about advance curves affecting idle and smooth running

Dave, sounds a plan  providing theres no side slop wear on the dizzy cam  spindle cant see why a 25 will work any different to a 45 type,  unless one has some defects.

a thought about advance and idle

   Timing is normally at a slow idle  600   with vac off so there is no centrifugal or vacuum having any effect on the static setting so there should not be on any curve.
  
Burlen list if I read right hs6 on a 2.5 triumph can have 0.9,  0.1 and 1.25 dia jets depending on the specification   hence the question

have a good weekend twiddling   good luck

pete

Hello Pete,

no, not for HS6, 0.9 jets for the 4 series carburettors, 1.0 for the 6 series and 1.25 for 8 series carburettors (Never fitted to the Triumph as standard)

Alec

Is it possible to (accidentally) use HS8 jets in an HS6 body?

Hello Rob,

good question, that would be interesting? A quick look at my S.U. manual didn't seem to give an answer. Incidentally the manual has two A4 sized pages of different jet types making it easy to make a mistake if picking up second hand jets.

A correction, some 8 series carburettors use the 1.0 jets also, as well as 1.25 jets.

Alec

After my experience, I'd still suspect the jets are worn. Very difficult to see by eye.
Tony.

as with the topic strange,   on tablet it lists all 3 sizes per engine size  hs6,      on laptop its drops down a individual list for each spec ( more as expected0  

need to go to spec savers

Pete

Fitted my ally rocker cover only to find the rockers are hitting it so the old one with a slightly dodgy filler cap must go back on 😒
I'll blank the breather hose off to by pass the possible loose fitting cap  


Are HS4 float bowls interchangeable with HS6 ones

Hello Dave,

yes HS4 and HS6 bowls are interchangeable.  In all your work, did you try forcing the throttle spindles closed and did that alter the idle speed?

Alec

Hopfully I've fixed my bathroom leaky roof and hopfully I've re sealed my shower cubicle 😊
As I got my jobs done later than I thought i only had a little play time,tomorrow I'll attack with vengeance between the rain showers.

Today I've reset the tappers,I'm happy there now good.
Buggered about with the rocker cover,I'll get a new cap now I've re bent the housing for the cap.
I had quick look at the float bowls and they look the same,the front one I believe is supposed to be slightly higher on the mount to compensate for the slant of the engine. I have a set of HS4 in the shed so I might be able to use one of those

All jobs for tomorrow

Gday Dave, the REAR float is meant to be higher, by approx. 8mm. The HS4 bowls are maybe?  the same size but I don't know about the different heights etc. Maybe check the part numbers to confirm
Rod

I thought the float bowls differed in height by measuring from the top,top lip to mounting shaft but having looked at the HS4's I see the difference is measured from the bottom of the bowl.
The HS6's may well be ok.

Hello Rod,

"Gday Dave, the REAR float is meant to be higher, by approx. 8mm"

Are you sure, that's a huge height difference? The only difference between the front and rear carburettor is the location of the float chamber, so the front carburettor has it forward and the rear has it backward,  The difference in fuel level due to engine inclination on those float chambers must be relatively small?

Alec

Interesting trip to work, having buggered about with the rocker cover and oil filler cap yesterday I found it refused to idle for the first couple miles to work, stalled at every set of lights.
On arrival at work the tickover was still quite lumpy but it was about 5-600 with the non charge light on, so I've now got to turn the idle up 😳
The oil filler cap still wasn't a good tight fit but I've now fitted one that is but due to the fact it's pissing down I've not been out for a drive yet but hopefully it's even better.
Now the tickover is slower I'll re set the timing just incase the fast idle was giving a false reading as the bob weights may have been moving.
I also want to put some jubilee clips onto the three way joint on the pipes going from carbs to rocker cover, carb and rocker cover ends have clips and are tight but there is slight movement at the junction.

With the tickover at a lumpy 600 ish,the engine still "ran on" a bit am I correct in thinking that means it's too lean on the mixture

So in short (ha ha) I'm getting there 😀

Everything is now airtight and the engine will stall if the idle screws are wound up enough, so that's all good.
However the idle is still to lumpy, I'm now all out of ideas. I've done everything I can think of and all that's been sugested.
Pulsing in the exhaust suggests to me it's a timing issue, I think I'm getting "timing scatter"
Play in the dizzy shaft is minimal although I have a 25d with pratacly no play that I'll fit later(waiting for bits) seems to make no diference if vacume is connected or not. Using a timing light the "mark" seems to jump every now and then, steady for a while the jumping then steady again. When driving the engine pulls well, it's just the idle that's not right.

Inlet manifold leak, findable with an inflammable spray in small quantities around the edges.

OR, butterfly leak, either poor fit in throat, or that the spring loaded leak buttons are jammed, one way or the other.

John

John
All nuts are tight and I've sprayed stuff everywhere and there's no change in the way the engine idles.
I refurbed the carbs and the butterflies are completely shutting.
I am getting quite strong pulses out of the exhaust which I've always been led to believe is incorrect timing

Exhaust
http://youtu.be/NbwWlwnGdEs

Engine
http://youtu.be/d9oc_qimPyk