Twin HS2 Carb needles

Started by Hercplt, October 27, 2019, 11:14:06 AM

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Hercplt

Interesting... thanks.

Just trying to get it drivable... gonna have to seek out someone to weld in the port for a WB at some point.
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Hercplt

 50.gif :-[ 8.gif

I am at a complete loss... Cold it will start with some choke, but not without a bit of cranking.  I have richened it out (AH2 needles but still with blue spring), and at idle it misfires, and misfires under load on the road.  Brief moments of smooth but not really.  Warm (hot start), the only way to start the car is to have someone crank and I physically lift up the carb pistons until it lights up... then idles misfiring.

Everything is new.... everything is connected etc... no valves sticking... plug gaps by the book .032

Driving, I can tell that it just wants to fly.... but is misfiring all over the place...

WTF.   9.gif
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

MiniDave

Did you say you have an HIF44 too? Put that on and see if it runs OK?
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Hercplt

That may be the next step... but I mean there has to be a way to get twins to work on what is essentially a warmed up 998 Cooper....

How far out does the timing have to be to cause the misfiring?  It runs well enough to think that the timing is pretty close...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

94touring

Misfiring may be more on the ignition side.  Too retarded will pop out the carb and cause lousy driveability.

Hercplt

Advanced being further BTDC? and retarded being closer to TDC or ATDC?
To advance the timing, i'm rotating the dist clockwise?
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

MiniDave

Yes, clockwise.....to advance

I was only thinking that if it ran good with the HIF44 you could rule out everything else. Likewise, if it ran the same with the HIF44 your problem is probably not the twins.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

94touring

Timing gun is ideal but you can get in the ballpark by rotating the dizzy clockwise to get the rpms to rise.  Once the rpms begin to drop the further clockwise you go, turn it counter clockwise to drop the rpms approximately 250rpms. 

Jimini II

Have you checked the distributor and coil?
A lot of problems that you may think are carb related are sometimes ignition problems.

Hercplt

Dist is brand new... Accuspark Electronic (45D), just replaced the cap as it was faulty.  Coil looks great.  Its an "Intermotor" sport coil from Moss.  3ohm 40Kvolt type.  How would I test if to see if it is good or not?
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

94touring

Plug wires in the correct firing order?

Hercplt

1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

94touring

Have the old coil to swap in to see how it runs?

Hercplt

Nah, the old coil was last used in 2006 when it was last on the road...  I could buy a new one and see, but that seems expensive.  I have no reason to suspect this coil is bad, but don't know how to check either.
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Hercplt

By all accounts this should run...

I moved the ground strap to a better location... no change.  Spark everywhere, but still misfiring at all times (idle, cruise and bad under load).... gonna borrow a timing light... ugh...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

MiniDave

OK, back to basics, run compression.....check valve clearances.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

Hercplt

Valve clearances were a bit tight, at .008  I brought them back to .012 per the book.

Carbs appear to be doing what they should.. I don't have a test gauge for compression... so more to follow.  When running and I remove the plug leads in sequence, nothing really changes in the misfire... just RPM drops a bit as you'd expect.  The Leads are in the right order... the timing is pretty close that it wouldn't be causing it... Coil tests fine (3.0oms and 98koms).

Back to the AH2 needles with stronger springs, it actually got worse.

I just don't get it...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

94touring

Vacuum leaks along the manifold?

Just for comparison here's the difference between your needle choices.  Nothing too crazy.


Hercplt

Yeah I did the same comparison... I don't think its the carbs.

It runs like its misfiring across all 4, but still running.  Absolutely now power at all... under load put the throttle even down a bit, and it just sputters and farts.  Nothing...
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Hercplt

Is it possible for the coil to test fine... but still be bad?
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

94touring

I'm sure it's possible. 

Verify this also.  Only takes a second.


Hercplt

yup.  checked that... firing order is fine.
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

MPlayle

Distributor advance not operating correctly?

Oil in the carb dashpots?

Just tossing out a couple ideas about things that have been known to have similar symptoms.


Hercplt

Dashpots have oil...
The distributor is new... (accuspark).  Not sure how I would check that, but I suppose its possible.
1980 Mini 1000 (Canadian Spec).
998cc +60.  12G295 Head (ported, skimmed etc), VP7 Cam, Twin HS2.... sweet sweet 7.5" Cooper brakes!

Jimini II

Do you have the old distributor to try?