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Triumph TR6 - idle stuck at 1300

Just when things were going so well : )

Idle seems to get hung at around 1300. I fiddle with idle screws to get it down then shortly thereafter it runs up to 1300 and stays there at idle.
Maybe a vacuum leak?
Choke is all the way off.
I did try all the normal culprits with carb cleaner and propane no luck at throttle shafts, manifold.

Otherwise engine runs great.

I did try search function, I must be doing something wrong when I search, I can't believe I'm the only one to have had this problem in the TR6 group : )
Ian Kinaid

Ian:
Don't know what year, but if a later TR6, did the hose disconnect from your vacuum retard? I often knock mine loose without knowing it.
Keith
Keith

Thanks Keith, 70 TR6 ZS setup, yup checked connections
to dizzy, all ok. also checked bypass by blocking off no difference.
Ian Kinaid

Could be the by-pass valves, or those pesky temperature compensators. I'm in the process of blocking off the compensators - should know how it works tomorrow. I don't recommend blocking off the by-pass valves. I had a very bad running engine after doing that - even after adjusting the mixture as has to be done.

If not - squrit some WD40 or comparable light oil on the shaft/body area - if that effects the idle a shaft seal leak is the likely cause. Time for a rebuild, then.
Brent B

I blocked off my BPV's last weekend and what an improvement. Rock steady 850 idle, great engine breaking/decceleration. Highly recommended particularly since it's such a simple mod.

Rick O.
Rick Orthen

Ian,
When I decided to block off ONE of my BPVs, it was because of high idle. When I had both idle screws backed off completely, I was also around 1300 or 1500. I checked with the garden hose trick (listened to the airflow into the carbs-it really works), and it was obvious one carb was sucking way more than the other.

When I put my hand over part of the faster carb, the idle came down. I knew the throttle plate was closed, so I figured the only other way to get anything to the manifold was thru the bypass so I blocked it. Like Rick, I'm very happy with results. The other BPV is behaving and still in use.

Another thing worth checking is whether the linkage needs adjusting. It happened to me once, that one carb's idle screw was at the stop, and the linkage was a little twisted which held the other carb open a little.

Hope it helps.
Mark
Mark H

If you're pretty sure all components are sound and the throttle shaft seals are ok, the problem could be something that keeps the butterfly from closing completely. I just had to file 1/16" or so metal off the throttle shaft cam because the interference where it contacted the float chamber vent lever kept the butterfly ever so slightly open. Now it idles down nicely! See the end of Part I of the Buckeye carb write-up if you don't know where the vent lever is.
Brent B

You guys were right about BP valves. took both apart found a small lead bb in rear carb????
I had only taped off front carb as this was easiest,no change. then broke down and pulled rear carb as you guys correctly hinted as most probable culprit.
Must have gotten in there from rebuild I had sent them out for in December. Anyway cut solid gaskets to block permanently. idles back down to normal 850-950 now have to readjust everything again : ) all good fun.

Thanks.
Ian Kinaid

Happy it worked for you Ian. Just for future reference, it is possible to remove the rear BPV with removing the carb; just unhook the throttle linkage and break out your stubby screwdriver.

Rick O.
Rick Orthen

Actally, you don't have to remove anything. I'm lazy so always look for the easiest way. With a long thin screwdriver, it's almost a straight shot from beneath the front carb to the screws of the rear BPV. Did both (front and rear) in 30 or 40 mins.
Peter Gooch

This thread was discussed between 22/05/2003 and 28/05/2003

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