Jump to content

High Tick Over Revs


Recommended Posts

Hi Folks,

having got the engine all built up I find that the tick over is high - 1500rpm apprx

 

What I have found is that the front SU carb does not return fully.

I have adjusted the forked levers so that they should return the butterflies but no joy.

 

The timing is at apprx 4' BTDC.

 

I think I may take the carbs off and clean/fettle the linkage.

 

Roger

Link to post
Share on other sites

Hi Roger

 

Sounds like the spindle might be binding in the body? Maybe it's worn a bit? I had a similar problem on my Mini and stuck new spindle kits in them. One last thought, is the piston dropping fully as if it's jammed up slightly or the needle is not central in the jet in might make it run faster.

 

Pleased to hear you got it running okay!

 

Regards

 

Kevin

Link to post
Share on other sites

Hi Kevin,

I shall dismantle the carb and see what is going on.

I have noticed that when the revs are higher than desired the piston is raised slightly but I think this is a function of the butterfly being open slightly.

I don;t think it is sticking.

 

Tomorrow we shall have an answer.

 

Roger

 

PS - probably

Link to post
Share on other sites

Yes you're right that is a function of the butterfly.

 

Sounds like linkage or wrong link on the spindle, or tightness somewhere. I suppose the butterfly disc itself has been put in centrally when tightened up as there is a bit of movement I've noticed sometimes?

 

No doubt all will be revealed when stripped down.

 

Good luck!

 

Kevin

Link to post
Share on other sites

Hi Kev,

carbs off and all now in bits :wacko:

 

Both spindles are badly worn - 0.005" at the free end and 0.002" at the link end.

If I fit oversize spindles who knows what will fail next.

 

The carbs were rebuilt back in 98, they've done 170K miles (probably more) - they owe me nothing

 

So tomorrow I shall investigate getting a new pair. I haven't time to get them rebuilt.

 

Roger

 

PS - I notice the new HS6 carbs have a brass pipe sticking out the front/top of the inlet - does anybody know what it is for

 

http://www.moss-europe.co.uk/shop-by-model/triumph/tr2-4a/fuel-system-induction-controls/carburettors-manifolds/hs6-su-carburettors-ddce02.html

Edited by RogerH
Link to post
Share on other sites

Yes that brass tube is for some sort of engine emission vent arrangement on later cars other than TR.

I have that design carb on my TR and the tube is blanked off with a plastic cap. I chose them from many for their cheapness.

I note Moss have the carbs on backorder. Give Burlen a call http://sucarb.co.uk/conversion-replacement-sets/triumph.html I would diddle around with the needles in these HS6 FZX3045 at the difference in price to Moss. What does a pair of SM needles and Red springs cost - 50 quid?

Cheers

Peter W

 

Or on ebay at £335.00 + P&P http://www.ebay.co.uk/itm/New-HS6-1-75-Twin-SU-Carbs-Carburettors-Triumph-TR4-/111997604032?hash=item1a1393d0c0:g:cfEAAOSw2GlXJIGK

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

Hi Pete,

the Burlen carbs don;t have the brass tubes and have a significant lower price - sadly they do not look like stock items and I haven't got the luxury of time.

 

I'll call TRShop tomorrow as they advertise them at present.

 

Roger

Link to post
Share on other sites

Hi Roger

 

Just in case you decide against replacements, you should be able to obtain standard spindles for a few quid.

 

I was just about to drill out my HS2's for the Mini, when an engineer friend of mine said he would be very suprised if the bodies were worn as the alloy used is extremely tough, so it didn't drill them, and the new spindles took out all the play, and are perfect.

 

Regards

 

Kevin

Link to post
Share on other sites

Hi Kev,

my bodies have bushes in them. I can see a wear pattern but a 5/16" drill feels like a nice fit - so not too much wear.

The spindles look much worse than the 0.005" suggests

 

I'll check out new spindles first but I'm also thinking of all the other bits that may drop off. It would irritate me if I replaced the spindles and lower feed pipe fell off.

 

Roger

Link to post
Share on other sites

Roger, on my carbs, the tube that goes out at at an angle has a pipe connecting the two carbs ?

Link to post
Share on other sites

I have those HS6 carbs and the brass outlet is for a crankcase breather. On the six cylinder engines there is an outlet pipe on the rocker box which connects to a tee piece via a rubber tube. From the tee piece further rubber tubing connects to the brass outlet on each carb. There is normally a plastic bush that is sandwiched between the brass outlet and rubber tube. Interestingly E-Types had a similar system fitted from 1961 onwards. It's also supposed to prevent excessive gas pressure building up in the sump by way of the carb depression acting as a suction pump.

Easy enough job to blank off if this isn't a standard fitment.

 

Cheers

 

Alan

Link to post
Share on other sites

My HS6's also have the brass tube. these were purchased from Cox & Buckles back in mid 70's.

the tubes are blanked off with a plastic cap.

 

Bob.

Link to post
Share on other sites

Hi Austin,

that's interesting. I'll have to investigate further.

 

 

 

 

Roger

Hi Roger

 

if we are talking about the same thing ?

 

428FDD5C-A067-4867-A998-CEA6A30B1595_zps

 

 

 

65B5DB52-FA6F-46FB-BA89-C908A2D99829_zps

Edited by McMuttley
Link to post
Share on other sites

Hi Austin,

they're the devils. I think I will blank them off rather than have another pipe in the bay if I go with the carbs.

There is a big cash difference between two spindles, a rebuild kit and a pair of carbs. serious things to think about.

 

Looking at your filters I would think Madonna feels quite naked without here bra.

If she had my K&N pancakes she would be more like Boadicea.

 

Roger

Edited by RogerH
Link to post
Share on other sites

Roger -

 

Have you tried Richard Turner at Turner Carbs? I'm sure you are aware of him, if not I'll dig out his details - he's always advertising on ebay and you can get the refurb kits from him as well. He often has HS6's available on an exchange basis - TR Shop has already been mentioned - their current offer on a pair of new HS6's is I beleive £490.

 

There is also another carb refurbisher, GW Carbs in Bicknacre Essex - Glen Watson on 07803 593126 - who may be able to help - I can vouch that his work is the dog's bo--cks!

 

cheers

 

Rich

Link to post
Share on other sites

Hi Roger

 

I'm so glad you didn't go for Mcmutley's carb and filter arrangement.

 

A quick check under the bonnet by a stray traffic cop and you might've got arrested for obscenity!

 

He needs to sling a bra over those!

 

Hope the repair kits worked out.

 

Regards

 

Kevin

Link to post
Share on other sites

Here you go How the rocker vent pipe connected to the carbs on a 2500S

There is a push on plastic stepped connector to fit the 1/2 bore pipe to the 3/8 diam brass tube on the carbs.

 

The carbs have the brass tubes you refer to Roger.

 

Peter W

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

Interesting, I currently have no vent on the rocker other than the leaky vented lid.

 

So i could connect what i assumed to be some sort of balancing pipe between the carbs to the rocker, no filter or space ship shaped discy thingy ?

Link to post
Share on other sites

I have been thinking of linking the 2 X brass pipes to my rocker cover for a while now, peter's photo confirms that it should work.

 

Bob.

Link to post
Share on other sites

Bob, my concern would be the muck oily vapour that will be drawn through the engine via the crankcase breather and vented oil filler cap on a sidescreen car.

 

The 2500 has a sealed crankcase arrangment like TR5/6, so there is not be a continual unfiltered airflow from the outside world through the engine crankcase.

 

More info needed - what about a flame trap? Will it reduce oil leaks? Will it increase oil consumption?

 

I think very late model 2500 specified N12Y = BP5ES sparking plugs (hotter) rather than N9Y = BP6ES, the standard temp items used on the TR5/6 PI & Carb. Does this mean they expected oiling in the combustion chamber from the sucked in crankcase vapour?

Cheers

Peter W

Edited by BlueTR3A-5EKT
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.