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V35II Carbs - The Saga Continues

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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 2019 at 22:08
Certainly is! In fact there's a wee bit of a gap down the back, which is normal. In all the years I've used them have only seen very light scoring on the front faces. My overhauls usually included a very light smear of grease on them.


"Chicken nuggets don't dance on a Tuesday."
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i24 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote i24 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 2019 at 06:56
Originally posted by AdrianW AdrianW wrote:


A neighbour loaned me a very swish balancer (Carbtune Pro) designed for 4 carbs but just used 2 pipes. It's a lovely thing, am almost tempted to buy a 2 cylinder one..

Got the beast to idle in balance but the whole thing went to Hell in a handcart as soon as the throttle was opened.
The bike will rev ok (3k rpm plus), tick over ok but theres a really rough bit in between.



Did you balance the carbs at idle, or also during the throttle opening? If one throttle cable is adjusted a little shorter than the other it will run rough as soon as the slides start to move. Once you get them both open, the difference will be less noticeable.



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Post Options Post Options   Thanks (0) Thanks(0)   Quote AdrianW Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 2019 at 14:33
Thanks i24..
This has occurred to me also, although I have not done anything about it yet (dreadful cold over last few days..)
Balanced at idle but gradually increaasing the throttle had one column rise and the other stayed much lower. Shutting off both raised together equally and then fell back to the equal tickover reading.

I bought some new cables from Gutsibits but have been too idle / impatient to fit them.. I think the time is maybe approaching..

Thanks again,

Adrian
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Brian UK View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 2019 at 15:14
That tells me that one carb is definitely opening before the other.

If you are in a quiet place, you can (with the engine off of course) open the throttles then close them fairly sharply. Listen carefully and you will hear two clicks as each hits the stop.

Balance at tickover as you have donr then raise the revs to a steady 3k and adjust the cable lengths until both are the same.
Then check at tickover again.

But first of all feel the slack in each cable at the carb end and adjust to get them both as close to the same as you can.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 2019 at 15:16
It doe sound as though the cables are maladjusted. If you listen carefully you should be able to hear the click as the slides hit the throttle stops. Two clicks means that one cable is tighter than the other......
Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AdrianW Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 2019 at 18:02
Thanks Ian & Brian,
That's the odd thing.. The first thing I did was listen to make sure both slides were hitting the deck together, which they are.. The Carbalancer tells me that they are not rising together, weird...

 It is a little difficult to judge the free cable play (there is some) and the adjusters are unscrewed different amounts on each carb (which may be normal).

When health (I'm less grotty today) & time permits I'll change the cables anyway. I can check the throttle end too, the unit has been "repaired" - I can see the end of a self-tapper protruding through the plastic outer cover of the switch unit.......

I'll also double check cable routing too. 

Thanks as always for your thoughts and support, appreciated...

Adrian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote i24 Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 2019 at 21:01
New, carefully routed cables and carefully fitted cables will make a big improvement. Easier to set, less friction, better feel - more fun!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 2019 at 09:05
Looks like Brian and I posted virtually the same thing at the same time!

A trick that you can use with Brit parallel twins is to put a small (3mm or so) drill bit under each slide so it's trapped when the throttles are closed (obviously with air filters removed). Then slowly open the throttle and watch the drill bits - they should move (ie start falling out) at exactly the same time.

May be tricky with the V50 layout however - I haven't neeeded to try it myself as the "click" method has been enough.

Hope you're feeling better soon!
Ian
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1952 Norton ES2
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Post Options Post Options   Thanks (0) Thanks(0)   Quote trophydave Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 2019 at 19:18
I balanced the carbs on my V50 recently.The balance at tickover wasn’t too far out of adjustment.Some twiddling with the mixture screws didn’t seem to make any difference to the tickover but the throttle stops sorted it.However when I opened the throttles the balance went miles out,the cables were way out of adjustment.Got that sorted but I am wondering if I need to investigate the lack of anything happening when the mixture screws are turned.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 2019 at 20:50
I never found the mixture screws did much either.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote i24 Quote  Post ReplyReply Direct Link To This Post Posted: 16 Oct 2019 at 07:04
Originally posted by iansoady iansoady wrote:

Looks like Brian and I posted virtually the same thing at the same time!

A trick that you can use with Brit parallel twins is to put a small (3mm or so) drill bit under each slide so it's trapped when the throttles are closed (obviously with air filters removed). Then slowly open the throttle and watch the drill bits - they should move (ie start falling out) at exactly the same time.

May be tricky with the V50 layout however - I haven't neeeded to try it myself as the "click" method has been enough.

Hope you're feeling better soon!


I took the carbs and inlet manifolds off the bike, but left the throttle cables connected. Then it is easy to see both slides at the same time and do a "static" balance on idle stop screws and throttle cables. Then re-assemble and test run the bike. I posted this a while back:

http://www.guzziriders.org/v35-imola-will-not-start_topic9577_post106704.html?KW=#106704

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Motty View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Motty Quote  Post ReplyReply Direct Link To This Post Posted: 16 Oct 2019 at 11:12
Originally posted by Brian UK Brian UK wrote:

I never found the mixture screws did much either.

As Brian says above. The mixture screws made little/no difference to the mecury(?) levels when balancing the carbs.
It’s more fun to try to ride a slow bike fast .....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote iansoady Quote  Post ReplyReply Direct Link To This Post Posted: 17 Oct 2019 at 17:13
I wouldn't expect them to as what you're measuring is inlet tract pressure which mixture strength will not affect. It's purely a function of airflow.
Ian
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Mike H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mike H Quote  Post ReplyReply Direct Link To This Post Posted: 17 Oct 2019 at 21:47
Yes I was going to say, not what mixture screws are for. Big smile

A Colortune should show something happening though.

For the big blocks, the blurb used to say screw each one in until idle rpm starts to drop, then back out to restore idle speed back to what it was. This of course assumes the carbs are in full working order and everything else is adjusted perfectly and the motor is fully warmed up.


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