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splatt
Joined: 14 Jul 2008
Posts: 21
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 Posted: Fri Sep 26, 2008 12:20 am Post subject: sticky mikuni |
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| The mikuni carb on my 850 becomes sticky in the cold or wet, ie wet greasy cold corner, button off & find out you are still pulling 4k. That makes the ring piece stick to the seat quite well. The other weekend while cruising along aboring streetch of road at 70mph @4000rpm I noticed the bike started to accelerate. It was like the slide was sucked against the carb body and moving up.A quick blip on the throttle and it was back to normal .How come when you put a jap carb on a british bike it behaves british. the slide is brand new. Any suggestion for afix,maybe apiece of front fork spring and the grip &wrists of a gorilla might help. |
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mikegray660
Joined: 05 Nov 2006
Posts: 115
Location: Long Island NY (ughhhh)
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| Posted: Fri Sep 26, 2008 1:21 am Post subject: Re: sticky mikuni |
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| splatt wrote: | | The mikuni carb on my 850 becomes sticky in the cold or wet, ie wet greasy cold corner, button off & find out you are still pulling 4k. That makes the ring piece stick to the seat quite well. The other weekend while cruising along aboring streetch of road at 70mph @4000rpm I noticed the bike started to accelerate. It was like the slide was sucked against the carb body and moving up.A quick blip on the throttle and it was back to normal .How come when you put a jap carb on a british bike it behaves british. the slide is brand new. Any suggestion for afix,maybe apiece of front fork spring and the grip &wrists of a gorilla might help. |
i had the same problem - are you over lubing your throttle cable and the excess lub getting into the carb body (i was, and the crap gummed up slide movement )
i ended up using the stock mikuni spring and fit one of the smaller amal carb springs inside of it (so 2 spring on the slide) - makes the throttle pull a bit harder (not to bad through) and i haven't had the problem since then |
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zotz
Joined: 15 Jul 2007
Posts: 33
Location: Cambridge, Ontario, Canada
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| Posted: Fri Sep 26, 2008 1:55 am Post subject: |
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| Mine has started doing the same thing recently. In my case I'm pretty sure that it's gumming up due to not being used enough. It's sat for periods of up to a month and I think gas residue gums up the slide. It doesn't seem to happen if I use it more often. ( there's a message there.) |
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mikie3117
Joined: 25 Feb 2008
Posts: 57
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| Posted: Fri Sep 26, 2008 6:23 am Post subject: |
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I had the same kind of issue when exiting a freeway. The carb stuck open until I "blipped" it. Turns out the whole intake system was gummed up with a brown residue from the fiberglass tank sealer. If you pull the carb and manifold off make sure that you put lock tight on the inner allen head bolts for the manifold. Don't ask how I learned about that!   |
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Fritz
Joined: 10 Sep 2008
Posts: 10
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| Posted: Fri Sep 26, 2008 8:12 am Post subject: |
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| mikie3117 wrote: | | I had the same kind of issue when exiting a freeway. The carb stuck open until I "blipped" it. Turns out the whole intake system was gummed up with a brown residue from the fiberglass tank sealer. If you pull the carb and manifold off make sure that you put lock tight on the inner allen head bolts for the manifold. Don't ask how I learned about that! |
Do you recall what brand of sealer you used? |
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DavidT
Joined: 10 Oct 2007
Posts: 4
Location: Argyll
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| Posted: Fri Sep 26, 2008 11:13 am Post subject: |
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| Interestingly I have had a similar problem but only when it was particularly hot (not in Scotland obviously - while on holiday!) When I stripped the carb there was a sticky residue around the bottom of the slide, possibly from sludge in the second hand tank I had fitted just before leaving. The odd thing is that with the engine off, the slide could clearly be heard snapping shut. Cleaning the slide & body and stretching the spring seemed to cure it. Later the next day, when it was really hot again, the sticking returned. I found that if I left plenty of slack in the cable that it behaved perfectly. At home with the cable adjusted exactly as it had been there is no sticking – I am convinced that the heat was playing some part. |
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Gino Rondelli
Joined: 03 Jan 2008
Posts: 44
Location: Perth Scotland
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| Posted: Tue Sep 30, 2008 9:06 am Post subject: |
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| I was on the same trip with David and experienced similar problems (and a host of others I won't bore you with) The double spring thing (using the old Amal spring on the inside of the Mikuni) is a sound idea, my MK3 Commando has that mod already although stupidly I left for a 4000 mile trip without modding the carb on the Commando I took. |
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mikegray660
Joined: 05 Nov 2006
Posts: 115
Location: Long Island NY (ughhhh)
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| Posted: Tue Sep 30, 2008 2:43 pm Post subject: |
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| Gino Rondelli wrote: | | I left for a 4000 mile trip without modding the carb on the Commando I took. |
4000 miles - wow -now that must be a tale of roadside repairs? |
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Yellow_Cad
Joined: 02 Apr 2008
Posts: 158
Location: Sacramento, CA
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| Posted: Tue Sep 30, 2008 2:59 pm Post subject: |
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| If you have a fiberglass gas tank that has not been coated with a two part epoxy sealer, the new gas will cause the fiberglass to breakdown and you will get a coating on the slide and inards of the carb that will translate into a sticky throttle. I guess there are some other carb spring related problems but I know for a fact that the fiberglass tank scenario occurs. |
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DavidT
Joined: 10 Oct 2007
Posts: 4
Location: Argyll
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| Posted: Thu Oct 02, 2008 11:22 am Post subject: |
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| I have been following various threads discussing fuel additives attacking fibreglass, but that doesn't seem to be a problem in the UK yet - different method of boosting the Octane rating perhaps. I normally run an untreated fibreglass Roadster tank and there is no sign of any attack. Have any of our European members noticed this problem? |
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mikegray660
Joined: 05 Nov 2006
Posts: 115
Location: Long Island NY (ughhhh)
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| Posted: Thu Oct 02, 2008 1:56 pm Post subject: |
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| DavidT wrote: | | I have been following various threads discussing fuel additives attacking fibreglass, but that doesn't seem to be a problem in the UK yet - different method of boosting the Octane rating perhaps. I normally run an untreated fibreglass Roadster tank and there is no sign of any attack. Have any of our European members noticed this problem? |
the fiberglass eating additive is ethanol - in the majority of the US its 10%- you know us wise Americans - spend a butt load of money to reduce our dependence on foreign oil by the addition of ETOH to our fuel - even though the cost of producing the ethanol is way more expensive ( and polluting) than just using it straight up not to mention the impact on global food/corn cost
more importantly though - i had to buy a new alloy tank  |
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BillT
Joined: 27 Jan 2008
Posts: 118
Location: Broward County, Florida
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| Posted: Fri Oct 03, 2008 3:41 am Post subject: |
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| mikegray660 wrote: | | DavidT wrote: | | I have been following various threads discussing fuel additives attacking fibreglass, but that doesn't seem to be a problem in the UK yet - different method of boosting the Octane rating perhaps. I normally run an untreated fibreglass Roadster tank and there is no sign of any attack. Have any of our European members noticed this problem? |
the fiberglass eating additive is ethanol - in the majority of the US its 10%- you know us wise Americans - spend a butt load of money to reduce our dependence on foreign oil by the addition of ETOH to our fuel - even though the cost of producing the ethanol is way more expensive ( and polluting) than just using it straight up not to mention the impact on global food/corn cost
more importantly though - i had to buy a new alloy tank |
Ethanol contains less energy/volume than gasoline and is hydrophilic, too.
This means our mileage goes down a little bit and we get water in our fuel.
The 10% mandate is federal law - we are expected to use at least 9,000,000,000 GALLONS of ethanol this year.
Ethanol is produced in the US primarily from corn, driving up the worldwide cost of cereal grains, and we use more energy to produce this than we get back.
On top of that, we subsidize ethanol production to lower the cost to the refineries, and place tariffs on imported ethanol. Brazil produces ethanol primarily from sugar cane stalks after pressing, and could sell the product to us for less than we produced corn ethanol, but this is considered not in our interests. |
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ludwig
Joined: 30 Aug 2006
Posts: 113
Location: belgium
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| Posted: Fri Oct 03, 2008 4:11 am Post subject: |
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| "..Brazil produces ethanol primarily from sugar cane stalks after pressing, and could sell the product to us for less than we produced corn ethanol, but this is considered not in our interests." (quote ) ...yes , and for that they are burning down the rain forest ... not in our interest either ! |
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splatt
Joined: 14 Jul 2008
Posts: 21
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| Posted: Tue Oct 28, 2008 9:29 pm Post subject: |
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| Fitted the spring out of an amal and it seemed to fix the problem,although I did notice the elevator stopped short of going all the way to the top.The mikuni spring was coil binding about 4mm short.We are just starting to get ethanol blend fuel here now,when we went unleaded 10 year or so ago the crap they blended dissolved older rubber hoses,we had cortinas & escorts burnihg everywhere. |
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Norton Commando Forum by Corporate Pages Web hosting using phpbb
The Unapproachable Norton Commando
At the end of 1967 the Norton Commando was announced.
The Norton Commando was greeted with a certain amount of scepticism because on first sight the commando appeared to comprise of the old Norton Dominator twin cylinder engine mounted at an inclined angle in a set of new cylinder parts.
It was not realized that the new Norton Commando Isolastic method of engine suspension damped out all engine vibration and produced a machine which had uncanny smoothness for a vertical twin. In due course the critics were silenced and the Norton Commando had the distinction of being regarded as the first of todays so called superbikes. There can be little doubt that the original design concept of the Norton Commando has proved correct, since comparatively few modifications of any real consequence have been made since production commenced during 1968.
Now nearly 40 years later Norton Commando riders like us are a breed of our own, and as far as we are concerned its still more fun to go for a blat on the old Norton Commando, and fast. As a Norton Commando owner and enthusiast, my goal here is to promote and give credit to those who keep the Norton name going.
It is more deserving to give credit to the Commando itself, for after all these years it continues to be respected. The original Commando designers like John Favill are those who deserve the credit for developing this incredible motorcycle.
The Norton Commando Roadster and Interstate of the late seventies, never died. Although the Norton Villiers factory dispersed the tradition lived on. Today Kenny Dreer in the USA is developing the new 952 CC Norton. What a great looking bike this is, and its engineering is still based on the original layout. It will be interesting to see how the new 952CC Norton does in todays tough motorcycle market. One thing is for sure, I would own one if I could afford it.
