Author Topic: carb problem  (Read 830 times)

Offline RGP750

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carb problem
« on: January 19, 2019, 05:27:37 PM »
Hi Guys
Not sure what is happening here??
Almost finished a CB175 for a mate in Wales and started today and when I CLOSE the choke the engine revs rise a great deal.
Can anyone tell me what is going on as I haven't a clue .
Cheers Rich
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: carb problem
« Reply #1 on: January 19, 2019, 06:45:32 PM »
Just a bit of girlie logic.
Are they opening when you think they are closing and vice versa? 
 ie, are you operating the lever in the correct direction.?
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Offline RGP750

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Re: carb problem
« Reply #2 on: January 19, 2019, 06:57:11 PM »
yes Julie same principal as the 750 Weird ????
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: carb problem
« Reply #3 on: January 19, 2019, 06:59:50 PM »
yes Julie same principal as the 750 Weird ????
Weird indeed Richard.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Rob62

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Re: carb problem
« Reply #4 on: January 22, 2019, 08:31:26 PM »
When you lean off the mixture the revs rise.... as long as it starts ok with choke in the cold and then runs ok without choke when warmed up, without being too lean. Its ok.

It may be initially set up too rich so the choke is killing it and the rich condition means it run ok without choke when cold.... whats it like when its fully warmed up?

Offline RGP750

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Re: carb problem
« Reply #5 on: January 23, 2019, 06:58:07 PM »
Hi Rob
I put another set of carbs on and all is fine .
I couldn't shut the choke without the revs rising to 8000 weird.
1972 500/4
1973 CB175
1972 CB175
1959 BSA Super rocket
1927 960cc Matchless 'v' twin
1969 750 K0

Offline Rob62

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Re: carb problem
« Reply #6 on: January 24, 2019, 12:42:42 PM »
wow! that is weird... did you get chance to examine the carbs to see if you could spot the issue? would be interesting to know..

 

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