Author Topic: no power under load  (Read 899 times)

Offline ricardo

  • SOHC Associate
  • Posts: 91
    • View Profile
no power under load
« on: December 02, 2018, 09:56:28 AM »
Hi all.
I hope that you are all well and loaded with tons of advice for me about this problem

After I bought the bike I noticed that revs needed to be well over 3.5k revs to get moving otherwise the engine stalled.
Since then I've refurbed the carbs. Then had that awful problem fitting the airbag back but just about managed. Then off road a while whilst I changed oil and filter.  Turned over yesterday and whilst I didn't ride it the engine sounded rough and wouldn't tick over at low revs. Needed 3 k or so to keep going.  After I refurbed the carbs I replaced ignition with electronic and cleaned plugs and checked that they sparked. They did.

While keeping the engine running at over 3k revs I removed the number 4 plug ht connector. No change in sound or rhythm of motor. Ergo no 4 Not firing??

I replaced and removed no 1 lead and the engine just spluttered to a stop.

Help. How should I proceed. I'l buy new plugs and check that they all spark. what then

Help

Ricardo

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: no power under load
« Reply #1 on: December 02, 2018, 10:51:31 AM »
Check to see if No 1 is firing also Ricardo, as 1 and 4 run off of the same coil. Is fuel getting to the carbs, is there enough fuel in tank, is the choke working and do you have lever in correct position. Check these for starters.
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 ricardo

  • SOHC Associate
  • Posts: 91
    • View Profile
Re: no power under load
« Reply #2 on: December 02, 2018, 10:57:32 AM »
Ah Julie.

How pleasant to here from you.

Yes No 1 is working. Engine miss fires to the point of stopping when I unplug it.
Tank nearly full. Choke operates but not sure what you mean by correct position. I can turn choke off and engine runs but need plenty of juice.

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: no power under load
« Reply #3 on: December 02, 2018, 11:05:15 AM »
For cold starting the choke lever needs to be moved from the down position to the up position. You may not need full choke to start it.
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 Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: no power under load
« Reply #4 on: December 02, 2018, 11:19:14 AM »
Just thinking, if you have refurbed carbs, have you reset air / fuel (mixture) screws out by 2 turns?. May not be spot on at this position but always a good start point.
« Last Edit: December 02, 2018, 11:30:34 AM by Nurse Julie »
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 ricardo

  • SOHC Associate
  • Posts: 91
    • View Profile
Re: no power under load
« Reply #5 on: December 02, 2018, 12:33:00 PM »
No I haven't . So do you mean close them all completely then turn them all on 2 full turns?

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: no power under load
« Reply #6 on: December 02, 2018, 12:39:11 PM »
Yes, from fully in, turn 2 full turns out.
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 Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: no power under load
« Reply #7 on: December 02, 2018, 12:40:46 PM »
Did you bench sync the carbs before you re fitted them to the bike?
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 ricardo

  • SOHC Associate
  • Posts: 91
    • View Profile
Re: no power under load
« Reply #8 on: December 02, 2018, 02:01:52 PM »
yes but I can't recall that bit. sorry about next question but I can't seem to find those screws from any photos in the manual

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8205
    • View Profile
Re: no power under load
« Reply #9 on: December 02, 2018, 02:12:22 PM »
They are these little brass screws Ricardo. One on each of the carb bodies, facing outwards. [ Guests cannot view attachments ]
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 ricardo

  • SOHC Associate
  • Posts: 91
    • View Profile
Re: no power under load
« Reply #10 on: December 02, 2018, 03:01:26 PM »
Thanks Julie.

I'll do it assign as it stops raining

Offline Chris whit

  • SOHC Associate
  • Posts: 56
    • View Profile
Re: no power under load
« Reply #11 on: December 09, 2018, 07:40:50 PM »
Hi Ricardo , i had a similar problem after getting my carbs back from being refurbished from Gerben in the Netherlands. Bought a set of balance gauges and balanced the carbs up , also check your valve clearances .
Mine runs sweet as a swiss watch.

Offline ricardo

  • SOHC Associate
  • Posts: 91
    • View Profile
Re: no power under load
« Reply #12 on: December 10, 2018, 08:48:57 AM »
Hi Chris.
Its gives me hope thanks. I'll put bike aside to hibernate for the winter and take your advice if I'm still troubled.
Ricardo

Offline billywingnut

  • SOHC Associate
  • Posts: 56
    • View Profile
Re: no power under load
« Reply #13 on: December 16, 2018, 04:40:59 PM »
Have you checked the plug caps? I measured the resistance on mine they are usually about 3500 ohms  (3.5kohms), one was measuring over a meg ohm ( 1,000,000) so I replaced the lot and plugs. People are saying buy the none resistor type spark plugs, Check the points and replace if necessary. My bike will not run smooth without the air filter in place with a good lid on the filter box. I think it's a good idea to buy an inexpensive compression tester if you have never tested it you could have valve issues. I don't mean to scare you should be prepared to put some  work in and learn new skills to get it running correctly, it's worth the trouble

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal