This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
Messages - PaulS
Pages: [1]
1
« on: September 02, 2021, 07:36:44 PM »
"WoooooHoooo!!!"  Just tried the bike after installing the (non-resistor) Nippon Denso plugs recommended by Nurse Julie and.... - the bike started first time AND on all 4-cylinders (that's a first!) - I tried it a few times just in case it was a fluke - and - it rides with the free flowing urgency I was hoping for. So far I have only taken it on a 20 mile test ride, but all is well. The spark plugs are showing a tiny bit of soot but I'll give the bike a much longer run before making any fine tweaks to the carburation. Looks like 7 years of miserable performance has been cured by 4 spark plugs. Thanks each!
2
« on: September 01, 2021, 09:02:39 AM »
Thanks K2-K; as a born and bred Yorkshireman* I like "low-no cost" suggestions.
And thanks to Oddjob for your comments. I checked the compression last year and that was really good. I also replaced the plug caps, leads and coils some time ago. I'm banking on the plugs being the issue, if not, then carburation, but will let you all know....
(*Yorkshire, where "tin tin tin" is a proper sentence)
3
« on: August 31, 2021, 06:46:49 PM »
Managed to finally track down a firm that has the Nippon Denso plugs in stock (buycarparts.co.uk) and they arrived today: from Germany!
Will get those into the bike in the next few days and let you know if I am on the way to solving my problems...
Fingers crossed.
4
« on: August 24, 2021, 11:47:55 AM »
Apologies Andrew-S; I have just checked and the pipes are HM300 (apart from one pattern replacement), all with O/E baffles.
Will let you all know how the 'tinkering' goes. I have ordered up the Denso X24ES-U plugs...
5
« on: August 23, 2021, 11:52:22 AM »
Thanks philward, yes, standard (original) intake, the gaiters and clips are in good condition, and the exhaust is standard HM340 except one replacement pipe to pattern. I'll adjust the needle to get the mix a little leaner.
In the meantime I will take the medicine offered by Nurse Julie and confirmed by spitfire - I'll replace the plugs!
6
« on: August 22, 2021, 08:34:47 PM »
Thanks all!
In summary it sounds as though the issue is either timing, carburration or perhaps plugs.
Timing; I replaced the points with an electronic system a few years ago, so assume that won't be the problem. Or am I fooling myself?
Carburration; I checked the plugs this afternoon (last run was around 40miles) and they are looking sooty, so the mix is too rich. I'll start by lowering the needle and check again. BTW, the carb refurb kits were genuine Kehin, so I'm hoping they are OK... before doing so I might try the 'choke trick' suggested by 'flatfour' to see what happens.
The plugs I am using are NGK DR8ES. Spitfire: should I change to ND plugs? If so, which ones?
As for the bikes I am used to riding, it's a real mix. My newest is a 1 year old BMW R1250RS that I use for touring. I previously had a Ducati 1200 MultiStrada Pikes Peak. However, I have been riding a '58 Triton for 10yrs (just sold it), a Ducati 916 for just over 20yrs and regularly ride my '56 BSA DBD34 Gold Star. In the past I have owned many old and new Triumphs and an old Norton Dominator. I am really convinced that the CB750 should have more 'urgency' than it displays. My very first bike, a '62 James Captain, had more 'get up and go'!
7
« on: August 22, 2021, 05:52:07 PM »
Thanks Laverdaroo.
Looks like we need to mull things over (with a mug of tea in hand)
I am having problems with my CB750 - see my posts in that section of the Forum.
Let me know when would be good to meet up...
8
« on: August 20, 2021, 02:56:13 PM »
Thanks Bryanj.
Ill check against Spec.
However, the engine is really wheezing, so I suspect its the power plant at fault.
9
« on: August 20, 2021, 01:20:40 PM »
Very sad to hear that John Wyeth is no longer with us.
A real character.
And I have his excellent book on the CB750 Restoration by my bedside.
10
« on: August 20, 2021, 01:09:31 PM »
Hi.
My first post, so I hope you can help.
I bought my bike 7yrs ago in UK, recently imported from USA. It's done around 25k miles in total to date but has been sluggish since I bought it. Whilst I don't want to thrash the bike, I'm disappointed that it struggles to get much beyond 80mph and wheezes to get there. Also it sometimes only starts on 3 (sometimes 2) cylinders - but rarely the same ones! That starting issue seems to cure itself when warmed up.
So far I have dismantled, cleaned and rebuilt the carbs (using a refurb jets, needles, etc kit from David Silver Spares) and checked the rubber gaiters. I balanced the carbs with a vacuum set. The fuel lines and tap seem to be OK. I have replaced the battery, all the plugs, leads and coils, installed electronic ignition and checked the compression (OK).
And still it's sluggish.
I am probably at the extent of my mechanic skills now, so unless there is some magic answer (??) I probably need to get a specialist to breathe on it.
I had Rising Sun Restorations of Tockwith, York, carry out an initial checkover/service when I first bought the bike, but their telephone number seems to no longer be working. Are they still around?
So,
A. Any magic answers to get the bike free revving again? and
B. Where do I find the best mechanic to diagnose the problems and sort this out?
I am based near Bristol, but happy to travel to find the best person/people.
11
« on: August 20, 2021, 12:47:35 PM »
Although I have owned my '71 CB750K1 for 7 years this is the first time I have been on the forum. I'll be looking for help and advice to keep my lovely bike on the road.
Just after I bought the bike John Wyeth of Rising Sun Restorations, near York did an initial overhaul. He was brilliant. Although I am based in Bristol, I was thinking of taking it to him for another refurb, but his telephone number seems to be no longer working. Is he still around?
Pages: [1]
|
Show Posts