Search found 766 matches

by gunnag
Tue Feb 02, 2021 10:07 pm
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

What makes you thing that the forces from an hydraulic brake are any higher than the forced from a (working) mechanical brake? The forces expanding the shoes will be the same for the same amount of braking but the hydraulic brake won't have the additional forces from the operation of the cam mechan...
by gunnag
Sun Jan 31, 2021 7:46 pm
Forum: Project bikes
Topic: B50/44 Hybrid
Replies: 28
Views: 2125

Re: B50/44 Hybrid

I once fitted a B40GB engine into a B25 OIF frame and this is what I found I needed to do:- - the frame was cleaned internally by using various combinations of hot soapy water, paraffin, paint thinners, engine degreaser, pressure washer etc. Each time I filed the frame it was vigorously shaken aroun...
by gunnag
Sun Jan 31, 2021 5:09 pm
Forum: Tech
Topic: B50 hydraulic drum brake
Replies: 53
Views: 2920

Re: B50 hydraulic drum brake

Great conversion, my only worry would be the strength of the brake plate and whether it can withstand the additional forces added by the hydraulics. I only say this because I once sold a B25 OIF brake plate on eBay, when it arrived it was broken in half, presumably due to poor handling by the courie...
by gunnag
Mon Jan 04, 2021 2:17 pm
Forum: Tech
Topic: b40 lubrication system modification ?
Replies: 15
Views: 972

Re: b40 lubrication system modification ?

ive read somewhere theres a conversion/modification to the lubrication system to make it more oil tight/breath easier/ lube more efficiently I suspect the mod you mean is the B50 conversion where two 3/8 holes are drilled in the crankcase drive side, just under the crankshaft and level with what wo...
by gunnag
Tue Dec 22, 2020 10:16 pm
Forum: News
Topic: Stan Millard
Replies: 20
Views: 2991

Re: Stan Millard

So sad to hear this news about Stan, I've learned much from his posts over the years on this forum, no doubt his expertise and knowledge will be missed by those seeking to improve their B44's & B50's.
by gunnag
Sat Jul 11, 2020 12:33 am
Forum: Tech
Topic: B25SS Rocker Box Studs
Replies: 10
Views: 1716

Re: B25SS Rocker Box Studs

If it was my bike I would remove the studs, run a flat file over the rocker cover surface, then helicoil all the stud holes with a suitable thread form (I used m6 on my B44) and replace with socket caps. The two bolts holding the head steady are probably strong enough and can be left alone. But its ...
by gunnag
Thu Jul 02, 2020 11:26 pm
Forum: Tech
Topic: Refurbishment of B25 cylinder head and rocker box
Replies: 5
Views: 1268

Re: Refurbishment of B25 cylinder head and rocker box

I can see several issues which you might want to address as follows:- - the valve seats look slightly pitted, I would get them re-cut ideally using a 3 angle valve job which helps efficiency, get the valves refaced at the same time - there is evidence of burnt oil on the inlet valve stem, this proba...
by gunnag
Wed Jun 24, 2020 9:46 pm
Forum: Tech
Topic: 441 Victor resurection
Replies: 45
Views: 6665

Re: 441 Victor resurection

I'm using a JRC 28 carb on my B44 and it works well, one advantage is that it has a separate choke circuit so starting is a bit easier. I'm wondering if your Amal 930 has a blocked idle circuit, which as you probably know is a common problem, so may be worth cleaning out. Also worth checking the thr...
by gunnag
Sun Jun 14, 2020 8:07 pm
Forum: Tech
Topic: B44 engineering item and a Piston recommendations?
Replies: 6
Views: 1627

Re: B44 engineering item and a Piston recommendations?

Back in the 70's and 80's a company called Basset Down near Newbury advertised their crank balancing services in the motorcycle press, not exactly near Cornwall but maybe worth a shot. Their website says they can balance any crank including single cylinder and they mention engine rebuilds on their w...
by gunnag
Thu Apr 30, 2020 2:30 pm
Forum: Tech
Topic: Which tank sealant?
Replies: 16
Views: 4734

Re: Which tank sealant?

Not sure what sealant you have in the tank but I've previously had good success with Acetone for removing very old Petseal used in my A65 fibreglass tank. Acetone sloshed around causes the Petseal to flake off the inside in big chunks which can then be further broken down by adding old screws/nuts/d...
by gunnag
Mon Apr 20, 2020 11:19 am
Forum: Project bikes
Topic: Converting a B50 to wet sump. (aka Boris Johnson)
Replies: 102
Views: 16812

Re: Converting a B50 to wet sump.

Some pics would be great :)
by gunnag
Sat Apr 18, 2020 10:00 pm
Forum: Project bikes
Topic: Converting a B50 to wet sump. (aka Boris Johnson)
Replies: 102
Views: 16812

Re: Converting a B50 to wet sump.

Hi Momus, for many years I've wondered whether a unit single BSA could be converted from dry sump to wet sump so I think it's great that you're having a go at it. I imagine there are several obstacles to overcome when making such a radical change to the lube system:- - a new oil tank will need fabri...
by gunnag
Tue Mar 24, 2020 7:19 pm
Forum: Tech
Topic: b44 gearbox leak/level
Replies: 15
Views: 2824

Re: b44 gearbox leak/level

i filled to the correct level (1/2 pint aqf ) Are you using ATF oil or gear oil? I use EP90 gear oil which is probably thicker than ATF with less tendency to leak out so is recommended. I'm using a level tube on my B44 without a dipstick and it seems to work OK, I dont know if this was the original...
by gunnag
Mon Mar 23, 2020 2:27 pm
Forum: Tech
Topic: b44 gearbox leak/level
Replies: 15
Views: 2824

Re: b44 gearbox leak/level

I would change the gearbox output bearing to one with rubber seals, these are prefilled with grease and don't need gearbox oil. If youre worried about lack of lube you can remove the inner seal but keep the bearing outer seal.
by gunnag
Mon Jan 27, 2020 11:57 pm
Forum: Tech
Topic: B40 in OIF frame issues
Replies: 35
Views: 6835

Re: B40 in OIF frame issues

Have a look at this thread where someone had a similar problem and solved it - viewtopic.php?t=4223
by gunnag
Sun Jan 26, 2020 3:11 pm
Forum: Tech
Topic: B40 in OIF frame issues
Replies: 35
Views: 6835

Re: B40 in OIF frame issues

Regarding the knocking, check you engine mountings are tight, particularly the rear mount which has a habit of becoming oval in the engine cases. Make sure the head steady is fitted.
by gunnag
Fri Jan 24, 2020 5:27 pm
Forum: Tech
Topic: B44 Primary Breather Pipe
Replies: 8
Views: 2320

Re: B44 Primary Breather Pipe

I've done the conversion on my B44 but without adding the external hose from the chain-case. My thinking was that allowing the crankcase to breathe into the chain-case would relieve some of the excess pressure and reduce leaks, it seems to work OK. For my conversion I drilled two 3/8 holes into the ...
by gunnag
Mon Jan 13, 2020 8:29 am
Forum: Tech
Topic: B44 Wiring/ Earth
Replies: 16
Views: 3328

Re: B44 Wiring/ Earth

When making the loom, I've found heat shrink butt connectors very handy when a piece of cable needs extending. These items are essentially a piece of clear heat shrink tube with a ring of solder in the middle. Cable is inserted from either end and then the butt connector is heated with a hot air gun...
by gunnag
Sun Jan 12, 2020 11:29 pm
Forum: Tech
Topic: B44 Wiring/ Earth
Replies: 16
Views: 3328

Re: B44 Wiring/ Earth

I have wired my B44 as positive earth as per original, I don't see any advantage in changing to negative earth. Make sure you use the right gauge cable, with a 180w alternator putting out up to 15 amps cable with inner core of 1mm square should be about right. Regarding the connectors I have no expe...
by gunnag
Sat Dec 28, 2019 8:59 pm
Forum: Tech
Topic: B40 in OIF frame issues
Replies: 35
Views: 6835

Re: B40 in OIF frame issues

Oil is coming out of the joint between the head and exhaust downpipe, which is a concern. I had a similar issue with my B44 when I first put it together, I found oil coming out from the exhaust manifold where the pipe fits in, also plenty of blue smoke and some leaks from the head gasket area. Afte...
by gunnag
Tue Dec 24, 2019 10:22 pm
Forum: Tech
Topic: B40 in OIF frame issues
Replies: 35
Views: 6835

Re: B40 in OIF frame issues

I once owned a similar bike, it was a B40WD engine in a B25 frame. As noted the carb doesn't fit very well without fouling the frame so what I did was to have an alloy inlet welded onto the head, I don't remember which way it was angled but it didn't use the original air filter. I was using a Dellor...
by gunnag
Mon Dec 16, 2019 7:52 pm
Forum: Tech
Topic: B44 - 2nd Gear Mystery
Replies: 6
Views: 2034

Re: B44 - 2nd Gear Mystery

Could be a number of things affecting the gear change, in addition to Kommando's advice I would have a look at the Post Here which describes and fixes a similar problem to yours.
by gunnag
Mon Dec 09, 2019 9:15 pm
Forum: Tech
Topic: Fitting Allen screws to rocker box on B50.
Replies: 35
Views: 7216

Re: Fitting Allen screws to rocker box on B50.

At the risk of sounding like a heretic, I've used M6 thread inserts on my B44 rocker-box together with socket caps. I think my main reason at the time was that M6 thread inserts were readily available, cheap and were only slightly different in TPI compared to the BSC/CEI originals (25.4 vs 26). I do...
by gunnag
Wed Jul 03, 2019 9:36 pm
Forum: Tech
Topic: B40 and B44 motor in OIF chassis
Replies: 7
Views: 3363

Re: B40 and B44 motor in OIF chassis

I once fitted a WD B40 engine into an OIF B25 frame, my thoughts are as follows:- - the rear engine mount needs spacers fitting as already mentioned - the frame cross member will foul the oil manifold as Kommando mentions, easiest solution is to cut out the cross member, it doesn't affect the frame ...
by gunnag
Sun Jun 09, 2019 8:22 pm
Forum: Tech
Topic: 1000-Series 2/4-stroke Concentrics
Replies: 102
Views: 24635

Re: 1000-Series 2/4-stroke Concentrics

Fantastic work MM and thanks for sharing this info which may be of some use on my B44 which currently uses a JRC 28 (Kehin PWK replica). I've often wondered about getting more performance from my B44 including gas flowing, bigger valves & carb etc. and why the unit single BSA's couldn't quite get th...
by gunnag
Sat Jun 08, 2019 1:12 pm
Forum: Tech
Topic: b25ss timing cover bung plug/past shortage of B50 kickstart quadrants
Replies: 17
Views: 5142

Re: b25ss timing cover bung plug/past shortage of B50 kickstart quadrants

Regarding the plug on the outer gearbox/timing cover, its definitely meant to be an oil filler/level plug for a B40WD. Have a look at the B40WD workshop manual on the BSA unit Singles website Here plate A10. There's also a handy B40WD parts list Here which shows the plug on plate A11 part 20 which i...
by gunnag
Sun May 12, 2019 10:35 pm
Forum: Tech
Topic: Dodgy clutch springs?
Replies: 2
Views: 1982

Re: Dodgy clutch springs?

IMHO the best way to ensure the springs and screws don't come undone is to use lock wire, don't rely on the pip or the springs being wound the right way, they invariably come loose unless lock wired in place.
by gunnag
Wed Feb 20, 2019 11:56 am
Forum: Tech
Topic: Electric Start
Replies: 635
Views: 180139

Re: Electric Start

Well done Beat, great to see you have finally got it working :)
by gunnag
Tue Jan 15, 2019 8:23 pm
Forum: Tech
Topic: B44 Oil consumption
Replies: 29
Views: 6408

Re: B44 Oil consumption

I had exactly the same problem when I rebuilt my B44 several years ago using a JCC piston and iron rings. The bike would smoke loads on startup and when warmed up despite a hard run-in process and a coarse hone. I swapped the rings for Hepolite versions and a fresh hone but the problem persisted. Ev...
by gunnag
Mon Dec 17, 2018 11:30 pm
Forum: Tech
Topic: B50s and modern fuel
Replies: 28
Views: 8330

Re: B50s and modern fuel

If you cant get the Esso ethanol free unleaded in your area then one possibility is to use Briggs and Stratton fuel stabiliser which claims to keep fuel fresh for up to 3 years. Admitedley its meant for lawnmowers but I cant see it doing much harm in our old nails, see This Link.
by gunnag
Fri Dec 07, 2018 11:08 pm
Forum: Tech
Topic: Chainguard?
Replies: 4
Views: 2041

Re: Chainguard?

Dont know if this helps but looking on eBay there is a B40WD enclosed chainguard and a B40/B44 chainguard available:-- - the first one is for a B40WD its the fully enclosed version, it seems original enough, maybe you could just loose the lower section if you dont want fully a enclosed chaincase, se...
by gunnag
Sun Dec 02, 2018 10:09 pm
Forum: Tech
Topic: B50s and modern fuel
Replies: 28
Views: 8330

Re: B50s and modern fuel

This does not apply to Scotland or the South West where there are no reliably ethanol free petrol of any description. I can't imagine why Esso would have different formulations for Scotland and the South West, but perhaps its related to the capabilities of refineries in these areas? I guess you wil...
by gunnag
Sun Dec 02, 2018 10:55 am
Forum: Tech
Topic: B50s and modern fuel
Replies: 28
Views: 8330

Re: B50s and modern fuel

The problem is that it does not have that big a demand so it can get old
Thanks for that info, luckily I have at least 6 Esso stations nearby which stock super unleaded and they all seem to be busy with customers. My guess is that the super unleaded is used alot so should be fresh in the tanks.
by gunnag
Sat Dec 01, 2018 8:05 pm
Forum: Tech
Topic: B50s and modern fuel
Replies: 28
Views: 8330

Re: B50s and modern fuel

From my research only Esso super unleaded (97RON) has no ethanol That's a top tip and the lack of ethanol is confirmed on the Esso UK website, see This Link , they also have a UK petrol station locator so you can find your local outlet. I'm going to fill my bikes with Esso super unleaded and see ho...
by gunnag
Fri May 25, 2018 9:45 pm
Forum: Tech
Topic: Vent pressure from inside B40
Replies: 20
Views: 5440

Re: Vent pressure from inside B40

Some worthwhile fixes I have tried on unit singles to cure rocker box and cylinder stud leaks are as follows:- - countersink the rocker box stud holes on the cylinder head to remove any 'pulled up' metal, this will help ensure the rocker box flange on the head is reasonably flat and help prevent lea...
by gunnag
Thu May 24, 2018 8:27 pm
Forum: Tech
Topic: New rings
Replies: 10
Views: 3607

Re: New rings

I'm using Cords rings on my B44 and can recommend them, see This Link for the original post.
by gunnag
Fri Dec 01, 2017 9:07 pm
Forum: Tech
Topic: Accelerator pump carb
Replies: 27
Views: 6996

Re: Accelerator pump carb

Good question B44Claus and as an owner many years ago of a Ducati Darmah 900cc Bevel drive which used Dellorto PHF carbs with accelerator pumps, I often wondered whether these carbs would be useful on other bikes. If I remember correctly, the purpose of accelerator pumps is to enrich the mixture whe...
by gunnag
Mon Oct 16, 2017 8:42 pm
Forum: Tech
Topic: B50 MX sudden death!
Replies: 41
Views: 12249

Re: B50 MX sudden death!

Some thoughts which might be of use:- - have you checked the gearbox oil level? Its common for the gear box oil to slowly leak out as well as emulsify into a brown sludge, hindering lubrication - the engine and chain-case share the same oil so although there are traces of silver in the oil, if youre...
by gunnag
Sat Sep 16, 2017 9:45 pm
Forum: Tech
Topic: Another valve guide question
Replies: 20
Views: 5542

Re: Another valve guide question

I have never tried the K-Line guide insert system but it looks like a good idea and I agree that its best to keep valve guides in place since removing them causes wear in the head. One of the motorcycle head specialists who offers this service in the UK is the Cylinder Head Shop, see This Link , so ...
by gunnag
Sat Jul 22, 2017 10:03 pm
Forum: Tech
Topic: B50 starting niggle
Replies: 18
Views: 6029

Re: B50 starting niggle

Try using a tank of fresh petrol, cleaning out the carb bowl and idle circuit, which is notorious for becoming clogged.

Additionally try a fresh plug and make sure the battery is showing at least 12.5v which is essential if using electronic ignition.