Classic British SparesKlempf British PartsBaxter CycleBritBike Sponsor SteadfastCyclesSRM EngineeringLucas Classic MotorcycleHepolite PistonsIndustrial tec supply

Upgrade your membership to: Premium Membership | Gold Membership | Life Membership | Vendor Membership | Site Sponsor Membership
Welcome to BritBike Forum!
Britbike forum logo
Member Spotlight
Richard Phillips
Richard Phillips
San Luis Obispo, CA
Posts: 773
Joined: August 2001
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Search eBay for motorcycle parts in following countries
Australia, Canada, France, Holland, Italy, United Kingdom, USA
Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Joined: Aug 2001
Posts: 3,249
Likes: 64
Britbike forum member
Offline
Britbike forum member
Joined: Aug 2001
Posts: 3,249
Likes: 64
Johnu, how did you find tdc? By sticking a screwdriver down the plug hole or with a piston stop and degree wheel?


Rich
"It's not always about going fast. Sometimes it's nice to slow down" (Wendy E.2016)

69 bonney
72 commando
75 commando
couple of beesas a ducati
and a Honda?
Support Your #1 BritBike Forum!

Check out British motorcycles for sale: British Motorcycles on e-Bay UK, British motorcycles on e-Bay North America
Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Thanks for all the replies and interest in helping me get this engine running properly. I have a timing light on order which should be here this week.
I am almost 100% sure that there is no leak at the exhaust header connection.
I have been finding tdc using a a dial gauge, rotating the engine in both directions to ensure that I'm exactly at tdc. This is what I have always done in the past on my other bikes but maybe this isn't the best method although I can't see why this wouldn't work.
Someone asked why the stator isn't exactly in the the center of the slotted mountain holes. It actually isn't far off center but I did have to adjust the staor slightly after tightening the rotor as something moved slightly. This is the reason for the slots being there.
I wish I had one of you experts close by to help me with this but hopefully I can resolve it with your help through this forum:)

Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Originally Posted by Dave Martin
Nah, sorry I don't buy that. If it was THAT retarded it wouldn't run, and the hottest part would still be by the head. This clearly isn't, it is much redder further down the pipe.[Linked Image]

Of course a rich mixture would not cause a hot exhaust (it would actually be a lot cooler) ON ITS OWN. but if you added more oxygen through an obviously leaking header .......... I only suggested a rich mix as he has changed the jet .... in actuality any mix is likely to combust in the head pipe if you add air.

This issue, as I said before, is going to be a combination of a load of things. Timing is possibly one factor, mixture is going to be another, leaking head pipe yet another.
Hi Dave, I just had another look at my video and I can see the smoke puffing in and out as you mentioned earlier. There is absolutely no leak at the header but I may have stumbled across a completely crazy scenario! I have noticed that there is a pretty decent oil leak on the right side of the engine with oil dripping down the fins on the barrel and head. I got my flash light out to investigate and in between two of the fins is what appears to be a hole! When I bought this bike the previous owner had some work done on the head in regards to drilling some oil ways. I think this hole that I can see is related to that and could be the source of an air leak and all of my problems.
[Linked Image]
[Linked Image]
[Linked Image]

Joined: Dec 2018
Posts: 198
Likes: 9
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Dec 2018
Posts: 198
Likes: 9
Hmmm ....... now the problem is how the hell do you fix it? by the looks it is going into the exhaust port, and if it is, the only way to get oil leaking out, it must be coming from the valve guide, which in turn must be well and truly shot!
Time for a head job! thankfully the parts are cheap and readily available, that weld is going to be a bugger to do though!
Tempting just to stick a self tapper in there and see what happens! smile

Joined: Nov 2011
Posts: 538
Likes: 53
K
Britbike forum member
Offline
Britbike forum member
K
Joined: Nov 2011
Posts: 538
Likes: 53
That hole looks to be into the drain hole in the bottom of the valve spring pocket in the head.

[Linked Image from i.postimg.cc]

You may be able to fix it by drilling the drain hole oversize and pressing in a sleeve.

So that would explain the oil leak, but unless it has broken thru into the exhaust port, how does it contribute to the over heated exhaust pipe? Back to timing?

Tom


Life's uncertain - go fast now!
Joined: Dec 2018
Posts: 198
Likes: 9
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Dec 2018
Posts: 198
Likes: 9
Remember this head has been "ported", the oil ways have been "drilled" (huh?) so much it has a broken through, it leaks oil and blows gas, could be crank case venting, could be exhaust, looking at the vid, my guess is exhaust. Occam's Razor suggests that there might actually be something wrong here.

"Fixing" timing would seem to me to be a remarkably futile exercise ............ the head has a bloody great big hole in it!

Personally I would be looking for a different head that hasn't been messed with as much, expect to do a rebuild, valves, guides and seats, and anything you get that needs less is a bonus. This is what I did on my two recent B44 rebuilds, happy I did.

Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Originally Posted by Dave Martin
Remember this head has been "ported", the oil ways have been "drilled" (huh?) so much it has a broken through, it leaks oil and blows gas, could be crank case venting, could be exhaust, looking at the vid, my guess is exhaust. Occam's Razor suggests that there might actually be something wrong here.

"Fixing" timing would seem to me to be a remarkably futile exercise ............ the head has a bloody great big hole in it!

Personally I would be looking for a different head that hasn't been messed with as much, expect to do a rebuild, valves, guides and seats, and anything you get that needs less is a bonus. This is what I did on my two recent B44 rebuilds, happy I did.
I just looked at photos of the head when I had the engine apart. It doesn't tell me much but you can see a sanding mark on there. I know some welding was done on it. I think I am going to do a bit of a bodge short term to see what happens. I'll try using a a self tapping screw with vht liquid metal to seal the hole. Not sure if it will do any good but worth a try. These are the only pics I have of the head.
[Linked Image]
[Linked Image]

Joined: Feb 2019
Posts: 477
Likes: 190
S
Britbike forum member
Offline
Britbike forum member
S
Joined: Feb 2019
Posts: 477
Likes: 190
Originally Posted by johnu
I'll try using a a self tapping screw with vht liquid metal to seal the hole.
Glad to hear you found an actual problem. Definitely get that sorted first. Konkreitkid suggested pressing a sleeve into that drain hole to seal it up. That is a good solution especially since it may also have broken into the exhaust port.

Sleeving is relatively easy in concept using brass or aluminum hobby tubing. The hole needs to be drilled for a snug fit with the tube size you choose. It's best to do a trial run or two on something that doesn't matter (a chunk of aluminum) to fine tune your technique, drill size, reamer if needed and so on. Then epoxy it in there. JB weld, the slow version, is temp rated to 500F or better.

With a self tapping screw, you risk blocking off the drain hole.

Last edited by Stuart Kirk; 04/25/21 1:21 am. Reason: More info
Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Well I've done a a bodge on the head just for now. I got some vht liquid metal and covered the hole. Hopefully it will hold for a while so I can determine if it was affecting the running of the engine. Should be able to fire it up this week sometime.
[Linked Image]
[Linked Image]
[Linked Image]

Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Ok so I fixed the hole in the head and adjusted the ignition slightly. My son came over and started the beast for me and it does run a little better. I tried checking with the strobe light with limited success. I could tell at idle that the blue dots lined up but it was hard to tell where it was at when we increased the rpms as there was some oil flying around in there plus you can't see that much through the inspection cover. The bike sounded much crisper. No glowing head pipe but definately a lot of heat coming off the engine area. Also I tried rolling down the driveway and clicking it into gear but it wouldn't have any of it, just stalled. Clutch doesn't seem to be releasing but I know darned well that the plates are opening up well enough as I checked it. You can't move the bike with it in gear with the clutch pulled in, doesn't make any sense to me

Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Originally Posted by Peter Quick
I know a guy who used the Electrex STK-010 in a number of his BSA unit single MX bikes. He reports that with his B50 it runs best when set up closer to 35.5 degrees BTDC using the Electrex. Something to consider.

Peter
So if I wanted to try using 35.5* rather than the 34* which direction would I rotate the stator 1.5*. Would it be clockwise or counter clockwise from the original setting shown in the photo.
[Linked Image]
[Linked Image]

Joined: Jan 2004
Posts: 5,020
Likes: 82
D
Britbike forum member
Offline
Britbike forum member
D
Joined: Jan 2004
Posts: 5,020
Likes: 82
Rotating the pickup in the same direction as the crank rotates will retard the ignition. To go from 34 degrees to 35.5 degrees, rotate the pickup 1.5 degrees clockwise.

1 member likes this: johnu
Joined: Nov 2020
Posts: 67
Likes: 16
J
johnu Offline OP
Britbike forum member
OP Offline
Britbike forum member
J
Joined: Nov 2020
Posts: 67
Likes: 16
Thanks!

Last edited by johnu; 06/16/21 9:35 pm.
Page 2 of 2 1 2

Moderated by  Allan G, Jon W. Whitley 

Link Copied to Clipboard
Job CycleBritish Cycle SupplyMorries PlaceKlempf British PartsPodtronicVintage MagazineBSA Unit SinglesBritBike SponsorBritish Tools & FastenersBritBike SponsorBritBike Sponsor






© 1996-2021 britbike.com
Powered by UBB.threads™ PHP Forum Software 7.7.5