Search found 49 matches

by Shawn_Mc
Mon May 04, 2020 4:25 am
Forum: Tech
Topic: B50MX cam in a B25 and Big bore ideas.
Replies: 10
Views: 1839

Re: B50MX cam in a B25 and Big bore ideas.

Hi Remember the oif 71 B25T/SS crankcases are essentially the same casting as the B50 but with different machining carried out. So it is possible to convert a set of B25 crankcases to B50, although there is a fair amount of work required. The crankcase throat of a oif b25 has enough meat to take a ...
by Shawn_Mc
Sat May 02, 2020 5:16 am
Forum: Tech
Topic: Hub Powdercoat???s
Replies: 14
Views: 2316

Re: Hub Powdercoat???s

Have them Cerakoted. It's insanely tough and doesn't build up as much as powder does. You may want to fit the spokes first and see if you need to chase that hole a touch first. That way you wont have to drill your new coating. Ok thanks, do you know somewhere local that does this? I do. Juggernaugh...
by Shawn_Mc
Sat May 02, 2020 5:05 am
Forum: Tech
Topic: B50MX cam in a B25 and Big bore ideas.
Replies: 10
Views: 1839

Re: B50MX cam in a B25 and Big bore ideas.

I don't know the answer to any of this but what cc would that end up being if it is possible. I'm pretty sure there is a 280 kit available. 334.5cc Big bore does a couple things for you. in addition to the displacement, it unshrouds the intake valve by moving the curtain away from the cylinder side...
by Shawn_Mc
Fri May 01, 2020 9:03 pm
Forum: Tech
Topic: B50MX cam in a B25 and Big bore ideas.
Replies: 10
Views: 1839

B50MX cam in a B25 and Big bore ideas.

Has anyone done this? (Post 71', 3/4" bushing type) The base circle and lifts appear to be very similar, it's just a lot more duration. And is it possible to get a sleeve in there that will carry a 78mm piston? I'm aware that this isn't a bolt on...Just wondering how much meat is in the jug. Could i...
by Shawn_Mc
Fri May 01, 2020 8:44 pm
Forum: Tech
Topic: Hub Powdercoat???s
Replies: 14
Views: 2316

Re: Hub Powdercoat???s

Have them Cerakoted.

It's insanely tough and doesn't build up as much as powder does.

You may want to fit the spokes first and see if you need to chase that hole a touch first. That way you wont have to drill your new coating.
by Shawn_Mc
Fri May 01, 2020 8:31 pm
Forum: Tech
Topic: Amal vs Wassell carburetor
Replies: 45
Views: 6001

Re: Amal vs Wassell carburetor

I got a brand new 928 Premier from UnitSingles. It was about 30 bucks more than the parts to completely rebuild the 928 my B25 came with. My old Beezer starts first or second kick every time. I was originally going to put the Mikuni VM28 on it because Ive got a TON of experience with Mikunis and Kei...
by Shawn_Mc
Fri Apr 24, 2020 3:20 pm
Forum: Tech
Topic: A kicker that actually folds away?
Replies: 23
Views: 3421

Re: A kicker that actually folds away?

Is the PES part like the MX piece? I cant find it anywhere on the Web. If you go to this page, and do a search (Ctrl + F) for "Kickstart lever" you should get 8 results, included is this for the B50 and there are some with splined shafts (splined quadrant needed, but then you can use a variety of j...
by Shawn_Mc
Fri Apr 24, 2020 2:46 am
Forum: Tech
Topic: A kicker that actually folds away?
Replies: 23
Views: 3421

Re: A kicker that actually folds away?

Seems like the stocker just sticks out way to fa, no need for all that clearance. Could almost be a straight arm! It could. The real issue is where it's indexed on the shaft and the fact that you cant change were it's placed because they used that wedge pin instead of a spline. They saved some mone...
by Shawn_Mc
Thu Apr 23, 2020 6:13 pm
Forum: Tech
Topic: A kicker that actually folds away?
Replies: 23
Views: 3421

Re: A kicker that actually folds away?

There's a Trials unit on BSA Unit Singles. He lists the MX part too, but none in stock. The trials part looks quite a bit longer. It's pretty expensive, but I really dont see an alternative... The stock kicker location is horrific. I cant believe I ever rode it as hard as I did as a kid, like that. ...
by Shawn_Mc
Thu Apr 23, 2020 2:37 am
Forum: Tech
Topic: A kicker that actually folds away?
Replies: 23
Views: 3421

A kicker that actually folds away?

Does anyone make a kick lever that actually folds out of the way? The kicker on my 71' B25 literally sits right in the path to the foot peg. I'm not opposed to breaking out the torch and reshaping it, but is it cast iron? Can I actually bend the thing without having it shatter or something (assuming...
by Shawn_Mc
Mon Apr 20, 2020 5:48 am
Forum: Tech
Topic: B25ss fork damper unit retaing bolt washers
Replies: 9
Views: 1511

Re: B25ss fork damper unit retaing bolt washers

I just put RaceTech emulators in my B25 yesterday. All you need is a copper washer beneath the Allen bolt. That washer is just a seal. Why they did it that way, was is too smart by half.
by Shawn_Mc
Thu Apr 09, 2020 3:59 am
Forum: Tech
Topic: Better OIF Damper rod piston ring
Replies: 16
Views: 2693

Re: Better OIF Damper rod piston ring

Here's how the damping rods work. This drawing is fairly generic, but pretty much, everything is there and applies.


https://www.racetech.com/page/title/Emu ... hey%20Work
by Shawn_Mc
Sat Apr 04, 2020 2:20 am
Forum: Tech
Topic: Better OIF Damper rod piston ring
Replies: 16
Views: 2693

Re: Better OIF Damper rod piston ring

Buying some PTFE washers from https://www.ebay.co.uk/itm/Bespoke-Custom-PTFE-Teflon-Washers-1-5mm-thick-various-sizes-available-to-80mm/302592678775?ssPageName=STRK%3AMEBIDX%3AIT&var=601431743100&_trksid=p2057872.m2749.l2649 These are to fit some Koni 76 series dampers where the iron sealing rings ...
by Shawn_Mc
Fri Apr 03, 2020 3:57 am
Forum: Tech
Topic: Better OIF Damper rod piston ring
Replies: 16
Views: 2693

Re: Better OIF Damper rod piston ring

Hi I have three points to make on this subject. I comment based on research I have done in getting to a similar point as the original poster here. One is that I tried to find an off the shelf solution to the o ring issue without luck. Eventually I bit the bullet and bought a set of ptfe seals from ...
by Shawn_Mc
Fri Mar 27, 2020 9:54 pm
Forum: Tech
Topic: Better OIF Damper rod piston ring
Replies: 16
Views: 2693

Re: Better OIF Damper rod piston ring

The stanchions I got were the heavy duty parts from the UK. I had to wash the cosmoline off/out of them and they were pretty good inside. Those phonelic parts probably work pretty good, but at $33 American, then being shipped to the US...YIKES...Gotta be a better way. I'll probably make a pair out o...
by Shawn_Mc
Fri Mar 27, 2020 4:25 am
Forum: Tech
Topic: Better OIF Damper rod piston ring
Replies: 16
Views: 2693

Re: Better OIF Damper rod piston ring

RaceTech makes a teflon one, and they're a 20 minute drive from where I am, but dropping $20 a piece for glorified orings..I cant do it. It's the principal of the thing.
by Shawn_Mc
Thu Mar 26, 2020 7:22 pm
Forum: Tech
Topic: Frame Geometry
Replies: 10
Views: 1880

Re: Frame Geometry

I don't know if I understood your query well, but you must keep in mind the fork suspension snicking, with the springs loaded, this changes the rake. you can find a lot of information about this in the books of tony foale books But that isnt the way things get setup on the drawing. Normal suspensio...
by Shawn_Mc
Thu Mar 26, 2020 7:17 pm
Forum: Tech
Topic: Better OIF Damper rod piston ring
Replies: 16
Views: 2693

Better OIF Damper rod piston ring

Besides Racetech, does someone offer a better, slicker option piston ring for the damper rods? I cant find it anywhere. Ive got a Gold Valve emulator coming for the fork, but I dont want to deal with those sticky OEM orings. Mine are brand new, but man, smooth, they arent.
by Shawn_Mc
Thu Mar 26, 2020 8:55 am
Forum: Tech
Topic: Swing Arm Design/Chain Adjuster/Geometry
Replies: 15
Views: 2780

Re: Swing Arm Design/Chain Adjuster/Geometry

That snail adjuster was probably a result of the night terrors left over from the Titanium frame and Swing arm attempts of factory BSA for the Factory race bike. The swing arm flexed so much they couldn't keep the chain on.
by Shawn_Mc
Thu Mar 26, 2020 7:55 am
Forum: Tech
Topic: Fixed my Exhaust leak at the head
Replies: 9
Views: 2179

Re: Fixed my Exhaust leak at the head

minetymenace wrote: Wed Mar 25, 2020 10:28 pm Poll added....just for fun :ban
300 miles of Motocross is a LONG TIME :laugh :ban <216
by Shawn_Mc
Wed Mar 25, 2020 9:41 pm
Forum: Tech
Topic: Fixed my Exhaust leak at the head
Replies: 9
Views: 2179

Re: Fixed my Exhaust leak at the head

Well, I'm not relying on the silicone to seal. That's what the foil is for, The silicone is just to give the foil more body. I've got another idea that is far more work, but it'll be bullet proof for when / if this fails in short order. I've seen this method work for an actual head gasket, but we'll...
by Shawn_Mc
Tue Mar 24, 2020 7:59 pm
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

That should work, but there will be oil thrown off the flywheel which may fill the breather up with oil. I am using the tach port on my TR25 race bike as seen here: Breather on TR25.jpg The O2 Sensor you got there seems pretty close to the head. Is there a specific reason for that? Because it is al...
by Shawn_Mc
Tue Mar 24, 2020 6:49 am
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

Little more here, little more there.
by Shawn_Mc
Tue Mar 24, 2020 6:32 am
Forum: Tech
Topic: Fixed my Exhaust leak at the head
Replies: 9
Views: 2179

Fixed my Exhaust leak at the head

Ok, this has been bugging me for 30+ plus years maybe... My dad made a couple suggestions...they didn't work yada yada Here's what I did: I took a 12 in long strip of Aluminum foil 1 1/2 inches wide. I spread a teeny bit of silicone on the header, wrapped the header with the foil leaving 3/4s of an ...
by Shawn_Mc
Tue Mar 24, 2020 6:22 am
Forum: Tech
Topic: Best Electronic Ignition
Replies: 23
Views: 4216

Re: Best Electronic Ignition

I just took out the points. Left Everything else. Made a plug for wire.
by Shawn_Mc
Mon Mar 23, 2020 7:37 pm
Forum: Tech
Topic: Best Electronic Ignition
Replies: 23
Views: 4216

Re: Best Electronic Ignition

Trevor, can you post a link the Podtronics ignitions please. Paul. Now I'm curious. Why the dislike of the Electrex? You're the second or third person I've seen try to steer someone away from the Electrex unit. Why marry yourself to another magnetic pick up (assuming that's the route) wedged into t...
by Shawn_Mc
Mon Mar 23, 2020 7:15 pm
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

I've got another question Why does everybody (including BSA) put the brake backing plate on the right side? Doing that give the brake cable an unnatural path to the lever. I looked at that and thought "that's just silly". The way I mounted it, on the left side (and Ive seen a couple others did it th...
by Shawn_Mc
Mon Mar 23, 2020 7:05 pm
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

koncretekid wrote: Mon Mar 23, 2020 1:06 pm That should work, but there will be oil thrown off the flywheel which may fill the breather up with oil. I am using the tach port on my TR25 race bike as seen here:

Breather on TR25.jpg
The O2 Sensor you got there seems pretty close to the head. Is there a specific reason for that?
by Shawn_Mc
Mon Mar 23, 2020 4:30 am
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

Nope, the B25 uses social distancing between the primary and engine oil. :laugh
The B25 primary breather are these tiny little holes in the fill plug.

Speaking of breathing, why doesn't anyone use the "timing plug" on the front left side for a breather? B50 or B25.
by Shawn_Mc
Mon Mar 23, 2020 4:23 am
Forum: Tech
Topic: Best Electronic Ignition
Replies: 23
Views: 4216

Re: Best Electronic Ignition

Thanks Shawn. You are the second person to recommend the Electrex so i will likely go with that. Is it simple to install and set up? Also where did you purchase it from. I see you are in SoCal as I am (Redlands). I got it from Peter Quick at BSA Unit Singles. It really is easy to install. All you n...
by Shawn_Mc
Sun Mar 22, 2020 8:41 pm
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

On my clutch spring nuts there is a hole to wire though to stop them from backing off Mine too, but the clutch slips if the nuts are back out far enough to take advantage of the hole with safety wire. I probably just buy new springs. A new set of clutch plates probably wouldn't hurt either. We'll s...
by Shawn_Mc
Sun Mar 22, 2020 9:07 am
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

Very nice I do like the provision to change the angle of the rear shocks and the centre stand >44 You like that stand? LOL....Took me twenty minutes and cost me $30 bucks. I was using one of my standard Moto stands and both wheels end up a foot off the ground and a bust my back picking that dinosau...
by Shawn_Mc
Sun Mar 22, 2020 8:50 am
Forum: Tech
Topic: Best ignition with lighting
Replies: 7
Views: 1542

Re: Best ignition with lighting

The Wassell ignition is good, why not just fit a capacitor and keep the Wassell ignition. Electrex support seems hit and miss. https://granttiller.com/2020/02/13/electrex-world-unboxing-fitting-opinions/ Well, these guys struggled, that's a fact. But, I just put an Electrex on my B25 and it fired u...
by Shawn_Mc
Fri Mar 20, 2020 6:27 am
Forum: Tech
Topic: B25 Oil circulation mod, why wouldn't this work?
Replies: 8
Views: 1854

Re: B25 Oil circulation mod, why wouldn't this work?

It'd have to foam the entire volume of oil. Returning the oil to the back would give it more time to defoam as it made it's way to the front down tube also. As it is, the oil that gets almost completely by-passed just sits there while the "foamy" scavenged oil just dumps back into the down tube. And...
by Shawn_Mc
Fri Mar 20, 2020 6:19 am
Forum: Tech
Topic: Best Electronic Ignition
Replies: 23
Views: 4216

Re: Best Electronic Ignition

I just mounted an Electrex on my B25. Pretty sweet. Spinning the engine over by hand with no plug makes a pretty significant spark. It's basically a PVL style and you cant beat it for the price.
No charging system, but if your setting up an MX'r, this is the ticket, IMHO.
by Shawn_Mc
Fri Mar 20, 2020 5:03 am
Forum: Project bikes
Topic: My 1971 B25 VT
Replies: 24
Views: 4526

Re: My 1971 B25 VT

Once I get it complete and running again, I think I'm going to tear it all apart, powder coat the frame after I add some tabs to carry the side plates. I'll pull the head and barrel and have them vapor blasted, pull the side covers and the tank and have them professionally polished. The rear fender ...
by Shawn_Mc
Thu Mar 19, 2020 4:12 am
Forum: Tech
Topic: B25 Oil circulation mod, why wouldn't this work?
Replies: 8
Views: 1854

Re: B25 Oil circulation mod, why wouldn't this work?

6. Drill a brass or alloy plug to .020" and insert that to a NP fitting into the oil pressure switch hole in the case. Is .020" enough? That doesn't seem like much oil. Granted, I'm used to flooding the rocker / valve train with oil to cool the springs, and that simply isn't necessary here..but .02...
by Shawn_Mc
Thu Mar 19, 2020 3:54 am
Forum: Tech
Topic: B25 to B50 conversion?
Replies: 8
Views: 1669

Re: B25 to B50 conversion?

Speaking of Big Bore B25's has anyone seen this guy? https://www.youtube.com/watch?v=7DT7NUZTr9Y He makes a 300 out of an FJ1200 piston and cylinder. The only issue being the wrist pin is smaller on the Beezer rod. Easy fix. Or even easier, a phone call to JE to get one made with a smaller pin and n...
by Shawn_Mc
Wed Mar 18, 2020 9:50 pm
Forum: Tech
Topic: B25 Oil circulation mod, why wouldn't this work?
Replies: 8
Views: 1854

B25 Oil circulation mod, why wouldn't this work?

If you put a check valve in the return off the bottom that is technically under pressure from the scavenge side, why couldn't you plumb that into the REAR of the frame to return there to circulate all of the oil, which would increase oil cooling pretty dramatically. I understand why you cant just pl...
by Shawn_Mc
Wed Mar 18, 2020 9:26 pm
Forum: Tech
Topic: B25 to B50 conversion?
Replies: 8
Views: 1669

Re: B25 to B50 conversion?

As well as boring out the throat and moving the studs, a boss needs to be welded (and machined) to the drive side case to take the extra bearing . Yes, as kommando says, Mark and Anita at CCM-Britain (aka Performance Engineering Services or PES) are tooled up to do this. While the cases are jigged ...