Vintage Road Racing Association

Ok so i found a T25, probably in bad shape (i will pick it up around chrismas time). This will be a joint venture for me , Patrick Gagnon and my dad... we will built/own the bike together and probably each ride it at different rounds...(this may only happen in 2014) I have access to a few BSA parts from my dads friend who is a BSA collector to help get this project moving so i need help with different questions i have. The point of this bike is to spend as little money as possible to get it on the track, free would be the best, but reliable and easy to work on would be at the top of our priorities as well.

so
- T25/B25 forks look like a pain to work on (from what i read), what other BSA front end would be legal and fit and perform better and be easy to work on, 35mm or smaller, bonus is the wheel attached to the forks is VM3 and has a decent front brake...

- T25 is a 28mm amal carb, dont know anything about them, other then jokes i hear.. the 441 carb is 30mm and bolts on, any other idea to make it easy to work on, i don't know anything about P1 era carbs, what is simple and fits and legal, and you guys know what a carb expert my dad is, so lets make it REAL simple...

- Electric, do i change the ignition? what is legal?

HEEEEEEEEELP hahaha you guys got me into this with your P1-200 Thread, now help me...

this looks like more of a tech question, but hopefully this thread will become a built thread soon enough

Take a deep breath Dom... I'll take the beating for you and get the suggestion out of the way fast. To make things easy, swap the entire front end out for an early RD//R5 drum brake setup. (Gasp!) I know it's probably gonna get me run out of town to suggest it, but they are everywhere for almost zero money have the correct size wheel already, and you can get Ferodo race compound (2 different compounds BTW) pads for them. Easy-Peasy.

As for the carb, I know zero about the little BSA (or any BSA for that matter) but when it comes to simple easy and cheap, Mikuni is the only carb for me. (Gasp again!)

Let the rock throwing commence! It's a long ways across that lake!

Hi Dom,
Ashton's suggestion re: front end has a lot of merit but I suggest you PM Peter Balfour - a lot of the stuff he's done to his B50 as regards suspension, etc should be directly applicable to your bike - probably a late model alloy front end and conical dls front brake will fit on (same steering head bearings I think). Use an 18 inch front wheel and get rid of the 19 or omigod 20" rim if your bike has that turkey on it (my friend's Beeza 250 has one).
Dump the Amal (give it to me) and get a Mikuni - tune what you're comfortable with, 30mm is max allowed I believe.
Don't know what your sponsor will allow you to do to the bike, but consider buying extra blades for your sawzall and start cutting. The 250 used the same frame as some models of the 500, so not particularly light. You know the drill for the rest of it - lightweight seat and fenders, etc etc.
Don't know what Peter B. is running for an ignition but probably a constant loss with points would work and it's cheap - you'll never turn that puppy tight enough to get points bounce LOL.
And I think the cutoff is 1970 for your bike - you might want to check the rule book on that one.
You can go pretty crazy on these bikes if you want to - just ask Peter or check some of the vintage British racing clubs. I can't think putting 5000 British pounds into a 250 makes much sense but what do I know?
Oh ya, and no 288 kits, okay?
Let me know when you want to order your new fiberglass bodywork for the bike.
Have fun. Just don't pick on us little guys with the 125's.
Pat.

Mine is a 70 i believe, but the VRRA or ARHMA rules don't state a year, i am pretty sure 67 to 71 are pretty much the same as far as engines go, the rest of the bike won't look much like the factory bike anyway...

My plan was to email Peter for sure... i just could remember if his was a single or not... i guess the forks he uses would work on my T25 as well...

Sponsor is a BSA "freak" , he doesn't care as much for Triumphs so i can chop/cut/rebuilt anything i want to make the frame lighter... we plan on doing that, i wont run any fenders... and probably wont run much bodywork either to start...

im going for something like this... (probably not as pretty)....

Hi Dom,
Nice bike!
Looks like it has the late model front forks and DLS brake I talked about earlier, probably the 18" rim too.
IMHO, run a front fender with a fork brace - you're used to the sturdy Hawk forks and those Brit forks aren't that stiff. Even a smallish front fender will keep the shite away from the motor, may help it cool a bit better and a little rear underfender will keep the crud out of the carb.
The Norton Manx nosebowl looks perfect - I have one in stock right now. A bunch of different solo seats will work too. Don't know what your thoughts are on tanks but I'm "meh" about the trail bike tank on the photo bike- maybe use a B25 or Spitfire tank if its not total blasphemy on the part of your sponsor?
When I get a chance, I'll go through my files and see if I have any articles on hotrodding the T25 / B25 motors and send you what I find.
Have fun with your project.
Pat

Welcome to the "dark side" dom! Your B25 will be virtually identical to my B50 except for a few chosen engine parts. The bottom ends are identical and the only real difference is the cylinder, head etc.. There are a ton of tricks out there to make these thumpers go but it will depend on your budget. Here is what I deem as mandatory:

Mikuni VM style carb
Electronic ignition running negative ground, I run a Pazon. Might have a spare Boyer, I'll look.
Balancing the crank is a good idea but not cheap
All the power gains for these things are in the head and I'm buddies with the best BSA single mechanic around if you need more info.

Running gear:

The chassis is awesome on these things, very stiff. Don't chuck the forks, they work great, very little mods required.
If it has the 8" drum you're good. Just some harder pads and the brake will work decent for a drum.
Run 18" rims, I have some spares.

Email me for more info. I always wanted to do a B25 since I can do a complete rebuild on these beezer engines blind folded. If you talk to me nice I may be willing to go through the motor for a reasonable cost .

Peter

Hey Peter, does this have one of those crazy open bearing clutches like what I helped Joel with two years ago on his 500 @ Mosport? If so you might want to start there with you Beezer 101 course. I don't remember the specifics, but I remember it seeming like the weak spot in the system, and being pretty tricky to get set up right...

Peter Balfour wrote:Welcome to the "dark side" dom! Your B25 will be virtually identical to my B50 except for a few chosen engine parts. The bottom ends are identical and the only real difference is the cylinder, head etc.. There are a ton of tricks out there to make these thumpers go but it will depend on your budget. Here is what I deem as mandatory:

Mikuni VM style carb
Electronic ignition running negative ground, I run a Pazon. Might have a spare Boyer, I'll look.
Balancing the crank is a good idea but not cheap
All the power gains for these things are in the head and I'm buddies with the best BSA single mechanic around if you need more info.

Running gear:

The chassis is awesome on these things, very stiff. Don't chuck the forks, they work great, very little mods required.
If it has the 8" drum you're good. Just some harder pads and the brake will work decent for a drum.
Run 18" rims, I have some spares.

Email me for more info. I always wanted to do a B25 since I can do a complete rebuild on these beezer engines blind folded. If you talk to me nice I may be willing to go through the motor for a reasonable cost .

Peter

Thanks Peter, i guess i will know more once i pickup the bike, thanks for all the great info...

What size are the T25 forks?
What BSA models come with a 18inch front?

pacomotorstuff wrote:Hi Dom,
Nice bike!
Looks like it has the late model front forks and DLS brake I talked about earlier, probably the 18" rim too.
IMHO, run a front fender with a fork brace - you're used to the sturdy Hawk forks and those Brit forks aren't that stiff. Even a smallish front fender will keep the shite away from the motor, may help it cool a bit better and a little rear underfender will keep the crud out of the carb.
The Norton Manx nosebowl looks perfect - I have one in stock right now. A bunch of different solo seats will work too. Don't know what your thoughts are on tanks but I'm "meh" about the trail bike tank on the photo bike- maybe use a B25 or Spitfire tank if its not total blasphemy on the part of your sponsor?
When I get a chance, I'll go through my files and see if I have any articles on hotrodding the T25 / B25 motors and send you what I find.
Have fun with your project.
Pat

I think a big point about the gas tank is metal VS fiberglass... that might be why that guy is using that gas tank...

Hey Dom,I think that triumph used steel tanks where bsa used fiberglass.Both used aluminum in thier all out scramblers as your pic above.If yours is a street version it will have the 7"tls brake which is better than the 350 yamaha/honda but not as good as the honda 450.The 7" would be fine for now as it has an 18" rim.
The 8"dls has an 19" but will bolt right in & you could lace one later.The front end is the same a the 500/650 & is good & stiff as is.

Great info, thank you...

Hey Dom,The carbs are very easy to work on.The only issue is sometimes people tighten them up to much & warp the flange causing an air leak & backfire.This can be fixed by valve grinding past on a plate of glass & rub until smooth.The 28 is good the 30 better.Walridge motors sells parts very cheep.They also have a mikuni type replacement carb that bolts on for around $150 I think.If you want to keep costs down a carb,pipe,& some rubber & your off.These bikes also have a 4 speed trans & shift from the right.There is not much of a choise of gearing.I plan to adapt a Kawasaki triple rear wheel which has a cable brake to brake from the right & make a linkage to shift from the left.Unless you are British.All things to think about.

Brad

I think shifting on the right will be part of the fun or riding this bike.... unless we find a very clean stock carb, i think we are going with a mikuni...