[Mr.Mazza]

Saw a few pictures and posts about this, basically getting a Bullet's frame and dropping an Intercepter engine into it, the frames look the same so I assume this can be done?
Would the same gearbox be used or were they different?
I'm really interested as this might be a eaiser, cheaper and cooler way of getting a Bulletcepter

[1 Thump]

Check this out:
http://www.enfieldmotorcycles.com/forum/index.php/topic,4823.msg108697.html#msg108697

[Mr.Mazza]

Thanks thump!
Seems like easy enough surgery!
Also end up with a cool different bike

[High On Octane]

I just read thru that thread that 1 Thump posted.  Here's my 2 cents:

Certainly this can be done.  ANYTHING can be done with the right resources, the right amount of money and the right motivation.  Tho there are several points that were brought up in that thread that need to be considered and addressed......

- The most important being engine mounting.  The upper head stays are CRUCIAL on these motors.  I know for a fact that if you run one of these twins without the head stays, it will damn near shake you right off of the bike.  I learned this last summer after replacing the head gaskets and taking a short 20 minute ride to get the motor to operating temp to hot torque the head bolts.  It was so bad I don't think I revved over 3500 RPMs.

- Another consideration is going to be that rear wheel alignment, you will most likely need the rear wheel that came with the motor and trans.

- Next, keep in mind that any time you put a motor where it doesn't belong, you are guaranteed to need some amount of custom fabrication.  It's almost impossible to say what exactly as there isn't much info on this conversion.  So unfortunately, you will have to Pioneer what needs to be done, unless you can get in contact with a person that has already personally done this.

Finally - The hardest part.  Actually FINDING a motor and trans.  How hard is this?  Well, I spent about 2 1/2 months searching damn near every day for just a motor.  I was wanting to build a race motor for the Blackhawk that I could build and just drop in 1 weekend.  I came in contact with 1 individual that had/has an Interceptor Series I motor and trans.  The motor needed to be rebuilt and the guy still wanted $2K.  No thanks, I'll pass on that deal.  I finally came across a deal where a member here on the forum had a '59 RE/Chief.  The bike was completely disassemble and had spun a rod bearing on cylinder 1.  I ended up getting the entire project for the same price that I wanted to spend on a motor.  So now I have found myself building a whole new bike. 

I guess what I'm trying to say is, unless you are very handy with custom fab and have access to the resources you need, I would find yourself an entire bike with a twin and just restore it.  Honestly, there is hardly much of a difference in the frames, but there are enough differences to cause a few issues.

And FWIW, the late model 700 ('58 on) motors are essentially the same motors as the Series I Interceptors.  It is very easy to turn a 700 into a Series I, that's what I'm doing anyways.  With the addition of a supercharger of course. 

Scottie J

[Mr.Mazza]

Yeah scottie I can get a whole engine gearbox everything easy enough
The top mount job should be easy enough, got an uncle who runs a laser cutting place and engineering mates who can autocad a mount system up.

[High On Octane]

Sound like you have the resources part taken care of.  Don't forget you will probably need to do some welding as well.  You might want to look into getting a rear wheel for a twin.  That would be the easiest easy way to make sure your chain runs true.

Scottie J

[Blltrdr]

Hitchcock's sells that widened swingarm that would work perfect for a project like this. I would assume the rear wheel on an Interceptor is a WM3.

[Mr.Mazza]

Sound like you have the resources part taken care of.  Don't forget you will probably need to do some welding as well.  You might want to look into getting a rear wheel for a twin.  That would be the easiest easy way to make sure your chain runs true.

Scottie J

Just checked at hitchcocks, they sell the mount with bolts washers ect.
Yeah with welding it, I imagine I'll have to weld it same way they welded it to the Intercepter frame, any chance you can snap me a pic so I can see what kind of weld it is?
And rear stuff will be easy, as Blltrdr said I can get that wided swingarm.

[High On Octane]

From what I can tell, the only real welding situation is going to be welding a bung to the bottom of the upper frame tube to mount the head steady.  Now after looking at pics of both my bikes' frames I noticed a short time ago that the frames themselves are the same, but the bungs and mounts are in different places.  Observe:

On the frame of the '58 Trailblazer, the head stay bung is mounted directly above the the heads of the motor.  Unfortunately I don't have a pic of the head stays mounted, but there are 2 angle brackets, that bolt to the top of the heads opposing each other and then a bolt goes thru both thru the brackets and the welded bung I have circled in the picture.



On the '59 Chief, the head stay is a bit different.  The bung is welded further back closer to the seat.  From what I can tell, there is a goofy (and not at all strong looking) tensioner bolt that connects the heads to the bung, and you then tighten the bolt to stiffen up the motor.  I'm pretty sure I am going to end up making a custom head stay for the Chief, as I am going to making around 100hp and I need that motor to sit still.  Also, notice how on the Chief frame there is a bung on TOP of the frame to mount the gas tank.  The Trailblazer does not have this mount.



Scottie J

[barenekd]

I would assume the rear wheel on an Interceptor is a WM3.

The Interceptors didn't get a WM3 rim until the '68 Series 2 version.
Bare

[Blltrdr]

The Interceptors didn't get a WM3 rim until the '68 Series 2 version.
Bare

If I was doing this build I would look for a later model Interceptor motor anyway. The cylinder was redesigned as a single unit unlike the two piece cylinders the older series used.

[Mr.Mazza]

From what I can tell, the only real welding situation is going to be welding a bung to the bottom of the upper frame tube to mount the head steady.  Now after looking at pics of both my bikes' frames I noticed a short time ago that the frames themselves are the same, but the bungs and mounts are in different places.  Observe:

On the frame of the '58 Trailblazer, the head stay bung is mounted directly above the the heads of the motor.  Unfortunately I don't have a pic of the head stays mounted, but there are 2 angle brackets, that bolt to the top of the heads opposing each other and then a bolt goes thru both thru the brackets and the welded bung I have circled in the picture.



On the '59 Chief, the head stay is a bit different.  The bung is welded further back closer to the seat.  From what I can tell, there is a goofy (and not at all strong looking) tensioner bolt that connects the heads to the bung, and you then tighten the bolt to stiffen up the motor.  I'm pretty sure I am going to end up making a custom head stay for the Chief, as I am going to making around 100hp and I need that motor to sit still.  Also, notice how on the Chief frame there is a bung on TOP of the frame to mount the gas tank.  The Trailblazer does not have this mount.



Scottie J

I've had at look at later model Intercepter frames, and it has the mount (or bungs) directly above the head, which should be an easy mod.

Thanks for the advice guys, work will start in around a year (After the police will let me mod my bike, new license ect.) so I'll keep you posted

[Afro Samurai]

What?...after the police let you mod the bike?....what does that mean...all I ever see is the ausies are speed nuts....v8super car series...i have a holden /gto ...the car is nuts...and all my rotary engne stuff...what is the world coming to when an australian has to ask permission to go fast.....im in.alabama...i dont ask permission to do anything...cause this aint california....

[ace.cafe]

What if I told you that you could make your Bullet 500 single go as fast as an Interceptor, and not have to buy that twin engine or worry about the police approving an engine switch?

[Afro Samurai]

That sounds like the solution Ace...

[Mr.Mazza]

What if I told you that you could make your Bullet 500 single go as fast as an Interceptor, and not have to buy that twin engine or worry about the police approving an engine switch?

Yes ace but this is cost effective and a more unqiue bike and the engine swap is more legal than modding an engine. And a better platform for prefomance

[ace.cafe]

Okay. Just thought it might be easier to get past the "modification police"

[Mr.Mazza]

Okay. Just thought it might be easier to get past the "modification police"

I appreciate the effort and ideas ace

[High On Octane]

I'm confused.  Why would it be legally easier to install a motor almost twice the size of the original than to slightly modify the original engine.  That doesn't make any sense to me.

Scottie J

[Mr.Mazza]

I'm confused.  Why would it be legally easier to install a motor almost twice the size of the original than to slightly modify the original engine.  That doesn't make any sense to me.

Scottie J

Its Australia mate, shit never makes sense. All I need is engineers cert which is easy.

[AgentX]

Its Australia mate, shit never makes sense.