Bang for the Buck, next level

[ace.cafe]

We've looked at the budget performance mods in a previous thread.
That's some really good punch for the money.
Many folks are happy right there.
That bumps the power from about 15 hp at the rear wheel, to about 19hp at the rear wheel. Maybe even closer to 20hp in some Bullets.

But, what if somebody wants a little more than that?
Where do they go from there?
And the budget is still somewhat of a concern?

One of the more popular choices is to get a larger and more capable carburetor.
This is quite popular.
There are a variety of choices you can make.
I'm particularly fond of the flat-slide types, because they are the most advanced form of carb for our bikes.
The type and size of the carb you choose is going to be somewhat related to your use of  the bike, and the expected power improvements at various parts of the rpm range.
The smaller carb sizes tend to retain better fuel economy, and also retain the most low-speed torque.
The larger carb sizes tend to give more power at wide throttle openings, but may not give as good fuel economy, and could give away a little low-speed torque, because they favor the higher rpm power.
The choice depends on how you plan to use the bike, and what characteristics are most important to you.
2 of the very popular options are the 30mm flat-slide, and 32mm flatslide, and another one that's been popular is the 34mm roundslide. Also, there are Amal carbs for those of you who prefer the vintage appearance of an Amal carb.
Personally, I have to admit that I'm not a big fan of Amal carbs.

Basically, going to a larger carb than the 28mm Mikarb gives you more power in the upper midrange and higher rpms. It doesn't give you much more down low, if anything. A larger carb doesn't really give you anything additional, until you open it up bigger than your previous smaller carb could give. But, when you do go to the bigger throttle positions, you get more power out of  it.
The flat-slides are better, in that they flow so much better, they even give increased torque in the lower midrange, and a real stable idle, plus giving you great results at the large throttle openings. So, flat-slides are real good.
And that's about as far as you can go, while still staying out of the innards of the engine. That's the end of the line for external "bolt-on" stuff.
The bigger carb will yield you about 1-2 hp more than you had with just the free-flow upgrades, so maybe 20-21hp at the rear wheel as a total, if you tune it right.


All right.. Now we've got a carb on there that can feed our powerplant better at the higher rpms.
The higher rpms are where the power is.
So, that's why we need to be able to feed the engine well at those rpms.

And what more can we do?
Doing more is going to require taking some of the engine apart.
With a simple top end removal, we can install a higher compression piston.
We'll want to use a new forged piston, instead of just shaving the deck of the barrel, because the OEM piston is a little weak, and we don't want to push that piston much harder. So, a better piston with some extra compression would be the order of the day.
Several hundred bucks, and an afternoon's work.
Going to a 535cc kit will give you extra displacement along with your extra compression, and will be worth another hp or two on top of whatever the compression increase is going to give you. Doesn't cost anymore to get the 535 piston, but it will cost you to get your cylinder bored out to fit it.
When choosing a new forged piston to put in your engine, and on your stock alloy rod, it's a good idea to get the lightest piston available, so that you don't put more stress on the rod than the OEM piston did. So, a light piston is best.
Installing this higher compression piston has some special requirements, so that you don't push the compression too high, and this is something you can ask me about when you need to. There is a certain way to set the compression on these engines, and it's not complicated, but it involves some spacers under the barrel when you install the piston. The amount of spacers will be determined by the piston you get, and the cams you are using.

Speaking of cams.
There is a new set of cams that CMW is carrying now, called the ACE Clubman Cams.
These are special sets of cams made in India, which I inspect, and measure, and re-time to meet high performance standards.
These are the most "bang for the buck" in cam sets for the Bullet.
They drop right into the timing chest with no mods, and don't require any special valve springs, or any special anything. Except they do need to have the high compression piston in the engine to make them work right.
They are the least expensive performance cams for the Bullet.
But, don't underestimate them!
These cams really deliver some power!
They will work just fine with a stock head. No porting required for good results with these cams.
They're just a few pennies under 200 bucks for the set, and they include a new timing pinion gear with them too.
You can't beat this for the money.


Ok, so I said this is Level 2 for "bang for the buck".
How much is it gonna set you back in the wallet?

You can get a basic carb kit for about $200 and up, depending on what you choose.
A high compression piston is going to be near $300 more.
If you do a bore to 535, it could cost anywhere from $50 for your local shop to bore your cylinder, to up to about $500 for a complete big-bore kit and alloy cylinder(but the high compression piston is included with that kit as a package).
Your choice.
And if you want the ACE Clubman Cams, add another $200.
So, you're talking about at least $750, and maybe more, depending on what you pick out for your selections of carb and barrel type.

So, what is this gonna give you for power?
Well, let's say you go the whole 9-yards, and do all I described.
If you have a stock head without porting, and you keep the revs under 5000 rpm for engine longevity, you're gonna be around 28hp at the rear wheel. Maybe as high as 30hp at the rear wheel with a 535.
Torque will be up there at around 28-30 foot pounds too, peaking at around 3500 rpm.
That's nearly double the stock rear-wheel hp of a factory "bone-stock" Bullet.
It's a real kick in the pants!

Now remember, this isn't involving anything in the bottom-end, like crank or rod or bearings.  And they are not the most robust parts in the world, in stock form. So, you gotta be a little careful with how high you rev the motor. It ain't gonna want to stop at 5000 rpm all by itself. It will run right past 5000 rpm if you let it.
So, you have to pay attention to your throttle hand.
Having a tachometer would be a good thing.

You also might want to look into a better clutch, like the miracle clutch or something like that, because it's probably going to make your stock clutch slip with all this extra power on tap. More power than the stock clutch can really hold well.

This REALLY wakes up a Bullet. When you've doubled the stock hp at the rear wheel, that's a pretty big upgrade.
And doing it for this little money, is unheard of in the world of engine modifications.
This is a very inexpensive cost for doubling your rear-wheel horsepower.
But remember, the bottom-end of the motor is not indestructible. So you're on your own to ensure that you take care of it, and don't go revving to the moon with all this new-found power. It would probably be a good idea to plan a bottom-end overhaul with improved high-performance parts down there, over the winter in a year or two, just to be on the safe side.

[REpozer]

ACE, your a sick man!
 In honer of the old  Dr. Oldsmobile adds ( the 442),

I hearby dub you  AKA.....Dr. Roy Enfield...mad gennious....... muuhaahaa!

[Merrill]

Hum, the 30mm amal on my
sixty-five is doing a fine job
in those three most important
categories. Idle, roll on, and pegged.
//
and I'm not even selling them
/
merrill

[ace.cafe]

Hum, the 30mm amal on my
sixty-five is doing a fine job
in those three most important
categories. Idle, roll on, and pegged.
//
and I'm not even selling them
/
merrill

Cool!
I'm glad it's working well  for you.
30mm is a good size for all around use.

I don't sell carbs either, but CMW has a nice choice of them.
Amals too!

[72westie]

The miracle clutch worked for us until around the 30-32HP range before it started slipping. After that, we went to the belt drive racing set-up. Awesome clutch, but expensive as hell.

[jedaks]

I'm blowing the dust off this thread, but it was just what I was looking for!

I was hoping there was a way to get the bike to cruise at 65mph when traffic conditions require it without going inside the motor. But now I know there isn't. I've already done the air filter/exhaust/jetting modifications, all with good results.

I am thinking maybe a 18 tooth sprocket might help and still be tolerable in hilly country.

I always ride in the 50-55mph zone and I always take backroads where I can, to avoid traffic. But sometimes I have no choice but to ride the highway and keeping up with modern traffic is necessary. So I need to think about a higher compression piston and new cams.

How can I tell the RPM without a tachometer?
What is the highest compression piston that is safe for the standard crank and bottom end?

Many thanks
Joe

[baird4444]

YES, the 18T is worth it...
below is from my files...
               - Mike

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 wanted to know my RPMs at different speeds, so got this little tach;
http://www.tinytach.com/tinytach/gasoline.php
Not bad for $37 US, being digital, it's useless for shifting. but, if you need
a
tach to shift a
RE, you're stone deaf, and yer butt has gone to sleep. Also has a 2 second lag.

Anyway, here are speeds/RPMs, with a 19T countershaft sprocket on the five
speed.
(XT- extrapolated.interpolated)

50MPH-2870 RPM
55MPH XT - 3146 RPM
60 MPH - 3450 RPM
65 MPH XT- -3737 RPM
70 MPH - 4025 RPM
75MPH XT - 4312 RPM
80MPH - 4600 RPM
85MPH XT- 4887 RPM
Theoretical;
90 MPH XT - 5175 RPM
MAX RPM-5500 - 95MPH

The speeds above are from a GPS corrected speedo, and I think they're pretty
tight
numbers.
I don't think the bike would do 95 MPH if you pushed it off the Sinny Arbor
Bridge, but it
touches 85 with my 220 lb on board, so I think a lighter rider would see 90.
(535cc, 8.5:1. 34mm Mikuni, short Brit exhaust, K&N)
More importantly, it means my "75 MPH all day, 80 to pass only," are usable
limits. I just
can't see that motor objecting to 4300 RPM. It sure sounds relaxed.
Below are extrapolated numbers for 19 and 18 tooth sprockets;
18T (19/18ths of above RPM)
50MPH-3029 RPM
60MPH-3642 RPM
70MPH-4249 RPM
80MPH-4855 RPM

17T (stock, 19/17ths of 19T readings)
50MPH-3207 RPM
60MPH-3855 RPM
70MPH-4498 RPM
80MPH-5141 RPM

[barenekd]

By my calculations, a G5 with and 18 Tooth sprocket is turning 4027 rpm at 70 mph, a speed that it will easily maintain. however,if your interested in gas mileage, mine dropped from about 68 at 62 mph, with a 17 T sprocket, to about 61 at 70. Even though it isn't pulling much more rpm, the manifold pressure (the throttle is open more) increases from the extra drag, which still requires more horsepower production, the mileage goes down.
On the other hand, if you continue to cruise at 62 mph (100 kph) with the 18 T, my mileage improved to about 72 mpg.
Bare

[rxr2012]

Nice post ACE., so 750 out of the pocket and the RE to 30HP with tach, i am sold.

[Jr.]

Ace,
My plan is to Fireball my 06 5speed in the future
,I already have Ace canister ,free flow Goldie
and larger jets.Which carb will work with what I have and
the upgrades  you mentioned  above and eventually to Fireball?Should I go 30mm or does it
need to be bigger .Would only like to buy one carb
Thanks
Jr.

[ace.cafe]

Well, the Fireball uses the Mikuni TM32-1 carb, with appropriately different jets than it comes with out of the box. It's a flat-slide carb that we have decided upon for our package.
It will also work fine with a stock bike that has a few upgrades like you mentioned.

So, if you want to buy only one carburetor that will work now, and all the way thru your upgrade process to the final Fireball, the Mikuni TM32-1 is the one. You will also want to buy our alloy manifold to go with it, because the stock manifold is too small and it doesn't match the bigger carb for flow or the outer dimension to put the connecting hose on it. They need to match in size, or you won't find any hose that can step from the carb exit boss to the stock manifold entry boss. So, to sum that up, you'll need our manifold, and then you can use a short straight piece of 1.5" I.D. radiator hose as the connector hose.

Also, anyone buying that NField Gear ACE Clubman Cams kit, make SURE that it has the 3-way timing pinion included in it. Otherwise, it won't time up correctly and my installation instructions won't match up to what you have.  So, contact me if you get that, or already got that, and let me help you with some basic tech-support for the install, so it is correct. If NField Gear is out of the Clubman cam sets, then they are out of production, so you will need to contact me about a suitable substitution.


And remember, you guys! I can't guarantee how well that stock bottom end is going to hold up with higher power. There is some risk involved. Holding the rpms down under 5000 rpm will go a long way to helping it, and our very light piston will help a lot too. But the stock internal parts are what they are, which is to say "unpredictable in manufacturing quality and assembly". So, you have to take that into consideration.

[Jr.]

Thanks Ace,That will give me one more part of the package.
Jr.

[jedaks]

And remember, you guys! I can't guarantee how well that stock bottom end is going to hold up with higher power. There is some risk involved. Holding the rpms down under 5000 rpm will go a long way to helping it, and our very light piston will help a lot too. But the stock internal parts are what they are, which is to say "unpredictable in manufacturing quality and assembly". So, you have to take that into consideration.

Very good advice about the bottom end. Thats the prime reason I was looking at all can do go get more "oomph" without going inside the motor. I only want the ability to keep up with traffic when I have to, not to routinely cruise faster just because the bike is now capable of it.

I've already done the K&N airfilter and free-flow exhaust. I put a 120 main jet in the VM28 micarb (maybe should have done a 130) and I want to put on an 18 tooth final sprocket. I am also looking at a 30mm carburettor.

From what I have learned from reading here, all that should really help get more speed without stressing the bottom end.

When the day comes that I need to open the engine for whatever job, then I will consider  a higher compression piston and better cams. While I'm at it I might put in a good bottom end and bearings if I start saving money now.

 But right now the bike runs so good that I am content to leave well enough alone.

[ace.cafe]

Yes, unfortunately all the Bullets need better bottom-ends, and it's just a matter of when to do it. Some do it early as a  preventive measure, and others do it after something breaks.

It is possible to do some of this stuff on the stock bottom end, but I have never seen one that lasts very long after doing it. So, you might be able to get a full season of riding out of it with a stock bottom end and some performance mods, but we just don't know exactly how long. I have seen the stock main bearings give up within 800 miles on some performance-modded Bullets. Others last longer, but we never really know how long each one is going to go.
It's safer to do the top-quality bearings and parts, if you can.

So, I just inform people of this, and then they have the proper info at their disposal, so they can make informed decisions.
It cuts deeply into my sales, because it often puts the price of a fully modded engine out of reach for some people. But I can't really live with myself if I don't tell people the right thing.

[mustangdave]

Ok guys...I stepped away for a bit after the the CARB issues that Justin and I resolved...needed to just relax a bit and not stress about the RE and finding new work.  Well I have a new job...wrenching and selling BICYCLES at a couple of local shops...then I come across this thread and I'm thinking of how to spend my paychecks..LOL...thanks ACE...and by the way the new carb jetting is working like a charm.