Bonneville America Forums Forums Technical Forums Performance Mods Huge Performance Increase the Easy Way

I recently tried three easy performance enhancements to my relatively stock SM, and they all work extremely well together. This was done after the few mods I already had done by the dealer at time of purchase(a K&N air filter, long TORS, and rejetting accordingly). OK, here's what I did:
1. side-gap the stock sparkplugs, as per previous posts
2. modified the snorkle, rather than just remove the snorkle: I noticed that the snorkle mouth was pushed up very close to the under-plate of the seat. So, really, the air restriction is at the mouth. Also, the snorkle could be shortened. The best access to airflow comes from the right side of the snorkle mouth, so I cut away the right side of the mouth, and also the center seperation. Then I cut the snorkle tube away from the mount.
3. I tried a bottle of Lucas Octane Boost

Results:
1. side-gapping the plugs provided a minimal amount of performance increase
2. the snorkle mod provided a much better improvement. The air accelerates into the snorkle at a greater rate, which gives it a turbo effect. Open the trottle and hang on. This proved to be much better than with the snorkle completely removed. Before snorkle mod, there was zero popping on decel. After snorkle mod, there is the odd light pop on decel.
3. As per instructions on the bottle of Octane Boost, I poured 1/5 of the bottle into a full tank of 89 Octane fuel(bottle will boost 25 gallons of fuel). Holy Cripes !! Instant rocket power!!

Now, I don't know how the Octane Boost works by itself, but combined with the other enhancements, it made an enormous difference. I thought the bike was fast before, but now it really goes like snot. I also noticed that the exhaust sounds different....it growls more like a big cat, is louder, and is smoother, too.

careful with that octane boost good way to cook the engine.

Robin,

I recently found another very cheap and easy modification and am equally pleased with the results. This mod does not have to be done with any of the others as it works exceptionally well alone or with any one or all of those you mentioned. I recently lost about 30 Lbs. Yes folks - 30 freakin pounds alone makes an impressive difference - seems its not just in straight line performance, but also has similar effect on handling and ride quality. I'm gonna keep losing until I get down to 12Lbs - This little baby ought to run like a GSX 1000 by then!!!

I'd think about dropping the booster too, and see how it goes. you should not need anything higher than 89 octane
G

There's a lot of confusion and mythology surrounding octane. The common urban myth is that the higher the octane, the more power you'll get from an engine. Yes and no.

The main way an engine makes power is not my combusting the fuel as most people think, but it's from how much the engine can compress the fuel before it's ignited. The biggest problem with compressing an air/fuel mixture is that if you squeeze it TOO far it'll ignite all on its own. This is what causes "pinging" or "knocking" in an engine with too low an octane rated fuel, as the fuel starts to ignite before the spark plug fires which makes the the piston "judder" in the cylinder.

However since there's only a certain amount any engine can compress the mixture there's a limit to how much you can gain from octane. If you're already using the correct fuel in the bike adding a "booster" is a waste of money unless you can figure out a way of compressing it more (ie: turbo, water injection, etc).

I'm not saying that you didn't get more power from using it, only that if you did it's because you're using the wrong fuel.

Another thing that might be occurring - you mention you rejetted after installing the filter & pipes, however opening up the intake more will let air in more easilly which will lean the mixture out again. You might find your boost is actually making the mixture run slightly richer which would explain your power increase.

Take the bike to a dyno-tuner and get them to check the jetting. With "home made" mods like the snorkle modification it's the only way to be sure you're getting the most from it.

pipdr, I like your performance mod...will have to try it someday.
I'll top up my fuel tank with 89 so it dilutes the Octane Boost, and go back to fuel only, just to see what happens. I didn't really expect any improvememnt with the claim of an octane boost, but reading the bottle shows that the mixture has upper cylinder lubricants. I thought that would improve valve movement, and prevent carbon deposits. Maybe avoid valve shimming at the 12,000 mile service. I have been occasionally adding a squirt of Lucas Upper Cylinder Lubricant to my fuel for that very reason.
I'm off for a 300 mile trip today, so I'm going to try out the modded snorkle, and carry my spare unmodded snorkle, and see if there is much of a difference. I'll also do a sparkplug read, and post the results. It's a bit nippy today, so I'm breaking out the long underwear.
Cheers

You'll find quite a bit of difference in response between the regular snorkle and the modded one. I performed similar surgery on mine recently and was impressed enough in the difference to start working on a sort-of-velocity-stack (not a bellmouth) for my airbox.

Not trying to hijack, but keeping with the theme...

Modding the snorkel, would that pretty much necessitate re-jetting if nothing else were changed but that?

If that was the only thing changed you would probably only need to adjust the mixture screws a little if even that.

Thanks Dog.

Hi,
On the sronkle how much of the snokle did you remove ?? the right side mening whikle sitting on the bike or facing it????

Hi, I'm back from my trip...here's what I tried. I checked my speedometer with a radar equipped construction sign enroute, and at 100 km/hr, the radar indicated I was doing 100 km/hr. I wasn't expecting that, of course, but, at least I know my speedometer is accurate. Also, I run with a 17-tooth front sprocket:
1. Stock snorkle installed...bike ran fine, so tried an open secluded stretch of hiway, and at WOT 5th gear got to 165 KM/hr...about 103 mph.
2. Replaced stock snorkle with my modded one, ran the same stretch of road, same direction of travel, and at WOT 5th gear got to 172 km/hr. Didn't notice the rev count on either run, was concentrating on the road. I didn't want to run too long at WOTon the second run, as I know the mixture is leaner than my usual set up, and I feared getting a hole burnt into a piston. I'll maybe see about rejetting.
Neither run was with the Octane Boost. When I am riding in the city, I'll use my modded snorkle, as I never go WOT on the street.
Now, I did notice previously an actual boost in performance with Lucas Octane Boost. So I would suggest to anyone who is interested to buy a bottle ( $8), and try it. See what if it works for you. If anything it will lubricate your upper cyclinder, and to my thinking, that is a good thing.
I will post a picture of my modded snorkle later today.

but it's from how much the engine can compress the fuel before it's ignited. The biggest problem with compressing an air/fuel mixture is that if you squeeze it TOO far it'll ignite all on its own. This is what causes "pinging" or "knocking..............................Vaporization drawn from compression and the heat of the engine? correct? Speedmasters don't have restrictor plates do they or at least if they do they are fiber- form fitted like the rest of the airbox or rather formed as part of the box itself? Speed.

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Man I miss those Krispy Kreme days.....

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Poison, Al - They're poison. Keep it up. It's amazing. I'm suely still a fat man by normal standards - But I feel so much better. Only trouble is that I'd have to move down a class or two if I were to start boxing - So, I'm stayin' oput of the ring for now.

Below are three pics of the modded snorkle on the left, and a stock snorkle on the right. Also, a shot of my bike during the trip.

[url=http://www.bonnevilleamerica.com/photopost/data/500/medium/DSCN0558_Small_.JPG]

[url=http://www.bonnevilleamerica.com/photopost/data/500/medium/DSCN0557_Small_.JPG]
[url=http://www.bonnevilleamerica.com/photopost/data/500/medium/DSCN0556_Small_.JPG]

[url=http://www.bonnevilleamerica.com/photopost/data/500/medium/DSCN0555_Small_1.JPG]

Well, I don't know what I did wrong. I've posted photos here before, and I think I used the same procedure. Can nyone figure out how I screwed up?

I can...here you go...

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Below are three pics of the modded snorkle on the left, and a stock snorkle on the right. Also, a shot of my bike during the trip.

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Here you go. Copy the info from the pictures Properties and paste that into the box after choosing - 'image'. (Right click on the picture and go to properties)

Thanks Rob

Singring
I took your idea one step further: I call it the velocity mouth

do you think this is more effect than no bell mouth at all