MotorBicycleRacing
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Introduction to Motorbicycle Racing: A Brief Beginners Guide
by #108 Sander Sindell
Congratulations on making the decision to be a part of the countries lowest budget racing series, Socal Motor Bicycle Racing aka SMBR.
Herein you will find some crucial tips to keep you on the track, because by far the greatest challenge for beginner racers isn't being fast enough, it's finishing the race.
The beauty of SMBR is how accessible it is, with a decent bicycle and a $150 engine kit you could find yourself competing against other people with passion for the same hobby as you. But that doesn't mean you can just grab your beater and make a B-line to the track, well, yes you can, but there are some things you would be wise to consider before you pack up, gas up, and head out.
The beginner class is designed for low-budget racing for new and intermeditate riders using the China Doll predominantly, but also the 49cc Hausheng, friction drive or any other slower bikes. If you have high performance parts and a big expansion chamber and are way out in front you will probably be bumped up a class, however there aren't many rules per se; any class adjustments made are done to keep it fair.
At SMBR you will be pushing your bike to the limits, lap after lap, after lap, after lap, after lap, after lap, after lap, after lap, after lap, after lap... literally. That's 10 laps of racing in which you will be exerting a generous amount of stress on your motor and your bike, through high rpms, elevated engine temperatures, constant on and off full throttle torque to the rear wheel, constant tension and release of the drive chain, and above average loads on the bike in the corners. And that is just the Final race. There's also 2 six lap Heats that precede your Final in which you will be getting a taste of your competition and taking note of any last minute adjustments to make, which means, in total, your looking at about 17.6 miles of racing if your at the Grange, and whether your at the Grange or at Willow Springs, you will be in the desert, where it gets hot. Average temperature falls in the 80's but can reach into the 90's on occasion. My little china doll was running a crisp 360 degrees at the track in May, about 50 degrees hotter than I've previously recorded. She ended up doing well though and took 1st place in the beginner class. With that said let's move on to what you can do to increase your odds of finishing
First off let's take a look at what you can do to help keep your engine cool and prevent overheating. Side effects of overheating include pre-ignition and detonation of which syptoms can appear as pits in the piston and head, or even a blown a hole in the piston crown. Go and get yourself an infrared thermometer(they're cheap) and aim it right above the exhaust port to find out your operating temps.
- Tuning, Tuning, TUNING!!!!!! It is unbelievably important to tune your carburetor properly. It doesn't matter how many fancy parts you add, if your engine is running lean then it will run HOT. It might run alright for your normal city riding, but that won't fly at the track. Thankfully most of these engines run extra rich right out of the box, and might run alright or even good, but inevitably, since you are a racer, and racers modify stuff, you will end up rejetting your carb. When you do that, please, do not jet it too lean
You want to find the point where it's ever so slightly running rich and "4-stroking" and then jet it down one more size. I've jetted mine so anytime I'm at partial throttle it "4 stokes" lightly but as soon as I crack the throttle open she screams. Remember, the tracks that we race at are probably at different elevations from where you ride normally, which means your engine might run different at the track and may need to be retuned. This is one reason it's very important to come to the practice day before the race or at least early on race day, to dial in the jetting on your carb. So don't forget to bring different sized jets when your packing.
- Aftermarket billet aluminum head. This is my 1st upgrade for any engine because it adds power across the entire powerband by increasing compression AND it improves cooling. A win-win. You can typically see your engine run 20 degrees cooler with one, even much cooler than that in some cases. I use a Fred head from CRmachine.com on my racing bike. Applying this upgrade will increase power and reduce heat, and you can still race in the beginner class with this modification.
-Spark plug heat rating. If you haven't already, ditch that crappy spark plug that came with the engine and get an NGK B8HS. The number 8 is the heat rating. For NGK plugs the higher the number the colder the plug. The stock heat rating is a 7 so a 6 is hotter(good for really cold climates) and 8 is colder(good for hotter climates and racing). Depending on your engines modifications and temperatures you might find that a different heat rating actually runs better(like a 7). Spark plugs are cheap so buy a few and find what works for you. It is not uncommon for spark plugs to be defective right out of the box, even NGK, so make sure your plug is good. You can Ohm test your plug with a volt meter.
-2stroke Oil. Pick a good one, I don't recommend running gas station oil. These engines have good enough gas mileage that it won't break the bank to run top shelf synthetic oil. More friction = more heat. Especially if your running your engine at high rpms. For normal riding at home your probably running 32:1, but on the track you want to run a ratio in the 20's, anywhere from 20:1 to 28:1. I'm not telling what oil I use so find out for yourself what the fast guys use and use that. Hmmmm, that is such a good tip that it deserves it's own line in capitals!!!!
FIND OUT WHAT THE FAST GUYS DO TO BE FAST!!!
You will find out things in a 10 minute conversation with someone that you would never have found out by reading stuff online. Pick up the phone, be friendly, and you might find yourself an insider to help you achieve better results <---Priceless.
-Fuel. High Octane fuel will not make you go faster but it will burn a little cleaner and IT WILL HELP PREVENT PREIGNITION AND DETONATION. In short, the lower the octane rating, the lower the temperature needed to ignite the fuel. So if your engine is running HOT then the fuel in your cylinder might ignite from the excessive temperature of your engine before the spark plug ignites it, OR if it's running HOT it can spontaneously ignite AFTER the spark plug fires which interupts the flame front from expanding evenly which yada yada yada. If you run racing fuel than you greatly reduce the risk of these problems. However, not everyone needs to run racing fuel. If your motor is high compression then I would recommend it, but if it's 80 degrees and your squish band is 6.0cc or larger you can probably stick with 91. I personally run 110 leaded at the track and 91 if I'm riding anywhere else. Ahhh, the smell of racing fuel alone is worth the extra $.
-Leaks. This falls under tuning but I just want to make double sure that your not running lean. If you have a leak, fix it.
Now that we've covered basic preventative measures for heating problems let's move on to mechanical problems that can easily be avoided.
- Check all bolts, screws, cables, levers, studs, etc. Make sure everything is tight and secure. If you don't want it coming out then consider using LOCTITE. Blue Loctite for things you would eventually like to remove, and Red Loctite for things you don't want to remove. This isn't absolutely neccessary, but it IS neccessary to pay VERY close attention to everything. I use Red Loctite on the head studs and Blue anywhere else, I dunno maybe I used Red on exhaust studs, I can't remember lol. But I do remember one thing for sure...
-I replaced all my studs with Grade 8 studs. It would suck if you couldn't finish the race because your intake stud came loose or broke. If you pay close attention to installing the bolts properly you can get by fine without doing this, but I wouldn't know because I changed all mine out asap. Let me interject here and point out that you might be thinking, "Damn, this is hella stuff." Well, let me remind you that you are totally capable of bringing your beater and doing well, but all this is here to help increase your chances of finishing. And after all, don't forget you are now a racer and it's now in your blood to do everything it takes to win. As if I needed to tell you! Lol
-Check chain alignment and chain tension. Make sure when your going over your bike, hopefully not any later than 2 weeks before the race(to allow shipping time for any last minute parts orders), that the chain is in perfect alignment and the tensioner is secure. Actually I recommend removing the stock chain tensioner, shortening the chain and running straight chain if you have adjustable rear dropouts, which I do not on my Trek Aluminum Mtn Bike, so I use a spring tensioner mounted on the clutch plate, similar to the TurboBuick Spring Tensioner, or others available from other manufacturers.
-Ditch the ragjoint sprocket mount and get a billet aluminum sprocket hub adapter. All your constant throttle on and throttle off is not nice on your spokes. Hub adapters are only $50 from Cortez Motorsports(Angel Cortez on Fackbook) and come in a 2" size with shims for 1.75" and 1.5" hubs available seperately. Also this makes changing sprockets really easy so you can quickly take off your 36T that you use on the daily and throw on a 41T or 44T for the track. Changing sprocket sizes is also something you might want to do during practice.
Introduction to Motorbicycle Racing: A Brief Beginners Guide
by #108 Sander Sindell
Congratulations on making the decision to be a part of the countries lowest budget racing series, Socal Motor Bicycle Racing aka SMBR.
Herein you will find some crucial tips to keep you on the track, because by far the greatest challenge for beginner racers isn't being fast enough, it's finishing the race.
The beauty of SMBR is how accessible it is, with a decent bicycle and a $150 engine kit you could find yourself competing against other people with passion for the same hobby as you. But that doesn't mean you can just grab your beater and make a B-line to the track, well, yes you can, but there are some things you would be wise to consider before you pack up, gas up, and head out.
The beginner class is designed for low-budget racing for new and intermeditate riders using the China Doll predominantly, but also the 49cc Hausheng, friction drive or any other slower bikes. If you have high performance parts and a big expansion chamber and are way out in front you will probably be bumped up a class, however there aren't many rules per se; any class adjustments made are done to keep it fair.
At SMBR you will be pushing your bike to the limits, lap after lap, after lap, after lap, after lap, after lap, after lap, after lap, after lap, after lap... literally. That's 10 laps of racing in which you will be exerting a generous amount of stress on your motor and your bike, through high rpms, elevated engine temperatures, constant on and off full throttle torque to the rear wheel, constant tension and release of the drive chain, and above average loads on the bike in the corners. And that is just the Final race. There's also 2 six lap Heats that precede your Final in which you will be getting a taste of your competition and taking note of any last minute adjustments to make, which means, in total, your looking at about 17.6 miles of racing if your at the Grange, and whether your at the Grange or at Willow Springs, you will be in the desert, where it gets hot. Average temperature falls in the 80's but can reach into the 90's on occasion. My little china doll was running a crisp 360 degrees at the track in May, about 50 degrees hotter than I've previously recorded. She ended up doing well though and took 1st place in the beginner class. With that said let's move on to what you can do to increase your odds of finishing
First off let's take a look at what you can do to help keep your engine cool and prevent overheating. Side effects of overheating include pre-ignition and detonation of which syptoms can appear as pits in the piston and head, or even a blown a hole in the piston crown. Go and get yourself an infrared thermometer(they're cheap) and aim it right above the exhaust port to find out your operating temps.
- Tuning, Tuning, TUNING!!!!!! It is unbelievably important to tune your carburetor properly. It doesn't matter how many fancy parts you add, if your engine is running lean then it will run HOT. It might run alright for your normal city riding, but that won't fly at the track. Thankfully most of these engines run extra rich right out of the box, and might run alright or even good, but inevitably, since you are a racer, and racers modify stuff, you will end up rejetting your carb. When you do that, please, do not jet it too lean
You want to find the point where it's ever so slightly running rich and "4-stroking" and then jet it down one more size. I've jetted mine so anytime I'm at partial throttle it "4 stokes" lightly but as soon as I crack the throttle open she screams. Remember, the tracks that we race at are probably at different elevations from where you ride normally, which means your engine might run different at the track and may need to be retuned. This is one reason it's very important to come to the practice day before the race or at least early on race day, to dial in the jetting on your carb. So don't forget to bring different sized jets when your packing.
- Aftermarket billet aluminum head. This is my 1st upgrade for any engine because it adds power across the entire powerband by increasing compression AND it improves cooling. A win-win. You can typically see your engine run 20 degrees cooler with one, even much cooler than that in some cases. I use a Fred head from CRmachine.com on my racing bike. Applying this upgrade will increase power and reduce heat, and you can still race in the beginner class with this modification.
-Spark plug heat rating. If you haven't already, ditch that crappy spark plug that came with the engine and get an NGK B8HS. The number 8 is the heat rating. For NGK plugs the higher the number the colder the plug. The stock heat rating is a 7 so a 6 is hotter(good for really cold climates) and 8 is colder(good for hotter climates and racing). Depending on your engines modifications and temperatures you might find that a different heat rating actually runs better(like a 7). Spark plugs are cheap so buy a few and find what works for you. It is not uncommon for spark plugs to be defective right out of the box, even NGK, so make sure your plug is good. You can Ohm test your plug with a volt meter.
-2stroke Oil. Pick a good one, I don't recommend running gas station oil. These engines have good enough gas mileage that it won't break the bank to run top shelf synthetic oil. More friction = more heat. Especially if your running your engine at high rpms. For normal riding at home your probably running 32:1, but on the track you want to run a ratio in the 20's, anywhere from 20:1 to 28:1. I'm not telling what oil I use so find out for yourself what the fast guys use and use that. Hmmmm, that is such a good tip that it deserves it's own line in capitals!!!!
FIND OUT WHAT THE FAST GUYS DO TO BE FAST!!!
You will find out things in a 10 minute conversation with someone that you would never have found out by reading stuff online. Pick up the phone, be friendly, and you might find yourself an insider to help you achieve better results <---Priceless.
-Fuel. High Octane fuel will not make you go faster but it will burn a little cleaner and IT WILL HELP PREVENT PREIGNITION AND DETONATION. In short, the lower the octane rating, the lower the temperature needed to ignite the fuel. So if your engine is running HOT then the fuel in your cylinder might ignite from the excessive temperature of your engine before the spark plug ignites it, OR if it's running HOT it can spontaneously ignite AFTER the spark plug fires which interupts the flame front from expanding evenly which yada yada yada. If you run racing fuel than you greatly reduce the risk of these problems. However, not everyone needs to run racing fuel. If your motor is high compression then I would recommend it, but if it's 80 degrees and your squish band is 6.0cc or larger you can probably stick with 91. I personally run 110 leaded at the track and 91 if I'm riding anywhere else. Ahhh, the smell of racing fuel alone is worth the extra $.
-Leaks. This falls under tuning but I just want to make double sure that your not running lean. If you have a leak, fix it.
Now that we've covered basic preventative measures for heating problems let's move on to mechanical problems that can easily be avoided.
- Check all bolts, screws, cables, levers, studs, etc. Make sure everything is tight and secure. If you don't want it coming out then consider using LOCTITE. Blue Loctite for things you would eventually like to remove, and Red Loctite for things you don't want to remove. This isn't absolutely neccessary, but it IS neccessary to pay VERY close attention to everything. I use Red Loctite on the head studs and Blue anywhere else, I dunno maybe I used Red on exhaust studs, I can't remember lol. But I do remember one thing for sure...
-I replaced all my studs with Grade 8 studs. It would suck if you couldn't finish the race because your intake stud came loose or broke. If you pay close attention to installing the bolts properly you can get by fine without doing this, but I wouldn't know because I changed all mine out asap. Let me interject here and point out that you might be thinking, "Damn, this is hella stuff." Well, let me remind you that you are totally capable of bringing your beater and doing well, but all this is here to help increase your chances of finishing. And after all, don't forget you are now a racer and it's now in your blood to do everything it takes to win. As if I needed to tell you! Lol
-Check chain alignment and chain tension. Make sure when your going over your bike, hopefully not any later than 2 weeks before the race(to allow shipping time for any last minute parts orders), that the chain is in perfect alignment and the tensioner is secure. Actually I recommend removing the stock chain tensioner, shortening the chain and running straight chain if you have adjustable rear dropouts, which I do not on my Trek Aluminum Mtn Bike, so I use a spring tensioner mounted on the clutch plate, similar to the TurboBuick Spring Tensioner, or others available from other manufacturers.
-Ditch the ragjoint sprocket mount and get a billet aluminum sprocket hub adapter. All your constant throttle on and throttle off is not nice on your spokes. Hub adapters are only $50 from Cortez Motorsports(Angel Cortez on Fackbook) and come in a 2" size with shims for 1.75" and 1.5" hubs available seperately. Also this makes changing sprockets really easy so you can quickly take off your 36T that you use on the daily and throw on a 41T or 44T for the track. Changing sprocket sizes is also something you might want to do during practice.
