How do we Bump-start a bike

There are loads of reasons you can get a flat battery. You can get any bike going by bump-starting it, but some are harder than others. The BMW G650 Xmoto of my girlfriend, 650cc single cylinder engine motorcycle is one of the harder once.

I have some pointers: A hill is your friend if you're bump-starting, don't say 'I know', it's incredible how many people know about the hill but still not use it. Even a slight gradient will make a difference. Point the bike down it to help you pick up speed. If there's no gradient, a mate can assist by pushing the bike. Grab a passer-by if necessary, they are for females easier to find then for men, but still.

If the bike's cold, set the choke to the normal start position. Test to see if the bike can be pushed while in gear, second gear is mostly the best, with the clutch in.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

An Easy-to-install, Primary Chain

Back in the day, adjusting your bike's chains was a chore that had to be done with annoying regularity. On a Pan or Knuckle, it takes about an hour or so to do the deed. You first have to loosen the transmission's four mounting nuts and one mounting bolt. Unfortunately, many a wrench has forgotten that one odd mounting bolt, which is over by the kicker cover, resulting in much distress and liberal amounts of verbal lubrication as he tries to get the still-bolted-to-the-frame transmission to move.

Once all the hardware is loosened, the transmission is slid back in the frame until the primary chain is properly adjusted. Once the transmission is again secured to the frame, you then loosen the rear axle and move the rear wheel to readjust the rear chain, since you screwed up its adjustment when you moved the transmission.

Once the chains are right, you have to readjust the rear brake rod, shifter rod, and, if equipped with a foot clutch, the clutch rod, because you changed their settings when you moved the transmission and rear wheel. Sounds like fun, eh?

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

Why Balancing and Blueprinting our Engine

Assuming no design flaws or problems arising from the cheaper parts favored by financial officers, and that the engine is properly tuned, as in previous article, and the oil changed frequently, a production engine can go 200,000 kilometer or more before it wears out. This being the case, is custom balancing and blueprinting really worth it?

Sure it is, and here's why: First, understand that those 'last forever' production engines you read about are the exception rather than the rule. Bucking the law of averages, the parts that went into them just happened to have ideal clearances when the engine was assembled. The slightly undersized shaft "just happened" to be installed in a slightly over-sized bearing, and the engine was custom-blueprinted by coincidence.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

The Yamaha FZR750 Engine Rebuild

Right from the first day I saw this bike I knew it was doomed, I mean it's a indescribable color and the engine makes sounds I never hear before.

It's another one of those bikes I just bored everyone about how good it was, and how if everyone bought one of these instead of being obsessed with style and getting an Yamaha YZF-R1 they can't control they'd all be better riders blah, blah blah.

But when all is said and done, it is still hand painted in the most ugly colors I ever seen, which is a bit like going our with a red headed bird, cos we all know the cuffs and collars match. Anyway, the Exup (Exhaust Ultimate Power valve) was so typically Yamaha I should have known it wasn't going to stand my imbecilic lofting techniques even after a decade of refinement. With a gear shift that feels like it's made out of dental amalgam, and a clutch basket that sounds like its full of broken Chinaware, the Exup and indeed the whole Yamaha range has always been the most frail of 4-stroke engines.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

Blueprinting and Building a Good Engine Case

Engine blueprinting, as in previous article, starts at the crankcase, where the builder confirms that the main bearing surfaces are within a few ten-thousandths of an centimeter of being concentric and in-line. He also checks that the cylinder decks are correctly machined, and the oil passages are clear, open, and go where they should.

From there, it progresses to the crankshaft assembly, where the flywheel, or -wheels, should be within 0.0254mm of being perfectly true (in twin parallel to each other, in single perfect to design). The connecting rods will also be fitted to the crankpin to allow the bearings their 0.0254mm of clearance.

Pinion bearings require slightly less clearance. To measure that, the builder measures the inner diameter (ID) of the bearing race with a dial bore gauge and the outer diameter (OD) of the pinion shaft with a micrometer. He then subtracts the shaft OD from the race ID and compares the difference to a chart to determine which size bearing to use.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

Dynamic Balancing and Beginning Blueprinting

Static of Dynamic balanced fly-wheel, the process we described before is know as static balancing because the flywheel is not in motion when balanced. Static balancing is still favored by many engine builders, but dynamic balancing has gained a large following.

Because it allows computer sensors to assess flywheel balance with the flywheel balance with the flywheel in motion, pinpoint any imbalance, and determine the magic number in matter of seconds, dynamic balancing is significantly faster. Proponents also claim that it is more accurate.

Although a flywheel may appear perfectly balanced on the stand, the story sometimes changes when the flywheels are assembled with the other crankshaft components and the assembly spun up to several hundred rpm. Shaft and flywheel flex can cause high-speed oscillations that throw balance off, as can minute imbalances that are undetectable by static-balancing methods but which increase dramatically with engine speed.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

A Well-Balanced Flywheel

A well-balanced flywheel, with all that, from the previous story, out of the way, let's plug the weight of some imaginary components into our formula and balance a hypothetical engine to 60 percent. Note that although some engine builders take pains to match piston weight exactly, others feel that a few grams 'difference is insignificant. To limit the story length, we'll ignore the controversy and work with combined weight rather than the weight of each component.

Rotating Weight: Rotating end of Rods: 865grams, Crankpin and keys: 565grams, Crankin nuts: 80grams, Bearing assemblies: 70grams, Lockplates and screws: 10grams, Total rotating weight: 1,590grams,

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

Turning a Yamaha Fino into a Racer

Before we start, we need to be clear that the Yamaha Fino will never be one of the top choice for speed geeks. We found after our installment of the engine modification that the Yamaha Fino becomes hard to drive at higher speeds. Some moments the Yamaha Fino was outright dangerous to handle. After we examined the cylinder of the Yamaha Fino we came-up with the idea to do a bore-up to 63mm, the stock bore of the Yamaha Fino is 55mm. Changing the bore from 55mm to 63mm will change the Yamaha Fino from a 114cc to a 189cc motorcycle.

After contacting some of our sources for accessories we found a manufacturer who produces a complete set, which includes a 63mm Ceramic Laminated cylinder, a high performance 4-valve cylinder head (the Fino comes standard with only 2-valve head), 63mm Piston, high performance racing camshaft and the materials to make this all fit and assemble.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

Carburetor Tuning, to Rich or to Lean Condition

In previous stories I talked about carburetors Rich conditions and Lean Conditions, this is all fine of course if you know how to detect if your engine carburetor is set Rich or Lean.

To help with that, I will explain simple means to detect the setting of your bike. With a perfectly tuned engine you will get the power you need, it amazes me sometimes what people spent on kits to improve performance, while all they needed to do is get the settings right.

Okay that said what is a Rich Condition, while a black, scooty spark plug is a sure sign of richness, there are other indicators that are a bit subtler and better ways of dialing in the carburetor jetting.

If your engine responds crispy at low throttle when it is cold, chances are the main jet is one size larger than it needs to be. Assuming, of course, that the idle circuit is correctly tuned.

Poor fuel mileage is another sign of richness and because of the way most of us ride our motorcycles, that richness is unusually the result of a needle that is too small.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)

Kidding Me I Not Have a Dynamometer

In some previous story, the tuning of a carburetor, I talked about using a Dyno, we got several reactions about this. A Dyno by motorcycle mechanics or dynamometer for English Professors, is a machine used to measure torque and rotational speed (rpm) from which power produced by an engine.

Okay this Dyno's are not something you would buy just to tune your carburetor, hence it is cheaper to visit multiple motorcycle tuning shops, until you have the right performance.

So if you don't have free access to a dynamometer, don't worry, I did years without also. With a stopwatch, tachometer, and some imagination you, too, can measure the power output of your engine accurately enough to get your carburetor dialed in correctly.

Consistency is the key to these types of performance tests. When doing any of these tests take into account air temperature and humidity.

Continue Reading

  • Currently 1.00/5
  • 1
  • 2
  • 3
  • 4
  • 5
Rating: 1.00/5 (1 vote cast)
Advertising
Poll

How many times have you crashed your motorcycle in the last three years?

  •  Never
  •  Once
  •  Twice
  •  Three times
  •  Four times
  •  Five times
  •  More than 6 times
  •  More than 10 times
This poll has 0 more questions.
Results
Other polls | 8,569 votes | 20 Comments
TMEA MEMBER
Thai Motorcycle Enterprise Association
Events
Site Events
Tuesday 14-Feb - Thursday 16-Feb
Motorcycle Thailand on Facebook
Motorcycle Thailand on Facebook
My Account
 New User
 Forgot Password