A self propelled two wheeled motor vehicle with an engine larger than 50cc's.

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24
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5answers
5k views

What is the technical reason the engineer decided the motorcycle gear pattern as follows?

The gear pattern is selected by clicking a lever with your left foot, and is typically laid out as follows: 6th gear (if applicable) 5th gear 4th gear 3rd gear 2nd gear NEUTRAL 1st gear What ...
22
votes
2answers
2k views

Why do two-stroke engine exhaust pipes look so strange?

Two stroke gasoline engine exhaust pipes are shaped strange. They expand into a wide diameter and then shrink down to a very small diameter where the exhaust gasses emerge into the environment. Why ...
17
votes
7answers
1k views

Seized nut & bolt - difficult to access

Last year I added crash sliders to my aging Honda CBR 600F (1998) Recently whilst trying to remove the fairing for other work, I found the nut and bolt were "seized". Actually, by using a spanner at ...
17
votes
5answers
51k views

Why should the fuel petcock valve be turned to “Off” position when not using the vehicle?

It’s mentioned in the user manual of my motorbike, that when not using the vehicle, I should turn the petrol tap (the one that has three positions “On”, “Off” and “Reserve”) to “Off” position. I don’t ...
17
votes
3answers
19k views

Why is my motorcycle losing power when accelerating?

I ride a Honda Rebel 250 motorcycle and over the past few days I find that the bike is losing power when accelerating fast. When I twist the throttle to accelerate quickly (in any gear) I hear the ...
15
votes
4answers
61k views

Symptoms of Lean or Rich carb settings on a motorcycle

I have a 1981 Yamaha XS650. I recently put in K&N stock replacement filter (ie, they are in the airbox and conform to the size of the original), however they may be leading to a leaner mixture ...
15
votes
1answer
3k views

What is happening when a two-stroke engine is said to be “four-stroking”?

Many years ago, I was involved in a hobby of building and flying model aircraft. The aircraft used alcohol-fueled 2-stroke engines with glow plug ignitions. When these engines ran rich (and always at ...
15
votes
1answer
2k views

How do I find the correct pins in a CAN-BUS connector?

This question might be too technical for this forum, but I'll give it a go. I have a 2012 BMW R1200R motorcycle with CAN-BUS. I'd like to make an Arduino interface to the connector on the bike, but I ...
14
votes
5answers
69k views

What does the 'cc' mean on a motorcycle?

I'm relatively new to motorcycles, my flat mate taught me how to drive his two Royal Enfields around New Delhi, and for the past year and a half I've been taking care of them as they break down ;) ...
14
votes
2answers
358 views

'00 Honda CBR929RR - Unknown issue, help!

Sorry for the ambiguity here.. I'm not sure what the issue is with my bike. I have a bunch of symptoms and my hypothesis is that it's a cascading failure and I'm just seeing a bunch of effects down ...
13
votes
4answers
951 views

Is there a benefit to belt driven motorcycles?

What are the pros and cons of belt driven motorcycles compared to chain driven bikes?
13
votes
2answers
529 views

Why do Harley Davidson engines suffer from such poor performance?

The modern Harley Davidson engine has very poor power output. Even when highly modified a 130HP engine can cost tens of thousands of US Dollars. Here are specs on one of the modern engines. ...
13
votes
2answers
3k views

Should motorcyle exhaust headers ever glow red hot

I've got a '99 Pegaso 650 which hasn't been running for about 7 years. It's was in a quite a deteriorated state when I got it, i.e. seized carbs, tank full of water, sump full of an ugly fuel/oil mix, ...
13
votes
3answers
11k views

Why (almost) all dirt bikes have single cylinder engine?

Every dirt bike i know has a single cylinder engine. I myself ride a Yamaha XT660Z which has a huge 660 cc cylinder. What are the characteristics of those engines? what are the benefits of such ...
13
votes
2answers
824 views

How do I drain the brake fluid for a 1999 BMW K1200RS?

I need to drain the brake fluid for my 1999 BMW K1200RS with ABS in order to do some minor service on the Master Cylinder, but I don't have a service manual for the bike. How should I go about doing ...
12
votes
3answers
2k views

What are the Advantages of a Single Side SwingArm on Motorcycles?

I have noticed that Ducatis , Honda and Triumph have bikes with a Single Sided SwingArm Much like most of the scooters. Are there any advantages of following this design , if so why are not all ...
12
votes
2answers
169 views

Motorcycle Four Body Carburetor Synchronization Balancing

I would like to adjust four-body carbs by myself, in order to avoid spent money every time. What are the basic rules, tools and secrets of synchronizing multiple carburetor bodies?
12
votes
4answers
4k views

Gasoline is dripping out of a rubber tube outputting on the bottom of my motorcycle - is this normal, or is it a problem?

What bike? A BMW 650, 1996 model. What's the problem? I noticed a slow, but steady, drip of gasoline from one of two rubber tubes that output to the bottom of the bike. I think the other rubber ...
12
votes
2answers
321 views

Yamaha R1 intake tract configuration

Interesting Configuration The Yamaha R1 has a very strange intake design. Notice the intake horns in the image below. They sit above the throttle bodies and are not attached directly to them ...
12
votes
1answer
94 views

What is cold tire shearing?

I have friends that goto Track Days frequently on their motorcycles. If the first session is very cold they use their old tires and don't ride real hard because they don't want to shear their good ...
12
votes
2answers
887 views

What is the motorcycle equivalent of OBD-II?

I once met an OBD-II expert while traveling and asked him if motorcycles (especially the fuel-injected ones) employ a similar protocol. He said that the use of such a protocol is not as widespread ...
12
votes
1answer
70 views

Can I drive with a broken/without the spider spring in my clutch?

Long story short: I managed to break the spider spring inside my slipper clutch. Apparently these things happen. Below are two pictures of this work of art: Now I have some 300km separating me ...
11
votes
2answers
2k views

Holding clutch when braking

I always hold my clutch when braking suddenly in traffic or to move in traffic. I heard that its bad driving. I tried to stop holding clutch and I am unsuccessful in it. How bad is this for ...
11
votes
3answers
2k views

How do you get the carburetors out of a 1983 Kawasaki KZ1000 P?

It's a 4-cylinder engine, and the carbs are really wedged in there. The best way I know is to loosen the boots on both sides, pull the carbs back, and try to slip them out sideways, but what a pain! ...
11
votes
3answers
635 views

How to start my motorcycle when the kick-starter fails?

This morning I tried to start my motorcycle but the kick-starter failed. It was idle for about a month but it was riding fine before that . My motorcycle doesn't have an electric starter function. ...
11
votes
1answer
117 views

How does one use a chain press to remove a motorcycle chain?

I recently found out about this tool from this answer. I'm interested in understanding the steps involved in using this tool to remove/install motorcycle chains. Also, would it be possible to use ...
10
votes
3answers
508 views

How to upgrade a motorcycle battery to a bigger AH battery?

My motorcycle (honda CBF150) came with a 12V 3AH battery. I want to change the stock 35w headlight to a higher power one and connect them directly to the battery (the stock ones are not, and they ...
10
votes
2answers
443 views

Motorcycle exhaust rattling / clunking / popping / burbling on deceleration

Lately I noticed a change in the sound my exhaust is making when decelerating from ~4000+ revs while in gear with the clutch not squeezed (that would be engine breaking probably). I'm unsure how to ...
10
votes
2answers
2k views

Pulsar 180 - How Can I Measure the Mileage?

Could anybody please tell me how to measure the mileage of my Pulsar 180 bike accurately? I have tried by emptying my tank. I failed miserably, and I had to take my bike walking long distance.
10
votes
1answer
141 views

Motorcycle Speed Wobble - How do I figure out the problem?

I have a 2005 GSXR 600. I took it for a test drive and the head shakes around 65mph or so and then goes away when I go past that. It's worse when I'm slowing down without the front brake. When I ...
10
votes
2answers
87 views

2003 Suzuki Katana GSX600F - No Start Issue

So I recently purchased this motorcycle from a third party. 2 days ago it would start up fine and you could ride it. The guy I brought it from said the battery was acting cranky so you should change ...
10
votes
2answers
321 views

Can't start a Kawasaki GPX 750

I'm in the process of getting my 1986 Kawasaki GPX 750 back in running condition. The bike was sitting in the garage for two years. In this period it wasn't started even once. Two years ago the engine ...
10
votes
4answers
11k views

How to stiffen up a loose ball & socket joint for a motorcycle mirror?

I have bar-end mirrors on my Buell 1125CR. They're fairly heavy anodized aluminum pieces that pivot on a ball & socket joint for adjusting the angle of view. One of them fits snugly on the joint, ...
10
votes
1answer
80 views

Is it possible to fit mashroomhead air filter in Honda Stunner CBF 125?

I have Honda Stunner CBF 125 2009 model. I just need to know is it possible to replace the typical air filter with mashroomhead air filter to improve the bike performance? Is there any other way ...
10
votes
1answer
494 views

Does the air screw only affect the pilot jet?

I have a 2 stroke motorcycle, it's Kawasaki KR150. When I try to do some jetting on its carburetor (it's Keihin PWL26), I saw that there's an air screw. So now I've been wondering about this air ...
10
votes
2answers
155 views

Unknown part fell out of my motorcycle

So I was taking the battery out of my bike (99 Honda Shadow 750 ACE) to ship it this past December, when two parts of the bike I'd never seen fell out from somewhere near the battery case. They sort ...
10
votes
3answers
749 views

Change in exhaust note after extreme backfires--what did I break?

I had quite a morning with my 1986 BMW K75 this weekend. The plan was to ride the bike to a friends house to store it for the winter. The weather was pretty cold on this particular morning, perhaps ...
10
votes
1answer
141 views

Cleaning mud from motorcycle radiator

Can anyone suggest a non damaging way to clean my muddy radiator? Preferably without removing it from the bike. Thanks! Update, after cleaning it with sprayed hot water and small brushes: ...
10
votes
2answers
110 views

1982 Yamaha Virago - Several things are wrong and i'd like to repair myself

Several things have happened in the past couple days and I would like to know what could possibly be wrong before I take it all apart. Engine dies after letting off the throttle while on the road. ...
9
votes
4answers
2k views

Is it OK to skip gears?

I'm not sure if this is on topic, but I'd like to know the answer before it comes a repair question. I have a Y2K Triumph Speed Triple - great bike. First gear comfortably takes to 90km/h. Needless ...
9
votes
5answers
935 views

How to become a self-taught amateur mechanic?

I'm a computer systems engineer (we did a lot of embedded systems and some electrical at university) and I own a Suzuki SV650S. I am considering doing several upgrades to it (e.g. replacing the front ...
9
votes
2answers
729 views

Motorcycle stood for over 12 months, turn over by hand first?

My 2006 GSXR 750 has been stood for over 12 months, I have drained the tank, and oil, and I'll do the coolant after I get it started, and give it another oil change. Is it worth me removing the plugs ...
9
votes
3answers
2k views

My motorcycle is refusing to start, which common problems should I look for?

I've just taken my motorcycle out of storage, I rode her around the block once, parked her, and now she is refusing to turn over. The starter seems to be running fine. I've just filled the tank with ...
9
votes
1answer
256 views

Motorcycle Headlight Conversion

I've decided to install a new headlight on my bike. The current setup is two bulbs, one is on for low beam and both on for high beam, with two wires going out of each (h11?). Here is a short video of ...
9
votes
1answer
741 views

Idling issues on 1995 Kawasaki ZZR600

The bike was running rough and could not get a constant idle speed. I checked the air filter and it was pretty well shot (contamination, etc.). As I awaited delivery of the new air filter, as a test I ...
9
votes
3answers
1k views

What are the causes of fluctuating intake manifold vacuum

I have a 2005 Honda CBR600 F4i which suffers from occasional hesitation at low rpm when accelerating. I also get occasional fault codes from the ECU indicating a vacuum leak. Today I connected a ...
9
votes
1answer
135 views

“Valve like” noise after modifying camshaft ninja 300

A friend and I bought a modified camshaft for his ninja 300/EX 300. After installing and checking/adjusting valve clearance everything seemed ok. After a few laps on our local track the bike started ...
8
votes
4answers
360 views

What is the best practice to maintain a bike?

I have an Avenger 180cc bike, I want to maintain the bike without much help from the service center, external help etc. What would be the best practice methods?
8
votes
2answers
411 views

Why is the engine on my Royal Enfield Classic 350 shutting down?

After travelling 7-8km on my Royal Enfield Classic 350, the bike acts as if the fuel is finished & the engine shuts down, but it starts again when I pull the accelerator. What could cause this ...
8
votes
3answers
150 views

What prevents engine oil from mixing with petrol in motor bikes?

Engine oil is used in the lubrication process, at the same place petrol is also there. What prevents engine oil mixing with petrol in motor bikes?