A two wheeled motor vehicle.

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21
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5answers
4k 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 ...
19
votes
2answers
1k 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 ...
16
votes
5answers
43k 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 ...
14
votes
2answers
15k 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 ...
13
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 ...
13
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 ...
12
votes
5answers
54k 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 ;) ...
12
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4answers
872 views

Is there a benefit to belt driven motorcycles?

What are the pros and cons of belt driven motorcycles compared to chain driven bikes?
12
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2answers
215 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. ...
12
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2answers
273 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 ...
12
votes
3answers
9k 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 ...
11
votes
3answers
1k 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 ...
11
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4answers
47k 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 ...
11
votes
4answers
3k 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 ...
11
votes
2answers
2k 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, ...
11
votes
2answers
88 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 ...
11
votes
2answers
752 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 ...
10
votes
2answers
107 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?
9
votes
5answers
720 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
620 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
4answers
9k 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, ...
9
votes
2answers
136 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 ...
9
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! ...
9
votes
2answers
248 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 ...
9
votes
1answer
55 views

What is cold tire shearing?

I have friends that go to 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 ...
9
votes
1answer
49 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 ...
9
votes
2answers
646 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 ...
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 ...
8
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 ...
8
votes
2answers
665 views

Motorcycle chewing through too many front tyres

I have a Y2K Triumph Speed Triple that has an excessive appetite for front tyres. It eats two front tyres for each rear tyre. This is reverse what it should be. I run the tyres at about 38 PSI and ...
8
votes
3answers
373 views

KTM Duke 390 - Does it have to be hot to ride?

I have a KTM Duke 390 - 2013, single cylinder 373 cc motorcycle for 4 months now. I bought it from another owner when it was around 9500 km. now It's at 12000. This is my first bike, and I'm trying to ...
8
votes
1answer
1k 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 ...
7
votes
3answers
85 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?
7
votes
3answers
2k views

How might I fix a dent in a Honda Rebel fuel tank?

In a silly move during an engine overhaul, I dropped my Honda Rebel's fuel tank and put a dent in the top side. Is it possible to pull this dent out? I've heard there is a method using heat and ice ...
7
votes
3answers
6k views

What may happen if I do not replace my motorcycle's chain

I have a aging (y2k) motorcycle with not too many Ks on the clock. I have been told by a mechanic that I need to replace my sprockets and chain. This seems reasonable since the chain has been poorly ...
7
votes
3answers
799 views

Is it okay to run aviation fuel (100 low-lead) in a dirt bike?

I'm wondering if it will be okay to run 100 octane low-lead aviation fuel in my 2007 RM250 motocross bike (two-stroke). Half of the people I've asked say yes, while the other half say no. Will it be ...
7
votes
3answers
5k views

Motorcycle popping on acceleration

I have a 1975 Honda XL250 that I bought earlier this summer. Up until recently its been running great. It was leaking a little gas, but nothing too serious. When it started to get worse, I opened up ...
7
votes
1answer
42 views

Suzuki 2004 sv650s wiring

I got a 2004 sv650s Suzuki when I turn the key on the fuel pump does not come on and the CHECK light comes on on the dash. All the lights come on and the starter button does not work.All the fuses are ...
7
votes
1answer
390 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 ...
7
votes
1answer
503 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 ...
7
votes
1answer
67 views

What is a chopper?

What modifications must be made to a motorcycle to classify it as a chopper and how does it differentiate from most stock designs?
7
votes
1answer
70 views

Clutch pulls in too easy after reassebling the clutch basket, what did I did wrong?

I have a 1982 Kawasaki KZ550C LTD. When I got the bike one of the bearings on the starter assembly was worn out and would slip. So I pulled the engine and had to tear it down in order to get to the ...
7
votes
0answers
70 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. ...
6
votes
4answers
319 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?
6
votes
4answers
4k views

Can a motorcycle's brake lever be bent back into shape?

I recently had a low speed spill on my bike leaving the brake lever rather bent. Can I bend it back (roughly) straight or it is likely to just break? Given that it is cast aluminium, I suspect is will ...
6
votes
3answers
6k views

2001 Suzuki Katana 600 motorcycle won't start

A few months ago I bought a used 2001 Suzuki Katana 600 with about 11,000 miles on it. I rode it without any issues for the first month or so. After that I started having occasional issues with ...
6
votes
3answers
159 views

Can a valve suddenly break in half? Versys 650 destroyed engine

this week-end, I had to disassemble an engine from a kawasaki versys 650 (early). The bike lost power while making ugly metal sounds. It never started again. RIP. context: 108.000km, mostly higway ...
6
votes
3answers
6k views

Motorcycle: Puncture in tubeless tire. OK to plug yourself?

I got a nail in my tire the other day. Its wedged in the tire so tightly that the tire isnt actually losing pressure. A friend told me I could fix it myself by using a kind of volcanised rubber glue ...
6
votes
2answers
304 views

Motorcycle transmission occasionally pops out of gear

I'm having an issue where the transmission will occasionally downshift by itself during a fast acceleration. I have a 2005 Suzuki Vstrom 650 and it's been a great bike so far. At pretty high revs, ...
6
votes
1answer
594 views

Clutchless Downshifts Using Throttle Blip on a Motorbike/Sequential Gearbox

This is with respect to non synchromesh, sequential transmission. Ducati along with several after market systems, implement clutchless downshifts by automatically applying a slight throttle to unload ...