Newbie questions on where to start

[Nikuya]

OK! Have been lurking here for a while, and have finally taken the plunge, signed up and am ready to start planning a conversion. Im not a huge fan of naked bikes/enfields/etc and would like to use an older honda CBR250RR as a donor as I love the look and am not averse to "modifying" the fairings but have a few niggling questions. I would like to point out that while mechanics isn't my expertise, I have done maintenence on my own bike and had bits and pieces out for whatever reason.

First and foremost... what does CVT stand for?!?!?!?! Its driving me nuts and is probably obvious but i cant see it :S

Second, are there any books that discuss conversions specifically for bikes and goes through a conversion? if not are there any other books worth reading?

I understand that you need an engine and gearbox but what other considerations need to be taken into account. i.e what gearbox would be good, what if i want to use a wet clutch and have it share the oil with the engine, modifications for electric starting, wiring, etc?

Also, one thing that concerns me is the big black cloud when accellerating and want to know if anyone has experimented in using a catalytic converter/charcoal cannister to cut the cloud down. Not worried about the power loss, this will just be a commuter.

Basically all I know at the moment is that I would like to stick to chain drive, use the honda, and this would be a slow process so i have plenty of time.

[sbrumby]

Well the best thing you can do is fill out your registration so people at least know what country you are from.

[coachgeo]

CVT replaces the gear box. A google search for "cvt" will find you lot of answers. Better yet... "Constant Velocity Transmission" will give you more.

If not a CVT think the easiest gearbox to use would be a Harley Ultima and belt drive. 2 or more inche belt. A big grunting engine like a 3cyl will need 3" belt.

[Nikuya]

oops, sorry. Have updated my location to Australia

[albertaphil]

...or search for Continuously Variable Transmission. The idea is that the transmission has an infinite number of "gears" such that the engine can stay in the powerband rpm range for any given ground speed. When talking motorcycles, the term is usually referring to a belt drive system with a driving and driven pulley that can vary in circumference based on torque, speed etc.

As for reducing smoke; just reduce the amount of fuel going into the engine. Newer heavy truck engines have soot traps that occasionally require "regenerating" whereby fuel is injected intot he soot trap and the carbon is burned out at a very high temperature. Now diesels have gone to injection of a catalyst (like liquid urea) into the exhaust which eliminates soot. Both of these are impractical on a home built motorcycle, no matter how much time you have Seriously, if you want clean exhaust, put in a bigger engine and turn the fuel delivery down. You'll have less power and less smoke.

Cheers,
Phil

[andrewaust]

First thing I'd do is contact VIC Roads and find out what red tape is required to convert a bike to Diesel.

If it's anything like NSW = have fun




A

[sbrumby]

Here are my thoughts, CVT constantly variable transmission. Bit of a cop out in my oppinion, you dont see many raceing on the Isle Of Mann. Automatic as well. Could be wrong here but I dont know weather you get any engine brakeing? What they do supply is a gearbox in a small space, apart from an ugly bulge on the left hand side. They also dont do anything till you hit about 1600rpm so quite a lot of your usefull rev range is not there.
Useing a gearbox off a unit construction petrol engine is possible but definately not easy. "Diesel Weasel " german bikes do it. The main thing to consider is power and size, a powerfull engine is big and heavy. So when building a bike you have to consider getting an engine and a gearbox into a space that it wasnt designed for.
On the smoke question, if its smokeing it is either set up wrong or you are in the wrong gear, ( giveing it to much work to do)
hope this helps.

[Crazymanneil]

Welcome on board Nikuya. Have a look round on here and dig around using the search tool - theres a ton of useful posts on here you will find interesting.

I've modded the forum to require location info on registration so everyone joining us should have something on there from now on. I know we like it on here though it was not obvious in the registration process before so sorry about that.

As for my 2p on smoke (this could turn into a big debate)... Smoke = incompletely burnt fuel. This can be caused by overfuelling, retarded timing (not enough time to burn the fuel), poor atomisation (cruddy injector) or lack of air (blocked air filter for example). Solve the cause, solve the smoke. Though having said that diesels don't throttle air and tend to run a lot leaner (excess air) than chemically correct, even at full load. So winding up the fuelling a bit can make a bit more power at the expense of smoke and chicks dig the black clouds you make too. Erm well ok maybe not...

Overdo it and exhaust temp goes quite high and you start melting stuff. So many factors involved!

N

[Nikuya]

ah. ok... cvt = automatic. would rather stick with manual.

So excess smoke is due to bad fuel set-up. I think i read somewhere that it was just something that diesels did regardless (note: read with sceptisism) and just wanted that cleared up. The bike itself would only need to do about 100kph (62ish miles i think) at max as most of the areas to work are 60/70 zones but may be needed for occasional highway/freeway travel.

As to gearboxes, so the brand/type ultimately (no pun [oh god, it just gets better and better :S] intended) depends on the motor chosen. I understand dry clutches to be rather noisey and so want to avoid them. Sadly, i dont have access to a 250RR so i am unsure as to the size I have to work with. I have been scouring fleabay and bikepoint for a wrecked/not working one but so far am finding nothing.

As to running an electric ignition, I would need a stator to recharge the battery, wouldn't I or am i just confused? and with regards to ... dash equipment ( i know there is a word im looking for but I've got a mental blank now) speedo would be a bycicle computer? what about a rev gauge? and what other... things... would be recommended?

EDIT: Also, Andrew. I imagine there will be red tape, but once I know what needs to be done I will contact vicroads and begin crying.