Advice on Cheap Driveline?

[devilishdesigner]

I know there's already a sticky post on complete bikes, but because most of the bike is irrelevant to me I thought I'd ask the question:

I'm working on a custom project using an old motorbiek frame, the frame can take a ct110 postie motor (straight bolt up, I've tested it), but for the purposes of this build I am not interested in spending over $1k for a 110cc motor with 30,000km on it.

My crude understanding is with some spacers any motor that fits a minibike will fit CT mounts with some spacers. I am after the cheapest possible complete driveline (motor, controls, electronics, carb) that won't fall to pieces on the first ride. Secondhand is my preference, Happy to take a complete bike and strip it or buy only the parts I need. Can you provide any recommendations on motors to avoid/aim for?

As an example I noticed a thread saying that TDRpro bikes are rubbish, but are the motors/carbs/electrics rubbish or just the frames and swingarms?

Thanks heaps

 

[bulldog93]

What type of frame do you have?

What size engine are you after?

What type of riding are you going to do?

Cheap good engines found here:
- Engines | Mini Bikes | Pitbikes | Dirt Bike Parts & Accessories | DHZ Mini Moto

 

[devilishdesigner]

The frame is a 70's Yamaha, it had a 100cc originally, aiming for a 125cc, won't argue with larger, won't be doing much riding, but on road/track (no offroad/jumping/etc)

 

[bulldog93]

Got any photos, modle of bike? Anything that would help us gauage what it looks like?

Lifan 125s are reliable and also their 140s. Lifan and ducar are pretty much the same.

Locin aren't bad too but I'd pick a Lifan over them.

 

[devilishdesigner]

No pics at the moment, as long as the bolt holes are the same distance apart as the CT motors I'm laughing, there's stacks of room in there as it's a fairly large frame set up for a horizontal single.

 

[bulldog93]

Most of the bottom ends are the same.

All lifans should fit with no modifactions.

People have put lifan 125,140,150 into their posties with no mods:
- http://www.miniriders.com/tech-talk/8342-postie-bike-lifan-125-a.html
- http://www.miniriders.com/japanese-minis/25038-150-postie-build-now-road.html

Just have a quick search on the fourms and you'll be right .

 

[motodevo]

There are a few mm difference between the the top and bottom mounts of the ct110 and chinese motors, but because the chinese motor mounts up with 8mm bolts and the ct110 uses 10mm bolts the mounting holes in a postie bike are big enough to cover the couple of mm difference(most of the time)allowing you to bolt up a chinga. I think the postie engines mounts are wider so you may have to pack it out with washers. Just make sure you loctite the mount bolts because if they loosen the already larger mount holes will flog out easily.

 

[devilishdesigner]

Thanks motodevo, I've got a welder and enough equipment to tweak the holes a little if necessary,so a couple of mm either way shouldn't be a problem.

 

[The_GDFP]

The frame is a 70's Yamaha, it had a 100cc originally, aiming for a 125cc, won't argue with larger, won't be doing much riding, but on road/track (no offroad/jumping/etc)

Can't find a decent Yama-dinger motor to put back in, or wanting to convert to the OHV lump for another reason? Freshened up, with a decent pipe, the 100cc rotary-valve jobs go like heck...

 

[devilishdesigner]

I'm sure they do, but I'm not in a rush to try finding parts for a 30 year old single, and haven't found a complete motor yet (The bike came complete minus motor). I'm no traditionalist, so if a near new motor with plenty of parts availability is going to get the old girl on the road then I'm happy to go that way. My other project at the moment is a 50cc rotary valve, good fun in a downright silly way.