Choosing the right bike...and.....custom fuel tank

If you are building a frame mount kit and the price of the bike isn't your first consideration:

The first thing I look for in a bike to build a motorized bike from is front suspension. I have had bikes with and without it and I won't ride one without front suspension anymore. Cruisers with front suspension from the factory seem to be fairly rare. I-paint found one I think called a Kettler. I built my favorite bike out of a Felt cruiser but I added the front suspension.

The next thing I look for is a rear wheel without a coaster brake. I like good brakes. I don't like the coaster brakes much and they make it difficult to discard the poor/dangerous chain tensioners that come with the kits. If it has a rear derailleur then the tensioner won't be needed at all. If I plan to use a SBP shift-kit then one of the internally geared hubs are my preference.

The third thing I look for is Disc brakes. Rim brakes do work pretty good too. Just not as good in the wet.

Usually you can get some portion of these elements in a bike but not all of them. You then have to plan on whether or not to add the rest.

The only frame problem that I have had to solve on my bike was some flex in the bottom bracket. I changed my motor mounts and that solved the problem. The Nirve bikes are similar and I have seen the top tube converted to a tank on one. I think it would be a bit small however. It should be easy to find some front suspension forks for that bike that are motorcycle-ish like those ones.

I like the fenders!

I´m looking at the same bike as it has everything, in my opinion, the bike should have. It even has this fatass 24x3 tire in the back. The Nirve Pyro is nice too a bid cheaper ($499) because it does not have the disc brake in front and an also nice old style suspension, but currently not in stock at Nirve.

you'll need some kind of front engine mount as that bike has the over sized front tube. don't try to use the adapter in the kit that needs the front tube drilled on an aluminium bike.