A true cafe racer has the following:
1. Low and narrow handle bars
2. Single humped seat
3. Long fuel tank ....with dents to compensate rider knees.
4. Free flow exhaust.
5. No or little fenders
Yes the signature humped seat is what gives a cafe racer its "LOOK" but I personally believe they don't look good without stretched fuel tank.
Cafe racer is all about the engine and I personally think a CD175 engine is a really good engine for this project as it suits the retro style of the bike very well..... Yaar koi tow hoga jo properly rebuilt ker sakta hoo is engine ko...... Yes the engine is revamped with modified parts but if clearances are keenly measured it may be reliable but if you are inclined towards replacing it then start thinking of something worthy.
Best of luck for the project...... Im sure you will come up with something extraordinary and this project will be a learning experience for all of us. Keep this thread alive. Keep us engaged...........ask questions......ask for suggestions.... generate ideas....... Cafe racer is a real treat for an eye......... build a classic one........ its a time tested design and looks awesome....a half hearted attempt to cafe racer look fugly and disgusting. I sure you're too smart to make such mistakes.