Honda Spree and Elite 50 Forums

Hello all, I have a 85 Spree and like evryone else, I too am looking for a few extra MPh. I have drilled the baffles in the muffler, and now want to do this intake manifold mod. I have looked all over the site and can not find a "how to" on this subject, can anyone help me or point me to a link that shows the steps needed. Thanks!

1. Take off the intake manifold (the tube where the engine, carb, vacuum line and oil injection line all hook up) this is a real b**** and its almost easier just to pull the whole * engine out (ALL the plastic shrouds have to come off, to do this removal of shock is required).

2. look in the the intake manifold while thinking about flow. Notice how it wasnt designed to flow very well?

3. Use a dremel to smooth out the transition from the rounded carb end to the square reed block end.

4. clean out the metal shavings from the manifold (wash it in the sink, then blow it out with compressed air, them wash and dry it again) put it back together (you can polish it if you want to for even better flow but I chose not to do this and still got noticeable improvement in midrange power and acceleration throughout the band).

If you need something more detailed you shouldnt do this sort of work.

My understanding is that polishing isn't recomeded nowdays. Something to do with the fuel droplets falling out of suspention and sticking to the runner wall.

fireblade wrote:My understanding is that polishing isn't recomeded nowdays. Something to do with the fuel droplets falling out of suspention and sticking to the runner wall.

Ya I live with a mechanic and he said something along the lines of the rough surface helps atomize the fuel.

You should be clearancing not polishing.