Honda Spree and Elite 50 Forums

What's the best bit for porting aluminum(malossi mhr)??

you need some daimond tips and they arnt cheap.Be very carefull.What are you trying to acheive ?

The mhr has nicasil plating so you better not be on your first porting job. lol

They make carbide bits for aluminum but you might just want to use the sanding rolls when polishing.

Thanks guys .. Planning on porting exhaust port..and yes this is my first porting job
Porting the exhaust port can't be to hard..

I have a ton of the diamond bits i use for porting they rock. I get them for 20$ a set and they seem to last a long time. I use the carbide burr bits to get started and finish and finesse with the diamond bits

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are you trying to change port timing ? is the mhr not good enough

Thanks pat.. The exhaust port on the mhr looks to small in my
Opinion so I'm gunna open it up a lil..there's 2 lips in the exhaust port
Gunna port it down to the 1st lip.

Follow the radius of the MHR port, do not just round it out. You will create a harmful angle if you dont. You really should not just go at it with a grinder with out first going over some serious measurements and math. Ive ported 2 MHRs now and let me tell you it will take a lot of work to correct a bad port job and a lot of time to boot. 1st one was 4 sessions later before it was back to great power, 2nd MHR was only 2 sessions. Im pretty sure I can get it perfect now but that is after 600$+ in cylinders and tooling. Let alone the years I shaved off my lungs with the fog clouds of metal shavings.
By session I mean measuring every port and assume angle on port, go through the math, porting it, installing it, tuning it as best as possible, getting disappointed at results, removing, remeasuring, remeasuring again, math math math, port port port, cough up a lot of crud for days, reinstall, retune, and either repeat or finally be happy. Then retune the trans again because you know its never perfect for at least 5 more times of riding.
In my opinion be happy with the MHR standard ports or just do ever so slight improvements. If you were to only open up the exhaust port by say 10% and not the transfers or boost port (which is super important on these MHR) you will have issues and probably end up burning the piston due to inadequate fresh air flow which will cause hot spots. Its a fine balance. Anyone who has ported their MHR will tell you it needs to be very balanced or it will be useless.

Dont be frightened to port also, but just be aware of what to do and not do. If you are experienced I say jump right in. If youre new to it or even semi new and have not successfully ported anything with good results I advise to start with stock cylinders. The MHR can turn some great numbers but you have to know when is too much.

Thanks for all the advice guys .. I found a friend here who's experienced
With porting mhr's.. gunna start tomorrow.. Thanks again