Honda XR150L Experiment (Part 2), Port matching the intake port for the modified carburetor adapter 

I don't really have any specific expectations with these experiments. I am just trying to see how much I can improve the overall performance without spending much money on aftermarket parts. FYI: I have the carb. removal down to under 5 minutes now. 🤣

Performance camshafts are available. I don't know what maximum valve lift and duration is possible yet. I plan to remove the head and do a mild port job pretty soon. Mainly just to see what gains (if any) can be had from this on the stock bore size. I don't want to go nuts here and turn it into an engine that's only good at high RPM. The current plan is to improve power at all RPM ranges (still have a good usable engine for trail riding). My plan is to open up the rest of the intake port to either 28 or 30mm (depending on the actual intake valve size), do some mild port reshaping, and try my hand at pocket porting. Depending on what else I see once the head and valves are actually removed, maybe even reshape the valves and/or seats some too. Just experimenting a little here. A big bore kit with all of this work done is the real plan and why I am actually doing all of this work. I just figured for the cost of a new top end gasket kit, why not find out how it acts on the stock engine size also. I am already making what I feel is pretty decent power for this engine. I have videos on most everyrhing that I did and am trying to share them all now. Bear with me as this takes a good bit of time to do.

@@MishMashMoto Can't find the valve specs on this thing. So little and so much misinformation on it. If I was to get one at some point I'd like to try and get the XR190L fuel injection setup. Looks like it could just swap over barring sensors I'm sure will either may or may not have provisions for already in the cases. Not much info on that one either.

It would have been better for sure, the intake valve was closed, and I blew it out good before putting the carb back on and running it also.

I have been a mechanic most of my life. I worked professionally as an engine builder and have been exposed to some race engines as well as a little engine dyno testing and R&D work. I don't claim to be an "engine wizard" but enjoy testing things on my own (without all the fancy equipment). I'm just sharing my experiment (good or bad) as we can all learn from it either way.

@@MishMashMoto you definitely have enough knowledge and experience to share the love here, we appreciate it

How about just carving the seat foam down? An electric fish filet knife makes it easier IMO. I have no idea how thick the foam is or what shape the seat pan is in. I would think that you can lower the seat an inch or two this way, though.

My wife is 5’4” and doesn’t have any issues with riding. Most of the time people only use one foot. I personally leave my right foot on the brake when stopped. She has to use the foot pegs to get on but once she learned that then it wasn’t an issue. Taller boots also helped her. She bought a steel toe Carhartt that she loves. I’ve considered just putting an adjustable coilover on the rear because ours is mainly used on road.

Nevermind. I just actually matched it to the intake. I originally didn’t take out much material. I just tried a top speed run in the wind and was able to get it up to 65mph. Still not what I was hoping for but it was windy.

I am 30mm at the cylinder heads intake port opening. It then tapers down to the stock port size a little over an inch in. I did this as a simple port matching exercise and not an actual port enlargement endeavor as I plan to do that when I pull the head off. One other thought. Did you remove the emissions stuff that was/is located in front of the valve cover? Some people have told me that it actually runs better with it on. I have not tested any of that yet.

@@MishMashMoto I did remove emissions. 65mph was on a flat road with heavier winds. I ended up going from 23ish mm with how far the micrometer would fit in the hole, to 30mm now. I also had forgot to bore the intake, it was still at 28mm. It feels a lot better and actually made the bike too rich at idle now. I had to turn to idle up a little bit to get it to stay running.

@@MishMashMoto only 3 BBR camshafts left!!

@dustysteele5408 Wish I could get one, but we have some other priorities right now.