CR 250 Exhaust Valve Question

[Melman]

I'm installing a 2001 cylinder on my 1997 CR250. The cylinder came with all the exhaust components so I'm wondering if there any benefits to using the '01 exhaust governor? I race scrambles and I've read that the '01 governor makes better low end power...any truth?

Thanks,
Melman

[Melman]

I've spent hours researching this topic and found that the earlier (pre-96) seem to give the low hit I'm looking for. Some of it could be port placement in the cylinder of the earlier models but I ordered a '92 governor to try.

I will do an update as soon as I can.

[Brett Campbell]

It's always good to get a follow-up so others can benefit. Thanks!

[Melman]

I received the 1992 power valve governor today. The immediate visual difference is the 1992 spring coils are much smaller than the 1997. This should result in the power valve moving sooner. I'm not sure if this will translate to more low end power or not??

I'm trying to have the motor together this weekend with the 1992 governor installed and then hoping to ride next week. I will report on what the butt dyno tells me.

More to come...

[Faded]

You will prob like the earlier governor better than the later. If you can, the 94 is the best year for the governor. After that it’s prob the 92-93, then the 95-96 and finally the 97-01. There is quite possibly subtle differences within these year ranges but they all tend to ‘feel’ the same respectively.

[cowboyona426]

Originally Posted by Faded

You will prob like the earlier governor better than the later. If you can, the 94 is the best year for the governor. After that it’s prob the 92-93, then the 95-96 and finally the 97-01. There is quite possibly subtle differences within these year ranges but they all tend to ‘feel’ the same respectively.

Good to see you posting again!

[Melman]

I had a chance to ride my Honda today. I had to first break in the motor as I just finished a COMPLETE rebuild of the engine (crank assy, piston, new cylinder, bearings, seals, all new internals except for 5th gear, etc.)

The bike flat out rips and pulls like crazy from the bottom up. I do run Lectron carbs on all my 2 strokes and it was on there prior to the rebuild but it does pull better than before. (Also to be fair, I did advance the timing)

I bought this to race scrambles in a Pre-modern class (20 years or older bikes) and can't wait for racing to resume. I also race a 2018 KTM XC-F 450 and this Honda feels like a 4 stroke. I'm so happy with the results and I am still planning on installing the '97 governor just to compare and complete what I set out to do.

More to come....

[Melman]

I rode the bike last week on the same track I've been riding since 2005 with the '92 governor installed. (about 2 hours total) Last night I installed the '97 governor and rode the bike this morning and here's the results:

Before I installed the '97 governor, I pulled the round inspection cover on the side of the cylinder to watch the shaft move while I slowly reved the motor. I then did the same thing after I installed the '97 governor and the difference is huge. The '92 opens way sooner than the '97 which was expected. The '92 is fully open before 1/2 throttle while the '97 fully opens a little past 1/2 throttle.

The difference riding isn't as much as I had anticipated (and hoped). The bike seems a little crisper with the '92 but not enough to get really excited about. I'm going to re-install the '92 but bottom line is: I wouldn't run out and buy up all the early governors. It was fun doing the test but I have a '97 governor, free to a good home for anyone interested!

[Kibler]

I have also noticed that there is quite a measurable difference between free-rev movement and actual movement under a load.
Wm. K