88' to 91' Honda CR250 HPP Cleaning and Setup info

[bcavmechanic]

Hi All.

I keep seeing people having troubles with their HPP valves on the 88' to 91' Honda Cr250s. I have been working on restoring a 1988 CR250 and when I put my engine together I had a bit of a hard time getting the valves setup correctly myself. I had an 88' back when they were new and did work on it back then but forgot much of the setup. Once I relearned it I am pretty good at the setup now which is good as I have another engine to assemble soon. I thought I would share some of my references and answer any questions if anyone has any trouble with this. I have shared some good PDF versions of some of the sections from the manuals. If you are a facebook user try joining CRs Only. https://www.facebook.com/groups/771937119520313/files/ There is a files section there where you can download the FSM and owners manuals for these bikes. There are also a copy of my files focused just on the HPP valves posted there. Here is some of the info converted to Jpeg to post here. A couple of those pictures are the 86'/87' valve setup which is very similar. There are only a couple differences. The pictures help to get an idea of how it all fits in the engine. I hope this helps out a few folks. Feel free to ask any questions and I will do my best to answer. 

Greg

[Pygmy Warrior]

Good info Greg. Thanks!

[Piney Woods]

?? And one ounce of SeaFoam to EVERY 2.5 gal of premix with a high quality oil appropriate for your use will forever eliminate a need to clean them again.

Edited August 17, 2017 by YHGEORGE

[ASP1227]

This is great, thank you! I'm building a '86 cr250, I will definitely be frequenting this thread now on how to do the powervalve.

[bcavmechanic]

19 minutes ago, YHGEORGE said:

?? And one ounce of SeaFoam to EVERY 2.5 gal of premix with a high quality oil appropriate for your use will forever eliminate a need to clean them again.

Yes. That might reduce the cleaning but there will always be a need to know how to disassemble and reassembly this stuff for other engine maintenance. Not to mention how to get them adjusted correctly. 

Greg

 

[bcavmechanic]

18 minutes ago, ASP1227 said:

This is great, thank you! I'm building a '86 cr250, I will definitely be frequenting this thread now on how to do the powervalve.

The 86' 87' is just a little bit different but it is quite close. You still adjust bolt #4 for the correct spring closing preload. Just a couple of different pieces but same overall application.

Greg

[ASP1227]

You can run the bike with the powervalve cover off? I thought that would be like an air leak and cause lean conditions.

[bcavmechanic]

25 minutes ago, ASP1227 said:

You can run the bike with the powervalve cover off? I thought that would be like an air leak and cause lean conditions.

Being it is not on the intake or crankcase it is not an air leak. This is only a slight exhaust leak when running. No problem at all.

Greg

 

[Piney Woods]

On 8/17/2017 at 7:02 PM, bcavmechanic said:

Yes. That might reduce the cleaning but there will always be a need to know how to disassemble and reassembly this stuff for other engine maintenance. Not to mention how to get them adjusted correctly. 

Greg

 

That had already been addressed quite thoroughly.

[Puddn421]

Following this

[ASP1227]

It’s easiest to do with the cylinder off

[Neil Wardle]

Thanks Greg for the Info,  I'm still a bit unsure where the engagement bolt is?  Can you confirm the location Thanks for your time Cheers

[Piney Woods]

He may have moved on by now. Maube send him a pm to see if he is still on TT. Good luck.

[Turboloader]

On 6/30/2022 at 4:50 AM, Neil Wardle said:

Thanks Greg for the Info,  I'm still a bit unsure where the engagement bolt is?  Can you confirm the location Thanks for your time Cheers

You looking for the engagement bolt? Hmmmm, I have that same bike, It might be right below the water pump, behind a little flathead screwdriver bolt...But dont quote me...

[SlowDinoDog]

Correct Turbo.

You engage the PV mechanism in the cylinder to the PV governor in the cases by turning the part with a flat blade screwdriver though this opening in the cases after removing the cap screw.

 

Edited July 2, 2022 by SlowDinoDog

[Turboloader]

5 hours ago, SlowDinoDog said:

Correct Turbo.

You engage the PV mechanism in the cylinder to the PV governor in the cases by turning the part with a flat blade screwdriver though this opening in the cases after removing the cap screw.

 

Twurbwo, smart, twrbro get a cookie.?

[marmstro]

My 1989 cr250 is all of a sudden running like crap.  Hard to start, won't rev out.

I've cleaned my carb/jets, changed fuel in case it was bad, new plug, clean air filter, checked the reeds, etc.  

The hpp mechanism is suspect to me now.  Looking at it, it seems like there is a lot of slip in it.  When I move them by hand, they will rest a quarter of an inch from the e clip being flush.   

I had the kick starter assembly apart in the spring and I'm wondering if I maybe didn't realign the shaft properly when I put it together again.

Any ideas?

[SlowDinoDog]

3 minutes ago, marmstro said:

My 1989 cr250 is all of a sudden running like crap.  Hard to start, won't rev out.

I've cleaned my carb/jets, changed fuel in case it was bad, new plug, clean air filter, checked the reeds, etc.  

The hpp mechanism is suspect to me now.  Looking at it, it seems like there is a lot of slip in it.  When I move them by hand, they will rest a quarter of an inch from the e clip being flush.   

I had the kick starter assembly apart in the spring and I'm wondering if I maybe didn't realign the shaft properly when I put it together again.

Any ideas?

Yeah... its easy to watch the left side valve work.

Fire it up with the cover off and watch its motion when you turn the throttle and the engine revs.

You can watch the right side as well, its just a bit more difficult with the pipe in the way.

[SlowDinoDog]

There's an adjustment procedure to try to get rid of that 1/4" play with the mechanism closed.

[SlowDinoDog]

If the kicker is ratcheting and springing back smoothly there's probably no issues with that.