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  #1  
Old 03-07-2013, 05:46 PM
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Default 2001 Honda Cr250 powervalve question after rebuild with pics

As some of you know i recently rebuild my 2001 honda cr250. Cylinder was welded, plated, honed, and surface ground by Millenium Technolgies. Weisco piston, plastics, clutch cable, yadda yadda ya, etc.

Whoever was the last person inside the engine didnt put the powervalve back correctly and the shaft that the powervalve pivots on was completely missing, and this piece (shown below) was broken.



I didnt see this piece in any sort of manual or anything online, so i put it back together without it.

Now, the bike runs great, but it will not hit the powerband

The valve is adjusted correctly, underneath the bolt on the right side of the engine, the slot it properly alligned at "L" when the bike is idling, when i rev the bike up, it does not flutter or move whatsoever.

Anybody have any ideas???

Heres a few pics of the bike:





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Old 03-07-2013, 06:43 PM
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Quote:
the shaft that the powervalve pivots on was completely missing,
and this piece was broken...so i put it back together without it
I don't know where to start. You are missing parts of the PV assembly
and have found broken parts as well, and you decided it was OK to run
without them?

I'm assuming you are leaving part of the story out. Like the part where
you took the PV assembly out and checked and cleaned each and every
component, replacing anything missing. Then you went over the PV
cavity and the rest of the cylinder scouring to find out what broke and if
there was anymore carnage laying around just waiting to trash your new
top end. Then, once satisfied you covered everything, you put it all back
together and installed and set it up per the manual, and now don't under
stand why the PV is not working, right?

If all the above is correct, the most frequent problem is failure to properly
engage the crowfoot at the base of the cylinder. As far as the broken part,
hard to tell without cleaning up the debris and providing some sort of scale
in the picture.

dogger
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Old 03-07-2013, 06:46 PM
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So you have all the parts in this picture?

[Only registered and activated users can see links. ]

If so, your problem may be with the power valve governer located behind the right case cover.
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Old 03-07-2013, 10:35 PM
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Quote:
Originally Posted by dogger315 View Post
I don't know where to start. You are missing parts of the PV assembly
and have found broken parts as well, and you decided it was OK to run
without them?

I'm assuming you are leaving part of the story out. Like the part where
you took the PV assembly out and checked and cleaned each and every
component, replacing anything missing. Then you went over the PV
cavity and the rest of the cylinder scouring to find out what broke and if
there was anymore carnage laying around just waiting to trash your new
top end. Then, once satisfied you covered everything, you put it all back
together and installed and set it up per the manual, and now don't under
stand why the PV is not working, right?

If all the above is correct, the most frequent problem is failure to properly
engage the crowfoot at the base of the cylinder. As far as the broken part,
hard to tell without cleaning up the debris and providing some sort of scale
in the picture.

dogger

The powervalve assy. was completely degreased with oven cleaner prior to installation. I did replace the missing shaft with a new one, and i checked the old one to make sure it was in spec. Forgot to include that, sorry.

As far as the crows foot goes, im about 99% sure that it was installed correctly. If i were to pull the jug back off and check to make sure that the two pieces are mated correctly, i would most definately need to use a new base gasket, correct?

I seem to have misplaced the broken part, but if i recall correctly, it was around the size of a nickel.


One more note, when the jug was off it didnt seem that the prong that comes off of the govenor shaft that comes out of the engine that the crows foot mates too, seemed like it was in the middle of it travel. Rather than one way or the other... Which also wouldnt make sense because then the PV would be halfway open, if it were adjusted properly.

Basically if i pull it back apart, and the crowns foot was installed properly, then there is an issue with the govenor inside the engine underneath the right side cover.

Do you need to split cases to replace the govenor?

---------- Post added at 09:35 PM ---------- Previous post was at 09:33 PM ----------

Quote:
Originally Posted by 351mustanger View Post
So you have all the parts in this picture?

[Only registered and activated users can see links. ]

If so, your problem may be with the power valve governer located behind the right case cover.
Yes i do believe i have everything installed in the pic
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Old 03-08-2013, 02:59 AM
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You don't split cases to get to the governer. Just behind right side cover. I would use new gaskets for the repair.
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Old 03-08-2013, 08:13 AM
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I think my basic question would be, where did you find the broken part? In the exhaust port, in the left inspection port, in the right side valve linkage cavity?
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Old 03-08-2013, 10:17 AM
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u need a manual, it will tell u every thing about the power valve, oem r the best. i was having trouble with my power valve
after countless times of taking it apart . i torque the two bolts down then worked like a champ.
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Old 03-08-2013, 10:37 AM
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you can take the cover off the left and or the right side and see if your powre valve is moving as the revs go up if you want to check that before tearing it down again. when the engine is not running the actuator porition down in the lower right side (the pin the crows foot goes on) would be in the closed position. was it free to turn from side to side etc when you put it back together?
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Old 03-08-2013, 11:57 AM
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Quote:
seemed like it was in the middle of it travel.
I think we're on to something with this statement. If the pinion
shaft is engaged with the governor correctly, the pin should be
parked to one side (see picture) allowing full throw when activated.
Left side of picture is front of engine:


This is a simple fix. Remove the cylinder, remove the case cover
and pull the pinion shaft up to disengage it from the governor, then
turn it to orient it like the above picture and push it back in place.
re-assemble everything with careful attention to engaging the crow
foot to the pinion pin correctly.

Since that broken part in the picture was covered in carbon, I'm guessing
it came from the PV cavity. Here is a picture of what that cavity should
look like if everything is intact for comparison.


dogger
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Old 03-12-2013, 09:40 PM
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Quote:
Originally Posted by dogger315 View Post
I think we're on to something with this statement. If the pinion
shaft is engaged with the governor correctly, the pin should be
parked to one side (see picture) allowing full throw when activated.
Left side of picture is front of engine:


This is a simple fix. Remove the cylinder, remove the case cover
and pull the pinion shaft up to disengage it from the governor, then
turn it to orient it like the above picture and push it back in place.
re-assemble everything with careful attention to engaging the crow
foot to the pinion pin correctly.

Since that broken part in the picture was covered in carbon, I'm guessing
it came from the PV cavity. Here is a picture of what that cavity should
look like if everything is intact for comparison.


dogger
Pulled the jug up, but not off completely tonight. Some things i noticed:

The pinion shaft which comes out of the engine has the ability to move back and forth about 45 degrees, it can also pull right out.

Also i noticed some slight scoring on the exhaust side of the piston. I know i cleaned the jug 4 times before installation, same with the piston, and i also know the oil/fuel ratio at 32:1. The bike also has a new air filter.I broke the bike in by starting it up and letting it idle for 10 mins, then letting it cool completely, then several 5-10 min rides with slightly more throttle each time. The plug is dark, but not black.

I ordered all the required gaskets, water pump, right side cover, base gasket, etc.

Im going to tear the bike down more tommorow, and ill write back with my findings.

Thanks for all the help, i really appreciate it (especially dogger)

-Chris
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Old 03-13-2013, 07:55 PM
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Pulled the side cover off just now, the govenor looks to be in good shape, nothing noticeably broken/damaged/worn out.

Now, when i hold the governor and rack assy down by hand, the pinion has no play, i put the right side cover back on, and the play in the pinion persists... what gives??

am i installing it incorrectly?
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Old 03-14-2013, 06:56 AM
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Noticed you said scoring on the exhaust side.
Did you drill your piston so oil can cool off the exhaust bridge?
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Old 03-14-2013, 10:03 AM
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Quote:
i put the right side cover back on, and the play in the pinion persists.
Tough to diagnose a problem over the internet, especially without pictures
or video of what you are doing.

For troubleshooting, you should leave the right side case cover off until
you have determined everything works correctly. Now it's a process of
functional checks and elimination.

Set the pinion shaft up in the case so that it's oriented correctly. Now try to
move it by hand (it shouldn't move). Make sure the pinion shaft bushing is
installed. Next, do the same with the cylinder. You should be able to open
and close the PV by hand. Verify this by watching the flap and two rotory
valves move when you rotate the linkage back and forth. Now make sure
you can't move the assembly if you hold the crowfoot - this test to make
sure the pinion lever is tight on the shaft. Also, there shouldn't be any up
or down play evident. Finally, make sure the upper pinion shaft bushing is
installed.

If all these test work correctly, and there is nothing else amiss from your
visual inspection of the PV cavity and the area around the flap valve, and
assuming the governor is not bad, the PV should work correctly.

PV are like automatic transmissions. They look complicated, but are really
straight forward and easily serviced as long as you work slow and steady
with strict attention to detail.

dogger
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Old 03-14-2013, 10:18 AM
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Quote:
Originally Posted by DBShred View Post


Bearing shield on either the right or left valve.....
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Old 03-14-2013, 09:47 PM
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have a look at this pic [Only registered and activated users can see links. ]

make sure you have both washer spacers (#19) on the governor shaft... if one is missing and you put the case cover on, there will be too much play between the case covers and the shoulders on the governor shaft, which will allow for radial travel of the whole mechanism, resulting in movement of the crowsfoot.. Because the governor is a pinion drive system, it needs to be snug betwen the cases for no movement, and remember that Honda also accounts for the thickness of the gasket material when calculating the clearance tolerances for that governor shaft!! hope this solves your end play problem..
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