1982 XR500r reed valves


19 replies to this topic
  • beezerjoe

Posted March 11, 2007 - 06:47 PM

#1

Yes another white elephant.My question today is where can I find suitable replacement reed valve in the event that the original ones break.From what I found out Honda no longer has them maybe Boysen,but from what little searching I've done I haven't found any as of yet.

  • Thumpage

Posted March 11, 2007 - 07:22 PM

#2

Yes another white elephant.My question today is where can I find suitable replacement reed valve in the event that the original ones break.From what I found out Honda no longer has them maybe Boysen,but from what little searching I've done I haven't found any as of yet.


Reeds are for 2 smokes you silly White Elephant! :lol:
Sorry I just had to go there, :lol::eek:.
All kidding aside, Reeds are for 2 strokes that operate without a valvetrain. They are a totally different engine design. You need to be looking for 4 stroke valves. Check this link at XRs Only: http://www.xrsonly.c...emart&Itemid=77
The valves for your bike are the second and third listing for valves, [exhaust and intake valves] listed below the pistons towards the bottom of the page. :applause:

  • Thumpage

Posted March 11, 2007 - 07:33 PM

#3

Oh,.. and since your bike has 4 stroke valves, you don't need to be concerned with breakage, unless you have other serious engine problems.
If you have many miles of wear on the old motor and need a rebuild, then it could be time to look for them there.

  • beezerjoe

Posted March 11, 2007 - 08:13 PM

#4

Ok you got me good on that one.:applause: Now here is the deal in 1982 the last year of the old XR 500 engine before the RFVC came out Honda for some silly reason thought it would a good idea to incorperate a 2 stroke style reed valve system in the intake track between the carb and the intake valves to help out with bottom end response.Tripped me the hell out when I saw it and all I could say was "why".If you want to see this rarity check BIKE BANDIT microfiches for an 82 XR500R,cylinder head section I believe.So you see us white elephants aren't so silly after all:D .No offense and none taken.Sometimes you gotta run with it:thumbsup:

  • HawkGT

Posted March 11, 2007 - 08:21 PM

#5

....learn something new everyday....:applause:

  • beezerjoe

Posted March 11, 2007 - 08:23 PM

#6

....learn something new everyday....:applause:


Kind of goofy isn't it.

  • HawkGT

Posted March 11, 2007 - 08:25 PM

#7

Will they run ok without them installed?

  • beezerjoe

Posted March 11, 2007 - 08:35 PM

#8

You know I'm not sure how it would operate with out them it might just kill some of the intake velocity.When honda made that head they cast it with a 2x3 inch hole in the intake port to accomodate the reeds.When Igot the bike the previous owner had done alot of work to it;needle bearing cam new valves new crank and rod,rings. I had to split the cases to change the counter shaft seal that got mauled.It's going back together now I'm real interested to see how it performs.

  • Thumpage

Posted March 11, 2007 - 11:25 PM

#9

Kind of goofy isn't it.


Well,...I'll be a monkey's butt, that is something new for me! :lol:. You got me back on that one, :eek: . I have never heard of that before. We'll I guess that serves me right for trying to answer a 1982 XR500 thread when i am a XR650R rider, [Heh,heh, kind of an inside joke about a recent thread about seperating the bigbore bike models, :lol:].
Heck, I tried anyway. Maybe I'll be more successful in giving advice on less obscure motors, :naughty: :lol:. I didn't notice any offering of XR500 reeds at XRs Only. If I had, I would have been astonished. Maybe they can at least tell you were you might find them. If you ever need anything from them though, I sure hope their business methods and customer service is not what it was in the recent past. It [was] :applause: from what was being said from quite a few people a year or so back. Hopefully they have been making changes for the better. Good luck with your '82.

  • cleonard

Posted March 12, 2007 - 07:25 AM

#10

I had an 81 XR500R and one of the first things that I did was remove the reed assembly. Mine was on it's last legs and if I had left it in a reed petal would have broken off soon. The bike ran OK without it. The top end was increased a little. It did cause some issues at low RPMs. The dreaded cough and die was increased. In time I built up technique to deal with that problem.

It also required low end jetting changes. I never really go it 100% optimum, but it ran fine. The issue is that the carb is setup like a 2 stroke. In a normal four stroke part of the intake charge gets blown back through the carb, then that air gets sucked in on the next stroke. This end up in a partial two passes through the carb. That makes it richer after removing the reed. I always ran that bike rich though since it ran so hot.

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  • beezerjoe

Posted March 12, 2007 - 05:12 PM

#11

Well,...I'll be a monkey's butt, that is something new for me! :lol:. You got me back on that one, :eek: . I have never heard of that before. We'll I guess that serves me right for trying to answer a 1982 XR500 thread when i am a XR650R rider, [Heh,heh, kind of an inside joke about a recent thread about seperating the bigbore bike models, :lol:].
Heck, I tried anyway. Maybe I'll be more successful in giving advice on less obscure motors, :naughty: :lol:. I didn't notice any offering of XR500 reeds at XRs Only. If I had, I would have been astonished. Maybe they can at least tell you were you might find them. If you ever need anything from them though, I sure hope their business methods and customer service is not what it was in the recent past. It [was] :applause: from what was being said from quite a few people a year or so back. Hopefully they have been making changes for the better. Good luck with your '82.


Thanks for the well wishes Thumpage.I had dealt with XR's only about a year ago when I got my 89 XR600 basket case.I had them do a rod and cylinder bore job and fix the center cam journal rebuild the oil pump and bought some other odd and end parts,just got it fired the other day by the way.Anyways I had mixed feeling about the customer service when I first called down to check on the progress a guy there gave me a tracking number for an order that wasn't mine.I called back and talked to Chris if I remember right and he told my job hadn't come up yet but was close on the list and I asked about why the other guy gave me a number and bad info. He basically told me that some of the people working shouldn't be and that if I had any questions to ask for him directly.I believe he was running the shop at the time.The qaulity of the work was good he took care of any problems I might have had.Pretty much a positive expierience.I haven't had any dealings with them in a while but I hope they do get whatever it is squared away.

  • beezerjoe

Posted March 12, 2007 - 05:57 PM

#12

I had an 81 XR500R and one of the first things that I did was remove the reed assembly. Mine was on it's last legs and if I had left it in a reed petal would have broken off soon. The bike ran OK without it. The top end was increased a little. It did cause some issues at low RPMs. The dreaded cough and die was increased. In time I built up technique to deal with that problem.

It also required low end jetting changes. I never really go it 100% optimum, but it ran fine. The issue is that the carb is setup like a 2 stroke. In a normal four stroke part of the intake charge gets blown back through the carb, then that air gets sucked in on the next stroke. This end up in a partial two passes through the carb. That makes it richer after removing the reed. I always ran that bike rich though since it ran so hot.


Thank you for responding Cleonard I rather enjoy your posts, always good information in them.I'm just happy to see someone else has dealt with the reeds.I'm sure when you had this bike it was a while back but do you remember what you did on the jetting?I was wondering if cam overlap was the reason they did it to eliminate the pulses back thru the intake and keep the charge captured.It seems like it would almost have forced air effect which would eliminated lag right off the bottom.On yours did you leave the reed block in without the reeds or just bolt the manifold right to the head?

  • cleonard

Posted March 12, 2007 - 09:22 PM

#13

Thank you for responding Cleonard I rather enjoy your posts, always good information in them.I'm just happy to see someone else has dealt with the reeds.I'm sure when you had this bike it was a while back but do you remember what you did on the jetting?I was wondering if cam overlap was the reason they did it to eliminate the pulses back thru the intake and keep the charge captured.It seems like it would almost have forced air effect which would eliminated lag right off the bottom.On yours did you leave the reed block in without the reeds or just bolt the manifold right to the head?


I took the reed block out completely and just used one of the two gaskets. I do not remember what I did with the jetting, but it was not too far from stock. It did run without any changes at first.

Before I gave it away, I had the Honda manual. It said just that. The reeds function was to prevent the charge from escaping before the intake valves closed. The book claimed that it allowed for later valve closing. However, when I got my current XR600 manual it turns out to have almost the same valve timing.

When I needed an air filter, I found that no one made them and the stock Honda filter element, if still available, was very restrictive. I made my own. One of the aftermarket filter makers, Uni I think, sells just a rectangular sheet of foam about 5/8 of an inch thick. I used a combo of crazy glue with a needle and button thread to join the ends. A little work and I had three filters for a total of $15.

  • beezerjoe

Posted March 13, 2007 - 08:08 PM

#14

I took the reed block out completely and just used one of the two gaskets. I do not remember what I did with the jetting, but it was not too far from stock. It did run without any changes at first.

Before I gave it away, I had the Honda manual. It said just that. The reeds function was to prevent the charge from escaping before the intake valves closed. The book claimed that it allowed for later valve closing. However, when I got my current XR600 manual it turns out to have almost the same valve timing.

When I needed an air filter, I found that no one made them and the stock Honda filter element, if still available, was very restrictive. I made my own. One of the aftermarket filter makers, Uni I think, sells just a rectangular sheet of foam about 5/8 of an inch thick. I used a combo of crazy glue with a needle and button thread to join the ends. A little work and I had three filters for a total of $15.

This is good.We're just about ready to hang the engine back in the frame and there's still afew things I hadn't looked at yet the air filter being one of them.I'm not sure what the previous owner had done but I know he was racing it until about a year ago who knows it might have an old K&N in it.I feel kind of silly because I usually check over basket projects pretty good when I get them,not so much with this one it's been step by step.Thanks for the tips Cleonard.This at least gives me some options when the inevitable happens.

  • eric318

Posted July 05, 2008 - 03:28 AM

#15

I have owned a XR500R since new in 1981 and I am currently resurrecting it. The valve stems seals were gone and the carburetor was stuffed with hardened muck. Some of the plastic is faded after some time in Africa but otherwise it has less wrinkles than me. Anyway.

The reed valve set up was actually quite clever. On mine, one of the steel flaps actually.... broke and disappeared in the engine. This was when the bike was about 1 year old. I discovered that one flaps was missing by chance one time as I was servicing the bike.

At the time, one my mates was racing a 125cc Husqvarna and we found out that the valves on his bike were almost identical to those on the XR although his had 4 flaps each and were made of synthetic material The XR's only had 3 flaps and were made of steel. I bought a set of Husky valves for a few pennies, cut off the 4th flap and .... they have been on the bike since then!

The funny thing is though that when I took the engine apart last year to replace the valve stem seals I was expecting some horrible scoring of the cylinder and the steel flap to be somehow welded to the piston. Well, I was wrong, all in there was neat as new, the broken flap passed all the way through the combustion chamber without a trace.

I now understand what causes the strange gingle bell noise in the muffler...

  • scalejockey

Posted July 05, 2008 - 05:45 AM

#16

Man i'm truely blown away! I was going to do this to a four-stroke and change the valve timing just to see how it would work.But NOOOO,Honda had to go and do it for me!! Well ok.. mark that off the list of "I wonder what would happen if.."

  • creeky

Posted July 05, 2008 - 08:09 PM

#17

I always ran that bike rich though since it ran so hot.


Hot is right! One of my riding buddies rode an '82 XR500 for several years. He would wrap several slices of pizza in aluminum foil and put them in the fender bag. When it came lunch time on the trail, he would lay the foil pack on the engine and the pizza would be warmed up in no time.

  • zrxer

Posted July 05, 2008 - 08:55 PM

#18

Back in '83 me and a couple buddies all bought new leftover '82 XR500s in about a 2-3 weeks time. As I recall at the time, the reed blocks were supposed to alleviate the big four stroke single coughing back through the intake and stalling when the throttle was whacked open quickly syndrome. It seemed to work fairly well but it took away about 1 horsepower compared to the non reedblock head. White Brothers used to make a reed block replacement which was basically a bolt in intake port. You could, if it came down to it in the future, swap the head out to a non reed '82 XL500R head. To this day, that old XR500R is my favorite wheelie bike. Smooth power and an excellent balance point.:thumbsup: Bruce

  • eric318

Posted July 05, 2008 - 11:35 PM

#19

This reed cage from a 81 CR450 looks furiously similar to the one on the XR500R of the same year... apart from the lightening cut outs and the two additional holes. It *MAY* fit...

  • eric318

Posted July 05, 2008 - 11:45 PM

#20

Or this one from a 99 CR250R...





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