CR500AF topend, jetting, and 18" wheel questions

[Panzer]

Hey All you AFers out there,

I bought my AF back in '01 and have have burned a case worth of honda hp2 premix. ( I'd guess about 48 gallons of gas.) I typically ride in tight woods and in a dirty, dusty conditions and I almost never rev it hard. I change my air filter and oil every couple of rides. I have not really noticed any change in power or difference in the sound (i.e., "piston slap").

I figure it might be time to start thinking about a putting a new top end in the beast.

1. Do you guys think I should have probably done this sooner or is now a good time?

2. Are there any tricks to doing a top end in this bike? I know that it is pretty cramped in there with that huge motor stuffed in 250 frame. Will I have to remove the entire engine?

3. What type of piston or piston kit should I get?

4. What else should be done will I have the top end off?

Okay I have a few other unrelated questions about jetting and the rear wheel.

5. What is the stock jetting from the factory?

6. I am pretty sure the stock jetting is a little too rich for my conditions. I have moved the clip postion to the leanest setting and that has helped but I think I should probably change a few needles to get to a more optimal jetting. What jetting would you guys recomend for my riding style at essentially 0-500 elevation with temperature variations from 15-85F, mixing 32:1? (Ohio river valley)

7. The final question is in regards to converting the rear wheel to and 18in wheel so that I can use michelin 140/80-18. Has anybody else used the "bigger" 18 wheels? I feel like that the stock 250 wheels aren't large enough for the 500.:) :)

 

[KiwiBird]

It sounds as if you haven't really thrashed it yet so pull the reed cage out and check the intake side of the piston for cracks starting from the bottom. Pop the pipe off if you want to check for any kind of exhaust seize, but that's fairly rare and less likely in the woods. If you don't have any cracks and the motor doesn't rattle and has good compression and power I'd keep running it. I have a little more time than you and more agressive open desert and hillclimb stuff and I'm finally noticing a decrease in power.

If you do decide to do it AJ is the man to describe the yoga move necessary to smoothly extract the motor so you can pop the jug.

I run the stock pistons but there are others available.

Replace all the gaskets, check your reeds, replace the exhaust ring that goes on the exhaust manifold or consider the Atomic-22 replacement. I usually replace all the rubber pipe mounts and muffler mounts at this time too if needed. It's a good time to remove and measure the cluch plates and springs and do the linkage and usual other stuff.

Stock jetting is 55 pilot, 1368N #4, 170. AF is 55, 1368N #3, 175. Stock jetting with needle on #3, for PC pipe, should be close but otherwise if you like the clip on #1 it's time to go buy some jets and needles - maybe 1369N or 1370N and drop the main somemore if there are no big straights or high load situations. Drop the pilot to maybe 52 and mess with the airscrew so it still starts well. One change at a time.

I had Service Honda convert my bike to 18" inch rear before they sent it and love the 140/80 X18 S12.

I also highly recommend the Hebo hydraulic clutch, much better action and totally easy to start in gear.

 

[singletracker500]

Everything Kiwi Bird said. Except his bike is jetted way leaner than mine

You can change the top end with the engine in the bike. But you have to remove the engine mounting bolts and slide the engine back as far as possible. That's the way I did mine, but I'll tell you, once your at that point, you might as well pull the engine and do it on your bench. You'll have to remove the head in order to get the engine out, at least I did when I pulled the whole bike apart right after I got it. There was just no way I could find to get it out with the head on. It would always get hung up on either the water pump or the head stay. I had four hands on the thing from every angle trying to find the perfect position to get the thing out. No dice.

BTW...I pull it apart once a year and at least put a set of rings in.

Oh yeah, the 18" rear, and 20" front are in my near future plans. I can't stand the skinny side walls on a 19" rear!

 

[thorman75]

while your at it change the ignition side crank seal

 

[jski]

Kiwi,

While I don't own the AF I do have a 2000 CR-500 that I bought last January and ever since the bike was new the motor has been noisy? ie sounds like piston slap but it checked fine several months ago when I looked at the piston. My question is how much noise and how much vibration would be considered normal for a 500? My bike is noisy at idle and when you free rev it but under a load the noise is less noticeable. Anyway I most likely am being anal this being my first new bike in 20 years. Thanks

 

[KiwiBird]

jski, the vibes could have several sources - replace the metal band that goes on the exhaust manifold and check all the pipe/muffler mounts. Check all your motor mounts too. If the pipe is bent it will tend to make the vibes worse as it will no longer be an "isolated" mount.

Sometimes the jetting being a little fat will cause the bike to run rough and vibrate, often you can clean it up with just the air screw, a lot of people never mess with the jetting as the bike makes heaps of power even when running poorly.

I've had several 500s and no 2 have been exactly the same. I always start mine with my helmet on so that decreases the apparent noise too.

I rode a Pro Circuit race bike with a rebuilt (from new) crank with Class 8 main bearings - it was very smooth <shrugs>. I figure if it runs good and wheelies easily in 4th gear it's doing fine - but you know how it is - every bike is a little different.

Tech 8 boots and Pro Tapers with bar inserts will help if it really bothers you.

 

[jski]

Thanks Kiwi for the information, the vibration is not that big of a deal I just was concerned about the noise because I have listened to other bikes and your right no 2 sound the same. Besides my 2000 I also have a 1987 CR-500 motor that is in a ATC and get this, very little noise from motor vibration not bad, I go to do the top end and find it is way loose, the rod is out of spec and crank is bad go figure this motor should have been noisy but was not.

 

[singletracker500]

A lot of noise can come from the pipe springs too. I put some rubber hose around mine. It's just auto gas line I bought at Checker.

 

[Panzer]

Thanks Kiwi and singletracker500 for the great advice that all sounds good. well I guess I'll put in my order for the 18" wheel, jets and topend kit and start to rip this thing apart. Hopefully I can have my ultimate bike by the end of winter. I'll keep you posted...;)

 

[singletracker500]

You're welcome Panzer. This much I can tell you for sure. There is no better big bore two stroke than one of Service Honda/AJ Waggoners' CR500AF's! Nothing even comes close!

 

[PsychoCR500]

John-

You got that right!:)

 

[AJ Waggoner]

All great advice here.

Very few things that i can ad...

On the jetting what is listed above is correct on an AF ..and also the same as several years of regular CR500's.
Honda flopped back and forth on a 170 or 175 main for the big CR over several years.
Sounds like for your type of riding i would go to a 52 pilot,possibly 172 or 175 main..needle in the middle clip..
but youll have to find what suits you.

On the top end..as norted earlier -
it is much easier to pull the engine.
by the time you get it far enough apart and back to pull the jug ..you have one bolt to pull it all the way out >shrugs<

and it weaves out fairly easily..but there is a knack to it it seems?
LOL John..i put um in all day with the head on? no worries!hehe
i'll have to see what your doing....
i mean i guy that good at GFX should be able to weave that engine outta there without even touching? WHILE doing a big double. hehehe


Panzer- On the 18 wheel..
...there are several widths of 18" rims available --
i like the 500 size- or wider one-
i believe that is 2.5? or 2.25..
anyone remember i dont want to pull a tire? lol
( i think the 250 size is 2.15)

in any case if your good at lacing rims you can just order the OEM honda spoke kit for a regular CR500..(18" rim spokes)
and then get a 18 rim.
it will lace right up to that hub.

 

[singletracker500]

LOL John..i put um in all day with the head on?[/b/

You've got to be kidding me AJ !! Me and a buddy had all four of our hands on the engine from every opening. We twisted, and tipped, and swung it around and could not get it out with the head on!! Like I said, it either caught on the head stay or the water pump!!

I thought about getting out the saw to cut a spar off!! ;) Then JB welding it back on! :) That would have worked, huh?? :D

 

[thorman75]

hey we just stuck my engine in,gave it a turn and it dropped right in.aj the 2.15 rim is the stock cr500 rim what you want is the 2.25.as per scott swinheart competition direct

 

[nephron]

My opinion probably means nothing here, as I'm sure you all are much more experienced than I. BUT, doesn't it seem odd that he runs rich with a factory setup at zero altitude? I don't get it.:think

 

[Lorin]

The 18 inch rim is indeed nice to have. You might try the IRC M5b as a good choice for the 500. It can be ordered as a true 140\80\18 (Michelins seem to size theirs a little smaller).

 

[AJ Waggoner]

John..lol

seriuosly i can weave a totally assembled motor in place without touching the frame even. :)
minus spark plug -

with the plug i can do it but might take a lil fancier threading of the needle..lol

 

[singletracker500]

Well, I don't know how you do it AJ. But I guess this spring when I tear it completely down again, I'll give it a try. Expect some e-mails! :cool: