The perfect 500

[markv]

So, I am in the process of restoring my clapped out 89, and I am down to rebuilding my motor. I have been reading all the posts about what to do and what not to do, and I think I have got a gameplan as far as the rebuild goes.

Specs as of now-

Stock 89 motor, I am the 3rd owner of the bike, and I know the previous 2. The first owner locked it up somehow, and it was stock at that point, he replaced crank and bearings, and did the top end. I am not sure if it has been bored or not, as I have not torn it down yet. The cases are almost perfect, except for the shit caked all over them and the worn out paint, not a hint of JB weld, and the chain gaurd is still there!

Here are my plans-

Complete rebuild, bottom and top end. Replace the clutch rod, replace all the bearings and seals, have it bored and honed.

Now, as for the hop ups, this is what my post pertains to-

I ride woods, Hillclimb, and drag some on fire roads. I have already bought a 250 ign. I plan on doing an overbore. I'm going to install a PWK Carb. Would it be worth my while to send my jug and get it ported? What about pipe choice? I have ridden a friends 92 with a Gnarly, and it seemed to fall dead on its face on top. Would a PC be the better choice? Any and all help will be appreciated!

[craigf40]

So, I am in the process of restoring my clapped out 89, and I am down to rebuilding my motor. I have been reading all the posts about what to do and what not to do, and I think I have got a gameplan as far as the rebuild goes.

Specs as of now-

Stock 89 motor, I am the 3rd owner of the bike, and I know the previous 2. The first owner locked it up somehow, and it was stock at that point, he replaced crank and bearings, and did the top end. I am not sure if it has been bored or not, as I have not torn it down yet. The cases are almost perfect, except for the shit caked all over them and the worn out paint, not a hint of JB weld, and the chain gaurd is still there!

Here are my plans-

Complete rebuild, bottom and top end. Replace the clutch rod, replace all the bearings and seals, have it bored and honed.

Now, as for the hop ups, this is what my post pertains to-

I ride woods, Hillclimb, and drag some on fire roads. I have already bought a 250 ign. I plan on doing an overbore. I'm going to install a PWK Carb. Would it be worth my while to send my jug and get it ported? What about pipe choice? I have ridden a friends 92 with a Gnarly, and it seemed to fall dead on its face on top. Would a PC be the better choice? Any and all help will be appreciated!

hey mate how you doing well im no expert but the few mods i did to my bike which was raising the exhaust port 2mm and the transfer ports 1mm i also used a thick base gasket aprox 1mm ...i polished the exhaust port mirror shiny and just smoothed or flowed not polished the intake side ...i also used a 86 head which i had and noticed the combustion chamber is wider and seems milled down more than the 2001 motor i have ...i have a fmf narly pipe and the 03 250 ignition complete with fly wheel and the 03 38 mikuni tps carb with all its wiring connected to the ignition and in my opinion the bike is a monster but im sure there is a lot more you can achieve with porting and pipes but as my bike is now there is more than enough power im only 81kg and its an AF 500 so it power to weight is enough best of luck to you and im sure you will get more than youl need in terms of info
regards craig

[caseyracing222]

The best pipe honestly for the variety of riding your doing would be the stock pipe, it has good power all around, the gnarly uses its power down low and the PC is a top end pipe, I also dont think you would need to do any radical porting, maybe just clean up some of the casting flaws to smooth out the flow

[thestuz]

for me, the perfect 500 is one that can get the power down to the ground without breaking traction and still having all the power and a broad power curve. i dont mine the gnarly, it enables me to use the low down rpm instead of seeking high rpm.and ive geared it up to 14/46 which gives me tractable power and longer gears(less shifting) with fresh motor and cleaned/polished ports. but im only light weight (84kgs) so this might bog down for you a little if your heavier.

[Tommy_J]

This may be controversial but for me a perfect cr500 must have a Rekluse clutch.

[AlisoBob]

The best pipe honestly for the variety of riding your doing would be the stock pipe, it has good power all around

The stock pipe sucks... I know... I have 6 of them.

Send yours to me, to add it to my collection.

Lets get these god aweful things off the trail, one bike at a time.

[lewisclan]

here here

[Roostius_Maximus]

]raising the exhaust port 2mm and the transfer ports 1mm i also used a thick base gasket aprox 1mm....i also used a 86 head which i had and noticed the combustion chamber is wider and seems milled down more than the 2001 motor i have ...

dude, the whole idea of changing the base gasket is to make it thinner or cut material off the jug to drop the port wotk for more torque, it'll take away having it raised, same with the ports beeing taller.
the head from 86 has the same squish and chamber til the newer R casting heads, its tighter compression which maybee saved you some power in that odd tall jug deal by compensating for the added base thickness and returning the compression close to stock.

[caseyracing222]

The best pipe honestly for the variety of riding your doing would be the stock pipe, it has good power all around

The stock pipe sucks... I know... I have 6 of them.

Send yours to me, to add it to my collection.

Lets get these god aweful things off the trail, one bike at a time.

I will take your comment as sarcasm

[JBaze]

To me, my bike is the perfect 500. It makes more power than I could ever need seeing I'm not a hillclimber. For mx, single track, woods or sand this bike is perfect, well almost, engine wise it's perfect, a few bucks in the boingers and it will be. It fits me just like I want and I love to ride it. And thats what I've been doing everyday!

[stu460]

yeah im with roostus the purpose of milling the jug is to drop the ex port roof to gain more compression,not raise it,most the fellas ive heard of doing that used a couple of head gaskets to compensate for the raised piston....its just logical really...im glad i havent taken to my ports with a die grinder before i joined this site,its all new to me aswell...but having said that im not a fan of two head gaskets,,i wonder how reliable it would be..

[Rosco-Peeko]

Perfect 500...cleaning running, stock pipe and an aftermarket stinger. Lemme know if you need help with the motor, I have rebuilt a few..... Best advice at this point....dont misplace where your thrust washers go or your tranny will not shift correctly. Lastly, do not forget the little black rubber do-dad that slides into the right case....keeps the bike from puking tranny fluid out of the breather. Seen a few people forget to put it back in. Dont loose the clutch lifter BB.