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since the center and left power valves on my bike are broken, and i hardly have enough money for a top end and cylinder replate as it is, would the bike run badly if i only ran the right side powervalve?

One of mine was busted for years

Sometimes I'd have a good top end and sometimes it would get all blubbery

I believe it was do to the valve vibrating around, sometimes it would be open and sometimes not

I've done a lot of searching and what I've seen a few times are that guys epoxying them into the open position and running them as fixed unit not moving.I too considered this on my 89 since the L subvalve is broke too.but I seen some issues with this the biggest being that the timing in the ignition is curved in sync with the kips.so I don't know how welll it would run.I bought mine and decided to go ahead and not take chances and do it right.maybe look on ebay for a used set but to answer ur question no I wouldn't run just one valve might make tuning a major PITA.

It runs with them epoxied in the open or closed position, however not very well.

ok, i'll probably just spend the extra $100 for new powervalves then

Buy spares if you can

how much would a crank rebuild, cylinder replate, top end, and powervalves cost for this bike including labor to rebuild the crank?

How much you got?

And does it really need all that?

it definitely needs the powervalves, and when i looked into the exhaust port i saw that the intake ports were chipped and there were a bunch of vertical scratches in the cylinder, and there was scratches on the piston skirt. i'm not totally sure about the bottom end, but the flywheel has some up and down play. the bike still starts first or second kick, but i'm not going to run it until i fix it because i dont want to break anything more. and my dad said he'd pay up to $300, and i can probably get about $200 between birthday and christmas money, so i'll have around $500.

I did mine for under 600, but I handled 90% of the labor myself.

Rod kit $90
piston kit (scored a wiseco on ebay for $60)
gasket set $40
cylinder replate $200, maybe more, maybe less. Mine had to be welded.
main bearings and seals $50
transmission bearings $50

The only labor I payed aside from the cylinder was for rebuilding the crank, and that was $60

Seems expensive for an old bike, I know. It was well worth it though. You might do without the crank rebuild, which would save you a bit. If I was gonna tear it all the way down though, I'd go ahead and replace everything I possibly can.


How do you do with sub valves Wibbens? I went through several sets. When I did the rebuild, I used a different cylinder, and made this sort of plate to secure that collar on the RH side that the kips rod slides through. Didn't seem that one set screw was doing it's job over there. That's been quite a while now, and many miles. So far no further problem with the valves.

if i didn't get the crank rebuilt, then wouldn't i risk ruining the engine?

tydev95 wrote:if i didn't get the crank rebuilt, then wouldn't i risk ruining the engine?

Not if it's not bad? The play you feel at the flywheel is the main bearings, not the crank. When you pull the cylinder off you will be able to check the condition of the lower rod bearing. That and the connecting rod are the only things that get replaced in a crank rebuild. If they aren't bad, no need to change them.

However, if the main bearings are shot, it's most likely that the rod bearing is gone as well.

I've only been into the cylinder twice in 8 years or so

The first time one valve was missing about 3 teeth, I left it in

6 years later it was broke and had been for quite a long time by the looks of it

After the first top end I do remember having the brass set screw back out on me, allowing the actuator rod to slide out. Sounded like an 80cc bike

I loctited it and never had another issue with it. But I should have made sure the valve was ok

when i said crank rebuild, i meant main bearings and connecting rod bearings, but if i rode the bike with bad main bearings wouldn't it end up destroying the engine? forgive me for being a dumba$$, i'm new to this stuff

If you got any play in the crank you do run the risk of grenading your motor.I don't suggest running it if you're concerned in any way better safe than sorry.my little brother just brought me his rm250 jug he got back from plating at us chrome and its awesome!total cost to strip and replate was 242.00 round trip.we were going to go sleeved but after reading on here about the plating he went plated then we find out my jug is sleeved on my kdx.but I hope that helps on price and is current.that didn't include any boring bis jug was not bad enough to need bored so they stripped and plated it.as far as labor goes most shops around here are about 60/hr I don't know about other places.

http://www.langcourt.com is only $180 I believe.

Yeah, Langcourt is generally about $180 for a strip and re-plate, and they do a top notch job. I was VERY happy with the cylinder I got back from them. It cost me a little more because the cylinder I sent needed some pretty extensive welding done.

J.

i'm probably going to take off the cylinder and head tomorow, so i'll post pics of the cylinder, and maybe get all of your opinions on it

here's a couple pictures of the cylinder , head, and piston.


http://s1125.photobucket.com/albums/l58 ... ure011.jpg

http://s1125.photobucket.com/albums/l58 ... ure009.jpg

http://s1125.photobucket.com/albums/l58 ... ure004.jpg

http://s1125.photobucket.com/albums/l58 ... ure008.jpg

can you feel the virtical scraches? it dont look THAT bad from the pics, but cant really tell..... every cylinder i have pulled had some lines in them. if you cant feel them, you can hone the cylinder and youll be fine.