85R Top End Rebuild and Upgrades

[MTS]

now thats a christmas gift!!! sorry i cant say i'm familiar with the ""A" but it looks like someone spent some time on it. wont really know what you have without taking a close look at the port angles and port timing along with the squish clearence and combustion chamber cc.

[Samjp22]

Gets even better! That ported cylinder is .50mm over and could use a bore so my new .75mm over piston will work perfect! I still have what I think is stock reeds (they're metal) should I upgrade to some boysen reeds or is stock fine? And would using the stock reed cage be okay?

[90guy]

Nice score there! Sounds like you still have stock reeds. I would atleast upgrade to Boysen on stock cage. Personally Being the cylinder already has work done to it I would buy Mossbarger reeds and cage for Vforce or ESR or the whole boysen setup. But thats just me.

[Samjp22]

I'll look into it! Thanks Todd

[Samjp22]

http://pages.ebay.com/link/?nav=item...d=391012141039 These vforce3s with a spacer or

http://pages.ebay.com/link/?nav=item...d=271529512692 Or these boyesen?

[90guy]

Dunno how much I bieleve in torque spacers. On paper they look good. I would run the vforce. But that my opinion I've always ran vforce in my sleds and it's always improved throttle response. My water pumper has vforce on it and you can tell the diffrence between with and without. But I've heard good things about boysen as well.

[Samjp22]

Yeah it seems that a lot of people go with vforce, and coming with that torque spacer lets me kinda "play around" with how it will react and run with this ported cylinder. I'm leaning more towards the vforce as well but I'll give it a day here to see if anyone has any reasoning why to choose boyesen over vforce. Not much luck finding mossbarger

[El Camexican]

I'll give it a day here to see if anyone has any reasoning why to choose boyesen over vforce.

According to what you'll see on some sites V-Force is a better torque reed and Boyesen is a little stronger up top. I always use Boyesen because A) I have been using them for 35 years with out issue and B) because the V-Force reeds that came on one of my bikes were eroded and distorted, both the carbon reeds and plastic cage. V-Force reeds do look cool though. I'm sure you'll be happy with either.

[Samjp22]

Ill do a bit more digging around before I spend $200 plus on reeds and a cage, thanks guys

[90guy]

With vforce reeds can you not just replace the reeds? That's what it looks like in the picture.

Some have screws. Most have plastic clip like setup that hold them in place. Easy to replace.

[Samjp22]

So went just with the vforce reeds and cage, didn't bother with that torque spacer plate, they wanted like an extra $60 for it and if I want it can buy one later. Next order of business is buying jets for this new cylinder and winter riding, currently have a 140 in it, was thinking about ordering 142 up to 152, should I go more/less?

[El Camexican]

So went just with the vforce reeds and cage, didn't bother with that torque spacer plate, they wanted like an extra $60 for it and if I want it can buy one later. Next order of business is buying jets for this new cylinder and winter riding, currently have a 140 in it, was thinking about ordering 142 up to 152, should I go more/less?

I don't own a 250R, but I would think you would want to start at no less than a 175 main if you are using a 36 to 39mm Keihin carb and that would be for summer riding. What's your slow jet # and clip notch at?

If you have access to a weather station (sled/bike or car drag guys) find out what your air density is the day you think you have it jetted right and make a note. It the future you can use that base setting to make changes for hot or cold weather riding. Rule of thumb after that is one main size every 1,000ft of change and a slow jet size every 2,000 to 3,000ft. You can use the air screw to compensate between slow jet changes.

[Samjp22]

34mm keihin and thanks for that info, ill look into the carb more to find everything else out. It's going to suck dialing this thing in, hopefully some warmer weather once shes back together or else ill be making lake runs and swapping jets out there at -20/25C

[El Camexican]

34mm keihin and thanks for that info, ill look into the carb more to find everything else out. It's going to suck dialing this thing in, hopefully some warmer weather once shes back together or else ill be making lake runs and swapping jets out there at -20/25C

I suspect you'll want something a little bigger if you plan to run that fancy jug.

[Samjp22]

Like a 38mm keihin pwk? http://pages.ebay.com/link/?nav=item...d=400822321112