84 250r carb swap

[xr650r]

Hey guys I'm new here and have an 84 250r I'm putting an 85r carb on.Stock with pipe.What jets should I run and needle and clip location?Been having problem in 2nd not catching power band.Have been chasing my tail and hope the carb is the problem.I know the stock carb is rebuildable but like the sounds of the upgrade.I have done compression test,cleaned carb,changed reeds,packed silencer,new plug,cleaned head and piston.The only thing i havent done is leak test and needle seat.Thanks in advance,Patrick.

[B18PWR]

Is the stock carb got a problem? You need a starting point ie when did it last run well etc, if it ran well with the original carb on then the prob will be with new 85 carb and not the rest of the set up. To get this right you need to know what's happening . Although I haven't tried this set up I would have thought a stock jetted 85 carb wouldn't be a million miles off, possibly a little rich top end but if you have a pipe on who knows? I use a wide band kit on my own to set the fuelling I guess if you have no access to fuel monitoring equipment then it's a bit of trial and error. Try the trike at different points ie part throttle, half throttle, full throttle and see how it performs , if it seems to pull cleanly through the revs. If say at full throttle its worse , have a pull through the revs, cut the trike and check the plug for colour , if it's black, oily try a main jet size down from what's in it, like wise if the plugs very light in colour , go up on main jet size. This is only the very basics and I'm sure some one has done this and can help u with some exact science . The clip will work well on the 3 rd groove for a starting point.

[xr650r]

Bike was running well 2 weeks ago with stock carb.Now just wont pull on the top end.Have the stock carb at mechanic and will get it running right with that one first.The only things left are crank seals and timing check.Crank seals being last resort.Noticed oil on air cleaner boot think she might need crank seals.Havent got new carb yet its coming in the mail

[B18PWR]

Although you have done a comp test in my experience this doesn't always give you the full picture, as it's more usefull to dee if there is any comp or it's very low . It gives an idea and that's as Far as it should be taken. It may be worth for the sake of a few gaskets pulling the barrel off and giving it a closer inspection for wear especially around the ports. At the least a proper hone to get some shape back, rings and gaskets would get her back to a good std on a budget if there was a problem here. Just an idea. I had a similar prob with an 85 250r of mine and this was the prob . Get carb serviced first though , may be the needle valve is not shutting off ?

[xr650r]

Ya for $40 I can get rings and gaskets if this carb doesn't work after mechanic tunes it.Whats the best kind of honer?Thanks