trx250r no top end

[2strokeman]

my 87 250r runs great except for the last 1000 rpm's. it boggs and dies out, you couldn't blow it up if you tried! im running a ct midrange pipe, mild porting, stock ignition, shaved head, 170psi comp. tried re and re jetting, makes no diff, 155 is best, up its worse, down its worse, im open for ideas. oh, and i'm running an NGK 8 plug, the 36 dollar shorty, got them from Ezra Lusk, cool plug, glad I got them free, he's from right down the road, Carmichel too!

[hartwill]

Curtis sparks says to run a b9egv plug. they say no resistor plugs and definatly no 8 heat range. maybe this will help.

[brokenmike]

I use a ngk b8es

[hartwill]

does anyone know their reasoning behind running this b9egv plug. I'm sure they know what they are talking about, but why does Honda recommend a resistor plug 8 heat range and then change to 9 heat range resistor in 89? could someone explain the difference, because the price definatly says their is a difference.$3-4 for br8es and $9.99 for a b9egv.

[wilkin250r]

Originally posted by hartwill
could someone explain the difference, because the price definatly says their is a difference.$3-4 for br8es and $9.99 for a b9egv.

You've actually got a few different things going on that account for the price difference.

For the same type of plug, just a different heat range, they'll be basically the same price, like a BR8ES vs a BR9ES. Notice, they're also basically the same part number.

However, you are looking at a different part number altogether. The "B" and "E" give you the thread type and length, but the "GV" portion is a special gold-pallidium electrode. It's the special electrode that accounts for the price difference, not the heat range.

[2strokeman]

thanks for the info but i dont think my issue is the plug, iv tried every kind of plug in the world, no difference. could it be the stock reeds? i know they LOOK ok, but could they just not be closeing fast enough. i took the air box off and fired it up, and at WIDE OPEN THROTTLE there is excessive gas pulsing out from the carb, or it seems excessive anyway. again, i have tried every jet setup and nothing improves it.

[86honda250]

on my 310 a few years back I could not jet this engine ether. I went up in jet and needle sizes and down in sizes. No matter what i tried it would not help. The only thing that help but not fixed the porblem was putting a new plug in. But it only helped for a little bit. It turned out that it was a electrical problem. My problem was that were the wire counected to the coil it was broken in side. It may not be the same place but it might be a electrical problem.

[2strokeman]

i had thought about a short, because it sounds like a wet engine, smooth until just before you shift. you may be right, i remember about a week ago i was powering around a long smooth right hand turn and it suddenly lost 100% power for about a half a second. I shrugged it off, but it could be a wire, and me shifting on the bike/tank could have moved it around. How much of a diff does a CR ignition make and how much trouble to change? what year is best to swap?

[rustyATV]

Have you checked for air leaks?

[2strokeman]

bingo! Could a case leak cause it? because i noticed the last time i added oil to my case i had about twice as much smoke as normal for the first 20 min or so of the ride, then it stopped. talked myself into the idea that it was just my imagination! Lol, knowing what it would take to fix it, I just put it out of my head. Could be a crank seal, or the gasket, I need to put fourth gear in anyway, it chipped a tooth about the third ride after I fixed second gear! Have you had a similar issue?

[rustyATV]

Originally posted by 2strokeman
bingo! Could a case leak cause it? because i noticed the last time i added oil to my case i had about twice as much smoke as normal for the first 20 min or so of the ride, then it stopped. talked myself into the idea that it was just my imagination! Lol, knowing what it would take to fix it, I just put it out of my head. Could be a crank seal, or the gasket, I need to put fourth gear in anyway, it chipped a tooth about the third ride after I fixed second gear! Have you had a similar issue?

I've had a couple of air leaks in the past.

One was a small, quarter inch long hairline crack in an early cylinder above one of the intake side cylinder base studs. Killed the engine totally; would barely start, had to throttle it to keep it running and then it wouldn't build RPMs.

The other was was a center gasket leak into the crank case (thanks to an ill fitting Hot Rods crank) that blew a bunch of smoke and caused the engine to not rev when I gave it wide open throttle (as I was approaching a do-or-die creek jump in a race). Less the 3/4 throttle, though, and it would run fine.

The second one lead to my "retiring" from racing as I faced the same chore of tearing down the engine totally when I was too busy with practice, races, gym, and work to do so. Now that I have the right tools to do it, and I'm not racing, it's not as big of a deal.

[2strokeman]

Well guess what my crankshaft says along the rod, HOT ROD! Whether thats my problem or not [and i think your on to something] i have enough probabal cause to go on and pull it down. YeeHaw, another 8mm bolt adventure! Thanks for the input, guess I can check wires too while its down. Any advise for an ignition swap, or if they are worth the trouble? I dont race, but I used to race mx. just want the most outta 250cc's.

[rustyATV]

Originally posted by 2strokeman
Well guess what my crankshaft says along the rod, HOT ROD! Whether thats my problem or not [and i think your on to something] i have enough probabal cause to go on and pull it down. YeeHaw, another 8mm bolt adventure! Thanks for the input, guess I can check wires too while its down. Any advise for an ignition swap, or if they are worth the trouble? I dont race, but I used to race mx. just want the most outta 250cc's.

Well, I rebuilt an OEM crank with Hot Rod rods for years without issues, it was the whole Hot Rods ( I think that's what it was, anyway) crank assembly that required untold amounts of hammering to get the cases to come together, and then to spin freely.

The way to check would be to do a leak test. Have you done one of those before?

No opinions here on ignition systems; I still use OEM.

[2strokeman]

Yea same problem with mine, its a complete assembly. I have done a leak test in the past on one of my CR's, only problem is that I have to get a REAL driveshaft colar [behind the sproket]. Mine is one that the pre owner had made and it leaks a little, I got info on another thread on where I may can get one though. Again thanks, Im the only R owner for 60 miles around, so its nice to finally be able to get some outside input, everyone around here is raptor this and outlaw that, but Im 36 and Ill never ride thumper. Besides, my R can eat up a 650 ds on a 200' run anyway! LOVE IT! lol