Lost to my pop's banshee... damnn

[250rCRazed]

Just picked up my 86R a couple months ago after inheriting an 81R a while back. The 86 is in real nice shape, has PT High Rev pipe/silencer, 38mm PJ (Crap) Carb, and Pyramid reed cage. Real clean bike. Only thing that is lacking is the compression, and I might try to work on fine tuning the carb a bit more. The bike baaaarely made 140psi. Anyways, to the point, I can definitely ride better than my dad, although for a 51 yr old he makes a lot of kids look badd. His 2000 Banshee is still in showroom condition and has SST Pipes and Silencers and is jetted accordingly. When we ran in softer dirt, I took him out of the hole and we seemed to be always real close by the finish topping out I think 5th. Today we battled in real hard packed (almost frozen) ground, and I still beat him til 3rd gear, but he pulled by pretty hard after 3rd every run. First off, do 250R's always like to sort've rev a bit after a quick full throttle run?? The rpms will be pretty high after every run when I pull the clutch in. Is it too lean? Too hot of a plug? We were riding in like 35 deg. temps by the way. It wont be long til I get some sort of big bore powervalve setup in there though. I will say I didnt think he was going to be able to pull on me this bad from 3rd onward. What should I do next?

[Dammit!]

Colder air will cause the bike to run lean. Sometimes dangerously so. It can cause it to seize.

The low compression has nothing to do with the carb. At best, you have a leak that's causing it to lose compression. More likely it needs new rings and/or a top end rebuild.

The high reving could be an intake leak. While it's running at a steady idle, spray some starter fluid around the carb, head and base gaskets. If the rpm's change, you have a leak.

[250rCRazed]

Colder air will cause the bike to run lean. Sometimes dangerously so. It can cause it to seize.

The low compression has nothing to do with the carb. At best, you have a leak that's causing it to lose compression. More likely it needs new rings and/or a top end rebuild.

The high reving could be an intake leak. While it's running at a steady idle, spray some starter fluid around the carb, head and base gaskets. If the rpm's change, you have a leak.

Well, I know all about the jetting and compression issues. I'm sure its just needing a top end rebuild as far as the compression goes. I've been riding dirtbikes since I was 7, I'm just new to this 86r. The kid that I got this thing had the carb wayyy off. First off, the lovely choke/idle adjust unit was missing its needle, second, there was a 70(!) pilot jet in it, I moved it down to a 55, and next I'm putting in a 45. The main jet was a 150 that he had in there, which seemed to be OK. I will say one thing is for sure, when the motor is cold it seems to be twice as strong. Even when its hot it is still fast, ruins my buddies 400ex badly and my 81r. However, do you think that with my mods and better compression I should be beating a strong running piped banshee (traction being equal). I'll probably be getting an ESR powervalved top end eventually anyways. As for the high revving thing, I don't believe it is a leak although I will check that. I think it is just a combination of things:
1) I'm running 87 octane gas which will pre-ignite more than higher octane
2) I'm running a B8 plug rather than a B9 which I might try
3) Although I will check today, the main jet could be a bit on the lean side
4) For all I know this motor could be on its last bore and that could cause it to run hot and idle high after each full throttle pass.

By the way, it only revs high for a few seconds after you nail it and pull the clutch in, and its not even that high of a rev, maybe like 3,500 rpm. Damn banshee, he loves rubbing it in my face too. Next time he does that I'm gettin the CR250 out on him, we'll see who laughs then.

[BigGreenMachine]

A lean pilot jet would cause you to rev high after idling down, clutch in and closed throttle. You should be winning that race and the low compression would be the major cause.

[md1985250r]

I think the compression should be up around the 175-190 range if I am not mistaken.

[RideRed250R]

a stock top end is 165..... yours is losing its breath... your pilot is to high... your jetting should be a 36-142.... that would be a fire breather
my 310 has 210 psi, 37 pilot, 185 main, with lid off it still is a TAD rich up top.... could use a drop on the main..... try clip position 2nd from top.... i have jetted many bikes and thats what i think you should... others should post knowledge also...
my carb is a PJ38 bored to 39.5

Adam

[Dammit!]

Stock pilot is 45.

[RideRed250R]

stock is also really rich.... remeber Honda didnt jett every bike for every area... but did a close "universal" jetting...
Adam

[Dammit!]

You need richer jetting on the east coast (lower elevation, higher humidity). I had to lean out when I brought my R out west. He's running a bigger carb so something even bigger than a 45 might end up being right (I forgot about the 38mm in my previous post). The high rev problem after giving it some gas is a symptom of too lean a pilot and the air screw being screwed out too far (unless it does end up being a vacum leak).

Once the pilot and screw are right, it should return to normal idle pretty quickly after a rev. I would spend some time adjusting the air screw before going down in pilot size again. Check for that leak too just to be safe.

[TravEX]

I can definitely ride better than my dad, although for a 51 yr old he makes a lot of kids look badd.


I had to laugh when I read that, my dad is 50, and loves to rip through the gears on my 400EX. He smoked me one day when I challenged him to a drag race with my 350X, LOL. He pretty crazy on my R, too.

[250rCRazed]

I had to laugh when I read that, my dad is 50, and loves to rip through the gears on my 400EX. He smoked me one day when I challenged him to a drag race with my 350X, LOL. He pretty crazy on my R, too.

Heh no joke, my dad got me into all this. When I was 10 he made me get on his 775cc Ski-Doo and PIN it. Since then I've had a need for speed. He is craaazy when it comes to riding bikes/atv's AND cars. He's got an '03 Cobra with ~500rwhp, while my 93 Turbo'd 331ci GT made 600rwhp with 10psi. We both LOVE the competition and I can't let his banshee win races. As far as the jetting, I think I'll leave the main jet alone til I do a long full throttle plug chop, but the pilot is getting swapped to a leaner jet. The clip is in the 2nd from the top, so after I lean out the pilot I may put the clip back to stock, we'll see. If all else fails I'm more than ready to put an air striker in. My KX has an airstriker and I have NEVER had a problem with that bike.