Thanks for the info MxDale71. I currently have a hinson basket in my 400. I also have a wb rev box for it too, although, I didnt like how it ran when I put it in. I put my stock back in. It seemed like it robbed too much low end. I did keep it for this occasion when I would hop it up. Eric gorr is doing my work, 440, mild port, valve work and I'm having him put an all around cam in it. I do have a full after market exhaust. I dont want too much unusable power that would make it too unreliable, or, make me need a longer swingarm. I just want some more grunt for woods racing. I also race some mx, but, mostly short supercross style tracks where the big boys(tricked out r's) can't use there top end to their advantage. Any helpfull suggestions are appreciated, like, after market airboxes and stock carb settings. If this hop up doesn't give me what I want, I may look into a different carb. I work second shift so it may be a while before you read this and vice versa.

 

Almost forgot, we have a raceway close so i can get race fuel. I think its 118 octane. When I do run it, I blend it half and half with amaco ultimate. Thats what the car racers said they do. I could tell a very noticable difference in my quad. I can hang with a Z-400(stock) with just the fuel and I take the sediment collector out of my air box for a little more air. The Z still gets me on top end though.

 

no, nothing in the above 185 range on any sort of gas. To me at least. 190-210 for methanol.

 

more bad info from the beechman. nothing above 185 for any gas. yeah right.

 

You need to PM me your E-mail address. I will forward a page from the Honda manual (that my motor builder sent me) that states the compression for a 250R should be in the neighborhood of 170-199 PSI.

I am personally running 235 PSI in my 250R on Av-Gas.

 

Hey get off my nuts grandma. I see a whole hell of a lot of info coming from you. Just shut your mouth and play with your broken bike.

235 is WAY too high. what are you thinking? drop that compression. Ive only been into racing our bikes for about 2 years, and ONLY 1 builder that ive ever known sets his motors up to 230-240 and he is on methanol, and is STILL slow. compression will get you torque, but it will kill you everwhere else. My bike redlines at around 12k. Im running 180lbs of compression. If i brought my compression up to 235 (alk dome) i wouldnt come close to hitting that mark. Tell me this. Go to ESR and say i want to buy a gas dome for my head and have it about 240. See that they tell you...

 

atc86 pissed me off a little too much so i did a little research. This is from Calvin Pollet, the God of 2-strokes. This guy has a hand in almost every cylinder cast to this present date:

"You can run high compression….240psi……250psi! You can do it successfully, but be prepared for the time it won’t be successful, it will happen. It has been my experience that when a 2 stroke cranks over 165psi of pumping pressure it will start losing top end performance. This is for a non-powervalve engine, an engine with a properly set valve should be approximately 20psi higher. If you have an engine that you don’t want or need to rev out, or an engine that doesn’t spend much time at high revs, raising the pumping pressure will increase the low-end and midrange throttle response."

So ill trust his opinion (as well as my own) anyday over yours. After all, yours is broken and mine does run right?

 

In beechmans defense,


When I had my Tri-Z and my bro had a honda atc250r we would race and his R would top out about 70mph,and my tri-z my top out about 67mph.

Well i wanted to beat him, so I had a fresh top end,and my head/cylinder ported and decked, It was a very powerful combo and I could easily smoke his R, but I now topped out at 65mph, and he was still out running me on top(when he could catch up,he he). I didn't know alot about engines, so I was dumb-founded and ended up gearing high enough to beat him on top, but of course it took away alot of my bottom-end. I always blamed it on his 6th gear, but I knew that the work I had done killed my top-end.






Biggerisbetter.

 

Dabeechman;
I agree you will lose top end with the more compression you run. I never said it wouldn't. But my bike isn't a drag bike, and I don't use it for all out speed. I could care less if I top out at 65 or 75 mph. My main concern is for torque, as I do a lot of hill climbing, and play riding in the sand.

The guy who built my motor (Dave Moore) has 17 yrs of motor building experience, and he is also the one who recommended the Av-Gas (which I might also add has absolutely NO detonation at this compression level, EVEN with my timing FULLY advanced!)

He was crowned "king of the hill" at dunefest last year at Winchester Bay Oregon, so he knows his stuff.

Like I said, he even E-mailed me a page from a Honda manual (not sure if it was specifically for the three wheelers, or from the TRX's, but regardless, it DOES state in there that the STOCK compression for the 250R is anywhere from 170-199 PSI. Also as I have stated, send me your E-mail address, and I will forward it to you so that you can see it yourself.

I know that the quality of the gauge used, AND the attachments used with it can DRASTICALLY reduce the indicated pressure.

My (cheapo) gauge for instance only reads the compression to be about 200 PSI, and my friends reads it to be about 10 lbs less, so many people (not talking about the guy you mentioned) have readings that are WAY less than what is actually in the cylinder, thus the write-up I posted about compression testers on another thread earlier.

If you have any questions about my builder, feel free to visit his site. It is MP Racing at www.motomallusa.com

 

yeah beechman thats how i felt. i usually just read and post once in awhile. when i get flamed it burns me for awhile. hope its cool tho. you got alot of info and a bad a** honda. mad or not your cool in my book.