250R Head Job

[PYF]

Hi, this is my first post on this forum and probably not the last :)...Ok, since I just registered on the forum I will describe myself a little bit ...I live in Alma,quebec,canada and I'm 18 years old. I'm currently studying mechanical engineering..I always dreamed of getting a R and finally got one one month and a half ago. Before that, I rode a 86 quadsport 230 and 94 300ex
I really loves the honda reliability and I like to be the underdog so I bought a R (Everybody here have 450 and 'shees)
I'd like to show them what the ''legend'' can still do today :devil:

I'm already registred on a few quads forums but I've been told to come here since the others forums were mainly focusing on the 450r, not the old R anymore :(

I attached a pic of about a month ago to show the quad. The previous guy painted them ( :confused: ) but I fixed the problem and will take new pics soon. I've got a killer for 1950$ but I had some ( a lot ) of work to do on it and had to travel more than 300 miles to get it but it was well worth it :devil:


I recently tore apart my R to rebuild my main bearings and seals since the flywheel side bearing had a little play in it and was probably going out but since it's already tore, I will change the piston/rings and some others bearings. I will as well give a little 'treat' to my cylinder/cyl. head... A porting/milling job

My question is about that. I was wondering about something...The 250r Compression ratio is 7.7:1... Would bringing it to about 10:1 (If it's doable)(Like a 250 mx bike) + a mild porting job bring the HP to a realistic mid-40 hp's?

Seems realistic since a 250 MX bike have about 50 hp. Don't know if it even have sense since I'm not an engine builder myself so I'm not sure if everything I stated is doable...

I'm still asking since there are a lot of knowledgeable people around here....



Thanks a lot in advance :)


Pierre-Yves

http://img475.imageshack.us/img475/1116/roost8jz.jpg (http://imageshack.us)

[zedicus00]

i gave some good suggestions for you on the everything 2 stroke board.... welcome aboard here too.

:D

[PYF]

Originally posted by zedicus00
i gave some good suggestions for you on the everything 2 stroke board.... welcome aboard here too.

:D

Yeah just saw that :p

Thanks for the welcome :)



Pierre-Yves

[hondardr4life]

A good port job will really wake up your R. As for the compression, you haveto get your head shaved down. But don't do it unless you want to run 110 octane gas. Where I got my motor done at, they told me a strong 48 HP with pipe, carb reeds, motor work, ect...

[beerock]

The r has never been the underdog ;)

i just wanna say, if your rebuilding your main bearings and seals and you said the main was worn out pretty bad you should definately look into a new crank or(shrugs) rebuild your crank.

the main bearings usually last for a long time so if your not sure how many hours that crank has on it and you reuse it with all new parts your asking for trouble.

you can check the tolerances of the crank and make sure there in spec and re use it but, if its a bike you just bought, who knows how many hours are on the crank.

[PYF]

Originally posted by beerock
The r has never been the underdog ;)

i just wanna say, if your rebuilding your main bearings and seals and you said the main was worn out pretty bad you should definately look into a new crank or(shrugs) rebuild your crank.

the main bearings usually last for a long time so if your not sure how many hours that crank has on it and you reuse it with all new parts your asking for trouble.

you can check the tolerances of the crank and make sure there in spec and re use it but, if its a bike you just bought, who knows how many hours are on the crank.

Yes I'm gonna have the crank checked for tolerances before putting it back in the crank. The bearing wasn't that damaged, just a little little free play when I played with it up and down with the flywheel. Still gonna check for safety sake anyways

And by the way, the R here is kinda underdog. People think it's really slow since you can't really heard it screaming as much as a banshee. I'm gonna show them :devil: ;)

Thanks :p

[TheFontMaster]

It's pretty easy to get a 250r over 40 horse power. Here is a dyno of a 250r with some minor bolt on mods, and no port.

http://www.exriders.com/vbb/showthread.php?s=&threadid=196189

And here is another 250r, but this one is bored over more, and has a good port job.

http://www.exriders.com/vbb/showthread.php?s=&threadid=197121

You can see by comparing the 2 how much of a difference a good port job can make. I would sugest you get a good port job, bigger carb, cool head, bigger carb, v-force reeds, and a full exaust.

[PYF]

Originally posted by TheFontMaster
It's pretty easy to get a 250r over 40 horse power. Here is a dyno of a 250r with some minor bolt on mods, and no port.

http://www.exriders.com/vbb/showthread.php?s=&threadid=196189

And here is another 250r, but this one is bored over more, and has a good port job.

http://www.exriders.com/vbb/showthread.php?s=&threadid=197121

You can see by comparing the 2 how much of a difference a good port job can make. I would sugest you get a good port job, bigger carb, cool head, bigger carb, v-force reeds, and a full exaust.

Thanks, it's interesting...

I'm already planning to get a 38mm keihin pwk airstriker + v-force reeds and to trash my FMF pipe for probably an ESR one...

I think I should not mill my head and get a cool head with interchangeable dome instead...Not sure though, since milling my current head would help since It's a little damaged and milling it would remove the damage. On top of that, I don't have the cash for the carb/reeds/new pipe combo right now (I'm s still going to school you know :D)

Thanks a LOT for the suggestion TheFontMaster,

Pierre-Yves

[TheFontMaster]

I actualy wouldn't go with a ESR pipe. Ether get your FMF silencer cut, so it's turned into a shorty, or go with a LRD, or sparks. Sparks doesn't make 250r pipes anymore, but I think it's the Paul Turner pipes that are exaclty the same as Sparks pipes. Since your on a budget you might want to just cut you FMF silencer. FMF is a good all around pipe, there are better pipes, there are worst. But I hear that if you cut the FMF silencer that it will give you pretty noticeable gains.

[PYF]

Originally posted by TheFontMaster
I actualy wouldn't go with a ESR pipe. Ether get your FMF silencer cut, so it's turned into a shorty, or go with a LRD, or sparks. Sparks doesn't make 250r pipes anymore, but I think it's the Paul Turner pipes that are exaclty the same as Sparks pipes. Since your on a budget you might want to just cut you FMF silencer. FMF is a good all around pipe, there are better pipes, there are worst. But I hear that if you cut the FMF silencer that it will give you pretty noticeable gains.

How come cutting my silencer will equal more power ? Never heard of that but I'm interested :)

And by noticeables gains, it is THAT good ?


Thanks,

Pierre-Yves

[hondardr4life]

Yea, cutting the FMF silencer gives you a lot more power. I can't remember how long they are straight from FMF, but cut them down to 9 inches, repack them, and put the end cap back on (if you want) Getting my head milled was only $40, so to me, it was just a cheaper route to go than a coolhead.

[86 Quad R]

Originally posted by hondardr4life
Getting my head milled was only $40, so to me, it was just a cheaper route to go than a coolhead.


or ya could always go with the three peice metal gasket and use the thinner of the three. works well and can be used over and over again.

[PYF]

Originally posted by hondardr4life
Yea, cutting the FMF silencer gives you a lot more power. I can't remember how long they are straight from FMF, but cut them down to 9 inches, repack them, and put the end cap back on (if you want) Getting my head milled was only $40, so to me, it was just a cheaper route to go than a coolhead.


Thanks, I'm gonna look into that tonight

The sound would be even nicer :devil:

[lee37vernon]

sorry to hijack your thread but ... does cutting any of the silencers to 9 '' increase power or is this a particular thing to the fmf ?

[PYF]

Originally posted by lee37vernon
sorry to hijack your thread but ... does cutting any of the silencers to 9 '' increase power or is this a particular thing to the fmf ?


It's probably because the FMF is a really long silencer

My 2 cents

[matt250r21]

Just to let you guys know I had a Paul Turner/ Duncan Racing 89 Race pipe and both Sparks MX and TT pipes. The Duncan pipe is not the same as the Sparks pipes.

[PYF]

Originally posted by matt250r21
Just to let you guys know I had a Paul Turner/ Duncan Racing 89 Race pipe and both Sparks MX and TT pipes. The Duncan pipe is not the same as the Sparks pipes.

Thanks for the info :)

[lee37vernon]

how do you rate that race pipe ?

[PYF]

Originally posted by lee37vernon
how do you rate that race pipe ?

Can't really tell you, never tried it :ermm:


And by the way, I checked to cut my silencer by 9 inches, and damn it would be short :eek2:

I need to take some pics to show you lol

[fireburns99]

i think they meant to cut it so that t is 9 inches long. Not cut it down by 9 inches...lol. By the way welcome to the forums, hopefully you're getting mroe help than over at atv connection forums.

[PYF]

Originally posted by fireburns99
i think they meant to cut it so that t is 9 inches long. Not cut it down by 9 inches...lol. By the way welcome to the forums, hopefully you're getting mroe help than over at atv connection forums.

Ok lol @ pipe :eek2:


Yeah I'm getting more help here since it's 250r specific and the forum is more active in general :) I love it :p


And thanks for the welcome :)