Author Topic: summer projects (Read 10705 times)

udontknowme · « **on:** June 01, 2014, 08:56:40 PM »

anybody got plans for new engines this summer ? i got 3 different projects lined up and hopefully ill be able to finish all of em. or atleast 2 of em. heres what i got

1- 300 looong rod. this ones my least priority but i have most of the parts needed so its just a matter getting around to it
2- 548cc that i never could get running quit right last year but i think the head was the problem. pretty sure dome profile was causing the issues. anyways i got a idea to use a smaller bore cylinder that would make it 510cc. it might sound counter productive but im thinking the smaller cylinder might be alittle better design for the particular way im gonna set it up and should nearly be the same power as the bigger one. this ones high on my priority list
3- had a cr500 jug that i did some work on couple years ago and used it last summer then took it off and used a different cylinder. figured i would get this old one back out and do some more work to it and put it back on. not changing the timings much from where they previously were just gonna widen the trans alittle and make the corners more sqaure then recut in the hook angle and do alittle somethin on the exh without making it any higher. left side ive got partially done this weekend

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udontknowme · « **Reply #1 on:** June 06, 2014, 01:31:55 AM »

got alittle more done. still quit a bit to go but its a slow process when you only got a hour or so a day to peck away at it.

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udontknowme · « **Reply #2 on:** June 06, 2014, 01:37:06 AM »

oh ya i should have the 510 cylinder in the next day or so and mock it up to see if it works out like i hope

Bowtie316 · « **Reply #3 on:** June 06, 2014, 09:30:47 AM »

Quote from: udontknowme;35876

got alittle more done. still quit a bit to go but its a slow process when you only got a hour or so a day to peck away at it.

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Wow, that is very nice work. I don't have the tools or skills for that kind of work.

For my summer project I am going to go all the way through my 88, pc frame, new shocks, plastic, a-arms, axle, etc. Also, need to finish up this cylinder for the stroker bottom end and start playing around with pipes to see if I can make it work.

udontknowme · « **Reply #4 on:** June 08, 2014, 11:57:58 PM »

previously there was some black in the boost port so i think it was pushing exh back in there. alittle extra blowdown should help that

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heres where im at with the intake side

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the cosmic avenger · « **Reply #5 on:** June 09, 2014, 07:44:20 PM »

II've always been curious about how to tell how big to take the ports? I know you can buy the pre made templates but I also know there's a lot of guys who just do it by hand, do you go by hand or use software? I was thinking of messing with some junk cylinders I have from a snowmobile but just don't know how much is too much.

Are you doing anything with the side transfer ports?

udontknowme · « **Reply #6 on:** June 10, 2014, 08:29:58 PM »

well if you mess with the same engine enough times you should be able to make it faster each time around. especially if you have a dyno and alot of time on your hands. even still its not hard to make the engine faster

im not sure if theres templates for 250r or not. if there is im sure they would work ok for a beginner that hasnt yet learned his own window shapes

i used a computer program on another engine but not the one posted above. the one above i ported it few years ago and just winged it more or less. it ran ok and beat alot of other bikes at the dunes. for a garage job by a amatuer i thought it did pretty good. im just doing alittle more to it now mostly for the hek of it. i dont think any program can ever give you 100% answers but i think they can get you going in the right direction with time*areas and stuff like that and some people have good results using programs. if your asking about the front transfers ya ill do something there but i dont know what yet. ill get some photos when i get that far.

i have no real experience with snomo engines but you might get the timings and widths and see if someone around here can give you a general idea which direction to go

the cosmic avenger · « **Reply #7 on:** June 11, 2014, 07:37:57 AM »

I figure I'll get some practice at least cleaning up the intake and exhaust ports. May not be as much gain as you can get but just having smoother air flow will help some.

udontknowme · « **Reply #8 on:** June 11, 2014, 09:39:40 PM »

if its your first time i would probly recomend practicing on something else atleast for a few days just incase you dont want to screw something on your own stuff. theres alot of junk cylinders on ebay for cheap. yz250 for $68 right now but im sure theres 100 different kinds

the cosmic avenger · « **Reply #9 on:** June 12, 2014, 08:19:40 AM »

I got some junk cylinders to practice on. I did a little bit on one a while back. I also fix a lot of people's junk so cylinders aren't hard to come by.

atvmxr · « **Reply #10 on:** June 12, 2014, 10:20:42 AM »

i have bought 3 250R this year (replacing 2 I had stolen and one i sold). the 89 I need to do a swap back to a thumb throttle and get it ready to give to my dad. the LSR needs the propeg welding and some carb work. the 88 baja one, just needs some more tuning on the 35AS carb, its already good to go

also taking MSF moto school and buying a Vulcan 500 to ride with my friends.

udontknowme · « **Reply #11 on:** June 13, 2014, 07:10:23 PM »

i had been using vf3 but theres a few things i dont like about it so im going back to a modified honda cage atleast for now. i think the vf3 was designed for one of the cp cylinders and since it used the cr5 bolt pattern mototassinari also sold it as a direct fit to the cr5 engines rather than design a new unit. kill 2 birds with one stone is what im thinking their logic was

since ill put the honda cage back in i had this idea to fill in some of the space behind the cage. whether it makes any difference one way or the other who knows but ill give it a shot. the slots are nothing more than pockets for the reed screws incase someone dont know

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the cosmic avenger · « **Reply #12 on:** June 13, 2014, 07:17:04 PM »

Vf reeds aren't my favorite. I prefer boysen myself, don't know if they make em for the trx.
For some reason vf reeds on EFI sleds you have to crack the throttle a bit to get em to start.
Another thing that I don't care for about reeds in general is unless you are heavily modded they aren't worth jack.

udontknowme · « **Reply #13 on:** June 14, 2014, 01:09:30 AM »

i think the vf concept is good but the v3 dont fit for crap on the cr5. got v4 on my other bike and they seem to work good

udontknowme · « **Reply #14 on:** June 28, 2014, 11:25:46 AM »

hey guys i started on the front trans yesterday. thats all thats left then put it together and try it. i have another cylinder with similar front slanted port so im using that as a guide how to shape the inside of the tunell

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