yz490 motor and electonics in a tri-z, any thoughts

[deathman53]

I'm about to get 2 yz490's, a exriders member brought to my attention that tri-z have the same motor mounts as a yz250 motor, and yz 490 and 465 motors, any immedite thoughts on this???? If so any of you guys got a tri-z roller around???

[my90rulz]

i thought about it, but if i was you i wouldnt use a 490...they suck to tune, can never get them to stop pingging eiether...they will bolt in tho, the only thing that will keep em from pre-det is some major head work...maby talk to Ronnie...

[deathman53]

you mean by reshaping the dome to lessen compression. I plan on using race gas anyway.

[CHAINSAW]

Its came across my mind many a times... the only problem is,.. the 490s arent abundant around my area. The only thing that will be a problem, and cost some money would be a pipe. Its highly unlikely a YZ490 pipe will just bolt up, so plan on having one made... unless you can work with that thin stuff to mod the stock one to fit. Thats the only thing I think would be hard on the whole swap.

[YAMAHONDAMAN]

Hey Neil...iv'e been checking in on this stuff...the bore and stroke on the 490 is 87x82 versus the 68x68 YZ,TRI-Z..THAT'S 3/4" Longer Rod !!! talk about HIGH Spacer Plates !!!and also i'm hooking up with a guy that work's for a Wiseco Marine Place .... he's gonna help me work on making a "bolt on" BIG BORE for the TRI-Z's...i wanna install a 4mil. longer rod along with a 71-72 mm piston with maybe a 1/8" to 1/4" Spacer Plate....if Honda did it .....WE CAN DO IT !!! :-)
Ronnie

[LonesomeTriZ]

Hey, you can't do that. Then I will not have the baddest Tri-Z. :hail:

I want to here how this developes.

[YAMAHONDAMAN]

:-) ..... You got it Bro..............

[CHAINSAW]

Im pretty sure you will have room to put one in. The monster motor I had, was a good inch, if not more taller then a stocker. Id post a pic of the comparison between my 87 YZ motor, and the frankenstien, but the stupid upload limit here is laughable.... and Im to lazy to resize or upload them on my server. DAN... Up the limit of our Uploads.. Im always 5 or 10 kb over the limit.

[my90rulz]

you mean by reshaping the dome to lessen compression. I plan on using race gas anyway.
They still pre-det on race gas when they get warmed up....its a viscious circle, i would suggest usin a 465 with thr 2mm smaller bore, they dont have any problems:thumbsup:

[deathman53]

I found out the bikes are 79 yz465's

[my90rulz]

I found out the bikes are 79 yz465's
All the better, 4 speed 465...they RIP.....i lay out new 250's on mine....:yup:

[deathman53]

now to get a tri-z complete without the motor. I will not be using the under seat gas tank, I will figure something out, I hear a tri-60 tank fits, but only holds about 1 gallon. my90rulz, you put the motor in a tri-z 250, if did any info would be nice. I might check out how easy it will fit in a 250r frame.

[my90rulz]

now to get a tri-z complete without the motor. I will not be using the under seat gas tank, I will figure something out, I hear a tri-60 tank fits, but only holds about 1 gallon. my90rulz, you put the motor in a tri-z 250, if did any info would be nice. I might check out how easy it will fit in a 250r frame.
I didnt put a 465 in a Z...would be nice i have a spare motor that needs some lovin but need another roller, anyways that zinger tank would be USELESS....my bike is tuned up good it gets an hour Maby and its a 16L tank...so like 4 gallons is it? you would be refillin every 10 mins with a zinger tank haah.

[deathman53]

well, another hurdle to look at.

[ridetrikes250R]

at trinity we did a 490 for hill shooting up in south dakota... the problem with the motor is from factory like stated they have super high compression and not very good cooling... unless moving like a 490! lol anyways at trinity we actually took the head out to 25cc dome.. had a pro mx port jobt thrown on it (very aggressive all around port job) and told the guy to mix it 20:1... dont know if he did but he did call back and tell us it ripped twice as well as good as any other he has rode and that the pingin went away... he ran 110 through it.
adam

[my90rulz]

at trinity we did a 490 for hill shooting up in south dakota... the problem with the motor is from factory like stated they have super high compression and not very good cooling... unless moving like a 490! lol anyways at trinity we actually took the head out to 25cc dome.. had a pro mx port jobt thrown on it (very aggressive all around port job) and told the guy to mix it 20:1... dont know if he did but he did call back and tell us it ripped twice as well as good as any other he has rode and that the pingin went away... he ran 110 through it.
adam
Thats good to know, i was lookin for a place with some experiance to send my 465 jug this winter if i get around to tearin it down..:thumbsup:

[deathman53]

I got the bikes, they are 400's, anybody know if they will still bolt in? anybody got pics of a 465 or 490 for comparism?

[my90rulz]

I dont think the 400 will go in as easy, its a wider shorter motor if i remember correctly it also has the straight exaust port wich will make it a PITA to have a pipe made....and for whaat its worth, i would just rather keep the 250 in there insted of the 400, make alot more power with the 250 mill....got pics of the 400's?

[deathman53]

not yet, the bikes are in somewhat rough shape. I need a new throttle, cluth and intake boot on the better of the two bikes. also the kill switch is stuck closed. the other one is weird, it has some kind of aluminium swinger with bmx style stunt pegs on it, sand paddle tire, the cluth is gone, cluth basket is grooved, another cracked intake tube, it looks like one will be a good runner and the other is for parts. I'm gonna replace the few things the better bike needs and ride it, I might try vintage mx racing, it will be weird for people to see a guy racing a bike that is older than him. I found some web sites with fixes to bring the rear shock up to current day standards.

[my90rulz]

Heh i race my bike and its WAY older than me :D, as for parts, i know where there is a YZ400 i may be able to pick up for parts....i think its locked up tho? let me know if you cant find anything.

[Curbomb]

I have a full rolling chassie of an 86 triz 250 lust to lrt you know..:thumbsup:

[Curbomb]

just to let you know lol..

[deathman53]

I'm not sure if I'm gonna do this project, the better yz400 is in pretty good shape and I don't want to break it up, and I'm running out of space quickly in my storage unit. I don't think I'm gonna do this, as I was hoping it was a 465, makes alot more power than a 400, I was looking and simple mods to a tri-z will bring it to about 5 horses of the yz400 conversion, not worth dismantling 2 classic machines.