ltr 450 motor build

[mike diesel]

Couldn't find a correct are to post this so I figured why not here.

Picked up an 06 Suzuki ltr 450 a few days ago and of course I want to bore it, stroke it, yada yada yada.

bike currently has rossier full exhaust, intake with no airbox, hot cams, and a dyno jet PC3 efi controller. Honestly its pretty freakin fast already but you can never have to much power ya know...I posted over on the ltr forums but wow those guys are no help. Maybe some of you guys have some experience with them.

Just picked my ltr up a few days ago and have since been tweaking it and changing all the fluids and what not.

Question i have is regarding bore kits. Because of course you can never have to much power. Had buddies that bored and stroked there yfz's and always had problems with them. Seems kind of the same on the ltr's. It would appear that most reliability issues come from when people throw a stroker crank in due to odd connecting rod angles? So it seems adding a bore kit alone shouldnt really affect reliability as long as quality parts are used? Is that safe to assume? I would most likely just do the common 474cc kits and while the head is off do some porting and polishing...throw some kms/arp head studs in then have my cousin do his thing with my PC3 and call it a day.

Would the bore kit really net me that much more or should i just do a mild build consisting of stock bore with a high comp piston (12.5:1-13:1) and some arp studs?

All i know is that when i put a 143cc bore kit on my klx110 it was like BAMMM OMG FAST. Would you really notice a 23cc increase on an already stout motor or should i keep the cash for a rainy day/do high comp piston?

 

[mike diesel]

I got the "odd connecting rod angle" statement from the ltr forum...A guy named Chris Williams (respected builder) stated that, incase anyone was wondering.

 

[dbev24]

Big bore kits are time bombs. I've raced Trx's and yfz's both with built and stock motors and the best I've came up with was stock bore and stroke with high comp piston and hot cams. Big bore kits would even last a season. Just my .02

 

[DaveB]

Give Toby @ Moto-Xperts a call. He, Mark Baldwin or Mike Walsh can lead you in the right direction.

I had a big bore Honda 470 and only made 3-4 hp more with my setup. I went back to stock bore bcs I liked the "feel" better. I would do a piston and head porting before a big bore.

 

[mike diesel]

Ok sounds good. I was leaning more towards a high comp piston and stock bore. I also like the "feel good" aspect of it. I wouldn't be so concerned with a big bore if it was a trail rider bike but I will mainly be at the sand dunes so it will be WOT all day long for the most part. Saves me some cash too

 

[Jakemax04]

My bud got his ltr450 built by Chris Williams and that thing rips, my yfz450r blew up on me so I also sent it to Chris Williams. I got a full build, big bore, pnp, Tb bore, 13:1, carillo rod, +1 valves, fuel customs intake, full barkers exhaust, and a dyno tune. Both of our quads rip at the dunes. Not many 4 strokes could hang with us at the drag strip.

 

[Jakemax04]

My big bore is a stock cylinder bored over to 478

 

[SSchmi5519]

I used to be big into racing and dragging the yfz bikes. You go stockbore with a real high comp piston and good cam setup. I was running at 14.1:1 with a custom cut CP piston. Port everything. The carb if you can afford/have means. Big main jets and around 95 octane fuel. Oh and don't forget to strip weight!!


Sent from my iPhone.

 

[mike diesel]

I used to be big into racing and dragging the yfz bikes. You go stockbore with a real high comp piston and good cam setup. I was running at 14.1:1 with a custom cut CP piston. Port everything. The carb if you can afford/have means. Big main jets and around 95 octane fuel. Oh and don't forget to strip weight!!


Sent from my iPhone.

Ltr's are fuel injected 95 octane seems pretty low for 14:1...need more like 110 or even 116.

 

[SSchmi5519]

Ltr's are fuel injected 95 octane seems pretty low for 14:1...need more like 110 or even 116.

That's what I thought when i built it as I ran on VP C12 for a long time. Actually picked up some power coming down on octane rating.


Sent from my iPhone.

 

[dman777]

Ok sounds good. I was leaning more towards a high comp piston and stock bore. I also like the "feel good" aspect of it. I wouldn't be so concerned with a big bore if it was a trail rider bike but I will mainly be at the sand dunes so it will be WOT all day long for the most part. Saves me some cash too

I have a 474 ltr built by Chris Williams and I LOVE IT! The guy who dyno tuned it did not do that great of a job in my opinion and it still put down 57hp. It has been a while but I went from PClll with intake and full Dasa exhaust to bored stock cylinder 474, 13.9 je piston, bigger valves, port and polish, custom grind (dune) web cams, and ported throttle body. Chris said 474 on a stock cylinder is reliable but some guys go up close to 500cc on stock cylinder and start having problems. Chris is a very knowledgable guy and answered all of my questions over the phone. We talked for almost a half hour. I would recommend at least giving him a call. Here is a vid of me and my buddy at the dunes after both our bikes received built motors from Chris. Mine had a very rough tune in. I didn't have time to get to a dyno before we went.
http://youtu.be/B57QJZy_7zc

 

[mike diesel]

That's what I thought when i built it as I ran on VP C12 for a long time. Actually picked up some power coming down on octane rating.


Sent from my iPhone.

Good to know. I will have to make a few different maps for fuel types and see what happens.

 

[mike diesel]

I have a 474 ltr built by Chris Williams and I LOVE IT! The guy who dyno tuned it did not do that great of a job in my opinion and it still put down 57hp. It has been a while but I went from PClll with intake and full Dasa exhaust to bored stock cylinder 474, 13.9 je piston, bigger valves, port and polish, custom grind (dune) web cams, and ported throttle body. Chris said 474 on a stock cylinder is reliable but some guys go up close to 500cc on stock cylinder and start having problems. Chris is a very knowledgable guy and answered all of my questions over the phone. We talked for almost a half hour. I would recommend at least giving him a call. Here is a vid of me and my buddy at the dunes after both our bikes received built motors from Chris. Mine had a very rough tune in. I didn't have time to get to a dyno before we went.
http://youtu.be/B57QJZy_7zc

Great video! Had any trans issues slamming gears like that with no clutch?

 

[DaveB]

They can get plenty of power out of the stock bore. I felt the big bore was lazy, I liked the higher revving of the stock bore. I liked to ride higher rpm's though. I had several built for racing GNCC's.

 

[mike diesel]

What compression would you guys recommend?

Thinking a 13:1 cp piston kit. I don't know if I want to go much higher and have to run race gas all the time. 110 octane is $9 a gallon out here! I would be fine with mixing 110 octane and 91 octane to net me 100 octane for about $6 a gallon..

 

[Jakemax04]

What compression would you guys recommend?

Thinking a 13:1 cp piston kit. I don't know if I want to go much higher and have to run race gas all the time. 110 octane is $9 a gallon out here! I would be fine with mixing 110 octane and 91 octane to net me 100 octane for about $6 a gallon..

That's exactly what I do with my 13:1 compression. That Yfz in the vid is me. Next video I'll be in front all the time Derek! oke:oke:

 

[mike diesel]

That's exactly what I do with my 13:1 compression. That Yfz in the vid is me. Next video I'll be in front all the time Derek! oke:oke:

Cool, 13:1 it is!

 

[e46_330i]

You will gain much more hp going to a hi-comp stock bore than you would a lower compression big bore. Get a good port'n'polish, 13:1 cp, Athena, etc. grab a bolt on kit off ebay. Comes with the jug and everything. Ice cubes are good. Valves, springs & retainers. Should be good to go. In my 400ex I had a +3mm powroll stroker crank in it with a custom wrist pin height stock piston with stock compression (420cc or so), cam, port n polish, 450r carb, valves. Had bearing clearance issues with the powroll crank a year later when i freshened it up & couldn't get in touch with them for nothing. Threw the stock crank back in and threw in a wiseco hi-compression piston stock bore and fell in love with the bike all over again. Much more responsive, revved quicker, pulled harder off the bottom. Launching in 2nd gear, I could walk bolt on 450r's all the way to 300'. Granted I had a custom axxis rear shock and Elka triple rates up front so traction was to my advantage, but still.

 

[Jakemax04]

Big bore and high compression!

 

[PureHybrid]

If you go stroker, or a BIG big bore, look at Falicon rods/cranks. Good quality and IIRC they can make the rod whatever length you want.

x2 on high compression and porting, run it until it needs rebuilt then look at BB kits. IMO there are better cams than Hot Cams, depending on riding style of course.