engine mods for a ltr450?

[tryandcatchme13]

what are some things i can do to my ltr 450 that are pretty easy to do and will give me some good hp gains. and that wont result in me working on my quad all the time.

[GPracer2500]

Since you didn't mention it, I assume you're showroom stock at the moment. So....

Air box lid off, spark arrestor out, and Yoshimura CRBM (aka "CherryBomb") installed. The first two are free and the CRBM retails for $39.95. Don't do each individually though--all three things work together as a team.

http://www.bareperformance.com/shop/images/Yoshi%20CRBM.jpg

[tryandcatchme13]

i have the lid off and spark arrestor out. i dont have the yoshi but a dg bullet. anything else?

[GPracer2500]

The spark arrestor I was talking about is the one found in the stock exhaust. If you're running a slip-on then ignore that part.

The Yoshimura CRBM is not an exhaust--it is the electronic gizmo pictured above. It plugs into your wiring and tells the EFI to richen the fueling. Without such a device (there are several options but the CRBM is the least expensive) then the EFI has no idea that any mods have been done. It is the EFI equivalent to rejetting your carburetor.

[GPracer2500]

Side-note: I rode a friends LT-R450 in Glamis that had the airbox lid and sparky removed but nothing done to the EFI. It ran so lean (and it was hot enough that weekend) that after the engine warmed up it knocked like crazy. I mean it was really bad--sounded like a handful of bolts was in the cylinder. The owner--who had no idea what deto sounded like--thought his engine was tearing apart. He didn't know what was happening exactly, but it was obvious to anyone something was wrong (bear in mind that only the knock-prone conditions of Glamis made the problem severe enough to be obvious to a laymen). Climbing Oldsmobile hill it was so bad and the power dropped off so severely from the knocking, it would not climb the hill normally. In third gear it would just fall on its face in a cacophony of engine knock. It probably would have made it up in second or first but we weren't about to experiment with how much abuse the engine could take.

I was sure he must have put low octane fuel in it but he insisted he did not. I even offered to help him drain the tank so we could put different gas in there but he declined. Had he been too embarrassed to admit he put low octane fuel in there I'm pretty sure he would have taken me up on the offer. Basically, I'm saying I do think it had fresh 91 in the tank [shrug].

It's tuned properly now but has never felt like I think it should since that weekend.

[tryandcatchme13]

is that cherry bomb something that you think i should do? i'd like to have a little more get up and go out of corners and stuff. i use to have a yfz before this one, and if felt a lot more powerful

[GPracer2500]

Originally posted by tryandcatchme13
is that cherry bomb something that you think i should do? i'd like to have a little more get up and go out of corners and stuff. i use to have a yfz before this one, and if felt a lot more powerful

Yes I do.

If you've got intake and exhaust mods you definitely need to do something with the EFI. The EFI on the LTR (along with almost all other EFI motorcycles and ATVs) has no way to sense the extra breathing abilities your mods are allowing. Right now, your EFI is delivering the same amount of fuel that it would if your airbox lid was on and the stock plugged-up exhaust was in place. You need to match the amount of fuel the EFI is delivering with the amount of air the engine is pumping or you're loosing power and possibly hurting the engine.

The CRBM tells the EFI to deliver more fuel so it will better match the greater amount of airflow you're getting from the lid off and your slip-on. With a carbureted engine you'd change the jets inside the carb to make that adjustment. With EFI you've got to do it electronically.

[tryandcatchme13]

are those things hard to put on? or can i do it pretty easily?

[pro-rider46]

all it is, is a plug in devise and probably takes like 5 minutes. it something you dont ignore unless you hate your engine. i think i read in dirtwheels that you gain like 7 horse power

[tryandcatchme13]

do you have to tune it or anything? or do you just plug it in and go?

[400exstud]

Plug and go. Simple as that.

[tryandcatchme13]

where can i find one of these gizmos??

[krt400ex]

at your dealer...they are a neccesity for the LTR