450R Ignition

[joe1l]

Has anyone released a hopped up ignition yet, like vortex or dyna?

[lukester720]

Duncan has one. I seen it one their website I believe it was a vortex. It said something about being able to switch power curves. Hope this helps.

[Silverfox@C&DRacing]

There is one that increases the rev limiter 1000 rpm and the vertex one.

[quadjeff]

Yes, Bob at Honda of St. Johns (503) 286-8816 in oregon has one that will let the bike rev up to 11,500 RPM. This thing is tight. He said it will be completed this week. He helped Yoshi on the design for the Z400. He is in the parts department. It will save you a few bucks also instead of paying full price for the Duncan. I know the one they have is awesome also. Doug Eichner was running it on his 450R at the WORCS race and he walked all over the Yamaha's.

[protraxcrf450]

how much is it? Thanks

[quadjeff]

I am not sure.. Give him a call...

[tkwarrior]

Someone explain to me the advantage of getting 2000 more rmps out of a stock 450? If the bike can handle 2000 more then why didn't Honda give it too us that way?


Oh and I saw a listing for one on the sparks webpage for $799.

[joe1l]

I talked to duncan and Dyna today both the vortex and the dyna will be ready next week (i always hear that when I call) i don't want too much over rev, i just want a little more, something like 1000 over. I will call Bob and ask him about his CDI, i know the vortex and dyna's work real well, and have different power curves you can use, for the track, dunes or dragging, and I like that Idea. I have a dyna igniton on my 250R and its awesome and I would those same gains with my 450R as well.

[lukester720]

Keep us posted on what bob says. Thanks.

[joe1l]

I talked to Bob at Oregon, and he is a few weeks away from coming out with his kit, but basically it will be a CRF CDI with a harness adapter that is meant to work with the TRX, all under $200. It doesn't sound bad at all! I may end up getting that!
Joe

[#1speedbump]

Joe, I also looked into this but when i started calling different builders I was amazed at their honesty. I wont name then all but Tc racing has built a few 450r's and said that with the new rev boxes you gain NOTHING. Take it for what it is worth but remember who all he builds engines for and that he gains nothing by lying to customers. Also do you truely plan on revving your motor that high?? Remember that these motors make peak hp way before the rev limiter

[86atc250r]

Originally posted by joe1l
I talked to Bob at Oregon, and he is a few weeks away from coming out with his kit, but basically it will be a CRF CDI with a harness adapter that is meant to work with the TRX, all under $200. It doesn't sound bad at all! I may end up getting that!
Joe


The thing that concerns me about this is that the timing tables are likely very different between the 450R and the CRF - not to detune the 450R, but because of differences in the engine itself and more importantly, differences in the weight and rotating mass of the vehicle.

A lighter vehicle like a dirtbike will want more timing sooner in the curve - this would cause pre-ignition problems on a quad that could actually threaten your engine's longevity if left unchecked.

Be very careful about retrofitting a dirtbike CDI box on a quad without knowing what the differences are in the timing tables.

[quadrcr161]

has anyone seen a dyno graph of these? i know at a certain point the HP curve starts dropping once you rev it past the peak HP, so i dont see how it would help by reving extra rpms if the HP/torque is falling.

[tkwarrior]

Originally posted by quadrcr161
has anyone seen a dyno graph of these? i know at a certain point the HP curve starts dropping once you rev it past the peak HP, so i dont see how it would help by reving extra rpms if the HP/torque is falling.


That was kinda what my question was implying. What is the advantage to reving past what Honda would set the limit at. The only reason to rev a motor hard would be if you bored and stroked it.

[joe1l]

More RPMS = more MPH, its part of the equation.
Say you were to drag 2 stock 450r's except 1 has and extra 1000rpm before the limiter. The one with the extra RPMS will ultimately have a higher MPH in top gear, which could translate into 1 or 2 bike lengths. That is the only reason i really want it, is so that i can gear down the bike a little without having to sacrifice max mph. Yes you do have a better chance of floating a valve and so on, but a I don't think an extra 1000rpm would hurt too much! I notice that the more mods I add to the bike, the faster I am hitting the rev limiter, i just don't want to reach it as fast!! That is a very good point about the motorcyle timing in comparison to the quad timing, and for that reason, I think i'll wait on the vortex box.
Joe

[86atc250r]

Only true under two conditions ---

You can pull 5th gear to the rev-limiter AND you are drag racing at the top speed of the quad in 5th gear (near 80 MPH).

Now, the problem is, unless your quad is heavily modified, you won't come even close to pulling 5th gear to it's rev limit.

2nd problem is - if drag racing, why are you racing to the top speed? What's the point of drag racing if you are going to have the race decided by the top speed that the quad can attain?

Why not just stick a GPS on your quad, establish your max speed, and see if anyone else can match it --- no need for a drag race if that's what you're concerned about.

With a stock engine, the power has dropped off long before the rev-limiter and you should have already shifted. The only advantage a higher RPM rev-limit will gain you in a drag race is if you are not good at timing your shifts and bump off the rev-limit regularly.

Now - as a counterpoint....

One reason for using a CDI box with a higher revlimit would be in a situation where you're on the throttle getting ready to come into a corner - you are in the top of 2nd gear. To keep accelerating, you'll need to shift to 3rd, however, you're very close to the corner and by the time you shifted to 3rd, you'd need to shift back down to 2nd to exit the corner.

In this case, having that extra 1000 RPM or so can make the difference in you being able to keep it in 2nd in this scenario - allowing you to keep accelerating to the very last second, keeping you from having to shift twice and allowing you to beat the other guy that had to shift to the preferred line.

This may seem like an off-the-wall example, but any experienced racer has had this happen.

Even though you're past peak HP, the quad is still producing some power and the benefit of even a few hundred more RPM can make a difference.

There are other valid reasons for wanting to raise the rev limit - for instance, if you have installed a more aggressive cam that develops more top end power.

The thing to think about is if you're willing to take the risk of possible spontaneous thermal self-disassembly, with the hope that you might gain an edge over the other guy.

[tkwarrior]

I rewrote a program that calculates top speed and one of the variables is RPMS.

Feel free to play with it here www.kg4vpv.com/~ncliborne/450r.htm


The YFZ calculator is not complete because I still don't have max RPMS stock and primary reduction.

[quadrcr161]

Originally posted by joe1l
More RPMS = more MPH, its part of the equation.

Joe

not always the case. only if the peak HP is above the rev limit. but if your hitting peak hp 550rpms below the rev limit yout not gaining anything. just taking my car for example, my peak HP is 6200 rpm's but the rev limit is 6800. what do i gain by reving to the rev limit?

i did a quick google and found this graph just to use as an example.
http://www.gtthunder.com/trx450rdynorpm.JPG

as you see peak HP is at 7800 rpms, then it starts falling, showing your not making any power. unless the rev box changes the power curve it isnt worth buying because you should never hit the rev limiter in a race, if you shift at the peak each time you will pull harder then the person over reving.

[86atc250r]

Originally posted by tkwarrior
I rewrote a program that calculates top speed and one of the variables is RPMS.

Feel free to play with it here www.kg4vpv.com/~ncliborne/450r.htm


The YFZ calculator is not complete because I still don't have max RPMS stock and primary reduction.

Hey bunghole - if you're going to ripoff my gearing calculators and call them your own, you could at least change the colors and links at the bottom :rolleyes:

BTW - since you are ripping stuff off, you might want to re-copy the 450R calculator, you have an old version that I corrected a little while back - it has the incorrect primary reduction...

[quadrcr161]

Originally posted by 86atc250r
Hey bunghole - if you're going to ripoff my gearing calculators and call them your own, you could at least change the colors and links at the bottom :rolleyes:

ouch, oh and very good post above 86act250r. :macho

[jmpulse]

A higher rev-limiter would help getting the next higher gear into the sweet spot of the motor quicker, thus allowing the motor to pull harder. By what I have read in here on acouple of posts, the YFZ should of only have a rev-limiter of 9000 rpm. The two quads peak within 500 rpm's of each other. If the R can take the added RPM's, then I say to do it

[joe1l]

There are other valid reasons for wanting to raise the rev limit - for instance, if you have installed a more aggressive cam that develops more top end power.
This is my main reason for doing it, the more mods I add the better top end i gain and once you add a pipe and intake,cam etc. the rev limiter is getting reached much quicker, when all the while the bike feels like its pulling consistently to it, it no longer pulls like a stock machine, it excelarates right to the rev limiter now.

[86atc250r]

Make sure you talk a lot with the person you buy the rev-limiter - make sure the timing curve isn't too agressive, I'm afraid simply dropping in a dirtbike CDI may advance the timing too much. Hard to say without knowing the timing tables.

[joe1l]

Make sure you talk a lot with the person you buy the rev-limiter - make sure the timing curve isn't too agressive, I'm afraid simply dropping in a dirtbike CDI may advance the timing too much. Hard to say without knowing the timing tables.
This is why I'm going to wait for the vortex cdi for the trx450R, they have mulitple preset curves, and 1 stock curve, but the vortex will provide a stronger spark.