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462+webcams+fcr Dyno run

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Posted (edited)

I was finally able to get out and get a dyno run to see where I was at with this bike. 

I was pretty sure I was close, but she still doesn't pull hard enough.

Everything was pretty much confirmed.  My jetting is about right. I'm suffering with squirt timing at the moment. The shop is going to fix that for me since at this point I don't feel like pulling my hair out. John at Jett knew exactly what to do to fix it

Baseline numbers: 50.8 hp and 33 lbft tq

 

94mm big bore

+4 hotrod crank

Web 539/540

Fcr41mx

168 main

38 pilotIMG_20180424_164808.jpg.d9c7594f46b0b61900bac848ed8417c7.jpg

IMG_20180424_164808.jpg

IMG_20180424_164756.jpg

Edited by Savage422
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I was finally able to get out and get a dyno run to see where I was at with this bike. 
I was pretty sure I was close, but she still doesn't pull hard enough.
Everything was pretty much confirmed.  My jetting is about right. I'm suffering with squirt timing at the moment. The shop is going to fix that for me since at this point I don't feel like pulling my hair out. John at Jett knew exactly what to do to fix it
Baseline numbers: 50.8 hp and 33 lbft tq
 
94mm big bore
+4 hotrod crank
Web 539/540
Fcr41mx
168 main
38 pilotIMG_20180424_164808.jpg.d9c7594f46b0b61900bac848ed8417c7.jpg
IMG_20180424_164808.jpg.d9c7594f46b0b61900bac848ed8417c7.jpg
IMG_20180424_164756.jpg.c06c3a5962009352007d336440cae3c7.jpg
Nice
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4 hours ago, ohiodrz400sm said:

Nice

Wouldn't have been able to dial it on without all your guys help 👍

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6 hours ago, ClutchinChrisG said:

Wow that thing has some yank! 

50HP is probably enough.

It's not that the power isn't enough, it definitely is. The issue is in the power v engine speed. It takes too long to get to max up. I should be able to shaffe about 2 seconds off the the time with some timing and squirter adjustments. I'm also going to switch my 38 rear sprocket to a 41

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Do you think the stumble in the torque is from AP timing? 

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6 minutes ago, xxdabroxx said:

Do you think the stumble in the torque is from AP timing? 

If you look asst the dyno sheet, it looks fine. The issue (I'll post a video) is when he runs it to 6500, dumps the gas and lets it engine brake, then hits it full throttle. The power map at that point shows a very slow rise to hit peak power.

Basically on a normal wide open run the AP is only ceding fuel for a short time so the fuel is being fed by all the circuits as normal. So, the dyno chart looks relatively clean. Which would be fine if the only time i hit full throttle was at 3500 rpm.  Its the runs from 0 throttle at 6500 rpm to full throttle that it shows it's deficiency. Plus when I times the AP I only had like a super short squirt time of like maybe an 1/4 second 

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Posted (edited)

That's a stoker motor for u. Mine felt the same, didn't like it. It feels like it don't want to Rev out and pull to the top very quickly. Longer stroke makes it Rev slower unfortunately..  I sold my 462kit n went with the billet 485 kit. Same +4 stroke but bigger piston. Hopefully it changes the characteristics of the motor a bit. I want it to be Rev happy. 

Edited by Stroked-Z3.0
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Posted (edited)

Also I heard lightweight flywheel with make it Rev up faster and return to idle faster. Less inertia. Heavy flywheel makes idle hang and come down slowly. Drz400 flywheel is way heavier than a ltr450. No wonder those 450s Rev like crazy. People don't use the trail tech bc it don't have TDC marks and u gotta use a degree wheel to get it dialed In. Not to turn this into a flywheel thread but does anyone know where I can get a light weight flywheel or have my stock one lightened?? 

Edited by Stroked-Z3.0
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Also I heard lightweight flywheel with make it Rev up faster and return to idle faster. Less inertia. Heavy flywheel makes idle hang and come down slowly. Drz400 flywheel is way heavier than a ltr450. No wonder those 450s Rev like crazy. People don't use the trail tech bc it don't have TDC marks and u gotta use a degree wheel to get it dialed In. Not to turn this into a flywheel thread but does anyone know where I can get a light weight flywheel or have my stock one lightened?? 
I heard Advantage Cycles used to do it for the Z guys. Might give them a call.

I have a trail tech. I used a dial indicator down the plug hole when I installed the BB kit. I marked TDC on the wheel with a sharpie and that works well enough for cam installations.
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35 minutes ago, Stroked-Z3.0 said:

Also I heard lightweight flywheel with make it Rev up faster and return to idle faster. Less inertia. Heavy flywheel makes idle hang and come down slowly. Drz400 flywheel is way heavier than a ltr450. No wonder those 450s Rev like crazy. People don't use the trail tech bc it don't have TDC marks and u gotta use a degree wheel to get it dialed In. Not to turn this into a flywheel thread but does anyone know where I can get a light weight flywheel or have my stock one lightened?? 

Down the road I may go that route. But I still need to dial my squirters to get that to peak correctly. Honestly, my guy says it's going to make a huge difference. And for what he's charging (minimal) it will be worth it. He said he sees that all the time. The Dyno looks perfect, but unless you drop the throttle and slam it at mid rpm ranges, you don't see it. I saw some charts of similar bikes that we're done and the engine speed time was much shorter. Like a full 2 seconds 

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What's your airbox look like? 3x3 or more? I'd open up top of box and relocate cdi. It'll pull harder. I only had the 3x3 and the dyno guy said it was starving for air. The box was restrictive. Since then I cut the white plastic  tabs off under the seat, moved cdi and cut off top of box. As much as I could. Even the cdi mounts that stick up. After that jetting was right on, with less bog down low and pulled harder on top. Plug was a nice brown color. Not black or white. But still revved slow. 

 

Question how much does a drz400 flywheel weigh and how much does ltr450 flywheel weigh? I'd like to make mine lighter than the 450. I'll be a Guinea pig with my 485 motor to see if I can free up some power

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19 minutes ago, Stroked-Z3.0 said:

What's your airbox look like? 3x3 or more? I'd open up top of box and relocate cdi. It'll pull harder. I only had the 3x3 and the dyno guy said it was starving for air. The box was restrictive. Since then I cut the white plastic  tabs off under the seat, moved cdi and cut off top of box. As much as I could. Even the cdi mounts that stick up. After that jetting was right on, with less bog down low and pulled harder on top. Plug was a nice brown color. Not black or white. But still revved slow. 

 

Question how much does a drz400 flywheel weigh and how much does ltr450 flywheel weigh? I'd like to make mine lighter than the 450. I'll be a Guinea pig with my 485 motor to see if I can free up some power

I have the whole top of my box cut out pretty much. But that's where my lithium battery sits also. I have cut out and screened the entire right side of the box also. It has plenty of air so far.

I'm not really looking to chase one or two horsepower as much as I'm just looking for it to rev. I think a flywheel will definitely help. But my 38 rear sprocket isn't helping either. I'll be changing it (after the fixes and the initial Dyno run) to see how big of a difference it makes. 

Down the road I'll add oversize valves and maybe a port job. But right now it's a stock head with kibble springs and ferea valves. 

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I found that with a lightened flywheel my 470 would sometimes stall if I got it a little wrong when leaving the lights.then I would have to wait a few min to let the fuel mixture to lean out a bit in the intake to restart.with the stock flywheel that never happened.another way to loose some centrifugal weight is to remove the balancer and the bearings

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Posted (edited)

He made my pulls traditionally, and also by dumping it at 6500 rpm, letting it engine brake, then pulling it. That showed where the deficiency was.

Also, the sound is weird. My bike doesn't sound that shitty. 

Edited by Savage422

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3 minutes ago, ClutchinChrisG said:

I hear you can play with leak jets on the MX carb. Maybe it's getting a bit too much squirt?

Not enough. The squirt is only about an 1/8 of a second. 

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The AF does get really rich between 4700 and 6200 rpm. Is that normal? I'm trying to learn something here.

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1 hour ago, ClutchinChrisG said:

The AF does get really rich between 4700 and 6200 rpm. Is that normal? I'm trying to learn something here.

Fair amount of reversion in that area.

Quote

Exhaust Closing
Excessively late exhaust valve closing is similar to opening the intake too soon-it leads to increased overlap, allowing either reversion back up the intake, or the intake mixture to keep right on going out the exhaust. On the other hand, late closing events can help purge spent gasses from the combustion chamber and provide more vacuum signal to the intake at high rpm. Early exhaust closing yields a smoother operating engine. It does not necessarily hurt the top-end, particularly if it’s combined with a later intake valve opening.

Reversion draws fuel both directions, so you wind up rich. Very common problem with carbs.

http://www.hotrod.com/articles/ccrp-9812-secrets-of-camshaft-power/

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