Got my bike on the dyno today, I was thinking it would have got a little more out of it. My a/f is very lean in the top end and I was thinking that I would try a 230 mj? I know I need to port the head, but besides that is there any way to get more out of it?

Mods are Athena BB, 13 to 1 cp, hc2, air box lid half cut out with stock filter, Rossier pipe, and yfz carb bored to 42.5

Jetting is: mj 200 pj 45 needle 3rd from bottom.

HP 35.04
TQ 25.55

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Please advise

Thanks

What kind of dyno was it?

dyno jet "WINPEP 7" according to the sheet. I'm also guessing they just ran with stock 20" tires.

Hmmm. . . . . .

I've said this before, but a dyno is just a tool to help you tune your machine and see the benefits of any parts that you add the "numbers" don't actually matter all that much. . . . .

But. . . . .

That is unusually low. My bone stock machine pulled over 37 hp. So either their dyno reads extremely low, or your machine is not running right.

Also a 200 MJ seems rather large for your build, but I am not an "expert" at jetting.

I forgot to mention that it has a yfz carb bored to 42.5.

what year is your quad? What does a stock bike make on this dyno?

I asked a couple different people in there service department and know one could give me a straight answer. I just called them and they said they would get back to me on Tuesday??? I can't believe that I was the first quad to get a dyno.

Bike is an 2005

Open your airbox, HC3, ported head, and a 14.1 piston..Dyna or vortex cdi.

Click to view attachment

I mean you definitely left some on the table with running the stock tires and an unported head. Now you have a baseline for when you do more mods.

Try a 50 pilot jet and 162 - 175 main, you will be amazed at what the dyno reads

actually the jetting might not be that off.
there isn't enough of a vaccum signal to pull fuel from the carb because of his STOCK head.
therefore the carb has to have huge jets to supply the fuel on its own if you will, rather than velocity helping it out..
just a thought....

just tried a 48 pj and a 200 main. felt like it pulled better, but maybe could uses a little more.

You will see a huge difference switching over to a DASA intake.
The way the DASA smooths the air and speeds velocity will greatly improve your high rpm lean condition.
Also look close at your carb boot that connects the carb to the head.
It likely needs some massaging.

try that and let us know.
It's scary lean on top right now, good luck!

We dynoed our 04 MX bike down in Oklahoma when we went to the dunes. It was an 04 with a UNI filter (stock intake otherwise) lid removed, sparks full exhaust, 14:1 Baldwin piston, Stage 3 hotcam. Everything else was stock, including an unported head. Running an extended swinger, we put down 46-47hp. Added an HRE ported head, but didn't get a chance to dyno again, but the butt dyno showed a great improvement. We ran our dyno run with bald trail tires.

I going to get it dyno tuned in Oregon in about a week. hopefully I could get some more hp from tuning.

well put, good info man..... so thats what this site is for! lolol

If you were the first quad on the dyno the dyno operator may have screwed something up. That is really low even on knobbies.

I took my quad to skagit power sports. They were ok to deal with but I got one run of 75 dollars. Asked if I could change the jetting and do a another run, they said yea its another 75 dollars. Then Asked what does a stock quad put out to see if everyone else was that low I was told that they didn't know.??? Now there not a honda dealer so I asked them about yfz or ltr's and still didn't know. Either they didn't care to help me or they don't use their dyno much. My guess is both. I will not be going there again.

That may have been the eddy current dyno that dynojet offers. If so, those number seem pretty close to being on par.

Dyno tuned at Craz-E-Dealz in Winchester Bay. Came out with 46 hp, 32 tq. Same mods as before. I was told that I was to rich on the mj instead of too lean. Bike runs a lot better now and starts easier. Here are the Dyno sheets.

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That is alot better than before.. I wish these charts were in rpm but oh well..

I bet you are loving that. What a difference. From what main to what main did you go on the jetting?
Must have been a pretty big change.

200 in first dyno to 172. The first dyno said I was to lean?????
My wife rode my bike and she even noticed a difference.

I believe 172 or 175 is where we ended up on our bike too. We were rich on all circuits when we ran ours. The plug looked great though!? Dynos are a pretty darn useful tool though!

46hp is a MUCH better number! Awesome!

after reviewing your air fuel chart there is still a fair amount of tuning to do still i could explain but i would have to type for an hour but there is still room for improvment. I tune alot of hondas about 3 a day. contact me and ill guide you in a little better.

By all means, begin typing. I would find this kind of interesting for someone who does this very often, and uses these types of pulls, ect.. to tune anything asides from the main jet circuit.

Not being a smart ass or anything like that, I tune on dynos as well.....just eddy current type. We do pulls like this as a final check before it hits the dirt, but we use programmed force testing to tune with so it gets all areas. I just went back and looked at the charts and saw the AFR chart at the bottom of one of them, then you mentioned theres still a fair amount of tuning to do so I would be interested in seeing how you inertia guys do it.

BTW, the dyno charts are hard to read when gauged by MPH....much easier by time or RPM.

05 produce 36 h.p.

Got it back on the dyno

My changes from before were Hc3 and a ported head

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Mods
air box lid removed no filter ran (out of time to try different intakes)
yfz bored 42.5 carb
ported head +1 intake
13 to 1 cp
Athena 480
HC3 cam
rossier pipe

I was told I needed clutch heavier springs and a better chain. I pretty happy with it but would like to get it in the mid 50's.

FYI stock 05 trx made 30 stock yfz made 38 on his dyno

That looks like you are not far off.. especially sae vs std.

Nice job, 20hp from those mods sounds about right. Those 04/05s take some time/money to get em up but once u get there its smooth sailing.
I say go to a 43.5 carb, dasa or fci intake, and maybe a Dasa pipe should get you there or real close.

I am thinking you may already have the mid 50's you are looking for seeing as the dyno runs were cut short of the limiter and you had not yet reached peak power.
Do you have any more graphs where a full pull was made?
A/F graphs?
Nice improvements.

I don't have any more graphs I will give him a call, maybe he can email them to me. Air/fuel had a lean dip in the start and was told that was due to the accelerator pump. Then he pulled the filter and the curve started to get better. I was pretty close on the top end for jetting. He also told me that little things like a chain and better clutch springs should help as well as going to a dasa pipe and a better intake would make a bigger difference. I got a intake and now I guess I will be asking Santa for a Dasa pipe.