help fast leaving for race

[desratt]

Drr 70 had stock 90 2peice pipe with 40 pilot 110 main 2nd clip screw 2 turns out ran perfect. Now a hetrick gen 3 70 pipe and wont spin the tires. Bog on take off with 45 pilot 110 main. 2nd clip screw2.5 out Put in 112 and was worse. All with 21mm pwk

[selbygirl]

a bigger jet will make it bog , bigger jet more fuel ,smaller jet less fuel . if you do go smaller on jet keep an eye on your spark plug color

[jakesdad6]

I would put the clip in the middle and your screw idealy should be 1 n 1/4 out try that's let me no

[desratt]

Will try after work tomorrow. Pilot with the 40 wouldn't even start moving. Yea with the screw it makes me think I should go leaner on the pilot thou. Idle has to be turned almost all the way in too.

[Hetrick Racing]

What clutch set up you have as well ?
Call me I dont want you upset with my pipe.
We will get it working!!!!

[EthansDad]

I'm sure Rich will get you straightened out. myself, I've had similar issues with the Gen III. in my experience, its all about the pilot and needle position with that pipe. it takes a "fatter than you think" pilot. you also need to make sure that the needle can be in the right place to help with the transition from that fat pilot to what ever main you are running. if your CVT is off, it will just amplify your jetting issues. I'd work on the jetting first.

I'd try -
48 (or maybe even a 50) pilot
clip in middle position
110 or 112 main

also, that little screw on the carb (not the idle, the other one) is your fine tuning for your pilot. turn it out = leaner, turn it in is richer. you're looking/listening for a high idle and crisp throttle response at the 0-1/4 throttle range.

I just went through this on our Hetrick built EVO-4 70 running a GEN III. The pipe does work very very well when dialed in.


-EA

[desratt]

I'm not doging the pipe. It is my jetting i'm sure of it. Will move the needle and try after work. Altitude here is 6000' altitude at race 1500'. That is what sucks 2.

[EthansDad]

yup, no worries. I'm not doging or promoting it either, just saying that pipe more than any other I've worked with is hard to dial in on the pilot. I keep going leaner, and it doesn't work. go big, go fat, ride happy.

hey, got $250 you don't know what to do with? of course you do, your a race dad trained in the art of losing money.

get one of these gizmos. I got one, really like it and use it. I don't understand all that it does, but basically, it can net out all altitude and weather factors into what it calls density altitude (DA). think of that like wind chill. its actually 50 deg, but FEELS like 40. this little guy will do they same for altitude and all other weather factors. DA is no matter what's happening outside, it FEELs like 1500 ft elevation to your carb. match that up with a jetting/altitude sheet and you are in business.

so you can get your baseline at home, then pull that out at the track, get your DA reading, then know which way to go on your jets. not for everyone, but the fact you have 5000ft in between you and the track, thought it might help.

http://www.weathershack.com/kestrel/4250.html


-EA

[desratt]

What carb are you running and if a 21 what jets . Just to give me a start.

[EthansDad]

This year on a bigger carb, so no comp. Last year I did have 50cc on a 21mm with the gen 3. I -think- I had a 50 or even 52, and 110-115 sounds right on the main. That was on oxygenated fuel at about 800ft above sea level. I'd start with the 48 and move up.

[desratt]

With the airscrew sounding best at 2.5 turns out makes me think the pilot is too big already

[EthansDad]

I'm telling you, I've been in this exact place and had the same confusion. that is why I leaned it because of the pilot screw being 2-3 turns out. That felt right, I argued that with hetrick and other riders with that setup until I finely went big on the pilot. Now Im happy.

Just throw a bigger pilot in there and let us know what happens.

[desratt]

Ok. Put 48 in was worse. Moved clip to 3rd spot was worse . Put 108 main in top end is superb. About halfway it kicks in and will wheelie with me on it. Dropped pilot down to 42 better. I have to start down the driveway. Will start going up but is slow to kick in. Could this pipe actually need leaner jetting then the stock 2 peice 90 pipe that was on it?

[EthansDad]

T&E is your best bet. I just remember doing the same trouble shooting. Spent a week on it, then some time on the cvt then back to the jetting. started with a 45 and all things pointed to leaning it out. Dropped to a 42. It was ok, but lacked launch off the bottom. Jumped to a 50, it popped wheelies and screamed all the way down the straight.

You will be rich on the pilot, and the needle needs to transition between the range up to the main. I'd put on my t&e list to keep the 48, and try leaning the needle out, them richen it and see what happens. If no joy, might jump to a 50 and try the same full lean/ full rich settings on the needle.

We ran a 50 pilot on our 70 this past weekend and it sounded real rich on idle, even with the pilot screw set. When the gate dropped though, it took off and ran very well.

[selbygirl]

does it feel like a sling shot building power then shoots ,, go lighter on roller wghts . if you dont have eny lighter ones just take one roller out . now that your running a smaller main keep a eye on the plug color

[selbygirl]

just test it with one roller out dont run it the whole time with it out

[desratt]

Does the same thing on a stand and the tires don't move while it is trying to get past the stumble. Put in a 38 pilot and was the same.

[desratt]

Ok clip in top. Pilot screw out so far it will fall out. Punch it then it stubles and bogs then burns out on concrete.

[selbygirl]

i changed a pipe on one our bikes once . i kept the carb the same just went with a smaller main and lighter rollers, the only time i change the pilot is for easer starts. and i try to keep the screw 1 1/4 out . and check all your wires for good conections .have done that before from taking carb off several times nocked a wire lose

[desratt]

With air screw even half way in it is crappier off start..

[EthansDad]

keep pluggin at it. as some has said, you might need to make CVT or clutch stall changes. going back and forth between cvt and carb can drive you nuts. my $.02, fix the carb first, then fine tune the cvt. taking a roller out is not a bad idea, kind of isolates cvt issues while you trouble shoot the carb.

might want to check this guide out. more background info, may help, may not. I will say the second link in the doc on more detailed tuning guide is worth a read. they go through tuning a delorto carb that is actually used on the cobra 50s. about as close as we'll get to our actual carbs.

clip in top position is full lean on needle. might want to try the other way. that pipe wants a lot of fuel at lower rpms.

http://www.exriders.com/vbb/showthread.php?s=&threadid=468491&highlight=jetting

[desratt]

ok put in 3.2 gr rollers and didn't effect it. my next thought was to take the belt off completely. but I am so close to out of time I am supposed to leave today. thinking on bringing the pilot down some I have went all the way up to no avail..
when you look at the 2 peice stock 90 pipe and the new pipe the new one is deffinitely alot smaller at the silencer. and about the same at the exhaust port. makes me think need to go down again.

[EthansDad]

what cylinder are you using? the stock 70 with the Gen III? any porting on it? any PVL? might be you are just not making the kind of rpms or the right about of "flow" to support that pipe, dunno.

If you're clock is ticking for a race, you might want to "punt" and put the other pipe back on until you can figure this one out. that 2 piece stock DRR pipe is not so bad. I think you can turn around 11k rpms on it nicely, the gen III is more for 12.5k or so.

I've never run the CVT without a belt. taking 1-2 rollers out will stick the CVT in first gear (won't shift out at all really) and let you test launch/take off really well. at full rpms the bike just goes 5-10 mph, kind of funny.

if you are not shifting out (with those 3.2s) and still bogging, its the carb/pipe giving you issues.

the smaller silencer hole size just creates more back pressure and that effects low end power VS higher rpms. not really tied to jetting.

[desratt]

would have put the other pipe back on by now but it broke and that was my excuse with the wife to buy this one.. i'm gonna load up and try it at the track elevation.
mallossi team2 70 cylinder.

[jerkyboy]

Everyone Has given some good ideas but he said hes at 6000'
theres not much air up there so less air equals less fuel.
Maybee try the 38 or 35 pilot clip at the to notch and a 108 main.
Also your stall might be to low, like trying to take off in 3 gear all the time. Just somthing to think about.

[asadad00]

I tried a gen3 and as Ethansdad said it is really hard to get tuned sometimes not responding logical but I think you would save time to call Hetrick and take him up on his offer to help if he should be able to tell you exactly where to jet and clutch.

[rmuscle]

Just throwing this out there but isn't a 21mm Carb a little to small for that cylinder and pipe combo. Maybe I'm wrong but I've never run anything smaller then a 28mm on our 70 .