Stalling off line when throttle pegged

[bigdaddy77]

I got the bike all put together running pretty good except when you peg throttle it dies. You can crank on it pretty good (but not wide open) and it takes off fine.You peg it even in neutral it dies. Any Ideas
I adjusted valves before race Saturday and it was better. But not cured. The main jet seems good due to plug color, went down one jet just to be sure and it ran worse. The needle is up 1 position. Pilot jet is stock 35 . Its a 20mm keihin carb.
Played with air / fuel screw and no real change.
It ran pretty good before changing leaking head gasket. The only thing different from then till know is 2 more teeth on rear sprocket, and I changed Trail Bike air cleaner to a UNI filter. Its a 90 with 114 big bore kit and stock head and pipe.
Any body running Fast Flex bars know what style as far as height ,and degree of bend. We have a chassis fab +2 steering stem.
We ran a pretty good track saturday took 1st in both motos due to the fastest kid on DRR braking back axle. He is 11 and my son Adam is 7. His dad was trying to convince me DRR is way to
go , didnt say much after axle broke 2nd one in 2 years. Any help would be great.

[Ride1Rob]

Been there and done that with the non believing Drr parent. I was told we would never compete and that same parent wanted Jam kicked out of the class once we got the bike dialed in. One of the reasons we ride 2 wheels now instead of 4.

You need a bigger main jet from what I can gather. She seems to be starving for fuel when you give it gas. Is it when you hold her wide open or only when you quickly hit the throttle?

We ran the regular Flex bars and not the high (ATV) setup. You don't need the taller ones with the +2 stem. I cut them down an inch on each side.

[bigdaddy77]

Thanks for the info . Had a 89 main jet when we put the carb on went to 87 because plug seemed a little sooty. it was real bad before I adjusted the valves. Now it happens when you go from idle to wide open. You can run it wide open but not just from a dead idle.
I can put it gear and hold the front brake and hammer the gas to half throttle and light the tires up. Not with me on it (too big). Seems like it is hitting rev limiter when you really wrap it out in 1st and 2nd. Also does it in neutral. If I remember it was more noticable with bigger jet.

[chunky0071]

If it is dying when you stab it lower your needle raise the clip. Needle possition on these little four srakes is the most important part to faster reving.

[Ride1Rob]

Is it gas on the plug or oil? Raising the needle is dumping less fuel through the carb and at a later time as well. Try it and see how it changes the performance (better or worse). Move it one clip at a time and make adjustments from there. Also, it just may be your carb. A 20mm seems awfully small. But then again if you're running the clogged up stock head.....:ermm:

[bigdaddy77]

I bought the whole bbkit and carb from Terry at Firepower he knew I was wanting to go to a bigger head and pipe soon. So the 20mm carb is what he sold me.
Talked to Vince at Tbolt today and he was pretty positive Its too lean on pilot jet. Says he talks to people every day with same issue and they buy a larger pilot jet and he never hears from them again. going to give it a try.
It did get better after valve adjustment. Before i put the uni filter on when it got good and warm it launched just fine. Ill let you guys know what I come up with. Thanks again for the help.

[Ride1Rob]

Man, I had to edit my post from last night nite. So it's doing this from Idol up to WOT? You could possibly have a carb issue. Some of these carbs are just hell to dial in or simply won't dial in. What kind of carb is it? I went with the Mikuni VM series because of the performance and they're so easy to dial in. Some of your others.... not so much. :ermm:

[bigdaddy77]

Its a keihin carb. You said raising the needle will lean it. Did you mean raising the needle clip? Because if not enery thing I have read is backwards.
I orderd my steering stem from Lew at Chassis inc April 6 or 7. How long does it normally take him to get 1 out the door? Ive called several times a week and its almost ready!!!
I have thought about throwing the carb in the trash but its to close to the next race this weekend . Hopefully Vince is right and going up on pilot jet will stop it.

[Ride1Rob]

Raising the clip position will feed it less gas thru the main jet til later. Lowering the clip position will feed it more gas sooner. ;) I normally try and have all of my clips in the middle and jet my main from there. Your pilot jet is for when the bike is at idle. It doesn't really have anything to do with mid to wide open throttle. The keihins are good carbs. But we ran a VM26 606 on our 125cc and had great results with it. You're only 10cc's less so I don't see why you shouldn't have just as good results. Check your spark just to make sure it's good as well.

[bigdaddy77]

Im with you 100% on the better bigger carb, but Ive been getting my advice from vince at tbolt and Terry at Firepower. That is also where Ive been getting my parts. With all the hours I have been working this is just frustrating. Im going to go back to the TrailBike air filter, and see if that makes a difference. When my pilot jets get here Im going to try the bigger pilot, If that dont work Im going to throw it in the trash and start over. Do you think switching air filters could make that much difference?
How long did it take Jam to get comfortable on a manual clutch motor. Was wanting to get through this 1st year and make the change over the winter.Whats your opinion on the clutch?

[Ride1Rob]

Jam was riding my yfz450 when he was 6. That's why I got the Typhoon and went with the full manual setup some months afterwards. He just had a nack for shifting.

If you swap the airfilters and it makes a difference in airflow it's definitely a jetting issue. When you changed them the 1st time you didn't rejet? What was the purpose for the change? Does one filter seem to allow more air than the other? Post pics of the filters.

[leager-n-ky]

We had one carb, that i never could get right. but Rob is correct, if you change air filters, and it makes a difference, then its in your jetting. Did you get your wheels bigdaddy??

[bigdaddy77]

Yes I got the wheels today thank you. The reason I changed filters is. I orderd UNI filters and Firepower sent me a Trailbike air filter.So when he sent me the right filter I put it on. We really need to just go out and ride the quad and work on the jetting.Not just in backyard and up and down street.
Im hoping the biggest change was re adjusting the valves. The first time out on the quad after the installation of the bigbor kit and carb it took a bit of riding it and warming it up before it launched off the line. I got it all put back to how it was then and were going to race it this weekend. Unless the pilot jets ever get here then I will mess with it. If the pilot jets dont fix it we are going to a new carb.
Recieved a set of Elka shocks front and rear remote rezzis today.There off a DRR 13" fronts the guy says the rear is 10" . Any body ever put a rear shock off a DRR on a Typhoon? If I have to I will rework the swing arm bracket To keep the same rear height. Even the 10" shock has to be a vast improvement over stock. Still keeping my eye open for a 14 1/2 or 15 " rear Elka.
On the posting pictures Im having issues. It says image is to large how do you change the size ? Thanks for the help guys

[Ride1Rob]

Originally we had a 10inch Elka off of a Drr. The more air Jam got though the more it was apparent we needed a setup with more travel. That's why we went to the 14inch.

[bigdaddy77]

I can see that a longer travel shock is needed. Got the Elkas on today and they seem a world of difference over stock. Had the bike on stand and did notice with the 13" shocks the steering seems bound up when the bike has front wheels off ground. Do I have something out of adjustment or is this normal? Frees up when you put it on ground.
Adam is airing it out pretty good, way past the limits of stock suspension. Im really excited to see how long he can keep up a fast pace. Before he either wore out or scared himself with a rough landing. If I can figure out how to reduce the size of pictures Ill post some.

[190banshee]

Between my sons and my nephew I've had 4 Typhoon in my garage for years and everyone came lean on the pilot. I heard it was to meet the California emissions requirements. If you stab the throttle in neutral and dies its lean on the pilot if it stumbles and coughs its rich on pilot. Its been a long time since any of our bikes were stock but I believe we went up to a 17 or 17.5 pilot and my son was was doing second gear starts throttle pinned no problems.

[bigdaddy77]

Thanks for the info guys. I went up one on the pilot to 38 on keihin carb 20 mm. Ran great.
For his 2nd race he did a fantastic job. Ran a little consevervative in 1st moto and finished 3rd, right on heels of leaders. With the new Elka shocks he was smoking them in the whoops and jumps but seemed to loose ground in the straight aways.
We had a little pep talk about hammering through corners and staying on gas longer.
In the main he got out the gate ok , came out the 1st corner in 3rd. On 2nd lap he got into a groove and passed 2nd place on the 1st big double and stayed on the gas over the 2nd big double, when the leader tracked out of his line and forced him off the side of a table top. That stalled motor in 3rd gear and it took a little bit to get it started. Got right back in the groove to finish 3rd about 20 yards behind leaders. I couldnt be prouder he over came adversity and finished strong. Right now its not about winning but racing hard to the checkerd flag.Thanks again guys for all the help I still have a million ? and Im sure you will see me on here quite often.