tri z motor bogs when flying through the whoop section at sand dunes.

[pcs]

i just got back from the sand dune. first off, i was surprised to run in to some other trikes so that was awesome and 2 of them were members here that was nice. anyway when i race on the hill, the motor pulls hard from start but when i hit the whoops hard the motor bogs and as soon as it clears it pulls good the rest of the way up the hill. i was running it on test hill, kinda pissed that i can take the hole shot and i stay on it through the whoops but when it bogs i get passed and then might catch up. if it didnt bog i would be out running more quads out there. im going back tomorrow so what do i check for any last min adjustments?
when i race on the flats i have no problems so my initial though is something to do with the floats, any help with be appreciated.

[shortline10]

Are you missing the plastic / maybe brass pick-up that attaches to the main jet ? What it does is makes it so the main jet doesnt have interuption of fuel suction during bumpy conditions , kinda like an extension so the main jet gets fuel closer to the bottom of the bowl . You can raise the float to see if it helps but just make sure not to go to high that it leaks out the over flow tube . The part just below #22 washer .
http://www.servicehondapsn.com/fiche_section_detail.asp?section=4164&category=ATVs&make=YAMAHA&year=1985&fveh=111

[pcs]

i have the small brass bell on the main jet so im going to try to set the float height up a bit

[pcs]

raised the float height 2mm, cleaned carb out again, new plug, clean airfilter and filled gas tank up. but no change :wondering
on the flats and on the smooth side of hill it ran just fine.

[MTS]

Your not kicking the petcock closed on the fuel pump with your boots? Just a suggestion..bin there a few times..

[pcs]

158653158654158655158656MTS: definitely not the boot hitting the valve. i wear mid level boots that just cover my ankles.
Glamy: here are a few pics, had my tri z and 200x out there this past weekend. i read that some guys use a fuel pump from a snowmobile?i also found an old tread on the site that somewhat shows how to rebuild the pump but did not have the part number for the kit. do any of you know if i could use a different mikuni fuel pump? i see mikuni fuel pumps that are used on banshees when they run alcohol and for rhinos all over the internet. im thinking just throw a new one in there. cant seem to find anything wrong with the carb.
i wish i can get my tri z to my ltr's level, it last made 69 whp. an 85 250r i took that had an ftz drag port, long rod, esr billet reeds, 39 pwk, fmf fatty made 49 whp on the same dyno and cant beat the ltr.

[MTS]

think it was the DF 52? mikuni fuel pump kit? been a while. Sounds to me like you may need to richen up your jet needle a bit..the quick load and unload of going over the whoops is puttin some extra load load on it when the back tires hit the ground and it cant catch up...could need leaned out...Play with the clip see what happens.

[Rigaman]

which tri-z is yours? The one with the checker flag on the seat, do you know what kind of front tire that is?

And the more stock looking z.. That front tire looks brand new. I need a nice front tire.

[MTS]

Might want too look at your clutch and clutch adjust
Ment also

[Mr350x]

It kind of sounds like a loose wire to me, especially since it runs good on the flats.. maybe a wire came loose but is still touching and everyime you hit a whoop it comes fully disconnected. I don't know Tri-z's at all but I thought I would throw that out there, maybe check all your connections to be safe..

[jb2wheels]

Boy , lifes a biotch when you can be @ the best riding in the world in 20mins.........feckin jealous !

I'm jealous you're in SD... only a few hours away right?

[pcs]

check the wire harness connections and the spark plug wire and it doesnt appear to be loose.
MTS, ill try the needle next. i tried to replicate the problem in the desert behind my house, i tried doing some WOT runs in 5th gear over some large whoop section and i cant replicate the issue. i also did a few plug chops at WOT and the plug looks good but none at 1/2 throttle.
think this kit will work?
http://www.ebay.com/itm/Mikuni-Fuel-Pump-Repair-Rebuild-Kit-Dual-DF52D-Triple-Outlet-DF52T-Free-Ship-/300761559802?pt=Motors_ATV_Parts_Accessories&hash=item4606c932fa&vxp=mtr
rigaman: mine is the stock one, the nice one is a member here but i cant remember his name. he has a dunlop 23 in tire that he said he could not find anymore bc the size isnt made. my front tire is almost new, the original owner parked it after a few rides bc his wife flew off of it. been dormant since 87, until now. im looking for a 23in for the front myself.

[Bryan Raffa]

I heard of a few racers complain of this in the woops..with a stock carb.. never had a problem with any of my bikes useing PWK carbs.

[pcs]

i just found a few pwk's carbs on flea bay, im going to bid on one and hopefully get one that is really cheap in $$$

[tri-Z ripper]

i use the PWK as well and have never had that problem. Look for one on fleabay i bought my 38mm air striker new for arund $150

[Bryan Raffa]

here's my theory on the bobbling on the woops... I think that the stock Mic carb's with the copper floats, are too heavy for really ruff use . I think the float bounces in the bowl, opening and closing the needle ,,allowing the flow of gas from the pump.

I Run CEL Needles in my pwk carb's , depending on what your slide is.

[just ben]

here's my theory on the bobbling on the woops... I think that the stock Mic carb's with the copper floats, are too heavy for really ruff use . I think the float bounces in the bowl, opening and closing the needle ,,allowing the flow of gas from the pump.

I Run CEL Needles in my pwk carb's , depending on what your slide is.I think you may be onto something.One of my trikes has brass floats and I have experianced the same thing.I don't really think it is the weight of the float though,I would think it is more that the brass floats are connected and would bounce around at the same rate allowing too much fuel into the bowl.The plastic floats could in theory bounce around at different rates which could always have one of the floats holding the valve shut until both floats drop enough to open the inlet valve.

[Mosh]

If you look at the bottom drain cap in most carbs, you will notice there are 2 holes drilled in the threads of the cap on the sides. You will also notice that there is 2 slots in the bowl casting that is supposed to line up with the holes in the drain plug. Your main jet is submerged somewhat into the cavity of the drain plug that should be full of fuel. But when they built the carbs, most times the drain holes were not lined up with the drain slights in the bowl. This will prevent the bowl area from filling up as fast as possible around the main jet. What you do, is index your drain plug when tightened with a marker usually at 3 and 9 o'clock, then remove the drain plug and re drill the holes to where they line up with the fill slots in the bowl once you re tighten it..It is not a sure fire solution to your problem, but was an old trick with motocross tuners/builders to prevent bogging in the whoops from fuel slosh not being able to surround the main jet quickly enough.