Tri-z fuel pump replace or rebuild?

[Citytrikeguy]

Hello all. I am currently working on an 85 Tri-z. When I test drove it the engine ran well, :p , in spurts. It would pull with full force and rev strong all the way through its rev range try to sustain a fast pace for any length of time and it would bog down.:cry:I could pull the clutch and feather the throttle to keep it running. After a few seconds of it wanting to die it would liven right up again.
I can only assume it is one of two things a fuel delivery issue or an incorrectly set float in the carburetor.
I have read that you can take the fuel pump apart to check the diaphragm. If I do and it is not damaged will I still need to replace any gaskets? I ask because the only rebuild kit I have seen is $40. Can someone point me towards a cheaper alternative? I also found a mikuni fuel pump new on eBay for $20 free shipping. It is square and I wonder if the shape would cause any mounting concerns. Has anyone used one of these? http://item.mobileweb.ebay.com/viewitem?itemId=280993460757

I am in the middle of splitting the case on the motor and got held up at the flywheel, so I'm trying to keep busy by trying to solve other issues while I wait for my motion pro puller to arrive.

Thank you all for previous help on my newest project and toy.

[Citytrikeguy]

I have been looking for the model number of the tri-z fuel pump so i can better locate and price a rebuild kit. Anyone know the pump part number or a place to order a rebuild kit? I see that Sudco has the pumps and kits I just don't know which is right for my ride.

[badass350x]

Look at my post's think I have all your part numbers listed, you can get rebuild kits cheap as 10 bucks or buy a mukini kit for 16 to 20 bucks, no need to replace the pump.

[old-yellow]

rebuild kit. https://www.denniskirk.com/jetlyne/rectangular-single-outlet-mikuni-fuel-pump-repair-kit.p1741.prd/1741.sku

[badass350x]

rebuild kit. https://www.denniskirk.com/jetlyne/rectangular-single-outlet-mikuni-fuel-pump-repair-kit.p1741.prd/1741.sku

Thats kit is not the stock rebuild kit!!!!

[Jammer700]

I've heard Fuel pump problems and Tri-Z's are common. Knowing this I'd say that's probably your problem assuming you've eliminated any of the more obvious things like you mentioned; float settings, or correct/clogged jetting, or just plain old dirty carb. Does it leak at all? If it was me and I found a new one that I knew fits I would choose it over a rebuild, just for piece of mind.
Does any one else agree that these fuel pumps fail alot, and when the tri-z's came out were they a problem right away, or just over time and sitting too long?
I was reading in one of the old magazine articles from 86 that someone modded out a tri-z to race it and allways had fuel pump issues comming off of big jumps, the went so far as to eliminate the fuel pump and build a one off small aluminum gas tank that fit up top where a gas tank usually sits, so that it would be gravity fed. Ive actually allways wanted a Tri-Z and wanted to know do they all have fuel pump issues comming off of jumps? Did many other people install normal gravity fed gas tanks?

[badass350x]

Really Brian?

[TimSr]

Swapping out parts will eventually get it fixed, but its a lot more cost effective to diagnose the problem and only replace that which has failed. unhook the gas line from the carb and kick it over a few times. If gas comes peeing out the line with each kick, your pump is good, and replacing or rebuilding it is peeing away money. Look at your floats, epecially if it has the brass type which begin to sag over time and shut off prematurely. Fuel pumps rarely fail, and when they do, they either work or they don't.

[Bryan Raffa]

Really Brian?
your right thats the wrong kit!! round 6 bolt is what you need! if thats the problem.

http://www.ebay.com/sch/i.html?_odkw=tri+z+fuel+pump+kit&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313&_nkw=mikuni+fuel+pump+kit&_sacat=0

[Tri-Z 250]

Jam-7 I haven't had too much problems with fuel pump issues. I have had them clog from using a new fuel conister and the plastic shavings jamming the system...I've also experanced the plastic baffel breaking(wear)inside the pump. Going over jumps in STOCK form never have I had the machine cut out in anyway. The topmount I believe was more of a weight saver than a way to eliminate the pump. You run less fuel Top Mount as apposed to 1.5gal on reserve, stock. Plus you take off all the tubing for the air system and the balky undermount tank...thats like 5lbs of wasted HP. Yes it removes the pump but when it comes to racing weight is the key. Unless it's endurance 2.75gal in a Z tank is pointless in MX and TT.

[New2Tri-Z]

So is the the correct one? it is a Dual Outlet Right? I need to order one myself and OEM one is $40.00.
http://www.ebay.com/itm/Snowmobile-Fuel-Pump-Repair-Kit-Mikuni-Dual-Triple-Outlet-Winderosa-/260951787008?pt=Snowmobile_Parts_Accessories&hash=item3cc1f04600&vxp=mtr

[old-yellow]

sorry citytrikeguy was not trying to steer you in the wrong direction, thanks guys for catching my screw up

[badass350x]

So is the the correct one? it is a Dual Outlet Right? I need to order one myself and OEM one is $40.00.
http://www.ebay.com/itm/Snowmobile-Fuel-Pump-Repair-Kit-Mikuni-Dual-Triple-Outlet-Winderosa-/260951787008?pt=Snowmobile_Parts_Accessories&hash=item3cc1f04600&vxp=mtr

Buy the mikuni kit if you want oem performance, like I said the part numbers are in my post, they are like 16 bucks!!!

[Citytrikeguy]

Thank you all. The motor is out and I'm splitting the case finally. Already found a badly bent shift arm assembly. I mean bent too, hammer and drift pin to get it to pass through the case. I've got all new seals and gaskets. I even got a tube of yamabond 4. I will count the seals after the case is split but does anyone know if the water pump oil seal normally comes with a seal set?

[Citytrikeguy]

TimSr, I will follow your advice and try to locate the problem before throwing money at it. Lord knows I'm not made of it!!! Thanks

[Citytrikeguy]

No worries man

[dnoftz]

I would replace the whole thing

[Citytrikeguy]

I would replace the whole thing

Great advice!!! So helpful.

[New2Tri-Z]

Did you ever get the fuel pump working correctly? I took badass350x advice and bought a mikuni rebuild kit. Cost me $15 off ebay, mine works great now. Must have been a vaccum leak at the gasket or something.