I would imagine your problem is with your jetting. My jetting was fine until I put on the k&n filter. If you have changed that factory filter that much you probably need to rejet. Sorry I have no part numbers. The local shops had what I needed. The carb is a Mikuni VM13. Call around and ask if your local shops have jets that may work in it. They will probably say," well we have a box of jets for Mikuni carbs." You will need to take your jets out and take them with you to be sure.

 

Order a main jet for an 07 LTZ90. It's a 80.0 main jet which will work.
Here's the diagram of it, but you should be able to get it through your local dealer.

http://alpha-sports.com/suzuki_atv_parts.htm

Way back many pages ago, we all had the same carb problem once we either modified the stock filter or replaced it with a K&N............too much air. I chanced it by purchasing the main jet for the 07 LTZ 90 from the local Suzuki shop and it works just fine. Other's have purchased through CTRacing which you can get different sizes for the Z50 if you really want to dial it in. Honestly though, now that it's warming up, I'm considering a 75.0 or 78.0 main jet.

 

i live in MN i say that for elevation purposes what jets should i run 80 & 22.5? they all say wow thats a big jump did you get
that response

 

cool would changing the cdi have also made me need the larger main i really appreciate u guys getting back so quick

 

<div class="FTQUOTE"><begin quote>Originally posted by: yammadogg

cool would changing the cdi have also made me need the larger main i really appreciate u guys getting back so quick</end quote></div>

I don't know what the elevations are in MN, but I'm in Cali, and most of my riding levels are from 200 to sea level and it ran just fine, but it was a lot cooler then. Before I found that jet, YES, everyone thought that was a BIG jump, but even at stock, completely stock, the Z50 appeared to run rich.

I had the same carb problem even before I put the new CDI box on. It just did not get enough fuel for the intake change. When I lifted up the rear wheels and let them spin freely, it ran great, but when I put them back down on the ground and put a load or some resistance behind it, it had just "bogged".

I still have the stock 17.5 pilot jet though.

 

ride! i appreciate that info a ton ive been starting to feel lost in the project and its still cool here have not had a race day over 65

 

65 degrees........the 80.0 will work great. In fact, someone else a few pages back said they were going to try the 80.0 from a 78.0 or 75.0 I forget which.

Also, you may need to adjust the fuel/air mixture screw once you installed the new jet.

 

It's been a great run guys but my time here is almost up... [img]i/expressions/face-icon-small-frown.gif[/img]
I put to the bike 4sale on Craigslist; already got some hits...

Before I go I want to say that went back to the stock sprocket because u lose way to much top end.... For the sand or big hill climbs this would be an assume upgrade...

Once I sell the bike I'm going to buy an Apex or DRR any suggestions on which
is a faster bike out the box and which is more reliable???

 

There are more DRR at the races compared to any other make out there. I have never seen an APEX. I was actually looking at the Cobra. It seems to be the best out there right now.

 

I know the cobra is the best but I'm not trying to spend $7,000 plus dollars when we don't even flow all the district races....
I can live with $3,000 bucks on DRR or Apex ... Yea you're right I do see a lot of the DRR but I've seen a good share of them brake down on the track... Apex, so I've heard is suppose to be the next best thing after a cobra.. I still haven't may up my mind though I don't want to make the same mistake I made with the ltz50 aka "THE PIG"