Hello all. Well I have had my first major issue with the 400cc xtav. My rear has been toasted, sorta speak. After I put a FMF pipe, 145 jet, and a new uni filter, it seems I have too much power now. I noticed a major increase in the midrange and tope end speed. It appears I have more tourqe as well. All the bolts holding down the ring gear have broken causing my buggy to be inoperable for the time being. I have started the parts ordering process already and hope to have this fixed in a week or two.

BTW: Dave from Awesomebuggy.com got a message I called today and called me back like an hour later from China. Now that’s service. I hope he is up there getting his new buggy ready for production.

Wow, that is some sweet service. Lets see how fast it takes to get you the parts now.

Ouch! Looks like you sheared all the bolts--what grade marking is on them? What are the thin wires in the pictures--were the bolt heads safety-wired together? If so, one might just conclude they've had issues in the gearbox during product testing and came up with a band-aid fix.

if you dont want it to happen again i would go with an american bolt ya no what i mean

I am asking the guys at QS who are working with the new yamabuggy if their diff will fit into my old yamabuggy. If so I might go that route. Apparently they mentioned a bad design with my diff on buggy talk radio the other week. If that will not work then I will get another like I had and replace with American bolts if I can.

The only problem I am seeing here is the wire that goes through the bolts. Are these to hold them from working out? How do I get the good grade American bolts to stay in? Drilling every head and running a wire through it does not sound real fun.

What grade of bolts should I use on this, 8? Will this flex enough? Should it flex at all.

I will also add that I have driven this around on pavement a bit and made some sharp corners, maneuverings. With this being a true posi and having zero slip I am sure the wrath of god was all over this diff at these times. I think I will keep it in the dirt from now on.

On another note it looks like the 145 main jet with the needle moved up a notch is a pretty good combo with the FMF pipe and Unifilter I put on it. Still not getting the color I want in the plug but it runs great. If I go to a 150 jet it starts cutting out big time under throttle and backfires a lot when coming off the throttle. Not sure why plug would not show any color here. I have replaced the plug with brand new ones gaped at 35 and ran for 30 minutes at a time. Pulled plug and zero color. I have done this three times while engine is warm and nothing. Any ideas out there? I am also 2.5 turns out on the idle air screw.

you could use locktite but you should figure out exatly what the wire does before throwing it grade 8 bolt dont break well shouldn't break

Worked on the buggy over the weekend. I have two striped threads in the ring gear and I am unable to find bolts that will clear the case when using lock washers and I am not able to find bolts that have holes in them for the wire. My guess is the wire is used to make up for the no lock washers. I think a new rear diff maybe in play here. I guess I will spend the $250.00 clams and get a new one.

Hi

@yamaboy !

I use a 150er Main jet , but i dont Use an Uni Airfilter , i only demount the Choke sheet from the orginal Filer , but i mean it works not fine , its to Lean , and the Consumption is more than the Buggy goes faster !

witch jet was in your Buggy in orginal Condition ?

Sorry for my bad english !

Thats my X-Atv





her are some threads oft the X-Atv is called in german Taurus !

http://www.buggy125.de/forum/forumdisplay.php?f=169

but is in German !

You havnt had this thing very long, isnt the rear diff covered under warranty? Van

On the first question of the jet, mine came with a 128.

On the second question of the warranty, yes it is under warranty. I paid the 250.00 to get this asap. It is in PHX now and I should have this delivered to my home today or tomorrow.
After I send back the original rear diff they will inspect and either warranty this or tell me it is abuse and go pound sand.