Baja Dirt Runner 90 Upgrades

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Baja Dirt Runner 90 Upgrades

Postby 4Strokes » Sat Jun 04, 2016 4:49 pm

Topic: New here, I have a Baja Dirt Runner 90
Author: integra evan
Posted: 02/03/2007 10:04:52 PM

Hey all, I'm new here, my name is Evan. Just got a Baja Dirt Runner 90 recently, this is my first dirt bike. Got it as a trade for car subs and amps. I already have my list of plans so far: UNI Hi-flow air filter, which I already have, but I need to find an elbow because it hits the shock if I just put it on the carb. Any suggestions for that?

I want to get an FMF exhaust for an XR70, as I've read the exhaust will bolt right up. I also need to get new plastics for it. I'm planning to get UFO body parts for the XR80, it looks like they will fit. I eventually want to get a different heavier shock and raise the bike up an inch or two. I've already changed the oil and the spark plug. I'm guessing with this new UNI air filter and an FMF exhaust, it will even out the big stock jet that it came with, so it doesn't run so rich even when leaned out a lot. I'll post some pictures once I get some new plastic on! -Evan

Reply by Smokin101 on 02/05/2007 11:28:23 AM
Good luck putting those plastics on that frame, as it's not a Honda frame and no Honda plastics will fit, well except maybe a front fender. I wouldn't waste the money on the FMF exhaust, I've seen them for like $200, why pay that when you can get basically the same exhaust without the stickers for $50-$75 on eBay. Unless you got a lot of money I wouldn't buy a bunch of expensive parts, because the parts will outlast the motor. Depending on how much you ride, you may be rebuilding the motor once or twice a year. The stock piston/rings/cylinder aren't very durable on the Baja's, they tend to wear down very fast. Just passing some info along, wish you luck on the plastics though.

Reply by superhondaz50 on 02/05/2007 9:10:00 PM
Any plastics will fit as long as you have a drill! Check out the picture of my bike,(wrecked now, took out the engine and built a crf50 around it ) it has a Kawasaki KX65 front fender which bolted right up using 2 bolts, the plate bolted on with a little jury rigging. a FMF pipe is the 2nd best thing you can ever do to the bike with the first being a 88cc BB kit. Spend the extra money for a real pipe because the cheap Chinese pipes on eBay don't have the care, time and engineering like the FMF pipe has, you may actually lose power with some of those Chinese pipes. Good luck!

Reply by integra evan on 02/05/2007 9:38:49 PM
Yup, the XR80 plastics have the screw holes in the same spot as the Baja frame and plastics. I am using Mobil 1 oil and 93 octane gas, to extend the life of the internals as long as possible. As far as exhausts go, it works the same way as cars; you get what you pay for. Those cheap exhausts on eBay are built with low quality material that will rust through easily, have been designed poorly, and do not compare to the performance of an FMF exhaust. Thanks for the recommendation on the 88cc kit, I will look into it! -Evan

Reply by Smokin101 on 02/06/2007 10:26:15 PM
Well whatever, the only difference with the exhaust is the silencer on the end. I've had mine for almost a year had it wet several times left it outside overnight and it has yet to start rusting. But I wipe everything down with a oily rag every time I get through riding. The silencer is what makes the difference in the performance of the pipe not the actual pipe itself as the diameter is the same either way. Unless it's stock. I get the same performance on my $70 pipe as those expensive ones, I know, I've compared it to my friends Honda's with the expensive pipes. When it breaks or bends $200-$300 is a lot for a new one. I know I've hit stumps and other things,(like the throttle cable stuck one time when I jumped a jump, and shot me straight at a tree! FUN!! lol) and bent my stock pipe, which was the need for the new one. Of course maybe I haven't seen the crappy ones you refer too. I managed to get a good one off eBay, but here lately it's been getting harder to find good parts on there for these bikes.

Reply by ikarus1 on 02/07/2007 12:39:02 PM
Did you get one of the new ones with disc brakes in the front?

The synthetic oil is probably a good idea, although I would run at least a thicker 30 or 40 weight in summertime. I run Castrol OW30 (GC or German Castrol) and it has minimized smoking. It helps offset a crappy ring setup on these bikes, and air-cooled bikes love synthetic.

Most of us in this thread have/had the DR50 which is basically the same bike (PW80 clone) minus some height. Plastics are the same as a PW80 and I have seen some white plastic on eBay as of late.

I put a stock XR70 pipe on mine for $25 off fleabay and it makes a tremendous difference, along with a better carb/air filter combo.

Another big upgrade is to lose the crummy foot-pegs. They are a liability just cruising trails. You can buy some HD cheap china ones off fleabay for $20-30. I got the "gusseted" version because I intend on doing some racing with this bike...

I put a KX65 fender on mine, but the yellows don't match up. I do have a green one if you want it, it's a UFO Kawasaki Team Green which might look OK with the stock green plastic DR90.

Reply by integra evan on 02/07/2007 9:53:54 PM
Yeah, I definitely want to upgrade the footpegs as well. I'm gonna go red with the plastics.

Reply by ikarus1 on 02/08/2007 12:24:41 PM
Originally posted by Smokin101
Well whatever, the only difference with the exhaust is the silencer on the end. I've had mine for almost a year had it wet several times left it outside overnight and it has yet to start rusting.
IMO Stainless is stainless regardless of country of origin. Granted, in headers from china I have seen crappy weld work, but these things don't have many welds. The better ones I have seen on eBay have the aluminum end-caps (no rusting there either!) and go for around $75 shipped. I'd like to try one of those cheap pipes eventually. My only issue is my kids still ride the bike and the heat-shields on the aftermarket (and clone) stuff is minimal at best. That's why I went with the CRF70 pipe and it works like a charm. When I go with the 88cc kit then I'll go to the bigger pipe as well.

Reply by integra evan on 02/08/2007 5:23:13 PM
I'm sure you can always custom-fab a heatshield.

Reply by ikarus1 on 02/09/2007 1:50:32 PM
I could probably fabricate a pipe too, but I'm lazy

Reply by integra evan on 02/10/2007 11:58:59 AM
lol. Duct tape always works LOL! My muffler fell apart where the pipe connects to it. so I duct taped it together. Hey, it works well, keeps the leak out, and keeps it quiet, haha. I also got the UNI filter on and it performs very well! I had to get a 90 degree elbow and then custom fab a hose to connect to the carb out of duct tape and clamps. ha ha.

Reply by mspike on 02/19/2007 5:08:36 PM
Hey Evan, what is the model number on the Uni Air filter you got. I have the same bike and want to get one of those filters. Thanks

Reply by integra evan on 02/22/2007 4:53:11 PM
I forget what the model number is, but it's a 1 inch inner diameter on the pipe, and has a 3 inch height. When I look at the package, I'll let you know the model number. I think it's for a Honda XR50.

Reply by mspike on 02/23/2007 2:40:27 PM
OK, thanks. I'll be looking back here occasionally if you find the enact number. Thanks.

Reply by integra evan on 02/25/2007 7:10:10 PM
Couldn't find the exact number for it.

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