[yz250f4ever]

Hey my name is alex I am new to this forum So i want to start off by saying Hi. I just had some quick questions, i am a new TW200 owner, i just picked up an 03' about 5 days ago. My TW's exhaust was rotted out from just being used it seems like, so i purchased a DG exhaust for it, which greatly improved the sound and even added some power. This TW had never been modded or touched before I bought it, just regular maintenance done for a daily commuter was what the previous owner did. So as of right now the entire bike is stock besides the pipe. I noticed it back fired/made a pop noise a couple of times when i was riding it, and i have been reading these bikes tend to run lean as is to meet emission standards. I was wondering what would be some base line jetting sizes to go off of for my bike with a pipe in California at sea level? I live in dana point, CA its a city pretty much right on the ocean, my plan is to ride this bike for fun up and down PCH (pacific coats hwy). I already plan on doing the air box mod (taking the snorkle out) and shimming the needle, I just wanted to know what stock jetting would be in my carb and where to go from there please? Thanks in advance, have a good one.........Alex

 

[yz250f4ever]

Also there was a warning disclaimer that came with the new DG pipe that said "may drastically change jetting". I went to DG's site but they dont tell you any jetting info like to go up a size on the main jet or anything so....idk??? anyways thanks again for your time.......Alex

 

[lizrdbrth]

Your stock jetting should be a 128.



With the added variables of the DG pipe and being at sea level the tendency is to overjet. Not really a problem and it will run a bit cooler but consider your intended overall use of the bike. Just climbing out of Dana on Ortega is an elevation change of 4,000 feet and that's pretty much true of most coastal areas in southern Cal. Keep it a bit on the lean side if you plan to do much riding elsewhere.

 

[yz250f4ever]

thanks Liz for the reply I appreciate it alot. So i should just leave the jetting alone for now is what your saying? I see that your a local SOCAL resident thats cool.

 

[Bullspit]

Check your spark plug to see if the fouling indicates a very lean condition. If it doesn't, then don't change anything!

 

[yz250f4ever]

I was thinking of doing that as well bull, i appreciate the tip! I am just trying to avoid hurting anything ya know.

 

[lizrdbrth]

thanks Liz for the reply I appreciate it alot. So i should just leave the jetting alone for now is what your saying? I see that your a local SOCAL resident thats cool.

Don't get too messed up about it, but make darned sure you compensate for the pipe and your local elevation. That should be your first priority even if it means overjetting but if you can err on the lean side safely I'd recomend it. Others such as Bikerjosh have similar situations and run aftermatket pipes. If you're looking for suggestions on jetting they will have more working experience and advice.



I live inland and a lot higher up. But let's just examine a typical riding day from your area. (Bullspit and I have similar situations but our starting point is much higher.. If we left here, came to visit you then detoured through Big Bear on the way home the total elevation range would be 12,000 feet).



Let's just take a typical day ride on 74 from Dana point. Dana Point is sea level. Hell's Kitchen is nearly 4,000 feet, only what? 20 miles later?



10 miles further on you're in Elsinore at 1300, Hemet's 2500, Idylwild around 6,000 and by Palm Springs you're back at near sea level again.



You can't really jet for that, but it's our reality. Just presenting it for your consideration in case you'd not considered it before. Unless your daily routine involves a north/south commute you got nowhere to go but "up" to have some fun.

 

[yz250f4ever]

liz that was brilliantly put, i didnt ever look at it that way. Thanks very much for the info. I think i will go up a size or 2 on the main jet and experiment with it, and try shimming the needle because i would rather run a bit richer then run too lean. Thats the nice thing about jetting you can always put it back to where you started. I checked the plug a few mins ago and its perfect color, but then again i have only been riding around dana point for 10 miles with the new pipe. hopefully Bikerjosh will see this or maybe i can PM him and ask him some questions. Thanks again..........Alex

 

[Bullspit]

To piggy back on what Lizrdbrth said, My TW had a larger jet in it and a shimmed needle when I got it. I found it was a little doggy when I rode it at 6000 to 8000 feet, which in the summer I tend to do more. The plug was carbon fouled so I put the standard jet in and found it works pretty well for me from 5000-8000 feet.



Now that it is cooler, and my riding is more between 3000 and 6000 feet I'm going to check the plug to see if I am good or if I need to go back to the fatter jet and shim.



I'm thinking cooler air is denser than hot air and since I'm riding lower I may be running lean.

 

[yz250f4ever]

thanks for the info bull. i appreciate you guys taking the time to share your experiences with the Tw's jetting. I am gonna fiddle around with it and do some testing to see how it goes and keep an eye on plug color and how it runs overall. I messaged josh so i will wait fr his reply too. Thanks again!

 

[lizrdbrth]

Yep. When you stop and consider it the highest and lowest points in the contiguous U.S. are both in SoCal, and both almost within sight of each other.



I can't think of very many other places where you gotts make as many jetting compromises in order to save your motor and still avoid becoming a speedbump on Ortega cuz you're overjetted and can't get the bike over 40. lol.



We're kinda skrewt in that respect, but then again we can ride around in Speedos in January....

 

[Skyking]

We're kinda skrewt in that respect, but then again we can ride around in Speedos in January....

Oh God; now that image is going to be stuck in my head. Ahhhhhh.................

 

[lizrdbrth]

 

[Bullspit]

Just remember that white Speedos are not to be worn after January 15. It is a big fashion faux paux. So we have to wear that color a lot up until then. Just got back from a ride in fact.

 

[assquatch20]

Given your varying elevations over there, you sound like the perfect guinea pig for a product I've wanted to see on a TW for years now.



Look into Dial-a-jets.

 

[MrDNA]

Hi Alex. I'm nearby in Aliso Viejo! I've got an 05 and a 10, and run both with 130 main jets and the needle shimmed at .5mm on one and 1mm on the other. I'm really happy with that set up around here and all through Cleveland NF up to Saddleback.

 

[yz250f4ever]

hahah speedos well i do look good in white hahah jk,

Hey mr.DNA your no more then 10 mins away. And i will try that setup then on mine, becuase your so close to me. That dial a jet seems really cool too, simplistic design and function and i could definatley see that working its kinda like efi except your the one adjusting it manually, it would be fun to try. Thanks for all the help guys, and its cool to see other member that are in the so-cal area too.

 

[Skyking]

There's always several on eBay. Check with www.Thunderproducs.com site for fitment.

 

[yz250f4ever]

I may end up trying that dial a jet mod, it seems like it would be cool to try and see if it would work like how they say.

 

[bikerjosh]

I may end up trying that dial a jet mod, it seems like it would be cool to try and see if it would work like how they say.

If you do, hope you do an indepth review.

My set up if I'm remembering correctly it's been a few years.

Main jet to 130 yamaha

Needle shimmed w/ 2 or 3 washers.

Drilled out the mixture screw so I could adjust.

TTr225 header pipe, and big gun can

Haven't opened airbox on this bike.



thanks

+2 on pulling plug to see what it looks like after and before changes.