I think I may have set a new record for the number of views without any replies 59 and counting! Below is a copy of my message. I really wanted to know what the easiest way was to change the jetting on the Raptor?




Tuesday, October 16, 2001 12:14 PM



Hey guys just did my first mod's on the Raptor this weekend. I've got quite a few questions. Being that I have built and raced many cars and snowmobiles in the past I decided to tear into the raptor to install the new pipes/jetting/pro-design/K&N filter. I am used to loosening the carb boots and rotating the carb enough to get at the bowl screws and then swapping out the jets. Not that easy on the Raptor atleast I didn't see how that would be possible. So I had to remove the airbox and eventually the boots from the head to get at the carbs.

I was also wondering about the jetting. I am running 155/160 w/25 pilots for my new DMC pipes w/no other mod's except the Pro-Design/K&N. I am currently running with an unmodified airbox.

Finally what spark plugs is everyone running, heat range, etc.

Thanks!
Brent

-------------------------
01' Raptor
DMC Alien
Pro-Flow K&N
155/160 Mains 25 Pilots
Lowering Kit
12/42 Sprockets

 

Sorry no one has replied. You might consider changing the title to "jetting problem on raptor" (or maybe that was your orig title!).

Most of the experts (exclude me) would probably want to know more about your setup, such as:
1. Are your jets and needles by Yamaha? They typically suggest using the dynojet jets and needles found in the kit they make for k&N. The stock needles suck.
2. What altitude do you ride at?

As for plug, I'm stock, though that may change.

Below is a copy of my earlier memo to bigbear about what exactly I've done to my raptor. Hope it helps!

As you know, the jet size is greatly affected by not only the exhaust pipe, but by the air cleaner type and airbox mods. I prefer the K&N airfiler that installs just like the oem model. Costs about $70.00, and installs in 10 seconds. For airbox mods, I followed NotuRaptor's advice and:

1.removed the snorkel from the airbox and put a $2 pvc breather on the crankcase breather hose.
2. cut off the back 2/3rds of the airbox lid and threw it away. The front 2" of the box holds the airfiler in place.

I already had a White bros e-series muffler.

I then called dynojet.com tech line and asked what jets would be preferred for the above configuration. They said to buy the K&N stage 2 jet kit (that dynojet manufactures) and use the 148 and 150 jets in the left and right carbs, respectively. They thought this would work best in the 0-3000 ft elevation, and run a bit rich above that (but with little consequence).

I tested this setup last saturday, and the results were suprising. The earlier muffler change had shown hardly any benefit, but now with new jets, K&N, and airbox mods, this baby flys! More low end torque, and more hp in the hi revs too.

I'm not sure if dynojet would recommend different jets for your DMC pipe or not. might be worth the call. Enjoy.

 

Thanks for the info "dooboarder", I will probably run with the airbox lid off when it is dry, but lately it has been raining every day of the week. What all do you get with one of the jet kits? I am assuming mains, pilots, needles. Again what is the easiest way to change out jets, needles on the Raptor?

Thanks

 

There really is no easy way unfortunaltly...you have to take the plastics off, the tank off, the airbox out. Ohh speaking of the air box...trim off the coned part of the airbox tabs. It makes it alot easier to put the airbox in and out.... losen the throttle cable up all the way out. Loosen up all the hose clamps.Then and only then can you rotate your carbs and pop off the float bowls. use a flathead screwdriver to remove the main jets. DON"T TOUCH YOUR AIR MIXTURE SCREWS. leave them alone. I was not able to get the tops off of my carbs so i left them be and just installed yamaha jets 150 and 155. i have a KandN air fliter and 6 uni vents in the airbox lid. White bros R4 pipe but i just got a Yoshimura full exhaust (thanks BASH) So i will be doing soe work tonight. Oh and don't forget to to trim the snorkle tabs...

 

The K&N Stage 2 kit (made by Dynojet) comes with main jets, needles (the most important part),and new diaphram springs to sharpen the response up. The cheapest place I've found is Rocky Mountain ATV for $50. The instructions that come with the Dynojet kit are very well written, including changing your mixture screw to three turns out. As far as installation, the needles and diaphram springs go in the top of the carb, and the main jets go into the bottom. My technique for the main jets is about the same as yours, only difference is I only slipped off one boot going to the head and pivotted the carbs to the side. That's another cool thing about the Dynojet kit, their information is usually spot on so you only have to do this once. I didn't respond to your origianl post because I didn't know an easier way. In fact I had my airbox completely reinstalled after putting on a ProDesign kit, only to have to tear it out again to re-jet a half hour later. Bottom line: the Dynojet is worth the money, especially on the Raptor.

 

Thanks "joeyd" and "95Warrior"! I will be ordering a jet kit this evening. Rocky Mountain has the Dynojet kit for $50? Most people are asking right at the retail $83. The uni vents, are they the small approx. 1" vents? I ride in all kinds of conditions, so I can't really hack up my air box too much, but the vents would probably help. Is there a website anywhere that goes through flipping the rear linkage in detail? I had heard that the Raptorzone did, but I haven't been able to enter that site for weeks. Thanks!

 

don't flip the linkage..you will damage your frame

 

How can flipping the linkage damage the frame?

 

If you search though the forum you will find many jetting responces (at least 1/2 dozen by me) since I am "high altitude" I am not a good source for jet sizes, but here are a few tips anyway. you have to pull all the plastic off the front including head lights and gas tank, I also like to remove the air filter cover. this takes you to the top of the carbs, if you get a kit you will need to pop the top of the carbs to replace the needle jets, springs, and clips. these screws are on really tight so I suggest and impact wrench or a ball screwdriver, use a no point flat tip phillips with a good fit, this will keep you from stripping the screws, replace needles jets and whatever else, close up the top and then work on loosening the the clamps and pulling the carbs. I do not remove throttle and starter linkage I just flip the carbs onto the frame and pull the float bowls off replace main jets and pilot jets and reassemble. make sure the carbs are properly seated in the boots. I usually put the gas tank on and give it a test start before putting all the plastic on. the process gets easier with time since rarely to you get the perfect combo the first time.
stick with the standard spark plug
and yes you can lower the bike by flipping the linkage on the rear shock, I have not done so but I know others who have with no problems
it looks like raptorzone lost his website too bad he had a nice site

 

I prefer to remove the choke and throttle cables and remove the carbs completely to re-jet, since I'm kinda fumble fingered. But I'm able to do so without removing the airbox.

Remember, lid mods affect jetting. Do the mods you feel comfortable with, then call dynojet to see what jets they reccommend for your setup.