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Jetting for an RK Tek head

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Hey Gang. Based purely on all of the positive comments people have said about the RK Tek head and it's impact on performance, I decided to order one for my 2017 300 XC-W. The motor already runs great, but as this is the first brand new bike I've ever bought for myself, I want it to be "special". I bought the bike in February, and had to wait 6 weeks to ride it (Michigan's UP) so while I waited I let the ThumperTalk forum talk me into a JD jet kit. I had run them in other bikes (my daughter's CRF150R four-stroke most notably) with great success, so I didn't need much convincing. But, as many people have experienced, when you order from RK Tek you get to spend 45 minutes talking to the owner about your bike and what you're trying to achieve. I told him I was running the JD kit and he was very negative about them. He says they're way too lean and shouldn't be put in a 2-stroke! Now, with the kit in my bike I LOVE the way it carburetes! It never loads up, never burbles, and doesn't spooge my silencer. I love it, but you could argue that everything I love about it are indicators of leanness. Not to the point of running poorly, but certainly maybe on the lean side. My question is, where should I start the jetting when I install the RK head? I ride between 500' and 2000', so altitude isn't extreme. 50f to 95f, depending on the weather. I asked the RK guy, but he was noncommittal. Should I ditch the JD kit entirely and go back to stock jetting? Just richen the main? What have other RK owners discovered about jetting after installing the new head?

 

Thanks!

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I don't know what a yooper is LOL. I am running a lectron as well but they had cause to know change in air fuel ratio anywhere along the powerband that was noticeable

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Yup, fellow Yooper. Between Curtis and Gould City. My home loops are Sandtown for technical riding and Danaher Plains for feeling like a Rock Star.

Anyhow, while I appreciate any feedback, I'm not looking to ditch the Mikuni (contrary to the Internet, there's nothing wrong with them) or get a Lectron. Just wondering what people that are running the RK head had to do to their jetting after install...

Thanks

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You don't mention where your at now. With the RK-Tek head I was at 420 main, 32.5 pilot, blue needle on the 3rd clip. AS about 1 1/2 out. I ride between 2,500 - 6,000 though.

But even with that I would get a hanging idle at times so I went to a 35. This was after climbing some longer, sandy hill climbs in the CA desert. Might have wanted to go to a 430 main.

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Thanks, that's helpful!

I didn't include where I'm at now cuz I wasn't sure it was relevant. I'm really asking if the RK head made people too lean, too fat, or no real impact on jetting. For the record I'm 420, 30, blue, and 2 turns out.

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Yea, I really didn't change. I did go all the way up to a 37.5 pilot and it ran great, but I started getting quite a bit more spooge.

The head really widens the power out, best improvement to the bike.

But as of last week I took a OEM 2015 300 XC-W 36mm PWK Keihin and sent it to RB Designs to have it bored to a 39mm which he then installs a divider plate in on the motor side, and modified the slide. Installed it and took it for a spin around the block but that's all I'm gonna be able to do for the next 7 months :cry:

IMG_1500514320.368186.jpg

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54 minutes ago, KennyMc said:

Yea, I really didn't change. I did go all the way up to a 37.5 pilot and it ran great, but I started getting quite a bit more spooge.

The head really widens the power out, best improvement to the bike.

But as of last week I took a OEM 2015 300 XC-W 36mm PWK Keihin and sent it to RB Designs to have it bored to a 39mm which he then installs a divider plate in on the motor side, and modified the slide. Installed it and took it for a spin around the block but that's all I'm gonna be able to do for the next 7 months :cry:

IMG_1500514320.368186.jpg

Well if you'd had Dr Mark do your acl you'd only have to wait 3 months... silly goose

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1 hour ago, 2strokenut said:

Well if you'd had Dr Mark do your acl you'd only have to wait 3 months... silly goose

I know all about that......

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I put the RK Tek head in my TX 300, and it has been the best mod for sure on the bike.

Before the RK Head I was experimenting a ton with jetting and bought a JD Jet kit. I thought it was way too lean for my bike to the point where it was dangerous. The stock jetting was better for me, but there was a burble I couldn't get rid of at 0-1/8th throttle, and it was still lean in the mid.

I went back to stock jetting and have been very happy with:

43-73 needle, clip 2, R8 needle jet, AS at 1.5-2, 42.5 pilot, 460 main jet. This jetting was good without the RK Tek head, and it has been GREAT with the head.

I've used it from 0' 30 degree weather - 5000' 80 degree weather. At 4000 feet and 90 degrees, I adjusted idle and airscrew. That is it!

It is rich on those hot higher elevation days, but I prefer it on the slightly rich side anyways, so I didn't bother adjusting it. Where I do most of my riding, sea level - 2500' the bike is perfect.

Most of my riding is tighter single track. What was once done in second gear is mostly 3rd gear riding now. I took my bike to Bend, Oregon (open desert type riding) and got to test out the main jet... HOLY CRAP, 6th gear pinned was way more than I expected!!! The bike RIPS in every gear.

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2 hours ago, rlucas1986 said:

I put the RK Tek head in my TX 300, and it has been the best mod for sure on the bike.

Before the RK Head I was experimenting a ton with jetting and bought a JD Jet kit. I thought it was way too lean for my bike to the point where it was dangerous. The stock jetting was better for me, but there was a burble I couldn't get rid of at 0-1/8th throttle, and it was still lean in the mid.

I went back to stock jetting and have been very happy with:

43-73 needle, clip 2, R8 needle jet, AS at 1.5-2, 42.5 pilot, 460 main jet. This jetting was good without the RK Tek head, and it has been GREAT with the head.

I've used it from 0' 30 degree weather - 5000' 80 degree weather. At 4000 feet and 90 degrees, I adjusted idle and airscrew. That is it!

It is rich on those hot higher elevation days, but I prefer it on the slightly rich side anyways, so I didn't bother adjusting it. Where I do most of my riding, sea level - 2500' the bike is perfect.

Most of my riding is tighter single track. What was once done in second gear is mostly 3rd gear riding now. I took my bike to Bend, Oregon (open desert type riding) and got to test out the main jet... HOLY CRAP, 6th gear pinned was way more than I expected!!! The bike RIPS in every gear.

I keep reading good reviews like this. I've got a '18 250 XC coming and Rk Tek is like 30 minutes up the road from me. Thinking of grabbing one now before the bike is even here. Trying to be patient and hold off and try out the bike in stock form though :)

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Here are the RK Tek install instruction from RK TEk.com under "TEK-Nikal"

I ended up going 1/2 turn richer on my Lectron metering rod Runs UNBELIEVABLE

I second the Best mod on my bike had a S-3 head way better.

for sure can run a gear or 2 higher can't believe how well it pulls from idle all the way up.

Great fuel economy 40.3 last check I actually measured the fuel left in the tank then refilled it to measure how much tank really held used gps for mileage not the computer on bike.

Runs cooler also, big climb 2800' in like 4.5 miles on 80+ day and bike was running 210 on the temp gage :)

KTM 300 XC-W 2014

 

RK Tek Torque-Line KTM/BETA/HUSQVARNA Head

Installation Instructions

 

 

1 Drain coolant on original head. We recommend removing the water pump drain bolt to do this.  Replace bolt after coolant is drained.

 

2 Remove fuel tank and seat.

 

3 Remove head stay from OEM Head. Removed coolant hose from OEM Head.

 

4 Remove head bolts and washers. These will be reused.

 

5 Remove OEM Head via lifting it off the cylinder. If any coolant is in the cylinder, it needs to be removed before proceeding.

 

6 If the 2 locating dowels remained in the OEM Head, remove them and install in the cylinder.

 

7 Cylinder O-Rings (2) should remain in cylinder. Make sure these are seated properly in their associated groove.

 

8 Install 6 Bolt Sealing O-Rings into the Torque-Line Head Shell in their associated grooves located at each bolt hole on the inside of the head shell.

 

9 Install Dome Sealing O-Ring (1) on billet dome around spark plug hole.

 

10 Keeping the head shell flat, install the dome, making sure that the 6 bolt sealing O-Rings do not get displaced. NOTE: This dome will only install in 1 position into the head shell.

 

11 Place the Billet Head, with dome installed, onto the cylinder. Make sure you do not displace the Cylinder O-Rings or locating dowels.

 

12 Install the 6 head bolts and washers (Step #4). Torque bolts first to 14 ft/lbs and then to 21 ft/lbs using an alternating “cross” pattern.

 

13 Connect coolant hose, securing clamp and re-install the head stay.

 

14 Fill cooling system with a 50/50 anti-freeze/water mix of your choice.

 

15 Remount fuel tank and seat. Start engine and verify there are no leaks anywhere.

 

Ride the motorcycle until the engine gets up to operating temperature. Park bike, let cool, and re-check coolant level to be sure it is full.

 

Jetting: Proper jetting will vary from bike to bike. There are MANY variables in play that determine the proper carburetor settings for your engine. IF your engine was jetted correctly before the head install, then it should be fine after. We find changing the needle 1 clip richer seems to work well with the head.

 

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On 7/19/2017 at 7:27 PM, 2strokenut said:

Well if you'd had Dr Mark do your acl you'd only have to wait 3 months... silly goose

I trust my Dr. as well, he comes from a long family history......but just my luck he was prolly the black sheep of the family:lol:

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Thanks for everyone's input. The head is installed and the alarm is set for tomorrow morning to go try it out! Headed to Missaukee Junction, where everyone feels like a Rock Star! I figured a faster loop was a good place to try to feel the differences between the heads, as I'll be able to use more of the motor more often. I'll check back in after the ride with my impressions. In the end, I followed the RK printed advice and fattened up the needle one position...

Thanks Again

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Well, in truth, I was intentionally putting off posting my results because they weren't very good. But I don't think the new head was to blame. First off, it was a hot and muggy day. Having richened the needle one position, and then riding on a hot muggy day, the bike was definitely rich. Not horrible, but some burbling off idle that wasn't there before. Add to that the fact that I personally rode poorly (was fighting the bike, kept pushing the front end, goggles and glasses steamed up to the point that I couldn't see) and it didn't seem like a fair test of the head. I've since put the carb settings back where they were before I installed the head, but I couldn't ride this past weekend because I had to help my daughter and her boyfriend move. I did rip it down my farm lane just to get a quick idea, and it ran great with clean carburetion and no burble, but this isn't enough of a test to draw real conclusions. I've got a ride scheduled for this weekend back in the U.P. where the bike was originally jetted to match the conditions, and hopefully I'll be in a position to better judge what the head did, if anything.

Thanks

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On 7/31/2017 at 6:54 AM, -AC- said:

Well, in truth, I was intentionally putting off posting my results because they weren't very good. But I don't think the new head was to blame. First off, it was a hot and muggy day. Having richened the needle one position, and then riding on a hot muggy day, the bike was definitely rich. Not horrible, but some burbling off idle that wasn't there before. Add to that the fact that I personally rode poorly (was fighting the bike, kept pushing the front end, goggles and glasses steamed up to the point that I couldn't see) and it didn't seem like a fair test of the head. I've since put the carb settings back where they were before I installed the head, but I couldn't ride this past weekend because I had to help my daughter and her boyfriend move. I did rip it down my farm lane just to get a quick idea, and it ran great with clean carburetion and no burble, but this isn't enough of a test to draw real conclusions. I've got a ride scheduled for this weekend back in the U.P. where the bike was originally jetted to match the conditions, and hopefully I'll be in a position to better judge what the head did, if anything.

Thanks

What was/is your conclusion? Very interested! Thanks

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