Graham Jarvis Mikuni carb mods and jetting specs

[Armbarn sailor]

Rk tek head is head and shoulders better then the rest. The texture atomizes the fuel and allows more fuel into the charge. Keihin with an rk tek head and a pc 304r and they run hard. Still keep a smooth power but lots more. Kelsey may come off defensive, but the head he sells is great. Super happy and though it isn’t a sweet blue like the s3, the engine loved it and I can say it really pulls hard.

[SmokeX]

3 minutes ago, hondaman331 said:

Rk tek head is head and shoulders better then the rest. The texture atomizes the fuel and allows more fuel into the charge. Keihin with an rk tek head and a pc 304r and they run hard. Still keep a smooth power but lots more. Kelsey may come off defensive, but the head he sells is great. Super happy and though it isn’t a sweet blue like the s3, the engine loved it and I can say it really pulls hard.

Same with mine using a Keihin 38 with Stic block. Coming up on 300 hours now on my 19 300 XC. 

[mog]

6 minutes ago, hondaman331 said:

Rk tek head is head and shoulders better then the rest. The texture atomizes the fuel and allows more fuel into the charge. Keihin with an rk tek head and a pc 304r and they run hard. Still keep a smooth power but lots more. Kelsey may come off defensive, but the head he sells is great. Super happy and though it isn’t a sweet blue like the s3, the engine loved it and I can say it really pulls hard.

Defensive isn't the word for Kelsey ,aggressive is lol 

[Armbarn sailor]

Just now, mog said:

Defensive isn't the word for Kelsey ,aggressive is lol 

You should call him on the phone and just talk to him. I blew an hour or so talking to him and can’t say I regret it at all. He has tried and true principles he holds key and it works. Wish I was good enough to create a product that works well. I had less compression then the s3 with the rk tek head, they weren’t even close to running the same, rk tek was simply better in every way. S3 would choke to death on fuel with what I’m at with the rk tek and I feel I could richer it more on my main. 45 pilot, red jd on 4 and a 175 main is a good start on the rk tek. Really can’t wait to ride hard for an hour or so at race pace to see how much cooler it runs, s3 did a great job on heat but rk has more volume by far for coolant, had to add a cup

[SmokeX]

That was fast

[Armbarn sailor]

Just now, SmokeX said:

That was fast

All the time spent could’ve bought a head and answered the questions

[SmokeX]

1 minute ago, hondaman331 said:

You should call him on the phone and just talk to him. I blew an hour or so talking to him and can’t say I regret it at all. He has tried and true principles he holds key and it works. Wish I was good enough to create a product that works well. I had less compression then the s3 with the rk tek head, they weren’t even close to running the same, rk tek was simply better in every way. S3 would choke to death on fuel with what I’m at with the rk tek and I feel I could richer it more on my main. 45 pilot, red jd on 4 and a 175 main is a good start on the rk tek. Really can’t wait to ride hard for an hour or so at race pace to see how much cooler it runs, s3 did a great job on heat but rk has more volume by far for coolant, had to add a cup

With a Stic block I’m running a 190 main and 50p. 
JD red needle 3 clip and a .113 emulsion tube. The bike is and has been on point. 

[SmokeX]

3 minutes ago, hondaman331 said:

All the time spent could’ve bought a head and answered the questions

Are you referring to me bro. Cause I’ve had the RK head for a while now if you remember. 

[Armbarn sailor]

3 minutes ago, SmokeX said:

With a Stic block I’m running a 190 main and 50p. 
JD red needle 3 clip and a .113 emulsion tube. The bike is and has been on point. 

I am not sure about the stic, I think with the s3 I was good enough, rk tek was better but I’m not lacking power. Hitting the rpms quicker was always my thing with the engine. I race mx, need more pop 

[Armbarn sailor]

1 minute ago, SmokeX said:

Are you referring to me bro. Cause I’ve had the RK head for a while now if you remember. 

No, was referring to mog. All the time in convo he spent with Hera could’ve bought a head for him to see. I’m pretty sure the rk advantage is atomization with that texture

[SmokeX]

?

[mog]

7 minutes ago, hondaman331 said:

You should call him on the phone and just talk to him. I blew an hour or so talking to him and can’t say I regret it at all. He has tried and true principles he holds key and it works. Wish I was good enough to create a product that works well. I had less compression then the s3 with the rk tek head, they weren’t even close to running the same, rk tek was simply better in every way. S3 would choke to death on fuel with what I’m at with the rk tek and I feel I could richer it more on my main. 45 pilot, red jd on 4 and a 175 main is a good start on the rk tek. Really can’t wait to ride hard for an hour or so at race pace to see how much cooler it runs, s3 did a great job on heat but rk has more volume by far for coolant, had to add a cup

I don't think I will be speaking on the phone haha 

 

I don't doubt his product is good or his knowledge 

 

His attitude is something I didn't get past , he tends to invalidate everyone else within a 1000 mile radius 

[mog]

2 minutes ago, hondaman331 said:

No, was referring to mog. All the time in convo he spent with Hera could’ve bought a head for him to see. I’m pretty sure the rk advantage is atomization with that texture

I have not needed to buy a head ever in 30 years , I've modified STD heads 

I don't believe the texture does anything, I think it's snake oil 

 

Never seen a rk head on a red bull straight ryrhrm or emx ( world 2 stroke championship bikes ) 

 

Mike allessi used the stic on his big bore yz 

 

 

[Armbarn sailor]

2 minutes ago, mog said:

I don't think I will be speaking on the phone haha 

 

I don't doubt his product is good or his knowledge 

 

His attitude is something I didn't get past , he tends to invalidate everyone else within a 1000 mile radius 

Well, just so you know, his head is worth the money. To the oem it would probably be shocking the difference. Feed it fuel is kelseys motto, and I did, and it worked well. A 45 pilot with the oem or s3 head had oil on my brake, on the rk the larger the pilot the more snap

Just now, mog said:

I have not needed to buy a head ever in 30 years , I've modified STD heads 

I don't believe the texture does anything, I think it's snake oil 

 

Never seen a rk head on a red bull straight ryrhrm or emx ( world 2 stroke championship bikes ) 

 

Mike allessi used the stic on his big bore yz 

 

 

He also used blendzall but I’m not seeing large orders of that

[SmokeX]

Since we are talking RK, RK head strikes again with TPi now. Check it out

 

[Armbarn sailor]

On 1/25/2021 at 1:55 AM, SmokeX said:

Since we are talking RK, RK head strikes again with TPi now. Check it out

 

The head works great. Rk tek has it right

[DanDeVries]

So I found a used kehin 38mm short body locally for 150 but it has the tps wires  will that affect anything? Running it on my 250?

[Burger72]

So did we conclude that “the notch” was necessary on the Mikuni mods ? ....

[mog]

On 3/3/2021 at 7:51 AM, Burger72 said:

So did we conclude that “the notch” was necessary on the Mikuni mods ? ....

The notch works to overcome some of the low speed issue , but you can do things like a 5.0 slide instead 

 

Edited March 4, 2021 by mog

[Cyclic]

This thread was valuable to me. The motor rips now.

I ended up at 22.5 pilot, 420 Main, S4 needle jet, JD Blue needle top clip, 1.5 AS. Full GJ mods, v4 reeds.

10-20 degrees Celsius, sea level, 2017 TE300

Edited March 21, 2021 by Cyclic