[Kyle450x]

Hey everyone,
My bikes been having some trouble idling these last few rides, so it was time to tear apart my carb. I found some fine sand in the bottom of the float bowl .

While I was cleaning everything up I thought I'd check my jetting against the database and I was kind of surprised to see I have a different jetting setup than most.

Main: 145
Pilot: 48
Leak: 55


I have the full Pro Circuit RC5 header with the t-4 muffler, 2002 R cam, TRX intake valves, no backfire screen, no smog.

Back when I forst got my X I had Precision Concepts take my smog off and re-jet it (I was a bit of a noob then ). And they said they put the JD jetting kit on.

Pro circuit seems to recommend a 155 main, 45 pilot, the NCYS needle in the 3rd position, and a 70 leak jet.

For the most part my bike runs great. the 55 leak jet really helped the bog issue I used to have. I guess I'm curious if it's recommended that I run a larger main jet to take advantage of my current engine setup? My bike seems snappy and fast, with no bog, so maybe I should just leave it as-is...

Thanks!

[crazybrother]

I would go up on the main to a #170 or #172 and go down on the Pilot to a #45 and adjust your fuel screw.

[hazard88]

I would think a 170 main would be too rich and 155 would be too lean unless you ride above 7k ft. I have almost the exact same setup (with exception to exhuast brands) as you and ride 0-4000 ft and have the NCVS needle 4th clip, 45 pilot, 50 Leak, but with a 165 Main, 1 3/4 out on the screw. Runs great everywhere.

Good luck

[crazybrother]

He has an R cam... it needs at least a 170 main.

[Kyle450x]

Looks like I will have to try the 170 jetting idea.

Going off what Pro Circuit recommends for the 2002/2005 crf450R is a 168 Main, 42 pilot, position 4 clip, and 2 1/4 on the fuel screw.

I'm curious as to what differences the X has after taking the smog off, putting the R cam in, and putting in the TRX intake valves (sa,e size as R valves I believe?)

So perhaps this is why my bikes runs a little hot sometimes? Lean jetting?

Thanks for the help guys!

[crfsonly]

My advice...never trust the jetting recommendations from exhaust manufacturers. On the TRX valves, yes, they will work and we build heads with them as well (see our head services section of our catalog). However, if you look at the RPM ranges for the TRX vs the CRF you'll see the TRX is not designed to rev as far as the CRF. This designed lower RPM of the TRX indicates the valve springs were not necessarily designed to control the valve at higher CRF RPMs and thus prevent valve float. For this reason we do not recommend TRX valves for anything more than light off-road use for someone who will not be on the rev limit. so, consider this when making your valve selection.

R cams in the X work great. if you match the R cam to the R head even better. then bump up the compression ratio and you'll have great power everywhere and it will keep pulling in the higher RPM's. removing the emissions equipment does nothing to increase performance.

[Kyle450x]

My advice...never trust the jetting recommendations from exhaust manufacturers. On the TRX valves, yes, they will work and we build heads with them as well (see our head services section of our catalog). However, if you look at the RPM ranges for the TRX vs the CRF you'll see the TRX is not designed to rev as far as the CRF. This designed lower RPM of the TRX indicates the valve springs were not necessarily designed to control the valve at higher CRF RPMs and thus prevent valve float. For this reason we do not recommend TRX valves for anything more than light off-road use for someone who will not be on the rev limit. so, consider this when making your valve selection.

R cams in the X work great. if you match the R cam to the R head even better. then bump up the compression ratio and you'll have great power everywhere and it will keep pulling in the higher RPM's. removing the emissions equipment does nothing to increase performance.

Very interesting... Sounds like if you run the right springs the TRX valves are still a solid option if they are controlled. I will say that I have YET to need to adjust my valves after a solid year of riding, which is a lot more than I can say about the stock CRF valves! aNot to mention there's plenty of threads talking about CRFR valves stretching quickly.

So other than valves, whats the difference between the X and R heads? And better yet, how would this relate to jetting?

[crfsonly]

honda continued to take the results of their R&D porting efforts in motocross and supercross and rolled it into their R production heads. they did not do this with the X heads. so, the primary difference is improved port performance on the R heads. they are bolt on compatible with their X counterparts with the exception of the emissions port.

on the valves, to control the stainless valves at high RPMs KW uses dual springs (two springs per valve).

ken

[Kyle450x]

I've heard of the two piece kibblewhite parts malfunctioning .


So I ended up with a 170 main, 48 pilot, and 50 leak jet, with 1.6 turns out on the fuel screws, runs sooo much better now! Very improved power

[crfsonly]

kyle...actually the KW valves are manufactured from one piece forgings. they are not a two piece construction. also, KW uses a high quality stainless steel...not a low quality stainless steel that honda uses on the stock exhaust and the TRX intake valves. KW Black Diamond process enhances wear properties and reduces friction. the one piece forging and surface treatment process produces a far superior valve than the stock exhaust or TRX intake valves. even still by biggest concern in using the TRX valves is the spring package. they were very likely not engineered or tested at CRF RPM limits.

ken