Ok so I know jetting is an engine specific thing but here is My current set up for TM R1. Looking for advice on its jetting and reliability
Current timing: advanced 20nn
Current dome size: 3.3
Current squish :110mm
Current main jet : 155
Current pilot jets: 60
Fuel/Oil Ratio 20:1
Fuel Peteo Canada Ultra 94 w VP Racing Octanium 8 points so 102 Octane)
How does this look. I was running with the timing retarded last season in this jetting and just running Ultra 94 octane. When I changed the dome out it was very black and sooty but not the top of the piston See pic below
- Check Squish - you meant 1.1mm? Should be 0.9-1.0 (highly prepped engines can go quite a bit lower)
- Check timing advance - not sure what that means…did you mean 2.0mm? That would be way too much - Should be around 1.6 +/-0.1
- Main jet is in relation to all the rest, you need to tell us what tube you are using (DQ / DP and the size) AND the needle
Was the dome there for longer time than the piston? Meaning, when you put a new piston in, do you clean the dome?
What do you mean tube( the emulsion tube)? Where do I find the DQ or DP identifier?
I wrote “Current” not “Check”
These are the #’s I was given by my engine guy. I was expecting the timing to be in degrees but this is what he told me( ya I’m confused as well) I can double check tomorrow
As far as I know the dome and piston were replaced at the same time
2.0mm advance isn’t out of the realm of possibility when using the Selettra ignition. Ymmv based on the fuel being used.
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It’s number 3. Type (DP or DQ) and size (3 digit number) are stamped on it
I said “check” because the numbers you provided for advance and squish didn’t make sense to me. Advance should be in mm (usually), 20mm doesn’t make sense though, could be 2.0mm. Same with squish, 110mm is not right, probably 1.1mm?
Generally, if you have an engine specialist, I recommend sticking to that person for everything engine-related. Not that we don’t have knowledgeable people here, but every person you ask will likely give you a different answer as we all do things in a different way. My own personal opinion is that dome insert has had better days, looks like it’s way older than the piston (BTW, how long have you run that piston since new?), hasn’t been cleaned and has survived some past trauma (I can see the marks from metal fragments) so I wouldn’t read too much into it. Clean it, polish it and run it more.
As for the jetting - how does the spark plug look? EGT min and max?
With the R1 engine, my go-to baseline setting was 1.6mm advance, 0.9 to 1.0 squish, jetting for this time of the year would be [email protected], DQ268,168,CD1/60, Air 2 turns out. Check reeds.
Go-to setup means if I were to go in blind, not knowing anything about engine fuel weather…nothing, just slap things together and hit the track in a productive and safe manner. Then I would fine tune from there based on feedback, EGT, track, weather etc. If you are running a different tube or needle, everything changes
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Here is a pic of the new dome On the right .
I actually want to learn instead of just paying for a tuner to tell me nothing even if they are right or wrong .
Current time in the engine is 4 hours
This is what the plug looked like in the old dome. Not surprising. Very rich.
I don’t have an EGT Sensor. I’m running a Mychron 1T
Looks like it, even though the wetness is more indicative of having run the engine at low rpm before cutting off, so it won’t read well.
Let us know which tube and needle you are running so we can help you more. When you warm it up on the stand, how many rpms.are you getting?
If you do that simple test (warm up, hold it at 10k.then floor it and read peak rpms) If you hit around 15,500, you should be in the acceptable zone. More, you are lean, less and you are rich.
you must run with the EGT sensor if you want your jetting right.
STD head with std timing (1.6 +/- 0.5) runs 420-610 celcius.
Below you are rich, above you are lean.
Which spark plug is that ?
Fantastic! Just need the needle now, letter and 2 digit code is stamped on it. Number 2 in the diagram above
put a NGK R7282-105 and tell us your needle
OMG, very difficult needle to drive and set-up 
I suggest you this set up as starting point :
k98 2 notch
dp 268
60
b53
main 178
air screw 1.75 turn
this is ok for 15-20’ celcius.
if it is very rich, go down to DP267
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Maybe I’m a weirdo, but I like the K6…just needs a way smaller atomizer. It’s no wonder he’s super rich with the current combo.
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As expected we all have a different take BUT let me clarify something for @RelentlessCRG: I think we all agree you were definitely running rich.
The reason why we asked you that info is that you can only evaluate by looking at the combo of the 3 parts (main jet, atomizer, needle).
What you got back was:
- @AndreaNieri21 Suggests a jetting using K98 which is a “lean” needle, which pairs well with a larger atomizer (and DP series at that, which is “richer” than DQ), all on a large main
- @Muskabeatz suggests keeping K6 which is a “rich” needle, paired with a much smaller atomizer
- Myself, giving you a middle-of-the-road setup, with a K23.
You will not go wrong with either, will be for sure leaner than what you are currently running now. Did you do an RPM test on the stand? When you run the engine, did it feel sluggish on the top (e.g. difficulty extending through top range) or sluggish in the middle (going from low to top). That will give you a good direction where to go.
Most important question: what needles, jets, atomizers do you have handy right now? Apologies for the tons of questions, but needed to pinpoint something virtually
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I am going to run it on the stand tomorrow. I have a race Sunday so I’m making the final preparations .
As far what extra jets/ needles I have…,., I have none. This is the way the carb came from PSL when I bought the TM R1 used(rebuild)
Do you have any suggestions for a jetting kit( if there is one) ? Or should I just buy the jets/ emulsion tubes/ needles separately?
Thanks for all the help. I’ve tuned dirt bike carbs in the past but I feel these carbs are more in depth( maybe because they are higher strung)?
K23 is one of the most used needle but for a beginner k98 is always a safe set-up.
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Just ran it I. The stand.
1/4 throttle: it was choking( rich)
1/4- 3/4 throttle: it was choking a but (rich)
3/4- Full: seem ok but I’m sure it could be soother
