I was out playing around with the jetting today. It has a 13.5:1 head, crankshop twin pipes and k&n filters. Unfortunatly no egts, but I ended up going 620's on the main jets with absolutley no engine studder or excess fuel loading. Judging by the plugs I could have went up another size. This testing is at 2500ft. Does anyone else have any experience with this same setup. I am still having a hard time believing that it needs 620's. I should say that I had detonation with 580's. Thanks for any input!!
Trygstad 800R Race Motor
- Thread starter rwjk0
- Start date
drop the hammer
Active member
Talk to the engine builder on that one. I would say that's a lot of fuel to give her, and if you are fighting detonation by jetting up, you should add better octane fuel first as the 13.5:1 head may be a really tight squish band as well as may have timing advanced being a "race" engine, thus causing the detonation issue. Throwing fuel at it can help deter detonation....but that's going to rob power and eat fuel. What color did you have with 580's and 620's?
Check with the builder first, add some race fuel to take that variable out of it, then monitor plugs and piston wash and go from there. Not too many "race" engines running on just premium fuel. Maybe someone else with first hand knowledge can chime in on this engine build, 620's seem high to me.
Check with the builder first, add some race fuel to take that variable out of it, then monitor plugs and piston wash and go from there. Not too many "race" engines running on just premium fuel. Maybe someone else with first hand knowledge can chime in on this engine build, 620's seem high to me.
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- #3
Is the motor ported (I'm assuming yes and full race job as well)? I'm at 540ish on a "700"cc motor of similar type so I don't think that 620s are too big for that race motor. I'm running 46mm oval bored carbs, twins pipes, and K&N's on a 50/50 blend at 13.5:1.
Yes, you can expect to pull a skimmer of fuel, maybe 2 skimmers worth.
Do not expect good fuel mileage with a race motor, this is why it's a race motor and will hand a stocker its a$$ any day of the week. Build a large gas rack and expect to always pack 5 gals and you will probably usually need just about every last drop to make it back to the truck.
Enjoy kicking some ass with your 800.
Yes, you can expect to pull a skimmer of fuel, maybe 2 skimmers worth.
Do not expect good fuel mileage with a race motor, this is why it's a race motor and will hand a stocker its a$$ any day of the week. Build a large gas rack and expect to always pack 5 gals and you will probably usually need just about every last drop to make it back to the truck.Enjoy kicking some ass with your 800.
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- #5
Thanks modman, I didn't have a sled to compare it too today, but I had a 07 xrs that was dialed right in with some bolt ons, but this thing on hard packed. All I can say is WOW! It caught me by surprise the first time I let her go, was just about sitting on the snow behind it. LOL:d
- Thread starter
- #6
Is the motor ported (I'm assuming yes and full race job as well)? I'm at 540ish on a "700"cc motor of similar type so I don't think that 620s are too big for that race motor. I'm running 46mm oval bored carbs, twins pipes, and K&N's on a 50/50 blend at 13.5:1.
Yes, you can expect to pull a skimmer of fuel, maybe 2 skimmers worth.
Enjoy kicking some ass with your 800.
Modman, heading for the hills tomorrow, do you run 50/50 up top or only around home????
What's your starting elevation where you will be riding?
For me - 50/50 when starting at 3500 - 4000 ft and above, otherwise 75% race gas when I am below 3500 ft. Might be a little high on the % of race below 3500 ft, but I'd rather go a little more than not enough. Race fuel ain't cheap, but its peanuts compared to rebuilding a race motor so it's worth it IMO. Might want to talk to Trystad as a confirmation.
If you are going to start at less than 3000 ft but going up in elevation quickly then you can mix less race gas but keep in mind that going up and coming down you will have to go really easy on the throttle. No racing back to the truck at full throttle at low elevations. :d
Have fun.
