sledracer
Extreme
Finally had the sled out to the track this past weekend to give it a try. Ive drag raced for many years the last 6 or so asphalt racing sleds. The last was an 99 mach z that made a best run at 10.27sec @ 127 mph. About 1900ft above sea level (should have gotten into the 9s by the ocean)
Course ya always want more but instead of the Z I wanted to try out a turbo'd yami. I found an 02 RX1 mountain that Ive modded for tar.
The sled has a stage 2 Bender on it which I started at the low boost setting (6lbs was the intent) on 94 pump gas and I even threw a lill octane boost in for insurance (but we know it can be questionable if Oct. boost actually adds anything)
Sleds got the 700 pitot jet in it. And pulls around 10200 rpm on boost. The intercooler also has a 2nd carb line added to it.
The sled was only running 1.7 or 8s in the 60 ft and it wasnt from spinning. It has a consistent bog out of the hole while holding around 3000+ RPM pre launch. By bog it stubbles and farts a bit till RPMS climb a short way out to say 8000 + or so. Then it runs well.
Sled ran a best of 10.9 @ 119 mph. Most the time in the low 11 sec range. I have a Autometer boost gauge on it that seems to bounce around a bit on the low setting but in the high boost setting it seems to reach 10 and the needle is pretty steady. Thought that was a bit odd.
Any tuning advice would be welcome. The bad news is I dont have a wideband on it yet. Ive been trying to get a Prologger but Justin at FFP has been a little incommunicado to say the very least.
Course ya always want more but instead of the Z I wanted to try out a turbo'd yami. I found an 02 RX1 mountain that Ive modded for tar.
The sled has a stage 2 Bender on it which I started at the low boost setting (6lbs was the intent) on 94 pump gas and I even threw a lill octane boost in for insurance (but we know it can be questionable if Oct. boost actually adds anything)
Sleds got the 700 pitot jet in it. And pulls around 10200 rpm on boost. The intercooler also has a 2nd carb line added to it.
The sled was only running 1.7 or 8s in the 60 ft and it wasnt from spinning. It has a consistent bog out of the hole while holding around 3000+ RPM pre launch. By bog it stubbles and farts a bit till RPMS climb a short way out to say 8000 + or so. Then it runs well.
Sled ran a best of 10.9 @ 119 mph. Most the time in the low 11 sec range. I have a Autometer boost gauge on it that seems to bounce around a bit on the low setting but in the high boost setting it seems to reach 10 and the needle is pretty steady. Thought that was a bit odd.
Any tuning advice would be welcome. The bad news is I dont have a wideband on it yet. Ive been trying to get a Prologger but Justin at FFP has been a little incommunicado to say the very least.
mbarryracing
TY 4 Stroke God
- Joined
- Aug 31, 2007
- Messages
- 1,922
- Age
- 52
- Location
- Springville NY
- Country
- USA
- Snowmobile
- 2006 Yamaha Attak Turbo
2015 SR Viper RTX-DX
1996 Vmax 600XT
Sure sounds alot like the typical symptom when all 4 carb slides aren't opening evenly. Most common pain with boosting thru the RX1 CV carbs...
Remove the intercooler, remove the line to the carb slide vents (underside of intercooler) and blow approx 2 psi of shop air into the line (T together if you have two).
The slides / needles should rise equally and fully. If not, you have a leaking diaphram and/or carb leak around the diaghram bowls. If they don't rise equally with shop air, for sure they are not rising together under boost and you get the picture from there.
I can tell you from past experience it's gonna be hard to get a hold of Justin at FPP around this time in the spring, as he is usually swamped with all the summer motorsport racing rush.
Keep trying and leave a message.
Remove the intercooler, remove the line to the carb slide vents (underside of intercooler) and blow approx 2 psi of shop air into the line (T together if you have two).
The slides / needles should rise equally and fully. If not, you have a leaking diaphram and/or carb leak around the diaghram bowls. If they don't rise equally with shop air, for sure they are not rising together under boost and you get the picture from there.
I can tell you from past experience it's gonna be hard to get a hold of Justin at FPP around this time in the spring, as he is usually swamped with all the summer motorsport racing rush.
Keep trying and leave a message.
sledracer
Extreme
Thanx for the reply. I will check it out. Carbs to have billet caps and T's already as well. Intercooler off yet again...Im gonna learn to hate that thing arent I? ;-)
Ratpack
Expert
When you put the cooler back on, spray the boots with carb cleaner. makes it much easier.
judger101
Expert
carb cleaner isnt good for rubber boots
DooAssassin
Expert
I use break cleaner. set boot in place and spray around it, then push it on. It works awesome and no oily residue. I used to do this with motocross hand grips too. never needed glue to keep them from slipping.
sledracer
Extreme
I've been using brake cleaner as well. Think I read that it helps keep the intercooler on the carbs as well. Out to the shop I go. Thanx for the input everyone.
sledracer
Extreme
A little more clarification please. I yanked the intercooler but as mine has been modified I wanted to clear a little something up. The only line currently on the underside of the cooler is the one running to the regulator on Bender system. The other has been plugged and new ones were added to the top of the Int Cooler. There are now 2 lines running to the carbs from the int cooler to the fittings at the top of the carbs closest to the gas tank side. The 2 - T'd lines near the int cooler side of the carbs connect together and run to the pitot jet. Is the the correct configuration?
I T'd the 2 rear lines together and put a little air pressure to them but the slides dont move in any of the carbs. Thought I should confirm the line locations before I went any further.
Kinda like the picture attached.
I T'd the 2 rear lines together and put a little air pressure to them but the slides dont move in any of the carbs. Thought I should confirm the line locations before I went any further.
Kinda like the picture attached.
sledracer
Extreme
OK pretty much ignore the last post. I re read the install instructions and its all good. I tried the slide vent pressurization again and the slides seem to open at pretty much the same time (slight lead by the 2 PTO carbs).
So now where does one look?
So now where does one look?
mbarryracing
TY 4 Stroke God
- Joined
- Aug 31, 2007
- Messages
- 1,922
- Age
- 52
- Location
- Springville NY
- Country
- USA
- Snowmobile
- 2006 Yamaha Attak Turbo
2015 SR Viper RTX-DX
1996 Vmax 600XT
OK, that is how they should be so the slides and diaphrams are good.
Next I'd play with the needle clip positions, richer and leaner to see if you can get the burbling cleared up... but don't SO ANYTHING ELSE UNTIL YOU GET AN AFR GAUGE ON IT!!!!! Might just be that the 700 pitot jet is too lean.
Next I'd play with the needle clip positions, richer and leaner to see if you can get the burbling cleared up... but don't SO ANYTHING ELSE UNTIL YOU GET AN AFR GAUGE ON IT!!!!! Might just be that the 700 pitot jet is too lean.
sledracer
Extreme
There was a good reason I wanted to get a Prologger on it before I started racing. 
Guess I will have to shop at MPI.
The kit had the 500 in it when I started, it had a couple test drives but no full runs with that one. Seemed to have same prob with that one in both the low and high boost settings on the toggle.
I was thinking that the jetting and needles were stock but remembered that I got diff carbs with the kit because they had billet T's and caps on them. The main jets were from the stock carbs, thats the only for sure. Pilots n needles....they could be anyones guess.
Thanx again for everyones help.
Guess I will have to shop at MPI.The kit had the 500 in it when I started, it had a couple test drives but no full runs with that one. Seemed to have same prob with that one in both the low and high boost settings on the toggle.
I was thinking that the jetting and needles were stock but remembered that I got diff carbs with the kit because they had billet T's and caps on them. The main jets were from the stock carbs, thats the only for sure. Pilots n needles....they could be anyones guess.
Thanx again for everyones help.
sledracer
Extreme
There was a good reason I wanted to get a Prologger on it before I started racing. Guess I will have to shop at MPI.
The kit had the 500 in it when I started, it had a couple test drives but no full runs with that one. Seemed to have same prob with that one in both the low and high boost settings on the toggle.
I was thinking that the jetting and needles were stock but remembered that I got diff carbs with the kit because they had billet T's and caps on them. The main jets were from the stock carbs, thats the only for sure. Pilots n needles....they could be anyones guess.
Thanx again for everyones help.
Guess I will have to shop at MPI.The kit had the 500 in it when I started, it had a couple test drives but no full runs with that one. Seemed to have same prob with that one in both the low and high boost settings on the toggle.
I was thinking that the jetting and needles were stock but remembered that I got diff carbs with the kit because they had billet T's and caps on them. The main jets were from the stock carbs, thats the only for sure. Pilots n needles....they could be anyones guess.
Thanx again for everyones help.
sledracer
Extreme
Needles are in the 3rd position (stock). Not knowing if its a lean or rich problem its hard to guess. Kinda think I should run ok in the stock position but not really enough experience to know if the turbo is playing a part in this.
givemeaboost
TY 4 Stroke Junkie
- Joined
- Dec 5, 2003
- Messages
- 689
- Location
- Great Falls, MT.
- Country
- USA
- Snowmobile
- 03 Rx1 Turbo
- LOCATION
- Great Falls,MT
Quit wasting your time trying to tune without a wideband. I tryed for two years to make my sled run right with a cheapo narrow band and once I spent the coin for the NTK wideband I figured out in one day what was wrong.
Ken....
Ken....
sledracer
Extreme
I hear you Ken. I intended to have a wideband inplace before the first race but didnt get the cooperation I hoped for. This coming weekend is the next race and I hope I would find something to make it run a little better....doesnt look like its gonna happen.
Similar threads
