Looking for more speed help ?

vollender

vollender

New member
I had two races this weekend, First day I made it to the semifinals by the way 104 temp. Second day lost 2 round 103 temp. 1/4 mile track 4600ft elevation, 2 year old pavment 1 year old launch pad.

I am the only sled that runs at our track and I have know one to ask any questions, I race cars and 1 gsx 1100 bike.

My question is can I get any more top end out of sled. I dont seem to gain after 3/4 track.

sled specs:
1995 800
all stock stock pipes with stingers
22-37 gear
no air box open carbs
white silver white primary spring with 2 shims
stock 8bu weights with 17.2 steel rivets
new yamaha belt
stock secondary spring 3-6 hole
straight 47 degree helix
130 main jets good plug color
50/50 gas 91 pump/110 sunoco
7500 max rpm off stock tach my digatron broke
polaris skid 15' wide track 136

Time tickets today
.500 tree .500 .500 .500
.108 reaction bad .022 .065 .256 bad
1.550 60' 1.590 1.750 1.577
4.533 330 4.621 4.786 4.580
7.142 660 7.242 7.390 7.187
92.87 mph1 92.65 93.12 93.49
9.393 990 9.496 9.626 9.440
11.521 1320 11.619 11.733 11.57
108.39 mph 2 109.37 110.38 108.53

I do not do a burn out, I go around water and line up in tire tracks, I am not sure if I can hold sled past water to heat up track, I have an ankel that cant take any weight on it. aand the cable brke system sucks I am putting on hydralic brakes this winter.
I have found on my semi loss that they sprayed vht all the way across the start line and when i took off it just spun real bad and then took off to the loss.

The first 3 races this year I went to all 3 finals and won one, that gave me a false hope, today it did not go so well.

I dont think my mph mach up to my ets and most of the time I can get to the other racer but not pass them. Now I know I am not the best on the tree the first 2 tickets listed were not that normal for me.

I know I need a set of pipes but it is not in the cards this year, my Daughter is getting Married in 6 days that has taken all the money.

I still have a nice points lead and want to keep it.

Thanks for any help that comes my way.
Ray
 

One little bit of advice...get rid of the "straight" 47 degree helix! That is a very steep finish angle and is probley one of the reasons your motor will only turn 7500 rpms. I would start by going to a "multi-angle" helix with shallower finish to get those rpms up to 8300. Also what are your jetting specs? Is the sled rich, lean? These are also important details to know.
 
YOUR GEARING WRONG, YOUR HELIX IS WRONG AND YOUR OFF BY ROUGHLY 800 RPM. I GUESS THATS WHY YOUR LOOKING FOR MORE SPEED.
1. NEED A 50-40 PROGESSIVE HELIX
2. RUN THIS SLED AT 8350
3. GO TO 24-37 GEARING. 3:16 (yammie tony)
 
Do you know were I could find a used 50-40 helix. I have a 24 gear, If I cant find a helix would the 24 gear still help with my 47 helix.

Thanks Ray
 
I think Tony (Yammiegod) has a pretty good setup going for the "stock 800" Vmax-4, follow his advice. That 24T top gear isn't going to help you as much as having the correct helix profile that will gain you that extra 800 rpm's your losing now. You aren't even utilizing the deeper gearing (22T) you have now only turning 7500 rpm's. You need that shallower finish angle on the helix or you will just chase your tail. Then gear up to 24T.

Also, you should post or PM your jetting specs. I realize you have nice "tan" plugs but you could be leaving lots on the table there as well. A "tan" plug can still leave lots of performance on the table, the electrode will tell you the most about jetting.
 
ACTUALLY JUSTIN IS CORRECT HERE. I POSTED BEING FUNNY MORE THAN GIVING YA FLAT OUT ADVISE. YOUR SHIFT/ RPM IS SO FARR OFF THATS REALLY KILLING YA. THE STOCK PIPES RUN AT 8350, BUT I BELIEVE YOU HAVE ABOUT A 250 WINDOW HIGH/LOW. BEFORE I DID ANYTHING, YOU WILL NEVER ACHIEVE THIS OPERATEING PEAK RPM CHANGEING A GEAR OR A CAM. YOUR GONNA HAVE TO REMOVE YOUR WEIGHTS FROM PRIMARY AND PROBLEY START OFF BY MAKING A RUN WITH TIP EMPTIE. THAN YOU CAN FINE TUNE WITH A HELIX THAT WILL NOT LOAD MOTOR ON THE FINISH. 52/42 WOULD WORK GREAT IF YOU WERE GRASS RACING. LIKE TO SEE YA WITH A 50/40, 48/40, 50/38. etc. 3:16 (yammie tony)
 
Do you have any of those helixs used. I will take any advice you give I want to win this champion ship.

Thanks for help
 
Does the sled run anywhere close to 8350 during the run? Start high, then come down, or does it just go to 7500 then stay there?

Is your primary spring a little baggy? Have you tried a spacer/shim behind the spring? Your sled with that gear ratio should only be running 93mph at 7500 and 103mph at 8300rpm. So you have to get the gearing up there to get the mph up there. Now with getting the RPM up there, you have to do what was mentioned before and remove the tip weight or change out your weights for lighter ones all together. Right now the combo of your spring and the weights are not compatible. If you want to keep the weights, you have to get a stronger spring. If you want to keep the spring, you have to go to lighter weights. Once you have your rpm a bit more in the target range, then use a helix to fine tune it.

A vmax4 should be running 120mph in 1320' and 108 in 660'. (sealevel numbers). 440's around here run 11.9 to 12.1 quite consistantly at 100 to 105mph in 1320'.

Go to http://racenssr.com/calc.htm to calculate gearing vs. rpm numbers.
 
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