Best pass at the strip with my GS 1100

[Guest]

Took my GS 1100 to the local dragstrip for test & tune this past weekend. It's a 1980 with a mild port job, 1mm oversize intake valves, 38 mm carbs from a 1150 and V&H exhaust. It also has a gsxr front end & Bandit swingarm. After some practice passes I laid down my best pass of the night. A 11:46 with a .04 light & 1.68 60 foot. Not bad for a guy who hasn't raced in 10 years.

I think there's more left in the engine so I plan on returning this weekend with a 1 tooth smaller front sprocket & I think I'll go with 125 air jets instead of 150's.

Check out the video just as it gets dark.

http://vid867.photobucket.com/albums/ab235/nastyjones/026-1.mp4

 

[bonanzadave]

Thats a cool vid ! I like your launch

 

[blowerbike]

repeat after me...
i will pull my clutch lever in after going through the traps.
seriously..your starter clutch hates you when you let the engine back down like that.
1150 carbs are 36mm..maybe that was a typo.
if you had a buddy with a set of 36mm RS carbs you could barrow...i bet you would be in the high 10's the 1st night.
gearing seemed ok...it didn't miss till after your time came up on the board.
anyways looked like you had fun..that's the important thing.

 

[Guest]

They call you NASTY
What was the air like it should run better in the winter. You like to zing that thing up there. You get that throttle peg quick enough. I would agree with the lower gearing. Not a bad looking pass though. Looks like your leaving harder than I am on my 1150 but your not.

https://m.youtube.com/watch?v=XM5C_gmdj-s

 

[Guest]

Ok, new clutch cable, 125 air jets & an oil change are on the books for tonight. The 16 tooth front sprocket should be in tomorrow. I could use a set of 36mm Mikuni RS's if anyone has a good used set.
Any other carb that would give me the same bang, RS's seem scarce?

 

[Rob S.]

I liked your launch also. And that sound...that's why I ride a Jap four with a pipe.

Two or more of them, winding out together on a summer night, there's nothing else like it.

You left out one or two pieces of info - your weight, and the bike's weight (sorry).

 

[blowerbike]

vacuum carbs are restrictive and don't breath very well.
the RS miks are the lowest price smooth bores carbs out there.
looking at 400-500 for nice used set.
around 800.00 new.
a set just sold on this site with filters for like 475.00 shipped i believe.
figure on an added 10-15 HP with the jetting being close.

 

[Guest]

Ok, new clutch cable, 125 air jets & an oil change are on the books for tonight. The 16 tooth front sprocket should be in tomorrow. I could use a set of 36mm Mikuni RS's if anyone has a good used set.
Any other carb that would give me the same bang, RS's seem scarce?

If your in Canada then look for a set of 38mm C/V carbs they were on the GSXR's up there. They will flow as good as a set of 36mm RS Mukuni's. But I would go with the Mukuni's RS carbs. If you want to know right size carbs to use for your ported head then when you have your carbs off take off one of the rubber manifolds measure your intake port from side to side (I would measure all of them to make sure they are the same) then chose a carb size between 1 and 3 mm larger than your intake port If your road racing go closer to 1mm over. If drag racing then go closer to 3 mm. over. But I prefer 2mm over. What is your gearing I use a 16/48? On my yellow GS it has a bone stock head the only mod to the motor is a 1175 pistons 39mm Keihins (way to big for the head) and the Harris exhaust I do have an extended swingarm so when I race it. It is set at 64'' wheel base. My best 60' footer with it so far is 1.60 and I know it can do better But I am old and broken.
Think Georgia in mid November take a weekend to have some fun and race the your bike in the street et class at SGMP. I'll line up with ya. You know by then you will be sick of all that snow right. Is it snowing up there yet? :nightmare:

 

[Rob S.]

Hijack

Hijack

Stetracer,

Sounds like you've got a couple of mean bikes there. Could I trouble you for some pics, and the horsepower/torque numbers?

 

[Guest]

Stetracer,

Sounds like you've got a couple of mean bikes there. Could I trouble you for some pics, and the horsepower/torque numbers?

I have never had one of my own bikes on a dyno. I use the track to see how much power my bikes are making. I use the track to fine tune my bikes. I make them run smooth on the street then take them to the track make some passes to establish a base line on what the bike is going. then I increse the main jet one size at a time to see what happened to my mph if it goes up the I keep increasing one size at a time until the mph goes down then I go back to the main jet that gave me the best mph. If the mph goes down after I put the first larger main jet in I know I need a smaller main jet and repeat the process installing one size smaller jet until I get my best mph in the 1/4 mile. It is the best way I know of to fine tune a bike. A dyno can only tell you so much like when to shift. It would be nice to have to have a dyno but I don't so I do things the old fashion way. A true drag racer only cares about one thing anyway " How quick and fast am I gonna go". I would say the yellow 84 one is somewhere in the 125 to 130hp range and the black and red 85 is somewhere in the 155 to 160hp range. In drag racing your mph is your hp indicator. Your 60' footer is deturmand by the rider and how well you have set up the chassis. I also set up my gearing the same what I do my main jet tuning one tooth at a time. I go up on the rear sprocket one tooth at a time until I find the gearing that gives me the best mph using all 5 gears except when setting a bike up for No2 you want to set it up to run the best mph in 4 gears so when you spray it you will have the extra gearing you will need for the extra hp and increase mph by shifting into 5th gear.

Rob,
If you look in my profile in have a few albums of pics of my bikes present and past and head work I do. When your looking the red 98 Bandit is a bike I built for my son. I built that motor similar to my 85 GS1150. I liked it so much I am building one for me. A silver 02 Bandit with a 1340cc motor.

.

 

[geek]

Took my GS 1100 to the local dragstrip for test & tune this past weekend. It's a 1980 with a mild port job, 1mm oversize intake valves, 38 mm carbs from a 1150 and V&H exhaust. It also has a gsxr front end & Bandit swingarm. After some practice passes I laid down my best pass of the night. A 11:46 with a .04 light & 1.68 60 foot.

That's a good time. I've had mine into the high 11's, but rare.

 

[Rob S.]

One of the things I liked about the launch was that Nasty didn't seem to be putting much wear on the clutch (that's my excuse for not going to a strip).

But hey, what do I know? The only racing I've done has been on the streets.

Who just typed that?!? My account must've been hacked! I plead the fifth, your honor. :biggrin:

 

[trevor]

Thanks for the Video Nasty...what was your mph?

 

[glib]

repeat after me...
i will pull my clutch lever in after going through the traps.
seriously..your starter clutch hates you when you let the engine back down like that.

I don't know much more about bike mechanics than I have learned in the last couple of months owning these two GSs. Would you mind explaining why the starter clutch is affected as described?

 

[Guest]

I don't know much more about bike mechanics than I have learned in the last couple of months owning these two GSs. Would you mind explaining why the starter clutch is affected as described?

When you chop the throttle at 10,000 rpm the engine rpms drop fast. The big magnet and starter clutch try to keep spinning at 10,000 rpm even when your motor has dropped to 8,000 rpm. Not a good thing at all.

 

[Guest]

When you chop the throttle at 10,000 rpm the engine rpms drop fast. The big magnet and starter clutch try to keep spinning at 10,000 rpm even when your motor has dropped to 8,000 rpm. Not a good thing at all.

Just a side note, I pull the clutch in now as soon as I go through the traps & let the revs drop.

MPH on that pass does show up briefly at the end of the video. 113.11. I've since gone to a one tooth smaller sprocket so I can shift into fifth before the traps but everything seems to have slowed down. My et's, my 60's & my mph. I think I'll put the old sprocket back on. I'm racing this Sunday at Grand Bend Motorplex & will report back.

Cheers,
Paul

 

[geek]

113 MPH is good. Around 108 with my GS.

Not had a whole lot of problems with the magnet. I use the engines oil pump to feed the turbos, so cutting off the oil supply at full boost may not be such a good idea in this case.

 

[blowerbike]

average fast street bikes needs to go through in 4 gears(topped out)right before the rev limiter(1/4 mile).
the reason i say 4 gears is because if it is a street bike this still leaves you enough gear to ride around without the engine revving really high.
gear it to go through in 5 and you will no longer have a real street bike...you will hate it unless it's just for around town use.
also you need to check water grains and altitude each day you race so you know what to do on gearing/jetting or you will be chasing your tail-scratching your head wondering why the bike slowed or picked up for no reason.

 

[Guest]

I used to just switch the counter shaft sprocket. It was a quick and easy change. Now on my bikes with the the adjustable wheel base I change the rear sprocket. I very seldom use the same gearing or wheel base on the street as I do on the drag strip. It takes me a little less than an hour to switch the bike from street to track. But for those who just mostly ride their bikes on the street and don't care about getting the quickest time possible more or less just want to see what she will run then I would say just run with the gearing you ride with normally.