Cafe Racer Forum banner

1 - 20 of 59 Posts

·
Registered
Joined
·
13,809 Posts
16/33 i think for gearing. it will depend on how fast you are though. but a stocker can and should pull 16/33. also, i find it depends on where youre comfortable with making speed. since nhis is kinda technical and small, i personally like more grunt, especially out of the final corner and t2, going up the hill, out of the bowl etc. to me i like to gear for drive out of those corners as opposed to trying to make top speed at the stripe.

i ran a 2-1 mac style setup for the first few years. made by tom at delux works in california. he doesnt do them anymore. it seemed to make good power, but the real plus is that it was nice and quiet.



jc


aaron, send my wheel.
 

·
Registered
Joined
·
4,508 Posts
I run 15/36 at NHIS.

jc - Do you use all five speeds with that gearing? That's lower than I use at Mosport...

Craig
 

·
Registered
Joined
·
13,809 Posts
wow. chris said he used to run 16/33 i think but hardly ever touched 5th at nhis. just for a quick second. but thats the gearing he ran at daytona unless there was a tailwind. but yeah, thats what i run. i cant believe you can run that gearing especially with being able to, probably im guessing, pull another 2k on the clock. that thing i bet feels like it pulls stumps! i just set up my gearing for 16/33 which is one tooth shorter in the rear than what i was running. it might be a little long for louden, but im hoping its good for summit. i did order a 34 and also have a 17 front and a 36 rear. but that gearing seems to get me off the line pretty good, and im hoping it'll not seem so short for summit. (which i feel like my gearing is a little)



jc


aaron, send my wheel.
 

·
Registered
Joined
·
13,809 Posts
you know, now that i think about it, youre gearing is probably pretty close. since you can rev an extra 2k, and its giving you plenty of ooomph out of the corners. remember im running a stocker.



jc


aaron, send my wheel.
 

·
Premium Member
Joined
·
11,267 Posts
I run 15/38 at NHIS...can go 12k rpm if I have too.

Ok...here's the deal on gearing...and yes I'll claim to know what I'm talking about on this topic.

You ALWAYS...at any track, using fixed gearbox ratios....want to be geared so you just kiss your rpm redline at the fastest part of the track.
You NEVER want to NOT use top gear at ANY track. If you are not using top gear you are effectively giving away a gear to your competitors, you have just changed your five speed into a four speed.

You'll note that the fast guys have a selection of sprokets hung on their trailer wall, and notes on which gearing to run at what track.

NHIS is a "short" track, a "slow" track. It's the shortest gearing I run anywhere. I'll go to 16/38 at Mosport and Beaver Run, NHIS gearing at Shannonville short track.

At Loudon you want to be close to red line at 2/3 the way down the front straight, you want to just kiss top gear coming into T3, and you might touch top gear after you come down the hill in back and approach t10...depends on how good your line is that lap.

15/36 sounds right for a 350...they pull a couple k rpm less than my 175. Craig...what's that about 10,000 rpm?

NEVER GIVE AWAY ONE OF YOUR GEARS.
JohnnyB

PS. And be prepared to change that gearing as you get more skilled. Come out of t12 harder you'll get to redline sooner. If all of a sudden you find yourself topping out 5th 1/2 way down the straight...or feeling like you are running out of gears coming into three....hey you are getting faster, drop a tooth on the back sprocket.


Edited by - jbranson on Apr 03 2007 9:41:15 PM
 

·
Registered
Joined
·
13,809 Posts
i bet craigs bike will pull 12k. 95-10 is stocker redline. i think chris could pull 12 on his. i think his limiter might have been set at 115. but im not sure on any of that. i want to know more. ill count sprockets at the fat house this week.

jc

jc


aaron, send my wheel.
 

·
Registered
Joined
·
13,809 Posts
id just get 5th into t3. but id always run out of gear on the front straight. i was always looking for 6th gear. it was worse with my old gearing. ive run 3 different combos at nhis. the last one seemed the best but still off. 17/34. since i just bought gearing i asked chris alot about it. he said 90% of those big gear packs you buy are useless. he has always claimed to pretty much run the same gearing at every track with very minimal changes. now im not saying thats the best, or anything like that, but im not planning on changing my gearing dramatically from track to track if i find something good. any other opinions?



jc


aaron, send my wheel.
 

·
Registered
Joined
·
13,809 Posts
oh yeah, rosko, i talked to chris tonight. he has slippers and pvl plates. drop him an email.



jc


aaron, send my wheel.
 

·
Premium Member
Joined
·
11,267 Posts
Joe...if you are just touching 5th and feeling like another gear on the straight at NHIS then that's about perfect. Same thing on my bike...if I gear for t3 then I'm too short for the straight...if I gear for the straight I'm a bit too tall for t3.

Even Chris isn't going to win at NHIS with Mosport gearing...and no one will win Mosport with NHIS gearing. Depends on what tracks you race...I can pretty much use 15/38 on any technical track, 16/38 on any long (fast) track.

Some people can live with being geared too tall...if they are light and on a bike with some balls they can get away with ignoring 5th gear...but they are still giving away speed. There's a big reason race bike builders go to the trouble to install 6 speeds and close ratios.
If you are geared too short you are screwed...doesn't matter if you are Rossi, and engine only turns so many RPM before it blows up...or if it doesn't blow up it will just sit there giving away 10mph to the bikes around it and floating the valves.

I ran NHIS gears at Beaver Run one year....led the first three laps running the engine up to about 13k...then it blew up. Wondered why it was so easy to stay ahead of everyone....that is until it blew up.
JohnnyB



Edited by - jbranson on Apr 03 2007 10:21:16 PM
 

·
Registered
Joined
·
4,508 Posts
Chris could win at Mosport with what he uses at NHIS if his NHIS gearing is 16/33.

My bike's redline is 12k. But power seems to flatine at 11. So I shift at 11. I put the close ratio fifth gear in my transmission this year so my gearing may change. We'll find out at the trackday.

jc, did you end up building a LWSV motor to go with the new body work? If so you'll see that different gearing at different tracks makes a huge difference.

Craig
 

·
Premium Member
Joined
·
11,267 Posts
Rosko...I forgot about that.

For 4" disks I'd start with about 6 or 7 disks.
For 3" disks around 10-12 disks.

That should get you close enough that it won't hurt power.


Craig...let me rephrase that. "You won't win at Mosport with CORRECT NHIS gearing" :)

JohnnyB
 

·
Registered
Joined
·
1,735 Posts
rosko/jb-

for what it's worth, and i don't know how to start comparing 2-1 with 2-2, but i'm running 12 on each side of 4"ers on a 2-2. i started with 10 disks, stock jetting, and stacks, and was OK in the early morning practices, but boggy-wet rich in the afternoon at frontierland last fall. recently, i ran 12 each and rattled them a little loose at 50-70deg VIR and seemed pretty good....so i may add more as the temps increase? steven baker was at 12 too i think...but he may be running 3"ers?

and rosko, i've been running 16/34 and seem to be touching the top everywhere jb suggests, but i'm thinking i'll try 16/36 next time at NHIS to see what it does....damn i wish we had transponders.

and valve clearance on the followers? .002" intake and .004" exhaust.

-tt
 

·
Premium Member
Joined
·
10,737 Posts
i run the stock setup everywhere and at nhis i hit 5th just past the stripe (i go thru t10 in 2nd gear usually).....

texy
 

·
Premium Member
Joined
·
11,267 Posts
There is a ton of mis-information about trap disks and 2-1 systems. If you are running rich with 10 four inch disks then the problem lies elsewhere...that's enough for a V8 to breath out of.
For instance...I run 6-7 3" disks on a 2-1 209cc bike that I turn 12,000 rpm..and it makes about 25hp.

Secondly...you don't need more disks on a 2-1 system than you do on a 2-2 system. I've almost given up trying to explain this. Both cylinders DO NOT breath through the exhaust at the same time...so you do NOT need twice the disks. Unless two exhaust pulse enter the collector at the same time...you effectively have only once cylinder exhausting through the megaphone at one time.

There is no convincing people that big loud exhaust doesn't mean more power.

TT, you JET for weather changes, you don't change the exhaust (yes I know you know that). Change two disks out of 12 will make absolutely no difference in rich/lean except in your mind ( Don't take that in a mean way). Sounds like your bike is altogether too rich...just like most 350's I see on the track. You have to get jetting close before you can begin to do the very subtle tuning of the exhaust.
If your exhaust is ever wet sooty in ANY conditions then it's too rich by quite a bit. Trapps will make them look richer just because most of the soot hangs around rather than disappearing out an open meg.
If you dropped a couple of jet sizes you'd probably see more of a power increase than anything you can do with the exhaust. On race fuel the tailpipe should be a medium gray...might be light gray on a cold day....darker on a hot day.
You dyno tuned it to get the jets dailed in right?
JohnnyB

PS. I started my exhaust system at 1.250" OD...now I'm going to 1.125 OD...yes smaller..the same system used on Mary's 175...you know..the one Zack rode and did times that would pretty much trash the whole FCB field. And I'm even going to build and try a 1" OD system...which by the way is what Mike Rich recommended....and I don't know what to tell anyone that doesn't know what a tremendous tuner he is.
Last big bore 175 I had in the shop (240cc)...built by Craig Hanson out west...guess what...had 1" OD head pipes.

It's about hp, not size, not noise.

This is a biggie folks...a bunch of you could be going faster. Get to a dyno. I trust nothing but a lap timer and a dyno.

PSS. I'll edit yet again...don't want you guys to think I'm being nasty here. I just feel for you guys...a lot of you giving up performance. A lot of you guys are getting fast enough that it's time to give up the wive's tales and guesses and do some research and development. Think about it...what do all the fast guys have in common...they know their bikes extremely well, or have them tuned by experts. Seek out the advice of the guys that are going fast, or the guys that build their bikes. Attention to detail is everything.



Edited by - jbranson on Apr 04 2007 02:26:55 AM

Edited by - jbranson on Apr 04 2007 02:38:59 AM
 

·
Registered
Joined
·
13,809 Posts
i lost my free dyno connection. damned ross! my bikes a stocker but i built the frame with the intention of doing a lw/v1 motor one day. chris ran daytona gearing at nhis and still managed a uscra championship. and that was when it was hard to win at louden! and that was with a "4 speed". itd be alot like zach winning fcb on that pos he was riding though. i think put him on just about anyhting half way decent and hes the kind of guy who can do well. im sure weight makes a huge difference. think pedrosa is running the same gearing as hayden? anyway, late for work....ill count teeth this week. i have chris' bike at my shop. i agree with everyone.


jc


aaron, send my wheel.

Edited by - joe c on Apr 04 2007 08:38:12 AM
 

·
Registered
Joined
·
1,735 Posts
jb-

no, all's good. i appreciate the help. i wasn't suggesting anything for disks, just relating my numbers for discussion. i've never run a 2-1 so haven't even thought that through.

and yeah, i'd love some dyno time and would kill for a lap timer (one of the great things with WERA is the transponders). i'm not looking for loud or chasing wives tales really, but just experimenting and stopping once the thing is running well. my only testing is seat of the pants and plug chops. the plug chops are where i've seen evidence of richness paired with the WOT bogging...and adding two disks did something? the bike was good before baker ran over the old megaphones and when i switched to the marshall/branson exhaust w/10 disks, it got rich? i've already got the smallest mains i can find for the OEM carbs, i'm running cheap v-stacks and am looking to cut the screens out, if for no other reason than to keep H2O from hanging there in the rain(thanks tanner) but maybe i'll get more air? i've been running race gas for the lead, obviouisly not the compression, but MikeO and Tanner have convinced me to run pump gas with marvel if anything at all.

no doubt you're right about proper testing....i'll get there. and just to put things back in perspective from my POV, i'm just pulling my alternator this weekend and trying to get the rear brake involved enough to do a little trailing. no doubt i'm chasing my tail on some issues, and once my bike is really race prepped i'll be stoked, which will include a fresh top end, i mean i've got decent compression, but have no idea what else is going on in there. but it's still a real hoot working in that direction, a process after all, and i don't mind riding around some issues as long as i have a chance to work on my riding each time out.

wankin'along-
tt
 

·
Registered
Joined
·
13,809 Posts
dude, that sounds perfect to me! youll probably chase your tail until you get everything freshened. its tough to diagnose shit when there are things in question. especially if you havent seen it for 40 years in a row like other guys here. (frank) i dont think you really need to be worried about being fast enough. ya seem to have that covered!



jc


aaron, send my wheel.
 

·
Registered
Joined
·
1,295 Posts
I run 16-36 and hit 5th at the start finish every time Right now I have 7disks on my 2 into 2 exhaust. I plan on taking one off.I still run very sooty exhaust with my 110 jet.I'm still looking for something smaller.
 
1 - 20 of 59 Posts
Top