Author Topic: Let's go roadracing...continuing saga (Read 194017 times)

Tintop · « **Reply #150 on:** June 19, 2011, 05:33:40 AM »

Excellent news Brent.

Does that mean the 'Runway Romp' is on the calender, as a pre Mosport prep.; or are you going to do a track day test session? If an extra pair of hands would be helpful, let me know.

Quote - ".....and I'm armed to the teeth with carb parts." At the rate your aquiring VM29 parts, your going to become the NA source.

tintop

bwaller · « **Reply #151 on:** June 19, 2011, 07:09:41 AM »

I may need a re-think on the chain slider deal. I'm going to replace the plastic?? material there now with some Delrin, plus machine some to re-cover the double bearing roller I tried first. I thought about making a Delrin sprocket too but that's getting more complicated than it needs to be. I like the roller idea best. It isn't a tensioner really but a means to take up some chain slack because with the longer shocks/swingarm position, the chain loosens with more travel.

Brian, I registered for NB. There is supposed to be a trackday @ Mosport the day before the VRRA round. Saves a whole lot of driving.

turboguzzi · « **Reply #152 on:** June 19, 2011, 02:28:49 PM »

i've been living with a fixed delrin chain slider for four years on my 500 racer and only now it looks like needs replacing.

built one for my current 750/810 kawi and it indeed suffers a bit more but should last a good season or so.

all dirt bikes, including big bores like KTM's Adventure, etc. have fixed sliders and live with them rather well.

Would be more worried with the stratospheric RPM's that a roller tensioner has to work at.
TG

MRieck · « **Reply #153 on:** June 19, 2011, 04:04:21 PM »

Happy to hear of your succes Brent. Those Ti nuts will drop lap .5 seconds.

Tintop · « **Reply #154 on:** June 19, 2011, 05:09:44 PM »

Given fuel prices these days, keeping the extra miles to a minimum makes sense. Depending on how many sign on for the VRRA/Mosport SOHC Ride-In, I may be there on the Thursday.

Quote from: MRieck on June 19, 2011, 04:04:21 PM

Happy to hear of your succes Brent. Those Ti nuts will drop lap .5 seconds.

Ti nuts, 6 spd, piles of rev's now, sounds like its time for some fun with the kiddies.

Jon · « **Reply #155 on:** June 20, 2011, 01:33:17 AM »

I set up a chain roller on a dirt bike & had all sorts of trouble with it until I sat the bike up on a stand disconnected the back suspension & worked it through the full suspension range.

The tightest point on the chain was quite different swingarm angle than thought, adjusted the chain to be slightly slack there, reconnected the suspension & measured the chain slack @ full suspension travel & used that to adjust it.

No more trouble, not saying that is what your trouble is but thought it may help.

Cheers
jon

turboguzzi · « **Reply #156 on:** June 20, 2011, 01:42:04 AM »

Quote from: Jon on June 20, 2011, 01:33:17 AM

I set up a chain roller on a dirt bike & had all sorts of trouble with it until I sat the bike up on a stand disconnected the back suspension & worked it through the full suspension range.

The tightest point on the chain was quite different swingarm angle than thought, adjusted the chain to be slightly slack there, reconnected the suspension & measured the chain slack @ full suspension travel & used that to adjust it.

No more trouble, not saying that is what your trouble is but thought it may help.

Cheers
jon

+1

many people dont realize how much tighter the chain gets when the swingarm reaches the point where all three axes align (sprocket, S'arm pivot, wheel axle) and the only way to really know is by removing the shock(s) and lifting the swingarm by hand. compressing the bike by stiing on it, etc. will not get the swingarm to that critical tension point.

you just need to do it once and then just right down the ammount of chain slack with s'arm is in the regular position.

bwaller · « **Reply #157 on:** June 20, 2011, 04:23:07 AM »

Thanks guys. Agreed, this was an exercise I went through while building it, the chain does need a lot of slack@ zero load to allow for the point where the pivot points align.

The slider material I have now wore quickly where the link plates run but once the rollers touched down it should have lasted a lot longer, but I'll try the delrin, sounds like it will be a better choice.

MRieck · « **Reply #158 on:** June 20, 2011, 04:38:49 AM »

Look how much slack is run on Motocross bikes.

simon#42 · « **Reply #159 on:** June 20, 2011, 10:06:44 AM »

brent , could you make a smaller chain slider? the one in the picture is very tall and the chain is having to pull across it at a very acute angle .

bwaller · « **Reply #160 on:** June 23, 2011, 11:00:36 AM »

I was booked for dyno time this am, everything warmed up and on the first pull the computer and dyno stopped communicating. After an hour fooling about, I left unsatisfied....again. Last time it was an ignition module.

Remember the kid on Charlie Brown named Pigpen who had the dark cloud always follow him overhead. I'm starting to feel a bit like that.

TimV840 · « **Reply #161 on:** June 23, 2011, 11:54:10 AM »

I thought you looked familiar!

That sucks Brent...how far away is the dyno shop? That would really suck if it happened to me, since the closest place is at least 3hrs from here....

Hope you have better luck next time,

TimV

Quote from: bwaller on June 23, 2011, 11:00:36 AM

Remember the kid on Charlie Brown named Pigpen who had the dark cloud always follow him overhead. I'm starting to feel a bit like that.

paulages · « **Reply #162 on:** June 23, 2011, 12:20:06 PM »

Quote from: bwaller on June 23, 2011, 11:00:36 AM

I was booked for dyno time this am, everything warmed up and on the first pull the computer and dyno stopped communicating. After an hour fooling about, I left unsatisfied....again. Last time it was an ignition module.

Remember the kid on Charlie Brown named Pigpen who had the dark cloud always follow him overhead. I'm starting to feel a bit like that.

Hey, at least it's a dark cloud behind you and not a dark puddle of oil below like me...

Sam Green Racing · « **Reply #163 on:** June 24, 2011, 04:36:25 AM »

We didn't have any problems with the dyno breaking down in the old days.....................
.............we just didn't have a dyno.

Sam.

bwaller · « **Reply #164 on:** June 24, 2011, 04:49:52 AM »

I have some oil showing too Paul, but nothing much to complain about honestly. This dyno was 1.5 hrs away, I'll set up time at another shop for next week, eventually things should work out.

Next outing in a couple weeks.

Yesterday I told the operator to roll the throttle on with these carbs, but they all have a mind of their own. Even cracking the throttle WFO from way down the rev range in top gear it pulled very well with only a slight bobble, probably on the needle, through to the rev limiter. I feel the ignition is in "happy land" now, plus I'm hoping I'm pretty close with the carburetion by the look of the plugs.

Sam, I thought this exact thing yesterday on the way home. Quite frankly I could dial this in close enough now, but letting the sniffer tell us exactly where it needs to be and getting it over in a couple hours appeals to me....spoiled I quess.

Tintop · « **Reply #165 on:** June 24, 2011, 02:53:49 PM »

Nice to hear that the ignition issues seem to be put to bed, and you can get to that missing top end. Now your really going to scare the kiddies in NB.

+1 on the dyno and getting it right, and over with in a few hours. Biggest problem I found, was locating a shop that will do a carb'd bike, majority only do EFI now.

bwaller · « **Reply #166 on:** June 28, 2011, 07:52:36 PM »

Any dyno information I've gathered is from here, so an expert I'm not. I took my bike to a different shop today and immediately was told my time was limited. (should have booked a morning appointment) The owner is a great guy but high reving fours are foreign to him.

Considering it was necessary to unstrap the bike to bump start each time, I had to focus on carburetion only. Not horrible considering there has never been issues with detonation and I felt the ignition must be close.

After five sets of pulls and wholesale jetting changes the engine now revs very cleanly through to the limiter. And this by cracking the throttle WFO from 5000 rpm and not just rolling it open. My goal was to see 60 hp with foam dual sock air filters in place. Fell short at 59.4 and torque of 35.7. I tell myself with time enough to try different ignition settings, plus any & all the other possibilities, there is very likely a little more to be had. I never even took time to try other plugs. Someone with 4 cylinder dyno tuning experience would have been invaluable.

Bottom line is I'm happy tonight. Air/fuel isn't perfect but at least I know what may be needed to make changes on any given day for atmospheric changes. It'll be a whole lot nicer riding this bike now.

I took a stab at designing a set of 30mm long velocity stacks to fit the smoothbore inlets perfectly so here's a couple pics of those.

fastbroshi · « **Reply #167 on:** June 28, 2011, 08:22:37 PM »

Blips aside there at the end, that's a great curve Brent. Did you ever get a chance to weigh the ol' girl?

Tintop · « **Reply #168 on:** June 28, 2011, 08:27:59 PM »

Well done.

Don't think getting to 60 is going to be a problem, as you say there are still lots of things to tweek. Should make the next outing more fun > more engine = bigger smile.

Do post it to the dyno thread.

I'm thinking from your description, the dyno operator was more familiar with twins of the V variety.

Andrew is still suffering the effects of his get off, so I'm looking around. Seems most are either EFI guys, or V twin guys; the operators weren't born when the bike was built!

Stacks look great, very nice fit.

turboguzzi · « **Reply #169 on:** June 29, 2011, 02:48:01 AM »

Hi Brent,

60 is not bad at all, though to better understand how your powerband looks like, a torque curve is quite important.

It can be derived from the HP curve, just dividing the hp by rpm.

from all i hear & read, AF graphs with our carb type are pretty meaningless, so you really need to jet for max top end swapping jets next time. I picked up 10% doing so.

would do a run without the stacks too, the graph peaks towards the end make me think that you have some strange resonances going on there

bwaller · « **Reply #170 on:** June 29, 2011, 03:28:45 AM »

TG. I just ran out of time to make a run without the stacks, but at the very end I pulled the foam off the stacks and lost 1 hp. I was most concerned just to clean up carburetion and the result seems good.

There probably is a better path I should have followed working on the dyno. This place is accessable and inexpensive since the owner just worked the computer while I ran the bike then disappeared while I made adjustments. Maybe it'll be worth a re-visit some day.

fastbroshi it weighs 322lbs dry with fairing & bellypan.

EDIT: I'm not sure why an A/F reading is meaningless, it was mostly what I was looking for going to the dyno.

The very first run the top end was perfect but was way rich on the needle. Ultimately every time you make a jetting change to alter one circuit, it has an effect elsewhere. I made sure to make one change at a time and dropping the needle 1 position started to lean out the mainjet. Lowering the needle again further took two sizes larger on the main. The last change I installed 1 size larger airjet instead which cleaned up the needle circuit but shows I may be still slightly lean on the mainjet.

I found the exhaust sniffer helped a great deal even if it may not be completely accurate. But as I mentioned.....I'm all ears.

Bill/BentON Racing · « **Reply #171 on:** June 29, 2011, 05:09:44 AM »

Way to go Brent.#$%* to pull it off to crank tho! ::)60 rear wheel HP with 322(50lbs less than mine w/fluids)! I know it puts a smile on your face @ 7500-10,000rpms.

Bill

MRieck · « **Reply #172 on:** June 29, 2011, 06:03:13 AM »

That's a good start Brent. Some fine tuning on the main will get you over 60. Also...the engine is still breaking in and will loosen up releasing some more HP. Looks good buddy!

kayaker43 · « **Reply #173 on:** June 29, 2011, 07:18:07 AM »

Brent, Just an observation,.. you are making 30 HP between 6-8K and only 10 HP from 8-10K. Getting near 60 HP with nice tractability is a great thing. However,. that's a pretty civilized powerband and might not really benefit as much from a CR 6 speed? It looks like a mismatch?

I ran a Yosh TT cam and played around with retarding it even further for crazy top end. I also had shorter intakes and real short exhaust primaries so It had a powerband like a motocross bike, and 8-10K is where most of the power was. The CR trans was necessary to keep me from falling out of the sweet spot.

I'm surprised how many race builds end up being torque monsters and wonder why people build street bike powerbands for the track? I suspect its because available cams and headers are typically street performance items and intake tract lengths come optimized for midrange? I was happy enough with the TT cam but when I added the short Yoshima race pipe and short intakes it REALLY woke up on top and I realized what CR gearboxes were really made for.

A tight close ratio trans gives you the big advantage of being able to intensify and focus all your power up into a narrower rpm range and keep it there. That's not such a big advantage if your powerband is a mile wide.

turboguzzi · « **Reply #174 on:** June 29, 2011, 07:59:57 AM »

kayaker,

have a look at the torque curves of any road racing two valve motor and they all look the same, kawis, ducs, suzooks, what have you.

being limited in valve area, 2-valvers deliver good volumetric efficiency at 3/4 of rev range and then taper off towards top end, just not enough valve size + you are also limited in overlap by the included valve angle so you cant go wild with cam timing as in a four valve design.

this bulge at 7.5K is going to be even bigger with a big bore like brent's got with not much larger than stock inlet valves.

How much HP's you got from how many C.C.'s in your bike? could be nice to see the torque curve with your retarded valve timing.

TG

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Author Topic: Let's go roadracing...continuing saga (Read 194017 times)