[Samir Shah]

We’ll be back at OVRP this coming Sat to practice and set up w/ the iKart/Leopard if you are around. #3 kart. Should be at the next race again, either w/ a Rotax, or a TAG Leopard.

Yup, I’m shopping around for Jr engines and upgrade kits.

Samir.

[Samir Shah]

Christian, you must be Aiden’s dad. I noticed him at OVRP last weekend.

We rented a non-EVO Rotax Jr Birel RY30 from Peter at OVRP, and ran in Rotax Jr. Spent the first 2 sessions jetting and gearing the engine to get rid of flat spots and bogging. And the new 11T sprockets were defective, and kept tossing the chain. So we missed a practice as well. Then it rained, and that was a new experience as well, to compound the Rotax experience.

Up to that point, my son did not like driving it, and he was ready to give up, as was I, due to the gearing hassles.

About halfway into the feature, while running last, he suddenly got the hang of the throttle, and started pushing and managed to pass 2 other kids, and now likes Rotax. Both of us think we need the EVO though.

So, I’m trying to decided on whether we try and rent an Jr EVO engine next, or just buy one. Of course, the EVO upgrade special has expired, and now they cost a bomb!

Know anyone with an EVO Jr kit that they got at the special price that they are not using and would sell?

Samir

 

 

[Samir Shah]

So, we switched from a Birel R31, which is a stiff chassis, to an iKart, which is very soft (28mm) and can twist a lot. He is still sawing and over steering in the turns. I’ve come to the conclusion that the problem is in his driving style, and he needs to slow down entry into turns, turn the wheel less, and get a LOT smoother.  Rather than adapt the chassis to his style (he is faster with a stiffer rear, but this likely means an overall slower kart), I am going to work on getting him to change his driving style to get faster with a faster/softer kart.

 

Samir

[Samir Shah]

Can you guys share your fulcrum arm position and popoff value? Thanks.

[Samir Shah]

Thanks. Very helpful.

[Samir Shah]

Still having carb problems, and attendent lack of power, and have learned how to service the carb. Discovered that the screw holding the pivot arm in the carb was stripped, and loosening up – it was a US size – 40 something – so I tapped the hole with a 3mm tap, and used a 3mm screw, and that is fixed now.

I found this document on EC’s website, that I think is very valuable. Thought I would share it. If you page, has information on HL carb blueprinting as well.

http://www.eccarburetors.com/pdf/EC%20speed%20secrets%2093.pdf

I need to get my son to reach over and adjust the carb while he is driving. The problem is that the seat is too far forward, given his 5 ft height.

Samir.

[Samir Shah]

I recently experienced something like this in a club race, where 3 Leopard classes – Junior, Senior and Shifter were mixed in one run group.

I don’t think there is any problem with younger kids running w older drivers, as long as you can figure out how to equalize performance.  And they should be racing as one class. But, I suspect the kids will be faster in many cases, raising objections from the adults!

On the other hand, within the senior class, I’ve seen very different driving and objectives from the younger group of seniors (say 17-25yr olds – out to prove something; very rough; lots of banging and pushing; no sense of mortality) versus the older seniors (out to have fun), which might put the pre-16 drivers (who don’t bang as much as the 17-25 year olds) in a dangerous spot.

At my previous club, we ended up splitting the seniors into 2 groups for this reason – a ‘Mediums’ for everyone, and a ‘Senior’ class for those of us that did not want the banging.

The issue I had with my most recent experience was that they had 3 classes mixed, with 3 different results tables, and the slower drivers were blocking faster racers from another class from passing, making for a dangerous situation, for example when the shifter missed a shift forcing my son to decide to either hit him or go off track (which he did), costing my son the win in his class.

Once people move into ‘cars’ or ‘open wheel’, the consequences of touching are much greater, and the intentional banging that exists in karting goes away – then you can mix young and old, as touching is not acceptable.

Samir.

[Samir Shah]

Thanks. That’s a great tip. Samir.

[Samir Shah]

Please let the admins know of this – David Cole.

Do you have his ebay id?

[Samir Shah]

Thanks TJ.

What about going from 17mm to 25mm stub axles. That should increase front grip too. Will it help with rotation?

Seat placement – I installed it so he can see properly and reach the pedals, with no other science involved. We scaled it at 43/57. I also welded tabs all over the place so I can put weights anywhere to get it corner balanced. As it turns out, he only needs about 10 lbs of weights, so only have 1 7 lb weight on the back of the seat, and use the fuel for the rest.

Any docs out there on how to install the seat?

Thanks, Samir.

 

[Samir Shah]

Hi Patrick. You are correct, I meant he was driving it hard and countersteering. I think the rear is sliding instead of gripping and lifting the other wheel.

We did have the front wider, and narrowed it, while increasing the rear by 10mm, and he likes it better wih the front narrowed.  We tried increasing castor (to max), but he only got slower – did not like it, prefers neutral caster.

The other kids literally get their topkarts’ inside wheel to life 4-6 inches off the ground (they have 50mm axles, I have a 40mm).

Should I see daylight?

I was going to try:

– widen front by 5mm each side

– add front torsion bar

– try caster at 7.5pm/4.5pm (instead pf 6pm when facing front).

Would bigger rear hubs help by effectively stiffening the axle?

Thanks.

[Samir Shah]

Thanks. Nicely put together. Good luck racing!

[Samir Shah]

I thought about also going to a 10mm kingpin, but that involves additional costs of a new kingpin, pills, spacers, and also I will have to drill out the holes in the chassis bracket that take the kingpin, so it will not be reversible. This way, I can use the 25mm for when my son needs more grip and switch back to 17mm when he does not. Or at least try both and decide which works better for my son.

[Samir Shah]

Where do you get the red handle low speed needle that is the P1 video? Mine is just a screw and impossible to adjust while in the kart.

[Samir Shah]

Paypal has refunded me too.

 

Samir

[Samir Shah]

Thanks. Maybe we hold off on Rotax this year.

[Samir Shah]

This still available?

[Samir Shah]

Thanks David. That is interesting. Can you share what you mean by under the Birel banner?

I see from old news stories that you tested one when they first came out in the early 2000s. Do you recall how they might fare today?

Thanks, Samir.

[Samir Shah]

Fred, contact me via email and I’ll give you my phone number and walk you through how to place the claim on paypal.

 

Samir

[Samir Shah]

I WILL DOUBLE THAT BUYER BEWARE – SAME STORY about POSTNET, no tracking etc.

I am trying to get refunded on a Leopard engine purchase from Dacey.

He has gone silent.

Samir.

[Samir Shah]

How many hours on the engine? Can it be converted to Junior and still be legal under current rules? (I don’t know much about Rotax).

Can anyone put on a JR cylinder, or does it need to be done by a Rotax certified shop – ie is the seal on the bottom end or top end?

[Samir Shah]

Another useful link.

http://www.arboristsite.com/community/threads/tillotson-hl-carb-rebuild-w-pics.64450/

[Samir Shah]

Thanks TJ. He is very cautious and in general a very clean driver. He does not have it in him to bump a driver in front, for example, or make any contact at all. I agree, he needs to work on his passing, and anticipation and setup-for-pass skills, instead of just following.

[Samir Shah]

Hi Mark. I’ve been going through the starter system on my engine, and have kind of figured it out.

Is there any life at all when you push the button.

A) Check the voltage going to the starter, either at the plug, or at the screw/blade on top of the starter when you press the button.

If power is getting to the starter, and its not spinning – then the harness and switch are fine.

B) Take the starter out. See if you can spins it by hand.

If it does not spin by hand, then the bearing is broken, or a magnet has come out inside the starter and jammed it up. You need a new starter.

C) Next apply power directly to the starter from a battery – positive to blade, negative to body of starter.

Does the motor start and spin? If is does not, then you need new brushes. Or your armature is shot.

D) Going back to A). If no power is getting to the starter, then most likey you have an intermittent break in your harness somewhere. A pin or connector in a plug might be loose, corroded, etc. Inspect it all closely. Play with and twist connectors and wires to see if it comes alive.

A weak battery will still make noise from the starter, and a ping or single crank from the engine, but it wont catch as there is not enough power to spin the bendix enough.

If it pings, try hooking a car battery to the system with jumper cable. That will have enough cranking power. If the engine starts, then you have a weak battery with not enough current.

E) Take out the bendix gear reducer. Clean it in gas. Many times. Also clean out the space it lives in. DO NOT LUBE IT. Dry it with air. See if it spins. Oil can coagulate and jam it up, and prevent it from reaching the flywheel.

In my case, it was many things – broken magnet inside starter, broken brushes, AND a bad bendix. I’m now waiting for a replacement bendix.

Stator is for charging the battery, so not relevant here. Coil is for firing the spark, so not relevant here. Both these parts have nothing to do with spinning the engine for starting.

 

[Samir Shah]

Can you verify my understanding: To get more jacking at the inside rear, I would need more castor – ie kingpins angled towards the driver.

Would one ever run different caster on each side? Since the tracks are counterclockwise, you need jacking on left side, rarely on right.

Would making the rear axle stiffer help in jacking the inside rear wheel?

Thanks, Samir.

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