[Samir Shah]

Aha. So, since I have 12 degree spindles in there, if I measure my camber, and its close to zero (or less than 2), I will know if I have the ‘correct’ spindles for the way the kingpin C brackets are mounted in the chassis, is that correct?

Thanks Steen. I think that’s what I was looking for.

Samir.

[Samir Shah]

The kart is a Birel R31, but it appears to be a Brazilian made import, and is slightly different than the US ones, that came in with a direct drive Parilla Sudam 125. For example, it uses KG nerf bars, and Freeline front nerf bars wont fit it. The spindle C is smaller than the one on a US R31 that I looked at. So anything is possible with this. The kart is full of Birel parts though – gas tank, steering, braking system, etc but there is no chassis plate, no information about year, and tie rods are the only spot with information – they say Freeline Sudam!

There is no information out there that I can find about what angle the kingpin is set at for ANY Birel R31s, or whether they changed over the years, or if they were all the same, and therefore no information about what the spindles should be. And in any case, the Brazilians could have done anything.

Birels in general came with both 10d and 12d, and the Birel dealer that I took it too (at OVRP) just wanted to look at the old one and replicate that (ie 12 degrees). It seems to work, and my son is fast, but I want to be sure that it is optimized.  The owner at OVRP is fantastic, super nice and very helpful and kind, and gives me great prices, but openly admits he is not technical. He might have the part I need for the Birel, but I need to know what I want. He will hunt for parts that might work, but at the end of the day I have to know what I want. And they don’t know anything about Leopards – they are a Rotax track.

I therefore need to go back to first principles, and measure things myself.  Thus, in this thread, I am looking to learn what this number means – 12 degree spindle – and figure out whether it is appropriate for my kart. I am NOT mathematically or mechanically challenged, and have all sorts of race car engineering books from when I campaigned an Alfa GTV6 in time trials, but none of them cover kart engineering, and I’ve not found the right books yet for karting. Would recommend any suggestions there too.

I appreciate the wealth of experience on this forum, and have been learning a lot from the archives. I wish there was a search function.

I have been climbing a very steep learning curve over the past few months of kart ownership, and we are testing and racing every weekend till the end of May, at new tracks that my son has to learn, and are scrambling to get this kart reliable and setup so we can do reasonably well at 2 upcoming regionals – NJ Sprint Series at Millville, and F1 Gearup at Englightown – so I need to do all the work on the kart during the week, get parts in, and repaired before the next weekend.

I apologize for the bombardment of questions about a plethora of topics, but as I mentioned, its been a steep learning curve, and the kart is getting better and faster and more reliable everytime. I don’t have the budget for a tuner, and in any case there are no kart shops, (let alone 2 cycle experts) or even engine builders nearby.

So I have to do it all myself, gleaning information from the internet, and from the kindness of forum members that share their knowledge.
Thanks again for all your help.

Samir

 

 

 

[Samir Shah]

Lube: I found and tried out the Lucas Oils Chain oil 10014 product.

It’s amazing, worked fastastically all weekend. I was lubing after every race, and I suspect I did not need to do so every time- chain was always still lubed well even when coming off a 15 lapper.

Much cheaper than all the spray cans, very easy to apply, no wastage, and no mess from spraying.

[Samir Shah]

I found this on youtube. This is not my engine or video, but this is the same thing as what is happening on my engine. Starter spins, might throw a pop, might push the piston bit, but wont generate enough power to crank over the engine before the bendix retracts. Even with direct 12V to the starter.

On my other one, direct 12V to starter will make it keep turning over the piston and keep cranking.

 

Tried multiple starters.

So got to be the bendix.

So either something is the wrong size somewhere, its not aligned properly, or there is friction preventing the bendix from spinning up enough, and it retracts prematurely.

The bendix seems simple enough comceptually, so I’m loathe to just replace it. How can I take it apart? Maybe the spring is not the right one, too weak or too strong?

Anyone with a spare?

Thanks, Samir.

 

 

[Samir Shah]

Thanks. Will look around for aftermarket spindles. I managed to repair my kart at OVRP – they had a spare for the one I damaged, but that was just luck – at another track I might have been SOL, and I should get a pair of spares.

Any benefits to 25mm over 17mm spindles? Which application is better for a Junior karter in an full size chassis (Birel R31)? Thanks.

[Samir Shah]

I noticed a rattle on my engine too, and it was the chain hitting the top of the front sprocket cover. Maybe that’s your problem too.

 

Samir

[Samir Shah]

This is still not working – tried 2 new starters, they engage briefly, but no crank. So it must be the bendix. Grounds good, battery good, harness, etc, works just fine on my other engine.

Do these wear out, or just get dirty and clog? I sprayed it out with brake fluid followed by a teflon spray. Should I soak it in gasline?

Or do I need a new bendix?

Thanks

[Samir Shah]

What is Junior 3? There is apparently a 30mm header for Junior 3.

[Samir Shah]

This is from a newbie, so take it with a grain.

– When I ran my engine with bendix in place but no starter, there is a rattle. Maybe the bendix is not in position correctly?

– Does the clutch drum have play? Can it be pulled outwards by a mm or so? If so, you washer under the needle bearings could be inverted, and the cone part of the washer is facing the wrong way.

Samir

 

 

 

[Samir Shah]

I am being told that if I bore it out, it is no longer ‘legal’.

I’ll just move the 28mm one I have around between engines until I find a used one. Pain, since I have it safety wired.

[Samir Shah]

I am set with this. A member has offered me a broken one, and I also picked up a new one off ebay. Thanks.

[Samir Shah]

Thanks. I’ll have my son test both flex, and see if he can make out the difference. Since we’ll have a restricted header, it could be interesting.

On a related note, is the silicone sleeve over the flex needed? Can I use either nothing, or header wrap? I see exhaust gas leaking from that area, will it make a difference?

Thanks again.

[Samir Shah]

So, I took apart the starter again, and found the problem – the magnet ring inside the starter had broken and fallen apart, and was rubbing against the coils of the starter armature, causing friction, and thus reducing the power of the motor, which now was not strong enough to get the bendix spinning fast enough.

Anyone seen this before? Can a replacment magnet ring be found, or is this starter toast?

Thanks, Samir.

[Samir Shah]

Been reading old posts – and they are pointing to either a bad ground, or a bad bendix.

Will tackle these tomorrow.

Anyone with advice on how to most easily remove the bendix? And how does one clean and test one?

Thanks, Samir.

[Samir Shah]

I just shipped an adult kart seat. I used a box from a filing cabinet, was a perfect fit, and the box was nice cardboard, so the seat was protected.

[Samir Shah]

Hi Joe. Thanks, but I got one over the weekend.

[Samir Shah]

Next, I think I’ll have to remover the starter again, and maybe rebuild it with fresh brushes.

Will fresh brushes take care of any dead spots in starter? The brushes I repaired were curved from wear but had a fair amount of depth left. Maybe the spring on 1 side did not get fitted properly?

How can I test the armature to make sure it is ok?

Thanks, Samir.

 

[Samir Shah]

Thanks.

I removed the sprocket, Bendix cover and clutch drum – starter gear looks straight, no broken teeth either.

I checked for spark – its there.

Fuel is flowing and there is suction from the carb.

Battery is good.

I had repaired the starter brushes, did not replace them.

I played around with trying to start w/ a little throttle. That seems to have helped. I got a few incidents of a single pop and flame from the header.

Once the motor actually ran for 3-4 pops, and died before I could catch it and rev the engine.

I tried the direct wire to starter. On this engine, same thing – clang or richochet or one pop.

I see what you mean – engine should keep cranking – I tried the direct wire to starter on my other engine (off the kart), and it kept turning the engine over.

So the problem lies in starter, or bendix. Could it also be a carb issue?

Samir.

 

 

 

[Samir Shah]

Thanks Tony. Great links.

Yes, that was the only chain test tool I found, but there was no link to purchase it, so I sent them an email. Waiting to hear back. In the meantime, it gave me ideas, thus the 3 methods I listed. I think measuring with calipers might be the way to go as it can be done on the kart.

Samir.

[Samir Shah]

No, I had it misaligned (I sighted by eye and spun it – a no-no for a newbie) and also did not have the right lube. I was used to 4 cycle guys using Triflow, and that’s what I used.

Had the alignment been OK, it would have probably survived. But, the clutch gear got chewed up and stripped due to the alignment (and presumably the chain was toast at that point too). Then I put in a new 10T gear, made sure it was aligned, but used the same chain, since it was ‘new’ and only had 1 session on it, and the 2nd 10T also got stripped, this time presumably by the stretched chain.

Then someone experienced (thanks John Ferris) took a look, identified the dryness of the chain, and educated me on what was happening. New chain, new gear, new sprocket, new can of proper lube, and not only did the kart run well the rest of the day (4 more sessions), but my son also won the feature race in his first race in a Leopard (yeah, yeah, I’m a proud dad and can’t believe it or get over it).

I understand the problem now. My learning curve in the past 2 weeks has been steep! And I’m glad there are such nice helpful people at the track, else it could easily have been very frustrating.

Samir.

[Samir Shah]

So, I think I answered some of my own questions.

Chain stretch – 3 ways of measuring or at least identifying;

– I used a straight metal ruler. Put a new chain against it. End to end, the new 219 chain fits exactly in the center of 2 pins. Next put the suspect chain against the ruler. If the chain pins overhang the ruler, it is stretched.

– I also put the new ‘benchmark’ chain directly against the suspect chain to verify that it was stretched.

– I then wrapped the chains, one at a time, around an entire new rear sprocket. and held the excess chain tight against the sprocket with with one hand. A new chain could not be lifted off the new sprocket and fit tightly, the used chain could be lifted off the teeth of the sprocket and had play.

Now to figure out how to tell if a sprocket is still good.

Samir

[Samir Shah]

This is timely. Ted and TJ – my son has been bugging me to get his helmet painted. We’re waiting for fall when the 2015s come out before we get him a new lid – he’s 13, and we’re hoping to get 1 more year out of the current helmet by removing padding.

Can you PM or email me with some price ranges, so I can budget it for it once we get a new helmet.

Thanks, Samir

sshobby100@gmail.com

 

 

[Samir Shah]

Hi. Still have the wheels? Are they magnesium or aluminium? What sizes are they? Thanks, Samir.

[Samir Shah]

Thanks. Yes, I used the silver based solder that I use for my audio stuff. It takes about 750-800 degrees to solder anything 18g or thicker, vs 400 for the old leaded stuff.

This is on my backup engine, so I won’t know for a few months how well this worked.

[Samir Shah]

I have one but it’s not for metric wheels. I ended up using the front hub on the kart instead to balance my wheels, and it works that way too.

Samir

[Author]

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