HOW TO: Tune The KA100 Tillotson Carburettor - POWER REPUBLIC

This week we're debunking the Tillotson carburettor for the IAME KA 100 engine.
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[@stevenperryman660]

Thank you for the reply! No lambda sensor since I bought the Micron 5 without that feature for my Rotax Evo (I had lots of jetting data on that engine already). However, your response reinforces my understanding that very small movements are needed to tune the Tillotson. Should be an interesting winter; this summer had more 100 degree + days than any other in our recorded history and we sometimes get a light sprinkling of snow in January or February.

[@PowerRepublic]

Hey steve, yeah that is some huge variations. I havent been karting in the snow, could only imagine how your finger feel after that session

[@chrisburnsed6349]

Excellent video! Simple explanation. 👍

[@PowerRepublic]

Thanks Chris, if you have any more questions please ask. And if you know anyone that would find the vid useful please share it for me.

[@elrafagonzalez79]

Sencillo, simple y preciso! Saludos desde Venezuela

[@PowerRepublic]

Gracias compañero apreciar las vibraciones positivas

[@A1UTV]

How exactly do you set that pop pressure? I’m working with a HC-102a and curious how the pop pressure is set. Thanks a bunch.

[@drewjames4316]

Hey, im moving up to Iame X30 jr and i was wondering if maybe you guys could do a video about like basic service and how to just check over it and stuff. Thank you

[@PowerRepublic]

Hey Drew, great question. we don't have the x30 junior here in Aus, but I reckon it will be very similar to the KA100, X30 and Tillotson vids we have for you to check out.

[@jimmydcricket5893]

Cool, now I have a better idea on the Echo chainsaw carb, CS100 with Tillotson carb.

[@PowerRepublic]

Jimmy D, Did it work? that sounds like a racing chain saw?

[@3dsignsolutions986]

Thanks for the video. Can you use the same setting when a restrictor is installed?

[@PowerRepublic]

Sure can. The best is to get an Easitune or Mychron Lambda sensor so you can see the engine tuning in real time and adjust as necessary.

[@pippen001]

Can you give some insights on the lamda and egt values you should be looking for when tuningthe carb?

[@PowerRepublic]

lambda is easy, 0.97 -1.02. EGT most people I know look for about 650c. I don't use EGT often as it is too vague IMO, but with some practise you could find some solutions

[@EugeneHavenga]

Hi Derek, thanks for the great videos that you post. Do you have any info on the carby setup for a ROK VLR 100? I have heard they said that they are very similar to the IAME KA100 but there is a slight difference. Any info would be appreciated. Keep up the good work!

[@PowerRepublic]

Hey Eugene, you are very welcome. Unfortunately we don't have those in Australia yet. Maybe you could talk to the guys at Vortex and get them to send us one for some videos 😂

[@EugeneHavenga]

@@PowerRepublic haha funny man! Thanks for replying!

[@carsonsauterracing28]

Very good video, would I use these same carb settings if I were in America at a low elevation?

[@PowerRepublic]

Hey Carson, I would start there. your ambient conditions would be similar to ours. but I would always use a lambda LCU 1 kit if I was you to get your tune spot on the money! hope that helps. DEZ

[@R.B_B]

Anyone. Know how to calculate the right pop off pressure for a carb in a modified engine?

[@joshburns9022]

Hi Derek, Great vid. are your baseline settings different now that we're running 22mm restrictors?

[@PowerRepublic]

hey josh, yeah still not much change from the older restictor . for ultimate tuning use the lambda gauge IMO

[@pauloagurto7154]

about pop off 10 to 8.2 is ok for ka100 Senior? with the spring of how many grams do you get to that pop off pressure

[@PowerRepublic]

we use the standard spring, and cut or stretch the spring to suit. otherwise I have used the 31gr spring as a replacement but it will need to be modified on most carbs to get the pop pressure correct.

[@ksundar6594]

Hi, great video. I rebuilt my Tillotson carb with a new diaphragm and it seems to be running leaner at same jet marking location prior to rebuild. Does that seem possible? Also at one point in the road race track my exhaust temp goes up high (around 1280F). If I make the high speed jet richer to bring this temp down, will it make the kart run way richer at other points in the track? How to handle this scenario?

[@PowerRepublic]

yeah could be possible. did you alter the float lever at all? otherwise richen the high as needed, then reduce the low to suit the slow corners. boom

[@paulogt007]

how can you change the popoff presure ? and wath are the corrects jets for a KA 100?

[@PowerRepublic]

Hi Paulo, you change the pop-off pressure by cutting or stretching the little spring under the lever. Start with the jet at 1.0 turns open on each jet. then adjust the High Speed needle a few minutes at a time leaner or richer depending on how it feels. Ideally you would use a Lambda gauge and measure the O2 readings and adjust to suit based off of that. Hope that helps, where do you race at?

[@basili010]

I can disassemble through the top of the carb without moving the settings for cleaning? Saludos

[@PowerRepublic]

Hola. Yes you can remove the gasket and fuel pump without even removing the carb from the engine. And leave the jet settings as they were. Hope that helps

[@stevenperryman660]

Folks -- I've got a VLR100 with a similar (identical?) carby to the KA100. Problem: At our Tucson, Arizona, track our density altitude can swing in one season from near 7,000 ft. down to 2,500 ft. This make as BIG difference in jetting for for my Rotax Evo. How about the jetting "range" (number of minutes lean to rich) for these Tillotson carbs?

[@PowerRepublic]

great question my friend, however we don't have those conditions here. we are pretty constant with air pressure, our only variation is some humidity. this we don't really need to accommodate for. So in answer to your questions, I'm not sure, but maybe you could open the HSJ by 2-4minutes as a precaution. are you using a lambda sensor in the exhaust?

[@johnruess9699]

Because pop off is a pressure differential, elevation does not have a comparable effect to slide carburetors. The pop off will measure the same at any temperature and elevation.

[@stevenperryman660]

@@johnruess9699 Thank both of you guys for your answers. By the way, GREAT video; when I rebuilt my carby, I followed it religiously.

[@kennyelwood7007]

Can x30 senior carb tuning be close to the same as the ka100 ?

[@PowerRepublic]

Hi Kenny, in regards to A/F ration or the jet settings?

[@kennyelwood7007]

I’m regards to The needle settings . Low end 1.5 and high end .625 . For x30

[@PowerRepublic]

@@kennyelwood7007 normally I use 1.0 on the low and 1.5 on the high for the new X30. it has been a while since I have used one so double check that. when in doubt start rich and work backwards, preferably with a lambda sensor or more preferably with an Easitune.

[@kennyelwood7007]

Power Republic : ok that is where I normally run it . 1.0 low and 1.5 high .it seems to feel good power . But at that setting The water temp would only get around 120 and egt around 910 .

[@kennyelwood7007]

What tips would you have for me learning how to tune the carb by feel. What would it feel like lean vs rich ?

[@Will-tb8vi]

Hey I was wondering if you knew anything about the old Yamaha Kt100j motor tuning? People keep pulling away from me on the starts and down the straights and I'd like to get a bit more power.

[@PowerRepublic]

yeah done a few over the years, how long you been racing??

[@Will-tb8vi]

@@PowerRepublic Hi I have just started racing I know at Bendigo Kart Club in Victoria. But I find on the race starts when you come around the final corner onto the straight I hit the accelerator before everyone and they still pull away.

[@el_minge]

@@Will-tb8vi about a year late but could also be a gearing issue instead of a power issue