RogerB Posted June 3, 2022 Share Posted June 3, 2022 Attempting to balance the T.B.s according to the Minister guide & there is an imbalance between No 1 & the other cylinders. 1 being at 7kg/hr and the rest at 6. As there is only a means to adjust between the two pairs any suggestions how this can be resolved. Link to comment Share on other sites More sharing options...
Dave Hardcastle Posted June 4, 2022 Share Posted June 4, 2022 Just had a quick Internet search and came up with a page on our site! This page, in the 5th paragraph, mentions adjusting air bleeds to get a pair aligned together, before getting the two pairs aligned.Hope that helps,Dave Link to comment Share on other sites More sharing options...
John Vine Posted June 4, 2022 Share Posted June 4, 2022 There's a useful thread here.Are we discussing a K or a D? I seem to recall that early RBs fitted to Ks didn't always have the air bleeds (I could well be wrong about this).JV Link to comment Share on other sites More sharing options...
oilyhands Posted June 4, 2022 Share Posted June 4, 2022 K RTBs dont have air bleeds AFAIK, the only way would be some subtle mods to the barrels themselves. It might be worth doing a compression test to see if anything is awry between the cylinders. If you cant resolve the imbalance in absolute terms, then it is worth opening the rear TB to 6.5KG/HR so that the overall draw is the same between the front and rear TBs.Oily Link to comment Share on other sites More sharing options...
RogerB Posted June 6, 2022 Author Share Posted June 6, 2022 Thanks Oily. As you say no air bleeds and I've done a compression test which was good. So I'll go for setting the aft 2 cylinders to 6.5 before modifying the barrel. Link to comment Share on other sites More sharing options...
RogerB Posted June 6, 2022 Author Share Posted June 6, 2022 I've now balanced as close as I can get at 1000rpm., cyl 1 to 4 at 6.2, 6.7, 5.9 & 6.5 respectively. Then carrying out the MBE reset by depressing the throttle 5 times with ignition on.I'm still getting a slight miss fire on No1, about 16/min, which clears above about 1500 rpm. The lumpy running at tick over is what started me to try this rebalancing process. Link to comment Share on other sites More sharing options...
RogerB Posted June 6, 2022 Author Share Posted June 6, 2022 I've now balanced air flow as close as I can get at 1000rpm., cyl 1 to 4 at 6.2, 6.7, 5.9 & 6.5 kg/hr respectively. Then carrying out the MBE reset by depressing the throttle 5 times with ignition on.I'm still getting a slight miss fire on No1, about 16/min, which clears above about 1500 rpm. The lumpy running at tick over is what started me to try this rebalancing process. Link to comment Share on other sites More sharing options...
oilyhands Posted June 6, 2022 Share Posted June 6, 2022 Have you checked the TPS alignment? AFAIK the 5 depressions of the throttle are for the Mems, not the MBE.Oily Link to comment Share on other sites More sharing options...
RogerB Posted June 6, 2022 Author Share Posted June 6, 2022 Thanks Oily I wasn't aware the reset didn't work on MBE's.. I have adjusted the TPS and its maximum alignment only gives me 0.41 ohms not the 0.45 stated in the Minister guide. Link to comment Share on other sites More sharing options...
oilyhands Posted June 6, 2022 Share Posted June 6, 2022 You may need to file the mount holes in the TPS in order to achieve the correct alignment.Oily Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 6, 2022 Share Posted June 6, 2022 Hi Roger, if you have a slight misfire on cylinder 1, check the connector to the coil with a magnifying glass and look for any arcing or fatigue fracturing of the wire. This connector seems to be the most prone to vibration which can cause either a fracture or the spring surface of the socket relaxing to cause intermittent contact. I put a strip of foam tape on the underside of my coil cover to try to reduce the vibration of the coil connectors Link to comment Share on other sites More sharing options...
John Vine Posted June 6, 2022 Share Posted June 6, 2022 Hi James,I'm not sure but I think Roger has K?JV Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted June 6, 2022 Share Posted June 6, 2022 Hi John, yes my comment would only be valid with a Duratec. Link to comment Share on other sites More sharing options...
RogerB Posted June 7, 2022 Author Share Posted June 7, 2022 Thanks guys, yes mine is a K. Link to comment Share on other sites More sharing options...
RogerB Posted June 7, 2022 Author Share Posted June 7, 2022 Trying to remove the TPS so as to elongate the holes to allow adjustment to the correct resistance I have eventually loosened all the screws on the TPS and mounting plate. However I still can't see how the TPS is removed. Link to comment Share on other sites More sharing options...
oilyhands Posted June 7, 2022 Share Posted June 7, 2022 You just need to undo the two screws that locate the TPS, then it just pulls off, it may require a ;title effort and some wiggling, you *dont need* to undo the plate on the end of the TB,Oily Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted June 7, 2022 Leadership Team Share Posted June 7, 2022 I have a similar issue with my K-RBTBs, resulting in one pair being near similar flow but the other pair needing a compromise, one high, one low. Is it feasible to add a bleed screw to correct the problem? It's probably only necessary to fit one to the body which draws a low flow reading? Link to comment Share on other sites More sharing options...
oilyhands Posted June 7, 2022 Share Posted June 7, 2022 You would need a substantial boss to support an bleed screw and ideally you would need to draw air from inside the air filter envelope which would be hard to arrange. The TBS would need to be removed to facilitate this. An alternative would be to make a subtle modification to the hole through the TB bar.Oily Link to comment Share on other sites More sharing options...
RogerB Posted June 9, 2022 Author Share Posted June 9, 2022 Success! To sum up - Following Minister Instructions on Basic setup of Caterham Roller Throttle Bodies available elsewhere on Tech talk. Throttle bodies balanced using an air flow meter. No 2 cylinder required subtle modification (using a round file to open up the crescent aperture at min opening. Taking care by stuffing a rag into the throttle body to catch aluminum filings complimented with vacuuming out)Removing TPS to file slots in the two securing bolt holes so as to allow adjustment of sensor to achieve correct reading of 0.45 ohm at tick over position.This required repeating the steps many times, adjusting the tick over setting screw and re checking the resistance of the TPS as adjustment of one would upset the other.Finally no miss fire and engine ticking over smoothly at 1000 RPM.Many thanks to Oily and other posts. We learn so much from this resource. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted June 9, 2022 Leadership Team Share Posted June 9, 2022 #19, Roger, did you file the roller itself?Stu. Link to comment Share on other sites More sharing options...
John Vine Posted June 9, 2022 Share Posted June 9, 2022 Re #19:...correct reading of 0.45 ohm...Certainly the Minister guide says 0.45 Ohms, but was your actual reading 0.45 KOhms? I've always understood the guide resistance to be a typo.JV Link to comment Share on other sites More sharing options...
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