Hi all I have aproblem I thought some of you experts might be able to help me with, I have a 1992 Trophy 900 which I bought as a non running project due to the faulty sprag clutch, I have replace the sprag clutch replaced the ECU, the ignition sensor, plugs and leads and one coil to try and get rid of the missing and unstable tick over, I rebuilt the carbs and now it is stable and running on three cylinders but it is having the odd pop down the exhaust and I can not work out what is causing it, if you rev it up it is clean but hold the revs at say 3000 there is still the odd pop down the exhaust the same as on tick over, I am sure there are no air leaks but I have not ballanced the carbs yet but they are close as I set them up on the bench for a starting point, I did think valve clearance but it would pop and splutter on the pick up if that were the case which it does not, Has anybody got any ideas Please. Keith
i would check the valve clearences as its not a big job. could be tight or even a burnt valve? maybe do a compression test 1st. a carb balance can only do good
Ok I have ballenced the carbs and checked the valve clearance there are a couple of inlets that are very slightly tight but not enough to worry about but, the odd pop down the exhaust is still there but it might be a shade better, I am wondering if it could be a sticky valve but I can not prove it, I have just about run out of ideas now, do any of you guys and girls have any ? Keith
were all the passageways def clean in carbs? mixture screws set right and needle and float heights are the exhaust gaskets good? not sure if a compression test would show sticky valve but may show if one is leaking. i had a similar problem when i got my tiger. i eventually found that a piece of inlet valve guide had broken off and had bent the valve slightly on its way through the engine. luckily the pistons/barrels were undamaged and a used cyl head fixed it
Hi Ram, thenks for,your reply, well I have never see that happen before it is good you found it, Yes my carb float levels have been set and the carbs stripped and cleaned with good use of an air line for the passages, the mixture screws were set at 1 1/2 turns the same of a second set of carbs I have , but I do not have an exhaust meter but it smells about right Keith
Hi all, can anybody tell me what the carb mixture settings are on the 1992 trophy 900 are please, they are currently set at 1 1/2 turns on each carb is this correct ??, I have replaced shims to get the valve clearance right but I am still getting a poping down the exhaust every four to five seconds and the mixture settings are all that is left to make sure it is correct. Keith
this is what i set up to with mikuni bst 36 105 mains and #40 pilots clip needle in middle position on all three one snorkel capped mixture screws at 1 1/4 to 1 1/2 turns out float height 14.5 mm The correct float level is listed as 1.5mm +/- 1mm above the joint face between the carb body and the bowl.
Yep done that Ram33 but it made no differance I am affraid, I think I will have to play ariund with the mixtures and see what happens but they are a pig to get to without the special right angle screwdriver, the only other thing I thought and someone suggested is a sticky valve ? because it only happens every four to five seconds running at 1000rpm, I do not know how long the bike has been standing, but going by the rear calliper in which the pistons are solid and will not move even with an air line or grips resulting in me having to order a second hand one, I would thing quite a while. Keith
i made my own "special right angle screwdriver" for about £6 buy one of these: http://www.ebay.co.uk/itm/Angled-Bi...002?pt=LH_DefaultDomain_3&hash=item5b0da76492 fit a length of pipe to hold on to and use a screwdriver extension up the tube to turn it pic below should explain better
Oh thanks for that Ram I have ordered one, when I re set the mixtures yesterday I was able to do the two outside carbs just, but I could not do the middle one and ended up taking the carbs off to alter the mixture, not something I wanted to do, this tool should do nicely Keith
Well THANK YOU all very much for you help, I opened up the mixture screws to 2 1/2 turns and the poping has gone and the tick over is now very stable, having got that right I can sort out all the other problems, I was worried at one stage because I can not keep pooring money in to it and I did not want to strip it down for parts as it is quite a good bike over all, so onward Keith
glad youve got it sorted now you can also make a tool for removing caliper pistons with a rawlbolt like this http://www.triumphtorque.com/messag...emove-seized-calliper-pistons-for-only-3.aspx
im not sure m8 iactually got mine out using a large hand tap which turned the piston as it bit into the metal. best take the caliper to a bolt supplier or maybe even b&q and see what they've got. i think the pistons are 27mm od and the wall is maybe 3mm thick so a bolt that expands past 21mm should do it
Thanks for that Ram I will have a look in b&q's, I got the new calliper from Triumph ant this afternoon complete with master cyl and pipes and it looks almost new so that was a result but I re sealed it anyway
