re500 Posted May 29, 2005 Report Share Posted May 29, 2005 Big John No choke..seems yours is the same as Dixies'. When you clean the carb' perhaps you could post the jet sizes/float level! Seems mine is the only one that struggles to start when hot...weird. Does your carb get warm to touch? Mine seems to pick up heat from the silencer, not sure if this is the problem but would have thought ALL 4T's would exhibit the same failure to start if it was. Measured the temp of the coil while practising yesterday. Ambient 18C , Coil 53C after ~ 1 Hr riding, pretty much non stop. Cheers Quote Link to comment Share on other sites More sharing options...
re500 Posted May 29, 2005 Report Share Posted May 29, 2005 Big John Sadly the 'old fashioned way' doesn't work for me, no problem with the 500 and 350 Bullet Trials though, first kick everytime! Did you get yours really hot..like you can't touch the right hand frame rail hot? Inlet manifold is neat....mine looks like its alive and 'breathing' rather heavily..like the pilot! cheers Quote Link to comment Share on other sites More sharing options...
martinm Posted May 29, 2005 Report Share Posted May 29, 2005 I assume all of you Sherco 4T owners have had a look at the set up advice on www. sherco-moto.com !!!!!! Also, having had a chat today with a man "in the know"!!!........I hear that one of the 4t's packed up in the Scottish due to a resistor type plug cap failing....so probably a good idea to junk this in favour of a standard one or carry a spare! Martin Quote Link to comment Share on other sites More sharing options...
marlintec Posted May 30, 2005 Report Share Posted May 30, 2005 Thanks for the photo, RE500. The system is definetively different in your carb. Mine (VHST26BS, year 2003) has the same set than in PHBL. Maybe Dell'Orto has changed the set to avoid the old problem. About the heat, it seems not so high for electrics (did you measure the HT coil temp?) Do you have any measurement of the oil temperature? (the stator runs on oil bath) The aluminium muffle radiates lots of heat around, I even know of a bike that got the 'seat' (mudguard) melted. The insolation like Ishy says could be the key for these problems. Cheers, JM. Quote Link to comment Share on other sites More sharing options...
re500 Posted May 30, 2005 Report Share Posted May 30, 2005 Marlintec Yes i measured surface temp of HT Coil. Also measured silencer temp ~ 155C. Didn't measure the oil temp, didn't want to stick the thermocouple in the engine without knowing where its going and more importantly coming out! I can understand how the mudguard melted..mine gets too hot to sit on and as i said to Big John, even the frame rail gets too hot to touch! I have already spoken to a F1/Champ car exhaust fabrication company to see what we can replace the silencers heat shield with. I have emailed him with photos of the sheild/insulation. He had some excellent suggestions as to what to try, unfortunately he's off on holiday for the week! see pic of heatshield, unscrewed from silencer...seems a bit thin in insulation. Cheers Quote Link to comment Share on other sites More sharing options...
re500 Posted May 30, 2005 Report Share Posted May 30, 2005 Marlintec Just did a quick test of the carb' bowl temp. Thermocouple was tapped to the bowl, heatshield side. Ambient 21C Fan cuts in 25C 37C after ~12mins riding on the drive, ie no load. Stopped engine, heat soaks into carb ~8mins. Max 40C !! However don't think bike is as warm as in a trial, it was still posible to sit on the seat. Kicked it over and started 2nd kick. Anybody know what the max temp of the fuel should be? Cheers Quote Link to comment Share on other sites More sharing options...
marlintec Posted May 30, 2005 Report Share Posted May 30, 2005 Lots of interesting numbers, thanks. Gasoline should remain as fresh as possible, as well as air intake. Peaks of 40 Quote Link to comment Share on other sites More sharing options...
g4321 Posted May 31, 2005 Report Share Posted May 31, 2005 Apart from that I like it! How does it compare to your RTL's John? Or is it too early to say. Does the Sherco have an oil pump or is it working off the same principle as the 1st Husaberg 4 stroke scramblers - using crankcase pressure to circulate oil around? Quote Link to comment Share on other sites More sharing options...
g4321 Posted May 31, 2005 Report Share Posted May 31, 2005 John Sorry to miss its debut on Sunday & will miss its competive debut in a couple of weeks as well, but glad to here you are happy with it Gordon Quote Link to comment Share on other sites More sharing options...
marlintec Posted May 31, 2005 Report Share Posted May 31, 2005 There isn't a mechanical oil pump, lubrication is by oil splash and oil circulation by crankcase pressure pulses. Yes, like early Husaberg/Husqvarna engines. Oil is shared among clutch, gearbox and engine, and filtered through a metalic mesh. This two features concerned me a little about mechanical reliability, but they may work in a less stressed trials engine better than in a high revved enduro or MX engine. We'll see this year. Cheers, JM. Quote Link to comment Share on other sites More sharing options...
g4321 Posted May 31, 2005 Report Share Posted May 31, 2005 There isn't a mechanical oil pump, lubrication is by oil splash and oil circulation by crankcase pressure pulses. Yes, like early Husaberg/Husqvarna engines. The main problem with the early air scrambles cooled engines was low oil capacity which lead to overheating & if coupled with lack of maintenance engine trouble. I remember seeing one in the Haynes series in the late 80's which had a set of cases from one of the later water cooled motors fitted with an air cooled top end - then reliability was not a problem since an extra 1/2 litre of oil was carried in the later motors. As a mater odf interest how much oil does the motor carry? Quote Link to comment Share on other sites More sharing options...
marlintec Posted May 31, 2005 Report Share Posted May 31, 2005 800 cc 10W50, at least in the prototype pre-series I could try last year, I think the final series also carry the same. I was told that Ipone has developed a special oil for this kind of work. I'm confident that the improved quality of oils on these last 20 years could be enough for the Sherco 4T requirements. As comparison, Honda 4RT carry only 450 cc of engine oil (+ 550 cc on clutch-gearbox) but, in this case, there is a very efficient oil pump. Cheers, JM. Quote Link to comment Share on other sites More sharing options...
re500 Posted May 31, 2005 Report Share Posted May 31, 2005 Big John Its 100cc /700cc according to the service tips. Anybody know how the mysterious decompressor works as mentioned in the T&MX bike test? Cheers Quote Link to comment Share on other sites More sharing options...
dixie Posted May 31, 2005 Author Report Share Posted May 31, 2005 Gents the information on this subject is really usefull,i am sorry i could not get involved earlier but i have to use my wifes work computer. big john it is interesting your bike needs no choke either! my bike just runs better and better the more hours i get on it I am just getting the hang of letting it go right back to virtually no revs without the clutch and just tickleing the throttle.the power is really quite amazing. when hot if it fails to fire first or second kick i open the throttle about a third and it seems to fire up really easily. The only problem in the mud seems to be to much grip when shutting off.i have flipped a couple of times in a steep section. Quote Link to comment Share on other sites More sharing options...
dixie Posted May 31, 2005 Author Report Share Posted May 31, 2005 I used a little scorpa 125 f for a year to try and adjust to the 4t s However this may have been a bit non productive it was relativly easy to adjust to less power but going the other way is a real culture shock. the big 320 really is quite a handfull.but as they say practice makes perfect and i really need the practice. Quote Link to comment Share on other sites More sharing options...
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