[Marky G]

Just read the Steve Saunders test on the Sherco 4T in the trials mag, he mentioned the old dreaded "pop and die" thing that has affected nearly every fourstroke trials bike (with a carb) that I've been on.

Do you get this with the Montesa, with it being fuel injection and all??

[Nigel Dabster]

Not at 1800 tickover.

[TordiJarres]

Which trials mag? Is it TBM (back pages thereof) or Trialsworld?

[Cota Kid]

I have no intention of switching to a 4 banger but the people I know who are thinking of switching tend to prefer the Montesa.

[AtomAnt]

I got that a few times when I first got the 4T. But since i upped the tickover to around 1200 rpm it hasnt happened since.

[munch]

so dabster did mine idle at 1800 revs ,and did it pop?

[Nigel Dabster]

oh no, the injection has certainly cured the pop and die, the suspension was loverrlly, but why did that sherco get so hot?

[AtomAnt]

The Sherco's oil sump has been extended so the generator runs in oil to help with the heat generated. 800cc of oil. Theres no doubt it gets hot but it doesnt effect its performance. On a hot day the fan runs around 80% of the time. Just shows that the design is spot on as theres no wasted energy or excess weight being carried in the coolant system.

This post has been edited by Webmonkey: 27 June 2005 - 08:41 AM

[Jools]

Have you had any problems/worries with overheating Webmonkey? Because they aint gonna develop a bike thats going to over-heat

Someone explain to more junior riders what you mean by 'Pop and Die'!?
Is it the bikes getting hot and fuel starvation or something

[AtomAnt]

Well, my experience of Pop and Die is when your riding in gear at low revs (probally tickover), and you open the throttle fast. Depending on where the engine is in its cycle and its load, It either responds or backfires through the carb making a popping noise and the engine cuts out. (A higher tickover cures this most of the time)

In relation to overheating, if the fan was running 100% of the time, then I would be worried ! but it doesnt, so this means that the running temperature is in control. Sherco obviously had a problem early on with the prototype thats why they went to a wet ignition system.. Its not the perfect solution but it works

This post has been edited by Webmonkey: 27 June 2005 - 11:46 AM

[AtomAnt]

HondaRS, on Jun 27 2005, 01:08 PM, said:

I think time will tell with the Sherco, and feel that in future after its gets an oil pump, so is able to run cooler, will probably be a much better bike.

Unless you know something I dont, I dont think they will go with an oil pump.. more cost and more weight with an oil rad needed also. The solution would be to make the current system more efficient. I think Josep Paxau is obsessed with keeping the weight down so Im not sure what he will come up with. ? The obvious way is to increase the rad size and pump flow rates but he may have some other ideas.

This post has been edited by Webmonkey: 27 June 2005 - 12:54 PM

[Jools]

Fair do's to Sherco, they've given it a really good crack at producing the 4 stroke motor. Honda have soooo much more experience at producing these engines and Sherco have really taken a chance with this bike and despite the odd problem, they've done damn well!! I admire that.
they'll get the problems corrected soon. Lots of expert riders may also prefer the bigger bore motor, coz the Sherco has got some grunt!!!

[AtomAnt]

Sherco's idea of extending the oil capacity to help with the cooling only has a limited effect on reducing the heat of the engine, unless like you say, the oil is being pumped and externally cooled. All it does is add more thermal mass but without an obvious place for the heat absorbed to be dispersed, its going to get hot and retain its heat for longer. This is what I experience with it.. Its gets VERY hot. But, whats interesting is that it seems to cope with no problems at all. Their testing ground being in spain must be dam hot so they must of been happy with it to release it for sale.

This post has been edited by Webmonkey: 27 June 2005 - 03:05 PM

[Marky G]

With my 125 Scorpa, I changed the oil every fourth trial, a good semi synthetic oil.....overkill??..maybe but oil is cheap compared to a new top end!!.
I'd advise you guys to do the same.

[AtomAnt]

I've done 4 trials and on my 3rd oil change from running in. It sounds real smooth now I will change the oil now every 4 trials purely for the reason you state.

This post has been edited by Webmonkey: 27 June 2005 - 06:34 PM