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4t @ The Scottish


dixie
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Anyone got any set up info for the sherco 4t yet

mine is a lot smoother and more powerfull after the second service

(did one at 5 and one at 10 hours, just to be sure)

but it still needs no choke on initial start up and will flood if i try it.

do i need to lean the mixture,or move the needle setting. or change the

pilot jet.

it runs ok when warm but seems quite thirsty

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My 4T requires the choke to start and run when cold.

Runs fine when warm although can be a sod to start when hot.

Maybe too lean on the mixture or the wrong technique for starting

when hot?

Also mine drinks fuel at an alarming rate, not helped by the distance

between 4th and 5th gear!

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Dabster

measured my 4T float level and is 18.5, so appears same as 2 stroke,

4T Stock carb' setting...on mine!

Slide 45

Pilot 32

Main128

mixture screw 1.5 turns out

How does this compare to the 290?

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Excuse my comment but there cant be much to gain by comparing 2stroke and 4stroke carb settings.

How is everyone who has bought one finding the 4T Sherco, there seems to be two distinct camps with th Honda - hate it or love it with very few people in the middle ground. As for reliability - any problems yet, given the problems that have been publisised at the SSDT.

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As the carbs are identical they may well be the same set up from the factory, who would think that a 125 is the same as a 290, not ness the same comparison but they are. Only trying to help the bloke not prescribe carb settings based on a 2 stroke, in case you were not clear. :hyper:

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They aren't exactly the same. Both are Dell'Orto, but 2stroke bikes use the wellknown PHBL26BS and the new 3.2 4T uses the relatively new VHST28BS (flat slide, bigger bore, emulsion-type pilot jet). This VHST carb series seems to have some problems with the float level, caused by the needle-float set. These problems are erratical, so may be present in a bike an not in other. (You could read more on this in http://www.terra.es/personal9/marlintec/taller , in the VHST section, chapter VI, in Spanish)

Furthermore, I know that some tests with Keihin carbs are being developed in the 3.2 4T nowadays.

In relation to the SSDT problems, seems to be addressed to the ignition system. A bike also developed the problem in Spain (not much rain) so it seems not to be a problem of wet, but heat on the coils.

I'm very confident that in Sherco will soon resolve these problems and we'll have a serious alternative to the 4RT.

Cheers, JM.

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Marlintec

My 4T exhibits some strange carburation, seeming weak, then rich

for no apparent reason.

Following your link, the google translation is not perfect but it would appear you have identified a problem with manufacturing of the float needle and housing.

Am i reading this right?

You solved it by fitting a float needle/seat from a PHBL type?

Was it a straight swap?

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RE500 your reading is right.

The rich-lean-rich-lean-lean-rich-rich-lean... with no apparent reason is the symptom of a fail in the fuel input to the carb. This could be a clogged line, a non-vented tank, a small floatneedle jet or as in this case, an erratical float level. You may check your float needle and ask to a friend to borrow his PHBL set. it's just a straight swap, yes.

BUT... in your bike there is one more thing to check: the heating of carb. A very warm carb also gives the rich-lean-rich-lean-lean-rich-rich-lean... symptom. It may not be a problem in UK... or do it? In relation to this, I remember the same problem in the bike of Eddy Lejeune when he changed from the old 360 to the new RTL engine. After all these years, when Honda bets for fuel injection in a trials (it could be done before in any CRF or CRX)... it is also a 'symptom' to bear in mind.

Cheers, JM.

Edited by Marlintec
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Marlintec

Does the PHBL float needle have a spring on top ?

Carb doesn't seem to get warm at all, even when the

motor is well toasty.

Thanks for the suggestions though!

Haven't popped the tank off to check the temp of the

coil, i'll stick a thermocouple to it and see.

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Sorry, RE500, I don't exactly understand what you mean with ''spring on top''. The top (tip) of this needle is covered with rubber, and the body has a tiny spring within (you cannot see it) that pushes out the T shaped part. Seems that a change on the stamping machinery of Dell'Orto has produced some defective units that were mounted on VHST carbs. You can easily found this needle on any bikeshop, but make sure that is of the same lenght and size. Also, I'd like to know your temperature tests!

Ishy, I think there are people that testing the insulation sheets between head and carb, as you note. I don't know if the problem with ignition is on the HT coil or in the mag coils. The bike I referred before was changed all the electrics, and I don't have more news on which was the faulty part.

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Marlintec

The needle valve has a bent thin gauge wire fixed to to the top that forms

a loop. This hangs onto the float arm/lever.

The float arm/lever doesnot have a notch for a T shapped needle valve

to fit.

Does this make any sense...if not i'll take a picture tonight.

Cheers

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