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sherpat250

Can't kickstart w/clutch pulled in: Normal?

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On my M91, with the clutch lever pulled in, the engine will not turn over when I push the kickstart down. Is this normal? If not, any ideas on what might be causing it? Just to be clear, the kickstart lever goes down (very easily), but the engine doesn't spin over.

Edited by SherpaT250

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Bultacos were not manufactured with a primary drive that allows this type of engine start. Bultacos have to be in neutral and the clutch disengaged for the kick start to operate.

Big John

Edited by Big John

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Bultacos were not manufactured with a primary drive that allows this type of engine start. Bultacos have to be in neutral and the clutch disengaged for the kick start to operate.

Big John

Unless you have a nice warm engine with little or no loading on the back wheel and a knack like vesty (I saw him do it first way back when) wherby a sharp stab fires here up in gear and whip in the clutch real quick!

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Interesting starting trick--I'll have to try it sometime!

Speaking of starting issues, I've experienced an odd thing just a few times over the years; The engine will actually start and run backwards! On each occasion I started it up, thought all was well, and let out the clutch to find the bike moving backwards! Anyone else experience this, or know what causes it? I have never had it happen on any other 2-stroke machine. The cure was to simply shut it off and restart.

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I've had it happen several times on my m159 sherpa. I used to think that it was because of improper ignition timing.... but my timing is spot on and occasionally the engine still starts backwards. It has more to do with the fact that it is piston port inlet, and that if the piston doesn't quite come over top dead center but combustion does occur causing the piston to reverse its direction of travel making then engine run in reverse. A word of caution when run this way the timing is severely retarded. If run for a decent length of time the ignited fuel will actually be "chased" out of the cylinder by spark propigation causing severe erosion of the exhaust side of the piston.

Only a select few bultacos had primary kick (bandito and late model 125 pursangs.) I routinely start my sherpa in gear with the clutch out.

steve

Edited by BultacoSteve

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I've had it happen several times on my m159 sherpa. I used to think that it was because of improper ignition timing.... but my timing is spot on and occasionally the engine still starts backwards. It has more to do with the fact that it is piston port inlet, and that if the piston doesn't quite come over top dead center but combustion does occur causing the piston to reverse its direction of travel making then engine run in reverse. A word of caution when run this way the timing is severely retarded. If run for a decent length of time the ignited fuel will actually be "chased" out of the cylinder by spark propigation causing severe erosion of the exhaust side of the piston.

Only a select few bultacos had primary kick (bandito and late model 125 pursangs.) I routinely start my sherpa in gear with the clutch out.

steve

At the last event I rode my 199a started backwards twice. It hasn't done that anwhere else. Timing is set at 2.5mm BTDC and the bike runs well. Would you reccomend advancing the timing further or just consider it an occasional quirk?

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I've had it happen several times on my m159 sherpa. I used to think that it was because of improper ignition timing.... but my timing is spot on and occasionally the engine still starts backwards. It has more to do with the fact that it is piston port inlet, and that if the piston doesn't quite come over top dead center but combustion does occur causing the piston to reverse its direction of travel making then engine run in reverse. A word of caution when run this way the timing is severely retarded. If run for a decent length of time the ignited fuel will actually be "chased" out of the cylinder by spark propigation causing severe erosion of the exhaust side of the piston.

Only a select few bultacos had primary kick (bandito and late model 125 pursangs.) I routinely start my sherpa in gear with the clutch out.

steve

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Even the el bandido/montadero and the later 125 pursangs didnt have the facility of being able to start in gear with the clutch lifted, they did have gear primary drive though

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The term used for bikes that can be started in gear by pulling in the clutch is "primary kickstart" and has nothing to do with whether the primary drive is by gears or chain or whatever.

"Primary kickstart" means that the kickstart turns the clutch basket.

"Non-primary kickstart" (Bultaco and many others) means that the kickstart turns the gearbox input shaft.

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I stand corrected the late model 125's and bandido/montadero had to be in neutral to start. Bultaco always used a layshaft and a mainshaft in the transmission with a sleeve gear that drove the sprocket. Not like most other transmissions that use a mainshaft and countershaft type design. the latter being more efficient i think, because power comes in through one shaft and is directed out the other. with bultaco power comes in, is transfered to the layshaft and then again transfered back to the sleeve gear that is on the main. My guess is that they had difficulty making a gear drive primary system work correctly without having heat expansion problems that would change the clearance or backlash on the primary gears. It was easier to use a primary chain and be done with it. The result being a somewhat stiff feeling trans. I won't say they weren't any good because i have never heard of someone having gear box probs on a bultaco. they're built like a bricksh&^ house . I think in 77 when the M194 125cc pursang came out bultaco had by then rectified gear drive problems. They by then were using the all new geared primary motor in the 75cc frontera, and eventually it made its way to some of the late streakers. i'd bet some of that r&d was transfered to the 125 pursang. a high revving motor like that was another reason to go to gears as primary chains would be prone to breakage. Bultaco had for a long time been developing other engine types. its a shame they couldn't have made them work. The engine used in the montjuich road bike had been around for quite some time (pomeroy used it in competition). I'd bet there are less than 6 or 7 of that engine type left in existence. The late model 75cc frontera and streaker were also totally new for those models and eventually the very late model prototype pursangs had a different engine yet again. I guess they rested on their laurels because they had to. With not being able to import decent accessories for their bikes left them at a distinct disadvantage. Better suspension units and braking coupled with decent metals for frames and the like and they would have been a force to reckon with. That and scaling back their production from all disciplines of the sport to just motocross and trials I think could have helped. Just my opinion

Steve

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