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Messages - doh13

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Sherco Tech / Re: 300 sefr top end
« on: January 21, 2021, 08:05:46 PM »
Are the cam lobes on these DLC coated? They look very dark.
They could be they are dark but im not sure.

Sherco Tech / Re: decompressor starting issue
« on: January 17, 2021, 09:19:28 PM »
This might be a noob question, but how did you track the problem to a compression problem? What are/were the indication?
The starter  motor doesn't have enough torque to overcome the engine compression fairly often for a lot of ppl but the bike will still start after a few presses of the starter ,the issue seems to be caused by the decomp mech not doing its job on each start to test you just roll the bike back and forth in gear before starting and it usually resets the decompression mech and will start normally. i believe it can be caused by a weak return spring.

Sherco Tech / Re: decompressor starting issue
« on: January 16, 2021, 06:13:35 PM »
Another reply to my own topic :)  I have installed a new spring and the decompressor mechanism  seems to return with more force. I have not tested it yet but it seems as if the old spring may have gotten weaker due to heat, if it works its a  cheap enough part to change on each rebuild.

General Discussion / Re: Crossover Parts Thread - 12/2020
« on: January 11, 2021, 10:34:53 PM »
Check  out the pro-x website .

Sherco Tech / decompressor starting issue
« on: January 09, 2021, 12:24:08 PM »
 From my understanding of how the decompressor mechanism works it should be fully "closed" when the bike is not running and the decompressor rod  will slightly press on the exhaust valve before the cam lobe  does to let off excess compression as the motor starts, then  centrifugal force from the running motor holds the decompressor "open".

 The problem may be  that the spring  has lost some tension or is not strong enough  and on certain shutdowns the part of the mechanism that keeps the valve open rests on the valve bucket on shutdown preventing the decompressor mechanism from fully closing/resetting.

My thought is that switching to a slightly stiffer spring or adding an additional turn to the existing spring may help the issue because the mechanism may now fully close on a shutdown before the motor fully stops spinning  which in theory should prevent the issue.  I checked the parts list for a 2020 sefr and mechanism looks to be the same p/n as the older models.  I do believe the intake cam timing has been changed on the newer models possibly to try and help with the issue?

The only problem i can see is that if the spring tension is too strong it may cause the decompressor mechanism to stay open at idle causing excessive wear. but if it were to work every time it would save a lot of wear on the starting system.

Sherco Tech / Re: Sherco 300se-r regulator
« on: January 04, 2021, 08:33:48 AM »
interesting.. i have random flameouts  on my 14 sefr (mostly at low rpm) the bike will start right back up , i wonder if the regulator could have something to do with it?

Sherco Tech / Re: 300 sefr top end
« on: January 04, 2021, 07:51:06 AM »
heres a couple pics

Sherco Tech / Re: 300 sefr top end
« on: January 04, 2021, 07:39:22 AM »
Since no one replied i thought i will post an update which may help someone else, I have installed the new piston and waiting on my valve shims the valves , cams cyl etc was  all still in spec , cam chain tensioner only was a few notches in so the cam chain was still good but i changed it anyways since i had the part.

I used an OEM piston kit and cometic gasket kit  here are the part numbers for the cometic parts incase anyone is interested.
H4850027S (OEM is 3016). There is also a top end kit for that bike which is C3748 (OEM# 5108).  PS these guys make a quality gasket.

Sherco Tech / 300 sefr top end
« on: November 20, 2020, 02:16:39 PM »
Hi I plan to do the top end this winter i bought the bike used and it has 110 hours now.  I have the piston kit ,and required gaskets to do the job but should i change anything else in the top end such as  the Cam chain ,tensioner ,chain tensioner sliders , valves etc? or just check them for excessive wear and go from there? Ps is there any suprizes to expect as this will be my first time rebuilding a sherco 4t.

Sherco Tech / Re: 14 300serf TPS adjustment questions
« on: July 10, 2020, 05:10:32 PM »
I have been fiddling with my tps trying to get the bike working good  i managed to get the idle working and  5.28 ohms did not help but  5.32  made a big difference and no idle surge/hanging but the idle is a bit "sputtery" so i tried 5.38 and its about the same. Before i try going back down below 5.28 ohms   does the ohms in the higher range = rich and lower ohms = lean? if i were to guess the bike seems rich as it is now but i am just happy it is running much better than before with no hanging high idle .

Sherco Tech / Re: 14 300serf TPS adjustment questions
« on: July 08, 2020, 07:09:20 PM »
I set my bike to 5.3 k ohms and it revs high when i blip the throttle and don't come back down unless i put it in gear and lug the motor back down and its generally not running that well at low speed (along with the revs not returning to normal) .
I have read the stepper motors can get gummed up ill prob clean it and if that doesn't work tweak the tps again. should i start with higher values or lower?

General Discussion / Re: sefr 300 water impeller torque?
« on: June 30, 2020, 12:39:59 PM »
I found the torque value its 8 ft lb in-case anyone else is wondering

General Discussion / sefr 300 water impeller torque?
« on: June 30, 2020, 10:50:28 AM »
Hi  after 8+ weeks my parts finally arrived  :o  ,  does anyone know the torque specs of the impeller I cant seem to find the info, in the service manual, and i am assuming i should use some blue loctite as well  Ps why wouldn't the impeller shaft have a left handed thread unless i am mistaken the shaft turns clockwise whick can loosen the impeller.

Sherco Tech / Re: 14 300serf TPS adjustment questions
« on: June 18, 2020, 07:42:26 AM »
The reading between Blue signal and Red should be set at around 5 .3K ohms  + or - .5  NOT voltage .Set your meter to the 20k range and I think it is the 2 outside pins .This is when the throttle closed.The reading between Red and Black will (should) be 5 vdc. Don't pay any attention to the way Ktm tps is adjusted. This will get you going
Thanks! ill try it.

Sherco Tech / 14 300serf TPS adjustment questions
« on: June 17, 2020, 07:43:50 PM »
Hi im looking for info on the adjustment of the TPS.

 After removing /reinstalling the tps (for cleaning ,yes I regret removing it  lesson learned)  I   get  only get a voltage reading of 0.58v-0.60v (with the throttle  held wide open)   every other vid /forum shows other bikes like ktm the low voltage reading is with a closed throttle and the high reading with it open but i could not figure out a way to put the tps back on to make it have a low voltage reading with the throttle closed i tried turning it every which way but it brings up before i can put the bolt back in and it only seems to go on one way.  what am i missing?  ps  0.58v-0.60 is the lowest voltage i can get as well because the adjustment is maxed and before i took the tps off the adjustment was about in the middle. i know somethings gotta be wrong.

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