Helpful ReplyHot!08 BruteForce runs on one cyl, after engine rebuild.

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Jontehson
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2019/12/19 02:34:24 (permalink)

08 BruteForce runs on one cyl, after engine rebuild.

Hi! Have a 2008 brute force 750. just rebuilt engine and now it only runs on one cylinder (front) when the air pressure sensor is plugged up, if unplugged it runs on both. it has no trouble starting. Another member Kyle145 have a thread pretty mutch the same as this but havent heard of a solution.
 
Already checkt timing, plugs, coils, and measured sensors and compression.
Was not me riding it when the engine broke, so can´t say if it was any troubel like running on one cyl or misfiring before.  
 
Anyone have clue?
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00_NUTT
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2019/12/22 20:15:04 (permalink)
Could be the cdi box is having issues. Also make sure you don't have a pinched wire to that sensor. Which could cause a false reading as well.

00_NUTT
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Jontehson
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/01/02 07:39:19 (permalink)
Have a similar working Brute next to min and have been swaping all sensors and also CDI and ECU. But still it doesńt rum properly.
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/01/02 08:00:49 (permalink)
Man have you done a continuity check on the wiring. You might have a wire that's grounding out causing a false signal.

00_NUTT
1997 Honda 300 4x4
Head Ported and Polished
317 Kit
Big Red Cam
Clutch Kit
SuperTrapp IDS2 Exhaust
K&N Filter
Carb Kit
32" Interco Interforce II's
16" MSA M30 Trottles
Snorkled 
54% gear reduction
Honda 350 rear axle assm.

6" BPC CUSTOM LIFT WITH 8" STRETCH AND 3" BODY LIFT OLD 300 LOOKING GOOD AS EVER THANKS TO WHITNEY!!!!!

SON'S BIKE
1998 Honda 300 2x4
6" BPC LIft with some sick a-arms
420 spindles and disk brakes
29.5" OL2'S
14" MSA M26 Vibes
 
Upcoming
4x4 Frame and Motor that's here now just got to get to work on the swap over!!!
54% Gear Reduction
#4
Jontehson
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/01/05 04:41:18 (permalink)
Hi.
Measured all the sensors trough the wiringharnes from ECU/CDI so i think thts ok. Is it possible the stator could hav been damaged on some spots when all the loose part where going around in the engine when it broke?
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00_NUTT
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/01/05 07:02:43 (permalink)
Ok to check a stator which IDK it's the problem but might as well do it. First ohm it pin 1-2, 2-3 then 1-3. You should get something but I'm not sure what it is for that stator. Next ohm each pin to the frame and you should get absolutely nothing. Then with the bike running and meter set to ac voltage measure the same pin combos. You should see the AC voltage. As you increase the throttle you should see voltage increase.

00_NUTT
1997 Honda 300 4x4
Head Ported and Polished
317 Kit
Big Red Cam
Clutch Kit
SuperTrapp IDS2 Exhaust
K&N Filter
Carb Kit
32" Interco Interforce II's
16" MSA M30 Trottles
Snorkled 
54% gear reduction
Honda 350 rear axle assm.

6" BPC CUSTOM LIFT WITH 8" STRETCH AND 3" BODY LIFT OLD 300 LOOKING GOOD AS EVER THANKS TO WHITNEY!!!!!

SON'S BIKE
1998 Honda 300 2x4
6" BPC LIft with some sick a-arms
420 spindles and disk brakes
29.5" OL2'S
14" MSA M26 Vibes
 
Upcoming
4x4 Frame and Motor that's here now just got to get to work on the swap over!!!
54% Gear Reduction
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Mikeyboy_esq
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/04 15:10:09 (permalink)
Are you sure the cams are installed correctly?  It is easy to accidentally install the cams out of sync by 180 degrees.
 

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Jontehson
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/04 15:17:10 (permalink)
Right now i'am not sure of anything. Checkt timing several times and the level marks are in line with cyl level and the arrow on camshaft upwards.
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Mikeyboy_esq
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/04 15:26:46 (permalink)
I've had that happen on a friend's BF750. I helped him rebuild his motor (I've done it several times on my old Prairie 650 and Prairie 700), then we installed it and it ran awful (sounded like firing on only 1 cylinder).  We checked the timing marks on the cams and all looked fine.  It turned out that we installed the cams 180 degrees off.  Meaning when you line up the front head at TDC to install the front cam, it was the wrong TDC.  We had to remove the cams, rotate the crank til it hit the next TDC, and then re-assemble the cams.  I hope that makes sense.  Just something to consider if you can't find anything else wrong. 

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Jontehson
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/05 02:17:07 (permalink)
so you mean the cams can be 180 off, even if i use the I- F mark on flywheel and the arrow on front cam pointing upwards and the lines on cam in line with cylinder level?
 
Still have the similar brute at home so think i might remove valve inspektion cover on both and se if its loks the same on them. 
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Mikeyboy_esq
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/05 06:13:37 (permalink)
Right. Even if the line up the marks on flywheel and the marks on the cams, it can still be off 180 degrees. Remember, each cylinder of a 4 stroke motor hits TDC twice during a full cycle. So it is critical that you insert front cams on the right TDC and then rear cams immediately afterwards. It is easy to mistakenly install one cam on the wrong TDC when you pull both cylinders off at same time. I hope that makes sense. Do a search on this forum (or kawieriders) for cams 180 degrees off and I’m sure you’ll find others with same issue.

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Jontehson
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/05 06:50:21 (permalink)
Don´t understand it.. but in some way it make sens
Locking forward to check later and i think this might be the problem.
 
Get back to you when i´ve checkt it..
//Thanks 
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Jontehson
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/06 02:44:04 (permalink)
Ok!! It was my fault all time, when i mounted cams i went the shortest way between the possitions (F to R) and not the full 270degree turn like it´s writen in all install papers 
Thanks Mikeyboy_esq for  the explanation you made my life a bit easier .
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/06 06:01:29 (permalink) ☄ Helpfulby Jontehson 2020/02/06 06:11:10
Jontehson
Ok!! It was my fault all time, when i mounted cams i went the shortest way between the possitions (F to R) and not the full 270degree turn like it´s writen in all install papers 
Thanks Mikeyboy_esq for  the explanation you made my life a bit easier .


Glad I could help!

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Happy trails...:)
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/07 22:20:35 (permalink)
Mikeyboy to the rescue!!!

00_NUTT
1997 Honda 300 4x4
Head Ported and Polished
317 Kit
Big Red Cam
Clutch Kit
SuperTrapp IDS2 Exhaust
K&N Filter
Carb Kit
32" Interco Interforce II's
16" MSA M30 Trottles
Snorkled 
54% gear reduction
Honda 350 rear axle assm.

6" BPC CUSTOM LIFT WITH 8" STRETCH AND 3" BODY LIFT OLD 300 LOOKING GOOD AS EVER THANKS TO WHITNEY!!!!!

SON'S BIKE
1998 Honda 300 2x4
6" BPC LIft with some sick a-arms
420 spindles and disk brakes
29.5" OL2'S
14" MSA M26 Vibes
 
Upcoming
4x4 Frame and Motor that's here now just got to get to work on the swap over!!!
54% Gear Reduction
#15
Mikeyboy_esq
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Re: 08 BruteForce runs on one cyl, after engine rebuild. 2020/02/07 22:21:15 (permalink)
00_NUTT
Mikeyboy to the rescue!!!

LOL

2018 Blue RZR Turbo EPS
2007 Red Honda 250ex
2007 Black Honda 250ex
Happy trails...:)
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