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Author Topic: 363 370 Vibration  (Read 3659 times)

Online havinnoj

363 370 Vibration
« on: November 05, 2018, 11:54:23 PM »
Fellas running 363/ 370cc motors with unbalanced cranks, what's the vibration like?  I can't remember back to the last 350 I had and am considering doing a 363 Sphynx for the spare duner over the winter.  I probably wouldn't care for myself but usually have a gal riding that bike so vibration becomes a bit more of a concern.  Probably won't go that route if I need to spend the extra coin to balance since that motor size is already getting big enough for the spare.
« Last Edit: November 06, 2018, 06:19:21 PM by havinnoj »

Offline broken1

Re: 363 370 Vibration
« Reply #1 on: November 06, 2018, 02:51:37 AM »
I have no experience with vibrations in a big bore but the fact a chick will be riding a 363 sphynx is awesome! My wife gets a measly 250cc oem cylinder.  ;)

Offline Skeans1

Re: 363 370 Vibration
« Reply #2 on: November 06, 2018, 06:16:01 AM »
From what I remember of my Sphinx the vibrations weren’t all that bad nothing like the 431 was.

Offline jwraymond6

Re: 363 370 Vibration
« Reply #3 on: November 06, 2018, 07:26:13 AM »
I don’t notice much vibration on my 363 sphynx
87 363 sphynx built by Pete @ hybrid engineering

Offline atvcrazy

Re: 363 370 Vibration
« Reply #4 on: November 06, 2018, 09:00:57 AM »
balancing helps very little in my opinion.  Running a standard stroke crank will help the mos with a big bore. Small motors like 72 mm bore or less a 4 mil is fine.  Once you go over that the more they vibrate.  Standard stroke will be easier to start as well

Offline Burns363R

Re: 363 370 Vibration
« Reply #5 on: November 06, 2018, 12:14:01 PM »
I havent had any issues.  I run 2 hour races without problem.  I would say its probably not at smooth as a OEM 250, but then again i cant remember the last time i rode one of those.
TRX 363R 02- Laeger Narrow Frame/CR500 Link, Motowoz Suspension, Roll Design +4 LT Arms,RPM Dominator +4 axle, LED 363 MX, LED 350G Pipe, 38 A/S CR Ignition

TRX 370R 86- Laeger Std,ISF-No Link Swinger, JD MGC LT Arms) Motowoz Shocks, LED 370/350D pipe, 38 A/S Carb, 200w OEM Ignition

Online havinnoj

Re: 363 370 Vibration
« Reply #6 on: November 06, 2018, 12:50:41 PM »
Thanks guys, appreciate the feedback.  Probably only one way to know for sure.  It'd be replacing a 300/310PV which could probably use a new piston so I'm weighing whether to put money into that top end or go bigger. 

Online havinnoj

Re: 363 370 Vibration
« Reply #7 on: January 08, 2019, 04:45:44 PM »
Motor is finally out of the chassis and in for inspection.. also found a cracked motor mount on the stock chassis.

Offline Burns363R

Re: 363 370 Vibration
« Reply #8 on: January 10, 2019, 11:47:28 AM »
They do vibrate some.  Defiantly noticeable when compared to a stock 250 cylinder.  But i ride my 370 for 2 hour races, and it isnt bad.  My 450 vibrates just as bad id say.
TRX 363R 02- Laeger Narrow Frame/CR500 Link, Motowoz Suspension, Roll Design +4 LT Arms,RPM Dominator +4 axle, LED 363 MX, LED 350G Pipe, 38 A/S CR Ignition

TRX 370R 86- Laeger Std,ISF-No Link Swinger, JD MGC LT Arms) Motowoz Shocks, LED 370/350D pipe, 38 A/S Carb, 200w OEM Ignition

Online havinnoj

Re: 363 370 Vibration
« Reply #9 on: January 10, 2019, 02:26:04 PM »
They do vibrate some.  Defiantly noticeable when compared to a stock 250 cylinder.  But i ride my 370 for 2 hour races, and it isnt bad.  My 450 vibrates just as bad id say.

Thanks Kyle, appreciate it.

Online havinnoj

Re: 363 370 Vibration
« Reply #10 on: January 10, 2019, 03:57:07 PM »
PRICE CHECK ----

What's a Pro-X Powervalve 310 cylinder worth used these days?  Comes with fresh bore/hone and good piston ready to run.

Offline Tbone07

Re: 363 370 Vibration
« Reply #11 on: January 30, 2019, 10:58:30 AM »
One of the things I'm surprised that nobody has come out with is a counter-balancer designed to be run on the big bores. There so many big bores out there, I bet they would sell like hotcakes for guys 350cc and up
LED Performance 350R
Laegers-JD Performance-GThunder-HLS-PEP-HiPer-GBC

RIP Laz

Offline 2Nubs

Re: 363 370 Vibration
« Reply #12 on: January 30, 2019, 12:14:26 PM »
One of the things I'm surprised that nobody has come out with is a counter-balancer designed to be run on the big bores. There so many big bores out there, I bet they would sell like hotcakes for guys 350cc and up

Agreed. I had a KTM 690 a few years back. Properly counterbalanced. Smoothest running engine I've ever been on.
‘86 330

 

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