880xp motor problems

[lilduke]

I have a Motts 880big bore,,This thing ran great,,(way better than a stock one in the mountains) the engine light would come on at lower altitude but still ran fine.

I almost always ride mountains,,, but it was nice out and decided to take my big bad mountain sled out, fieldin/riverin with some friends that mostly do that. It was around 0.. i warmed the sled up for a bit..took it real easy on it for about 5miles, then we get to this field open up on it not even 10 seconds later the motor siezed up solid,,,you couldn't pull on it or nothin,,,siezed solid...made it a hole 5miles with my kick ass machine....lol

so im pissed off,,put it in the shop,,start pricing out crate motors& forget about it for a few days...

So im there today and for some reason decide to try to pull on the thing,,,
Not only does it pull over but it backfires then starts right up..running a bit rough,,but running....

I think it may have been caused by the fuel?not sure though. I was running a shell91 mix with c12. my thoughs are i wasnt running eneogh c12 or it may not have even been c12... im paranoid.. i think this idiot sold me nitro methane or something...lol


So the motors is now running,,but kinda ruff,, not to to bad though...Any one care to guess WTF happened? why it now runs? And is the motor any good or is it hooped?

probably going to take it to the dealer and see if they can get it running properly...might just need a few parts? A crate motor is 3grand and i dont really want stock power after riding this...

 

[maxwell]

the motor is not fine. you should not have started it agian you probly did more damage.

if its siezed there could be 1000 things that happened. its hard to make a guess without seing the pistons.

just fyi depending on your cylinder head some of those kits require 100% race fuel at low elevation.

dont waste your time taking it to the dealer it does not just need a few parts. it will need at leasat one piston. which they will not have.

almost sounds like a ring issue or a heat issue. i cant say. no one can without seing the pistons plugs and head.

 

[team dirt]

detonation heated your ring alignment pin and you stuck a ring. once it cooled it broke free. after starting it you just caused alot more damage and for sure you will need renikisal. i was having the same issue and recut new domes for 12.5/1 so i dont need race fuel at lower elevations. still have my other domes for racing and spring riding. what compression ratio were you running. i would run straight c 12 if you were prairie riding with anything over 13.5/1. do you want the number to mongoose. they will recoat your cylinders and probably have the pistons you will need. was it your engine light or your water temp light that was on. also det sensor should have retarded your timing, is it still hooked up.

 

[sledslut]

wihth the 880 kit it shold have ave gas in there for lower elevations. you did some good damage on it. exact same thing happened to a custmer that dropped of his sled on thursday. locked up, wated over night, and ran, 3km up the trail motor is done. rode thought the side of the case.

 

[slednek]

I'm guessing with the big bore kit, there would be no dpm, which means jetting is required for high altitude and low altitude. If set up for the mountains then running way to lean around here.

 

[team dirt]

dpm should still work. you just need to change jetting before riding and dpm will compensate from there. its more a compression issue with the big bores. pre ignition of fuel.

 

[Modman]

Yup - detonation very likely. That little light that kept coming on should have been your warning - your sensor was acting up meaning that the lower altitude was messing with your motor and that you didn't have enough octane. You probably have been causing damage to the motor for quite some time, mainly everytime you came up and down the mountain when the light was on. This last little run at home was just the icing on the cake.

Doubtful that you bought nitro-methane, no one buys and re-sells nitro, its just WWWAAAAAAYYYYY to expensive to have lying around. Besides nitro would have more octane than you need, if anything if you could get it to ignite, it would more likely blow your rod bearings from the added combustion energy (yes I had this happen so I've been there ). More than likely you bought AV gas or a cheaper (or old) race gas with not enough octane (or you didn't mix enough) and this was the cause of not enough octane.

As stated, often times the cylinders will cool and release a stuck piston, but damage is already done at that point. If you are unsure, pull pipe and sticl a flashlight up there, and have a quick look down the spark plug hole.

Best thing is to pull the head and look though.

Fixing the 880 will be cheaper than a crate motor though probably.

 

[maxwell]

talk to motts. depending on what domes your running you may need 100% race fuel for low elevation. wait i alreay said that.

anyways like modman said best bet is to fix the 880 forsure. especially if it worked. just take care of it

 

[lilduke]

Thanks for the replies every body,,, yeah i think ill call motts,,, i really did like the motor hopefully they can fix it for me.

 

[Boost Monster]

Thanks for the replies every body,,, yeah i think ill call motts,,, i really did like the motor hopefully they can fix it for me.

Tom is a great guy and builds an awsome Big Bore kit for the XP's. I have one myself and installed many others with no prblems to date. IMHO you always call the engine builder first and try to rectify any issuses before posting it over the internet

 

[maxwell]

Tom is a great guy and builds an awsome Big Bore kit for the XP's. I have one myself and installed many others with no prblems to date. IMHO you always call the engine builder first and try to rectify any issuses before posting it over the internet

he wasnt bashing motts he said it works great was just curious to what went wrong

 

[EMANAARON]

Just curious as to how much motts 880xp kit is and what kinda hp it is putting out?

 

[Boost Monster]

Just curious as to how much motts 880xp kit is and what kinda hp it is putting out?

Call Tom @ Mot's (780) 418-5595. He will give you the details and answer any questions you might have.

 

[lilduke]

Tom is a great guy and builds an awsome Big Bore kit for the XP's. I have one myself and installed many others with no prblems to date. IMHO you always call the engine builder first and try to rectify any issuses before posting it over the internet

he wasnt bashing motts he said it works great was just curious to what went wrong

As Maxwell said I have no problem with motts the motor was awsome,,,i had some fuel problems though,, i think that were my own fault...now its just a matter of how much$$ to fix it