demon 125,first things to be done??

[lo-cou]

hey fellas,
im new to this site and just bought a demon 125cc pit bike,im quite mechanicly minded and know a bit about engines,im just wondering what i will need to change once it arrives, if anything,i've got 1 litre of magnatec oil that ill change after its run in,is their anything else i will need to change or know about>?,stock air fliter and spark plug ok to keep,that chain looks piss weak aswell, any help would be much appreciated
thank you

 

[mjc85]

What is a Demon 125cc? Post a picture please

First things to do, remove zip tie of crank breather tube near rear shock on back of engine, and drain and replace the oil that is in the motor with a SEMI-SYNTHETIC 10w/40.

 

[crazzy #1]

id get a new chain!!!

 

[lo-cou]

http://cgi.ebay.com.au/NEW-DEMON-DI...2QQihZ011QQcategoryZ11329QQrdZ1QQcmdZViewItem

thats the bike

 

[mickalomaniac]

my sugestion is change the oil.... if you like the bars keep them otherwise get yourself some pro taper mini's, strong as hell and cheap too. Also check the back bone of the frame... If its got a small indentation under the fuel tank you can bet your ass off it will bend after a few decent jumps, or if your lucky it wont fold in half when your about 10 km's from your car... Other than that just thrash the hell out of it... It will let you know wats good and bad after a desent ride..

 

[lo-cou]

ah sounds good,i doubt ill be doing much jumping just a paddock thrasher,thanx alot for your info

 

[Mack]

Don't run in with semi or fully synthetic oil. Use mineral based. Switch to synthetic after run in.

 

[lo-cou]

mineral based?,will the engine come with this in it already?

 

[sik-pj]

yes do what mack said thats what i done with my bike. but i used motul oil after i ran the bike in.

 

[Poppy]

My new bike should arrive tomorrow and I'm prepared to do a little welding if necesary. I noticed the braced frames on e-bay, is there any point in welding additional bracing prior to riding the bike? If so what should be braced apart from the top if the frame (what's the indentation Mickalomaniac is talking about)?

 

[Redstar]

Keep away from the Magnatec. Its a very good 4-stroke oil but is for cars and not for our motorcycles where the gearbox/clutch runs on the same oil as the egnine. Your clutch wont like it.

Second, factory oil is mineral based (I've never encountered otherwise) and I'd keep it there until after run in period. No need to spend on this by replacing it immediately regardless of the "low-quality" notion.

As for welding the frame, since you've mentioned not subjecting the bike to jumping anyway, no need for it either.

What I would do is to strip the bike apart, and re-assemble. I know how tempting it is to ride it straight-away but unfortunately, doing so will make you discover what parts you may damage as a result of loose bolts and nuts. In my experience, its only the engine that seems pretty well torqued at the factory. I cannot stress the advantages of fully stripping and re-assembling everything back again. To say the very least, you've got peace of mind that each and every bolt and nut is properly tightenned and things are aligned properly (fork, chain). Using some threadlock would be good as well.

This is only the start. Having a new bike will surely keep you busy as there are quite a lot of things you can develop and building it up is where most of the fun is.

Wish you well!

 

[lo-cou]

damn about oil,do you have any recomentdations of oil? prices?,once the bike arrives i will give the whole thing a once-over check and tighten and locktight wherever i can,obviously no moving parts etc,i cant be bothered stripping it back,ill just do the best i can whilst its built.thank you redstar

 

[Redstar]

I would use any of the more popular brands like Shell, Castrol, Motul, Repsol, Total, Elf (enumerated not in order of superiority). I tend not to be too picky unless I have a more than a fairly modified engine already. Again, part of my practicality in this matter is that where I currently am, it is not easy to find choice brands and only a few are available. It will be different if I'm back home. Then again, I'll have to do some research about motorcycle oil as my knowledge is actually more on cars than bikes at the moment.

There's some argument about synthetic based oils for bikes due to its slippery characteristics, that again, the clutch may not function in its optimum but I tend to leave the belief for highly modified angines, if at all. I use a snythetic based oil and I'm happy.

As for grade, I tried finding the thinnest viscosity available. While it can get hot here (33 deg C), I dont ride my bike for extended periods anyway. Anyhow, I could only get 10w-40 at best. I opted for a 0w or a 5w, if there's such a thing for bikes but just cant find any.

Prices? Cant be much of help as I dont live where you live.

Hope it helps.

P.S. "Cant be bothered stripping it back..." Hahaha, I know how you feel. Honestly, I didnt follow my earlier reco either. Some things are easier said than done. I did it not long after I got it though and still saved me trouble.

 

[sik-pj]

use Motul i get it for $12.

 

[lo-cou]

bought some stuff today.got a 38mm uni airfilter full foam style which i shoudlnt have because dont know size of carby(idiot),scott handle grips and some oil (bel-ray thumper semi syenthetic 20W-50 racing 4 stroke oil) bloke at moto bike store recomended it,going to go back tomoro and get a thicker chain ,air filter oil ,change 38mm filter to a 26mm(most likely to fit)and pobably a better spark plug,by the way no one would happen to know the size of carby on one of these bikes would they???

http://cgi.ebay.com.au/NEW-DEMON-DI...ryZ11329QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

 

[Redstar]

The carb from the pics looks like its a 19mm.

Good job with the oil BUT DO NOT use it yet or you wont get passed running the engine in.

In getting a thicker chain, make sure you observe the correct size for your sprockets. Yours seem like its a 420.

 

[lo-cou]

yeh ill change air filter for a 22mm one,and yeh ill run engine in on the mineral based then change to semi after 3 tanks,im might wait until bike comes before i buy a change chain,dont wanna get the wrong one.needa buy some air filter oil aswell

 

[lo-cou]

19mm is pissss small,i just bid on a mikuni 25mm on ebay gonna try make it work on my bike,anyone heard of this being done easily and succesfully?or even a keihin 28mm on 22mm manifold??, can i just bolt it on to old manifold and hook up cables?,i read the thread on 26mm on a 110 but i assume would be easier on my 125??

 

[mjc85]

No 25mm maximum, 28mm is too big. Yes you just put on existing cable, you might have to trip the outside of the cable back to expose the inner cable some more otherwise when not throttling the slide will be open a bit causing a high idle. Would be best to also purchase a matching manifold for the new carby.

 

[lo-cou]

ah yeh,ill wait and see when the bike arrives,this week sometime,and measure the carby to see how big it is,im assuming its a 22 as 19's are usually on 110's,i lost the bid on the 25mm damn ebay(ahahah)