dt bottem end squeak/vibration

[metalskin]

my bikes got a weird squeak in the engine somewhere, 1 in 3 times i start it it squeaks from a bearing
somewhere for anywhere between 10sec to 2min around 3 - 4k rpm. it also has a rough feel/vibration
that comes through the bike around 4k rpm most of the time. any help appreciated.     metalskin.

[crossedup2]

Metal

Check the engine mounts are tight for the vibration.
As for the squeal, it could be the little bearings at the transmission shaft.
Does the noise go away if your in gear and standing still or does it do it at all time (still and rolling).
Is the chain over tight?

Then we can progress to the next step!

PB

[metalskin]

g'day, its not the chain. not the engine mounts, but actually in the engine itself. possibly in the gearbox.

the feeling though, is like the chain is to tight and my tires are overinflated but they arent.

the squeak is happens when im in gear as well, and when rolling (under throttle). seems to come and go but is
always there on a cold start. i want to find out what it is/could be before it does some damage as its my daily transport. cheers.

[LWC82PE]

Has the engine been rebuilt? have new bearings been fitted? if so what clearance spec......C3?

[metalskin]

Has the engine been rebuilt? have new bearings been fitted? if so what clearance spec......C3?

the bikes done 14,000k's.. no idea about the engine, very possible its all original..
would new bearings squeak? ive never encountered that before, and the motor seems pretty
well worn in, the bike itself rides fine, suspension is as good as, or better than a new ag bike.

heres a short vid http://www.youtube.com/watch?v=7CuJXu9Z-rU

its most noticeable from 5 - 13sec. the bike/noise sounds like a squeak/screech, not a vague high pitched
rattle sound that is in the vid, its the cameras crappy audio that made it sound that way. cheers, metalskin.

[LWC82PE]

ok its not a tight bearing then if its all original stil. Some engines dont like bearings that are not C3 clearance and so they heat up and tighten up and can squeel. I was only reading about it this afternoon when i was looking through some notes on rebuilding Adler motors which i was doing (so it is fresh in my mind today) and as they are well built German twin motors they dont like it when C3 bearings are not used as theres not enough clearance so a few guys have have had this problem. One inparticular sent a bearing away to be tested and the bearing company said ' not enough clearance for this application, you require C3' I have always used C3's so never had a problem.

have you checked on the gear box oil level? could be low on oil

[metalskin]

checked the gearbox oil too. oil is clean as, just sitting it on without doing it up tight it sits at max level,
so i assume if it was done up it would read just over the maximum.
the previuos owner had maintained the bike to original specs, so would more than likely contain the right amount.

[metalskin]

it also seems to struggle a bit around the same rpm, bit of a dead spot around 3700rpm,
i just figured it was the points but its getting worse and it also seems to be around the same rpm. i have a
pinhole in the header section of the expansion chamber about 2x3mm, could this cause the dead spot?
also in 1st/2nd gear if i let it hit 6500rpm it sounds like a bucket of bolts being tipped over the top end.
also sorta lags coming back to idle, but i again put that down to the  points ignition system but im thinking
it might be an air leak, possibly the crank seals as it seems to get worse when the bikes hot.

whats the lifespan of a single cyl 2 stroke? will it be reliable even though its not running 100%?

sorry for all the questions. i guess its looking like a full rebuild/replacement engine might be the go. cheers for the reply's. metalskin.

[LWC82PE]

i reckon you would be better off to take it to a bike mechanic who can then listen to it run and stick his stethoscope on it to determine where the noice is comming from before you jump in for a rebuild which may be unecessary.

[metalskin]

i would but most places want like $80 to 'look' at a bike, and it doesnt fit into my budget. also, i've had probs
in the past with bike shops not listening to me. like doing work i never asked to be done, or that didnt need to be done.

for eg, i have a honda cb400 i cant get a straight quote on because they all want to see the bike,
even though i told them exactly what the prob is, and told them i just want new rings and a quick hone,
but even then they cant give me a rough price.. then when i say look i'll supply the parts, they are always quick
to tell me they would prefer to get what it needs because it 'will' need more, and how do they know when
they haven't seen the bike witch is why they cant tell me in the first place?
every 2nd place i speak to says, 'oh yeh, its not your rings, give us your bike and we'll fix it for $300 it will just be dirt in the carbys'...
right, like im going to take my bike to someone that will charge $300 (yeh thats a whole 4hrs!) for a job i already did myself..
if anyone can reccomend a bike shop in the melb city area thats straight up with their customers then please let me know.
i cant find one, im sure there is one though. cheers.

[dalesween]

good luck in the city ,they all seem to treat people like they have been riding for 5 mins.I have had all my work done at slipstrem m/cycles in Sunbury and have been happy so far.

[LWC82PE]

Ok I understand that. i am in the trade myself but dont treat customers like that. Its too bad your not out in the country somewhere where a repairer will value you and treat you right. Sometimes i will have people ring up and try to get you to work out whats wrong with their bike over the phone and you can be talking for 15/20mins sometime. That could be time I’m doing some actual work but in the end if you can help them you do because if they have a good experience with you they will pass it on and tell their friends or will come around an buy a bottle of oil off you or give you a 6 pack of beer so it all works out good in the end. I’ve said this before but, I dont understand how some shops/repairers treat their customers and still remain in business, like telling them they need a brand new $350 carby when all thats wrong is dirty points or a broken wire.

[Canam370]

 If the bike has done 14,000k's and a lot of it on the road its pretty likely its going to need a rebore given the description of the rattly top end. If you've been around bikes for 'more than 5 mins' then pull the top off yourself and check it. If you don't know what the specs need to be to check the wear then take the bits to a shop and let them have a look - most won't gouge you for that and your labour doesn't cost.
 Having a hole in the chamber header wont be helping matters either as the engine will be sucking air from there too.
 If you suspect that it is drawing air then check the obvious spots by spraying some CRC around the joints etc. You might also have leaks at the base and head gaskets which will give you a squeak at lower rpm until the engine heats up and closes the gap. Either of these gaskets leaking will give you running issues. Also check the centrecase sealing using the CRC too. The CRC will provide a temporary seal and will change the way the bike runs either by sealing the leak or by being drawn into the engine and changing the mixture. Aerostart or Start ya Bastard is also good and it kills spiders too!
  Most shops will want to see the bike just in self defense. Old bikes can be a can of worms where any number of repairs have to be performed just to get to the initial problem and fix it. Most old bikes have suffered through owners with 'intercourse fingers' in their life. While it can seem condascending getting all the questions shot at you the idea is to try build a picture about whats going on with the bike so not too much time is wasted chasing the wrong diagnosis supplied by a knowledgeable mate.
 If you don't want to pay a shop then get a manual and learn to do the basic stuff yourself. You'll feel better knowing that you've repaired it to your own satisfaction.

  I am happy to echo Leiths sentiments.

[oldfart]

Is it the old model with a push rod clutch   worm drive .

[LWC82PE]

good point about the leaky head/base gaskets, i was going to suggest that aswell. Canam370 makes a good point. Sometimes once you start working on a bike, problems can snowball and you can find more unexpected things wrong. Usually i will give a rough quote but always say 'thats if we dont find any horrors inside'