i tok my clutch basket apart to check the condition of the clutches and when i put it bacck together the pressure plate wont tighten up it acts like im holding the clutch lever in at first i thought i forgot a plate or two but have all of them (7 cork plates and 6 steel plates) all r how they supposed to go its a problem i cant figure out....i have slack in the clutch arm at the pressure plate so i know thts not the issue please help

Hi Dave,
The brain's a little fuzzy these days, but I recall an arrow on the pressure plate that needs to line up with an arrow on the inner hub.

I had an IT490 for a while, but let me know how you get on

Cheers

Glenn520, on 10 April 2012 - 03:18 AM, said:

yup thats probably it, most of the old yamaha clutches have those arrows that need to be lined up there should be 3 of them pointing at 3 of the holes for the springs

i got it thank u guys.....now i cant get it to run i cleaned the carb it acts like it wants to but then it just quits ive had the same gas in the tank for a few weeks ive heard of gas going bad but surely itll still run off it....this bike has been sittin in a garage for 12 years without a clutch cover i fibally gound one i had it going for about a month in a half i have to push stary it cuz i need a new spring the spring broke inside so it locked the tranny in first i had it running twice tht day it did tht thn i tryed it again and now its doing this

Hi Dave,
First, nothing beats a fresh fuel mix with a good quality 2 stroke oil, but a couple of weeks old will run just fine. Maybe not so good for the wearing parts though.
Try running with the choke on for 15-30 secs. If it runs then the fuel isnt getting through the main jet or the float level is wrong. Check them both.
While your at it put a fresh spark plug in. Cheap and takes most spark issues out of the equation.
Please tell me you've got all that spring out. Your gearbox will go out to lunch if you haven't.
Let me know how you get on.
Cheers

yes i got all the spring out....i have killer spark its getting fuel getting air has exhaust its got compression i have fresh gas mixed 32:1 theirs no reson it shouldnt run ot acts like its going to start but thn it quits amd yes i do have the choke on ive tried it with it off  it dont do anything

David Rogers, on 11 April 2012 - 01:03 PM, said:

David Rogers, on 11 April 2012 - 01:03 PM, said:

how old is the plug, could be fouled but still have spark happened to me once. try pop starting choke on and off

since the spring broke pop starting is the only way to go....its firing idk y it wont start up and go like i said it acts like its gonna go but then putters out stops in its tracts.....its making a wierd pinging sound tht its never done before i think i need to take the jug off and look at the piston it may b binding up in the cylinder its a pretty tired motor to begin with its never been rebuilt tht ik of i do no on the piston it says .017 idk what that means the head has been shaved 50 thousandths....i wonder if the gasket is blowed and letting tranny fluid into the crank the plug is govered in wet blqck oil i have no idea this is the first bike ive ever owned it ran like a scalded ape thn i shut it off and tried starting it and it started this stupid crap

Well the yz 490's were definitely not known for their resistance to detonation. They had horrible problems with pinging and it's suggested to have the head modified to reduce the occurrence of pinging. It probably wouldn't be a bad idea to tear into the motor to see what's up. Crank seals could definitely used replacing on a bike this old if your going to tear into the motor that far. Replace the plug even if it's getting spark, they cost 2 bucks and it may solve your problems, especially if it's covered in black goop. Just check everything out, float levels, fuel filter, etc.

Hi Dave,
If you haven't alreeady got one, get yourself a workshop manual. Invaluable reference data and how to instruction.

BTW, remove the carb and the reed block, make sure the reed petals are all there. If not, it's build time.

Good luck.

its not the plug i gotta new one same shit....all the reads r there i just had it a part...i wonder if it could b the coil? i dont wanna have to take the motorapart unless i have to when i take the plug out and kick it it sparks only half the time

i dont have the money to buy a manuel does nebody know where i can download one off the internet? i can find em for an 84 it465 but not the 82 yz 490

Looks like its time to sell your bike if you don't have 30$ for a manual. How can you afford to feed that thing gas/oil? Or buy new parts for it? I can blow through 30 dollars worth of gas/oil over a weekend riding. If anyone posts things it can get them in trouble because generally free downloads aren't legal. The it465  manual would be better then nothing. It would have told you about the three arrows which are on just about every older yamaha clutch. Generally you don't have spark or do you have spark. If it's a nice spark like you said it was i'd move on to other problems. Sometimes when you kick the bike you won't get a good ground on the plug. Pushing the thing will only cause the spark plug to bounce around even more if that's how your testing spark. If it sparks I doubt you have an ignition problem. I'd retrace your steps and make sure you put everything back together correctly since you had it apart.

Have you checked float levels?
(specs from a manual come awfully handy)

Are all your jet's seated correctly?

DId you lose/ damage any parts from the carb?

Are the jets the correct sizes?

Edited by 79yamdt, 12 April 2012 - 11:49 AM.

Hi Dave, The engine ran ok until you cleaned the carb right?? If this is the case, then thats where you need to focus your attention. Retrace your steps as you cleaned it to make sure all is ok inside. Post your email address and i'll give you a PDF of the Mikuni VM service manual. It's only the carb though, not the bike.
I guess we've all been short of Benjamins at one time or another. Keep a it, its a great (but sometimes frustrating) learning experience. I cut my teeth on a DT175 in '76 as a 14 year old. Lots of mistakes lots of lessons learned.
Cheers

Save some money and get a good manual. I have a manual for every machine I own. Its possible you may have an electrical/ignition problem. I had an 83 YZ490 that had spark at times then finally no spark at all. With the help of a manual I traced the problem to a bad source coil on the stator plate. A manual also has all the specs you need for setting up and adjusting your beast.