push start only - wont kick start

[yosi]

Ive got the original yamaha manual. Pretty sure it has similar stuff in it??

[bansheesandrider]

You are supposed to keep 1 of the plugs in when you do the test, otherwise all of the pressure that you are trying to read will escape out of the open plug chamber. Also, the aluminum plate that attaches to the carb side of the airbox on the inside usually made by pro flow is what hes talking about. The filter slides onto a cage which is part of that plate, on an aftermarket setup. If yours is stock, the aluminum plate wont be there, and the filter will slide into a plastic groove moulded into the front of the airbox, and can rattle loose under bumpy conditions.

When I went to mechanic's school many years ago, I was taught the proper wat to do a compression test on ANY engine was to warm up the engine and remove ALL the spark plugs.I have always done it that way and on my personal bike I got 185 psi after the rings were seated doing it that way. So, how was the compresssion transfering from 1 cyl to the other if my compresion was that high? How would it transfer anyway as they are two seperate cylinders and it is certainly NOT the spark plug that seperates one cylinder from the other? If the plug is out of the second cylinder it lets the motor turn over easier as the second cylinder has no resistance from compression and you are only wanting to read the compresion in the cylinder the gauge is installed in.

 

Yes there is a groove in the airbox, but the lid has 2 fingers that come down and hold the filter into the groove.

Edited October 30, 2010 by bansheesandrider

[yosi]

Hey

 

Ok so i havnet found the time to take off and clean the carby's and check the reeds but Ive had a quick look at the bike and i noticed that the pilot air screws were scewed out way too far. On the left carby it was screwed out 4 1/4 turns, and on the right one it was around 5 turns out. So i changed them to be 1 1/2 turns out. But still it wont start.

 

I also noticed that where the exhaust attaches to the engine, there seems to be a little air which is leaking out form the seal. Is a gasket supposed to be there, its kind of hard to see whether there is one or not. The exhaust springs are also quite loose, might need to get some new ones. (Will this leaking cause the compression to become less, for the fact the air is escaping from the cylinders??)

 

Thanks

[yosi]

anyone??

[12 0 Clock P I M P]

anyone??

DO you know if u have a cracked reed? - check that......

 

your chasing a dead horse if you have an issue that your not addressing first.......

 

adjusting pilots on a dirty carb is pointless as well.....all it takes is a piece of dirt or sand to clog something.......so take them off....find out what jets are in there....clean them up....and adjust to recommended specs

 

with both spark plugs out you should still get a very accurate reading on your compression test......they are seperate cylinders and wont matter .....if it runs by jumpin it...but wont kick.....its very possible u have a low compression issue.....

 

your carbs also may be dumping wayyyy too much fuel in causing flooding but when u jump start it ....it will run........then fire up afterwards when warm because the fuel is burning at that point..........

 

you need to take it slow and take time.......get it right or u will be chasing all day

 

make sure the carbs are synced up as well............that means both carb slides rising and dropping equally.......and when u release the throttle u hear one solid thud...not two

[yosi]

righto will get everything checked this coming weekend.

 

As for the leak where they attach to the cyclinders, will that cause a lower compression reading?

[thrill-billy85]

Dude..... For fuck sake.... Check your reeds... That's MOST LIKELY what's wrong. I had the EXACT SAME problem... It was cracked reeds.

 

Stock setting for the pilot air screw is 2 turn out.

 

If you're talking bout air leaking at the cylinder/pipe joint, no it won't cause low compression. You're probably gonna need a new top end, but get the thing running first. When you take the carbs out, don't take them apart till you fix your reeds. And make sure you put the choke tube between the two carbs back in place. Also if/when you take apart ur carbs to clean them, do one, put it back together, THEN do the other one. This will help u keep from getting the parts switched up (which look the same, but are NOT always interchangeable.

 

Good luck

[yosi]

Ok so ive found some time to pull out the carbys and clean them and check reeds jets etc. im currently putting back together the second carb.

 

So i now know that im running 340 main jets........and the stock 25 pilot jets. Is this jetting good for my bike ( running fmf pipe and silencers, open air box... no lid, and K&N air filter with outer ware). Im also at sea level, and will be running the bike between 10-35 degrees celcius.

 

Checked reeds, they are not stock but carbon reeds, not sure what brand, but they are in the stock reed cages. No cracks or nothing, look new.

 

I will get it started tommorow and post to say whether it started or not.

 

Thanks again for everyone that helped me, much appreciated, just tyring to learn here.

[fastbanshee8]

Put some 27.5 pilot jets in those carbs. It's starting hard, because it's lean.

Edited November 12, 2010 by fastbanshee8

[bansheesandrider]

Ok so ive found some time to pull out the carbys and clean them and check reeds jets etc. im currently putting back together the second carb.

 

So i now know that im running 340 main jets........and the stock 25 pilot jets. Is this jetting good for my bike ( running fmf pipe and silencers, open air box... no lid, and K&N air filter with outer ware). Im also at sea level, and will be running the bike between 10-35 degrees celcius.

 

Checked reeds, they are not stock but carbon reeds, not sure what brand, but they are in the stock reed cages. No cracks or nothing, look new.

 

I will get it started tommorow and post to say whether it started or not.

 

Thanks again for everyone that helped me, much appreciated, just tyring to learn here.

Yes, it would seem that you need to go up on your pilots, but I think you also need to go down on your mains. My wifes bike at sea level and setup similar to yours ran 290 mains and 27.5 pilots.

[yosi]

yes i was thinking the same. but how big should i go on my pilots because if heard quite a few people run 30/32.5. would that be too big? Also for the mains i might try 300's or 310's.

 

Thanks for the advice guys

[fastbanshee8]

27.5 pilots. No more questions about them.

[yosi]

Righto, went shop today to get my jets, didint have any is stock, so i ordered some 27.5 pilots and 310 mains. Should hopefully get them in 3 days and get bike running.

[yosi]

Ok so i just got my pilots and mains, and when i was installing them i noticed that where the main jets screw in there was a brass washer in one carby, but in the other carby there was no washer. Is this normal??

 

Am i able to install the jets with no washers, or do i need to get another washer....if so must it be the same factory one.

 

Or can i just use the one washer in one carby and no washer in the other carby.....does this affect performance?

 

Again sorry for all the questions

[Larry's Shee]

Yes you need it. You are sure it was missing when you took it apart ? Look real good around where you took it apart , crawl on the floor if you have to. Don't know if it's available seperate from Yamaha . Maybe a mate has a dead bike/quad you might swipe one from. Worse case get a complete carb rebuild kit. The slide needle goes into the jet therefore without one both carbs won't opperate same.