Z400 Backfireing Through Carb Wont Start. - Suzuki Z400 Forum : Z400 Forums
  Yamaha YFZ450

Suzuki Z400

Suzuki LT-R450



Kawasaki KFX450

ATV Videos

Can-Am DS450
 

Reply
 
LinkBack Thread Tools
Old 11-24-2008, 07:51 PM   #1 (permalink)
:::Rookie Rider:::
 
Join Date: Nov 2008
Posts: 19
Default

I have an 03 z400, a while back it jumped timing, I put a new timing chain and piston/rings.
It cranks over, but wont start. If I spray starting fluid through the carb it will spin over but back fire out the carb when it attemps to start.

I checked the valves, they all look straight, The timing marks are 2, 2 top dead center and 15 notches on the chain. What am I doing wrong here?
brandon1566 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 11-24-2008, 09:47 PM   #2 (permalink)
:::Mini LT80 Rider:::
 
Join Date: Nov 2007
Location: south louisiana
Posts: 245
Default

when you set tdc which way did you spin the 17mm crank shaft nut. dont go clock wise. spin the crank counter clock wise or you will have some slack in the timing chain which could cause your timing to be off a bit.
__________________
04 dvx,05 shocks, ims bumper,rebel riders desert grab bar, full yoshi rs3 exhaust, pro design intake, dyna programable, cylinder works 435, stg 2 hotcams, port-n-polished head,kibble white valves, drz springs
deviousdvx is offline   Reply With Quote
Old 11-24-2008, 10:12 PM   #3 (permalink)
:::Ozark 250 rider:::
 
Join Date: Sep 2008
Location: Gaston, Or
Posts: 288
Default

QUOTE (deviousdvx @ Nov 24 2008, 06:47 PM)
Quote:
when you set tdc which way did you spin the 17mm crank shaft nut. dont go clock wise. spin the crank counter clock wise or you will have some slack in the timing chain which could cause your timing to be off a bit.[/b]
sounds like it's 180 out to me like it was set on tdc on the intake stroke instead of the exhaust stroke.
jbsilverado is offline   Reply With Quote
Old 11-24-2008, 10:18 PM   #4 (permalink)
:::Mini LT80 Rider:::
 
Join Date: Nov 2007
Location: south louisiana
Posts: 245
Default

you mean it should be tdc on compression not exhaust
__________________
04 dvx,05 shocks, ims bumper,rebel riders desert grab bar, full yoshi rs3 exhaust, pro design intake, dyna programable, cylinder works 435, stg 2 hotcams, port-n-polished head,kibble white valves, drz springs
deviousdvx is offline   Reply With Quote
Old 11-24-2008, 11:40 PM   #5 (permalink)
:::Rookie Rider:::
 
Join Date: Nov 2008
Posts: 19
Default

QUOTE (deviousdvx @ Nov 24 2008, 07:18 PM)
Quote:
you mean it should be tdc on compression not exhaust[/b]

That I didnt know, so I need it to be tdc on compression stroke then put the intake one 3, exhaust on 2 with 15 links inbetween?

When I did it, I just did tdc 3,2.

Ok heres another ? How do I make sure its tdc on compression stroke.

Thanks for the help
brandon1566 is offline   Reply With Quote
Old 11-24-2008, 11:54 PM   #6 (permalink)
:::Rookie Rider:::
 
Join Date: Nov 2008
Posts: 19
Default

Okay, I just checked it.....

I spun it over counter clockwise with a rod down the spark plug hole, then 3 intake 2 exhaust is straight up, The cam lobes are pointed out and the piston is tdc.

If it was 180 out wouldnt the piston at this point be at the bottom?

brandon1566 is offline   Reply With Quote
Old 11-25-2008, 09:12 AM   #7 (permalink)
:::Ozark 250 rider:::
 
Join Date: Sep 2008
Location: Gaston, Or
Posts: 288
Default

QUOTE (brandon1566 @ Nov 24 2008, 08:54 PM)
Quote:
Okay, I just checked it.....

I spun it over counter clockwise with a rod down the spark plug hole, then 3 intake 2 exhaust is straight up, The cam lobes are pointed out and the piston is tdc.

If it was 180 out wouldnt the piston at this point be at the bottom?[/b]
yes you are on tdc then
jbsilverado is offline   Reply With Quote
Old 11-25-2008, 09:32 AM   #8 (permalink)
My Mechanic is a Loser!
 
blackkawi400's Avatar
 
Join Date: Sep 2005
Location: Oklahoma
Posts: 1,842
Send a message via Yahoo to blackkawi400
Default

Check your valve clearances...

I'm betting they are pretty tight....
__________________
'04 KFX400

On the lookout for the best part's ever made for this bike....if you have something interesting or unique, let me know.

LRD Attitude Frame - thanks lsmokinredneck!
Laeger Pro-trax front end - ?
Hinson quick change clutch cover - ?
blackkawi400 is offline   Reply With Quote
Old 11-25-2008, 09:55 AM   #9 (permalink)
:::Rookie Rider:::
 
Join Date: Nov 2008
Posts: 19
Default

QUOTE (Blackkawi400 @ Nov 25 2008, 06:32 AM)
Quote:
Check your valve clearances...

I'm betting they are pretty tight....[/b]

If they are tight, what do I need to do replace the shims? Also does anyone know the tolerances? Thanks again
brandon1566 is offline   Reply With Quote
Old 11-25-2008, 10:04 AM   #10 (permalink)
My Mechanic is a Loser!
 
blackkawi400's Avatar
 
Join Date: Sep 2005
Location: Oklahoma
Posts: 1,842
Send a message via Yahoo to blackkawi400
Default

stock cams?


Cold engine, set at TDC..
IN: 0.10~0.20mm (0.0039~0.0079 in)
EX: 0.20~0.30mm (0.0079~0.0118 in)
__________________
'04 KFX400

On the lookout for the best part's ever made for this bike....if you have something interesting or unique, let me know.

LRD Attitude Frame - thanks lsmokinredneck!
Laeger Pro-trax front end - ?
Hinson quick change clutch cover - ?
blackkawi400 is offline   Reply With Quote
Old 11-25-2008, 10:43 AM   #11 (permalink)
:::Rookie Rider:::
 
Join Date: Nov 2008
Posts: 19
Default

QUOTE (Blackkawi400 @ Nov 25 2008, 07:04 AM)
Quote:
stock cams?


Cold engine, set at TDC..
IN: 0.10~0.20mm (0.0039~0.0079 in)
EX: 0.20~0.30mm (0.0079~0.0118 in)[/b]

Alright, I think we found the problem, now what to do about it, I bought some feeler guages and a compression tester,

on exhaust I was able to get a .010 under one side and .008 under the other.
on Intake side, I couldnt really get the .008 under it.

Assuming I did this correctly, you put the lobes up in the air, and measure under the backside correct?

Also spun the engine over, has no compression I mean it really didnt even budge the guage. It has a new 12.1 piston and rings
brandon1566 is offline   Reply With Quote
Old 11-25-2008, 04:03 PM   #12 (permalink)
:::Rookie Rider:::
 
Join Date: Nov 2008
Posts: 19
Default

Alright got her going, its slow, It was the valves being too tight...

mid way through the rpm it kinda falls on its face then picks up. Now that I have the 12.1 piston and full exhaust im assuming I need jetting. Thats another task. thanks all for the help
brandon1566 is offline   Reply With Quote
Old 11-26-2008, 11:22 PM   #13 (permalink)
:::Official Spammer:::
 
Join Date: May 2008
Location: Sweet Home Alabama!!
Posts: 3,766
Default

yes if its midway then it would be the needle or main jet depending on exactly what you are considering the middle. good find on the valves. when it gets hard to start go to the valves....
__________________
Suspension & Appearance
GT Thunder front and rear shock with link, pro armor skid plates throughout, shredder rear tires 20x11 R9, IMS pegs with kick up, IMS nerf bars, IMS heel guards, IMS brake and clutch lever, +2 lone star a-arms, +1 houser Stem, pro taper fat bars, DRZoo2 dash, gusseted frame, RTC scoops, louvers & levers, RPM axle, yz start buton, precision stabilizer, quadtech seat cover and memory foam seat upgrade
Engine
ESR intake with splash guard, yoshi full exhaust, megacycles cams, (ricky stator and new starter gears thanks to flywheel bolts), vortex 10x ignition, Athena 434 FCR 39mm carb, Kibblewhite black diamond valves & springs, DRZ base gasket,DID timing, engine ice, -16oz flywheel, pro design impeller, secret clutch package with hinson basket.

Build Thread
eric.w.13 is offline   Reply With Quote
Old 11-27-2008, 10:38 PM   #14 (permalink)
:::Ozark 250 rider:::
 
suzukiray's Avatar
 
Join Date: Feb 2005
Location: SoCal
Posts: 370
Default

Look, if it jumped timing & it is now back firing through the carb you need to do a leakdown test to see if you bent any valves. If you DID it doesn't matter what else you do, it is NOT going to run correctly till you fix that. It's called "process of elimination" when trouble shooting. You don't even need the cams in the motor to do a leakdown & that's where I would start. Ray.
__________________
06LTR450 05LTZ400 03LTZ400 01Blaster 96LT80 92LT80 87Badger80 86LT250R 85LT250R 96GSXR1400Dragbike 96GSXR1500Dragbike 90GSXR1170Dragbike 85GS1150E 83GS1100SD 83GS1100ESD 83GS1100E 82GS1000SZ 04SDG110 Pitbike
suzukiray is offline   Reply With Quote
Old 11-27-2008, 10:58 PM   #15 (permalink)
:::Official Spammer:::
 
Join Date: May 2008
Location: Sweet Home Alabama!!
Posts: 3,766
Default

QUOTE (suzukiray @ Nov 27 2008, 09:38 PM)
Quote:
Look, if it jumped timing & it is now back firing through the carb you need to do a leakdown test to see if you bent any valves. If you DID it doesn't matter what else you do, it is NOT going to run correctly till you fix that. It's called "process of elimination" when trouble shooting. You don't even need the cams in the motor to do a leakdown & that's where I would start. Ray.[/b]
yeah thats true i just figured that if it ran then the valves should be straight. i could be wrong considering they did not have any clearance when he checked.
__________________
Suspension & Appearance
GT Thunder front and rear shock with link, pro armor skid plates throughout, shredder rear tires 20x11 R9, IMS pegs with kick up, IMS nerf bars, IMS heel guards, IMS brake and clutch lever, +2 lone star a-arms, +1 houser Stem, pro taper fat bars, DRZoo2 dash, gusseted frame, RTC scoops, louvers & levers, RPM axle, yz start buton, precision stabilizer, quadtech seat cover and memory foam seat upgrade
Engine
ESR intake with splash guard, yoshi full exhaust, megacycles cams, (ricky stator and new starter gears thanks to flywheel bolts), vortex 10x ignition, Athena 434 FCR 39mm carb, Kibblewhite black diamond valves & springs, DRZ base gasket,DID timing, engine ice, -16oz flywheel, pro design impeller, secret clutch package with hinson basket.

Build Thread
eric.w.13 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 12:36 AM.




Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.1