KX Riders

Maintenance & Technical => KX500 Original => Topic started by: danimal on March 11, 2010, 11:24:29 AM

Title: cold start issues
Post by: danimal on March 11, 2010, 11:24:29 AM
littel info on the machine:86 tecate 3 wheeler KX5 engine out of a 92 model year,ported,piped,stock 39mm carb,clamp on filter.....main jet is a 175 pilot is a 52(right now)i have gone from a 68 and everywhere in between on the pilot and still cold start sucks.i have tried some of the teqniqes on this forum with no luck,it will pop out the exhaust for a while,then i usually have to hold the throttle wide open for it to fire,any thoughts????
Title: Re: cold start issues
Post by: Motorrad on March 11, 2010, 11:28:50 AM
Have you checked compression?

Title: Re: cold start issues
Post by: Polar-Bus on March 11, 2010, 11:35:09 AM
Have you checked compression?



+1 !

CHECK THE SIMPLE THINGS FIRST.
Title: Re: cold start issues
Post by: Motorrad on March 11, 2010, 11:52:54 AM
Low compression motors are hard to start when cold
Title: Re: cold start issues
Post by: danimal on March 11, 2010, 11:35:37 PM
thanks what should it be?
Title: Re: cold start issues
Post by: cbxracer30 on March 11, 2010, 11:44:05 PM
Can you pull off the lean over trick with a trike ? If your compression is fine you may want to look into a mikuni jetski stlye primer setup. They work great on the souped up skis.CBX
Title: Re: cold start issues
Post by: kwakman on March 12, 2010, 12:04:48 AM
88 on motor should be in the range of 135 to 164psi.
Title: Re: cold start issues
Post by: Polar-Bus on March 12, 2010, 03:37:20 AM
Low compression motors are hard to start when cold

And hot.
Title: Re: cold start issues
Post by: danimal on March 12, 2010, 05:24:17 AM
Can you pull off the lean over trick with a trike ? If your compression is fine you may want to look into a mikuni jetski stlye primer setup. They work great on the souped up skis.CBX

yes i can tip it and allow fuel to come out of the overflow,still hard to start.i guess i should have said earlier that the topend is freash with less than 5 hours on it,soi dont think that compression would be an issue
Title: Re: cold start issues
Post by: danimal on March 12, 2010, 05:25:21 AM
88 on motor should be in the range of 135 to 164psi.
its a 92 motor
Low compression motors are hard to start when cold

And hot.
starts on the first kick hot
Title: Re: cold start issues
Post by: stewart on March 12, 2010, 09:38:30 AM
its the condition of the crank seals not giving a good vacum to pull fuel and get it up to the top end i would wonder about on a older motor..
Title: Re: cold start issues
Post by: dave916 on March 12, 2010, 07:53:46 PM
is the choke working properly?
does the choke kill the motor when hot?
whats your plug colour. does it look lean?
what is the condition of carb ?[could be badly worn throttle slide]
going from 68 pilot to 52 is now going to make the bike much harder to start.
 maybe your clamp on airfilter and porting requires richer jetting
 the 68 pilot could have been fitted to mask a  lean condition ,witch  could be caused by a worn or dirty badly jetted carb or a air leak in motor [a leakdown test would be needed ]


when i am starting mine from cold i have the throttle closed,  choke out,  i only work the throttle when i give it a few primer kicks,
 
Title: Re: cold start issues
Post by: kwakman on March 12, 2010, 10:18:10 PM
88on includes a 92.135 - 164psi.
Title: Re: cold start issues
Post by: cbxracer30 on March 13, 2010, 12:13:24 AM
Do you get a full kick , with the K5 motor in the 3 wheeler frame ? you may need quite a few primer kicks. CBX
Title: Re: cold start issues
Post by: danimal on March 15, 2010, 05:06:07 AM
is the choke working properly?
does the choke kill the motor when hot?
whats your plug colour. does it look lean?
what is the condition of carb ?[could be badly worn throttle slide]
going from 68 pilot to 52 is now going to make the bike much harder to start.
 maybe your clamp on airfilter and porting requires richer jetting
 the 68 pilot could have been fitted to mask a  lean condition ,witch  could be caused by a worn or dirty badly jetted carb or a air leak in motor [a leakdown test would be needed ]


when i am starting mine from cold i have the throttle closed,  choke out,  i only work the throttle when i give it a few primer kicks,
 


the choke seems to work properly,i have tried another identical carb off of 1 of my other machines and had the exact same results,so that would eliminate the carb being worn or the choke not working.
its hard to tell the plug color,i have done the WOT plug chops and have that dialed in,so i guess the plug looks normal,but the 2 stroke oil may give mixed results?

that is what i ma saying,i have gone from a 68 to a 52 on the pilot with all the increments inbetween,with almost the same results
Do you get a full kick , with the K5 motor in the 3 wheeler frame ? you may need quite a few primer kicks. CBX

yes i get a full kick,and im 6'3 240 lbs so there is some ass behund it as well :-D
Title: Re: cold start issues
Post by: fluffy on March 15, 2010, 12:08:43 PM
1989 stock 500,dont touch the gas,pull up the choke,kick it 7 or 8 times starts every time. has to warm up at least 5-6 minutes at least before i can get it off the ground.
Title: Re: cold start issues
Post by: 98kaw500rider on March 16, 2010, 10:55:55 AM
This is how i start my 98 k5 . Choke and gas on , hold the kill switch in and kick her 3-4 times like your trying to start it . Let go of the killswitch and find top center and boot her , mine fires up in 1-3 kicks everytime.
Title: Re: cold start issues
Post by: Motorrad on March 16, 2010, 01:27:26 PM
I still say low on compression... My 87 was exactly the same.   New rings cured it.  Would have to be dragged when cold, after lit it would be good till the next time it sat for more than 4 hours or so....
Title: Re: cold start issues
Post by: kawi4ever on March 16, 2010, 02:34:14 PM
Hi wanted to also agree with stewart that its most likely your crank seals, they are not alowing a proper vacuum when cold to suck the fuel in  and causing a lean backfire out of the exhaust. Hope this helps  :-D
Title: Re: cold start issues
Post by: danimal on March 18, 2010, 02:35:27 AM
thanks for all the help guys,unfortunatley i leave for little sahara ok next week,so i wont be have time to do a vacuum test until i get back,i will keep you guys updated.....Also Stewart expect a pm from me for port work when i get back as well :evil:tahnks again