Suzuki Quadracer HQ

LT500R Quadracer => LT500R - Engine => Topic started by: MrMendo2 on January 06, 2013, 08:07:58 pm


Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 19, 2013, 05:28:57 pm
I know it is but im at a crossroads listen to my wife or not lol . Jerry is an awesome guy and knows his stuff very intelligent and easy to talk to definitely would recommend to anyone. Weather you are seasoned in motors or not he will explain everything in layman's terms and more advanced terms depending on your knowledge.
Title: Re: LT500 Spark Plug Piston Problem
Post by: GrkGuy on January 19, 2013, 05:01:19 pm
 your bike is in great hands. when you get it back
it will be better than new.
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 19, 2013, 02:52:36 pm
So I dropped off my bike with jerry. It might end up being up to 2200. I paid 1600 for the bike I might just part it out. He's going to open up the bottom end and let me know the good or bad news. :( or :)
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 14, 2013, 01:11:04 pm
Thanks guys will do!
Title: Re: LT500 Spark Plug Piston Problem
Post by: Rider414 on January 14, 2013, 09:41:26 am
DO NOT RUN THE MOTOR LIKE THIS!

I think I know what happened.

I'd bet the guy who o-ringed the head took off the original head gasket then o-ringed the head and stuck it back on without checking anything much less cutting the squish, dome, adjusting the deck height.

Take it to Jerry he should be able to fix it pretty easy.

It might be faster and cheaper to just bring him the head, jug, & piston but check with him first.






THIS x2
Title: Re: LT500 Spark Plug Piston Problem
Post by: Glamisrider on January 14, 2013, 08:53:27 am
DO NOT RUN THE MOTOR LIKE THIS!

I think I know what happened.

I'd bet the guy who o-ringed the head took off the original head gasket then o-ringed the head and stuck it back on without checking anything much less cutting the squish, dome, adjusting the deck height.

Take it to Jerry he should be able to fix it pretty easy.

It might be faster and cheaper to just bring him the head, jug, & piston but check with him first.



Title: Re: LT500 Spark Plug Piston Problem
Post by: GrkGuy on January 14, 2013, 07:01:47 am
just take head off of bike then cycle motor over and watch to see if piston rises above cylinder, if not
you will need a new head, someone just took way to much off of that one, not sure if you can double
up on the gasket tho, but 250 heads are cheap
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 13, 2013, 05:17:13 pm
I work 5 days a week. and bike is not in my backyard or else id love to do all the suggestions i am planning on picking up the bike tomorrow if not the day after so i can report to you guys, take pictures, then hear next suggestion. Had a bad day today:( Oh yea and battery went out on my truck too F MEEEEE :(
Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 13, 2013, 01:44:16 pm
I would say that is the first thing you need to check. The head to piston clearence. I know a few guys have said to do it. You really need to see how far the piston is hanging out of the cylinder and than run a squish test.

Bring piston almost up to TDC and get a piece of solder an place it across the top of the piston. From transfer port to the opposite transfer port. Install head with gasket or no gasket if you are running an o ringed head. Tighten head down and rotate the piston up and past TDC. Remove head and post picture of solder and measurements of solder closest to the bores edge and where its no longer smashed which would be toward the dome of the piston.

Also post a picture of the piston at top dead center.

What base gasket thickness are you running?

I am wondering if it was a trinity cool head. They were known for there turbo cut domes but also known for cutting the dome not with any divergence in the dome but with a convergence into the squish band.
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 13, 2013, 01:27:42 pm
Haven't had a chance do do squish test haven't had bike around. ( it's at my parents)
Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 13, 2013, 01:20:15 pm
Oh yeah. How far is the piston sticking out of the cylinder or did you do a squish test?
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 13, 2013, 01:05:50 pm
Can this be why it was eating up plugs?
Title: Re: LT500 Spark Plug Piston Problem
Post by: Rider414 on January 13, 2013, 10:07:53 am
I would thing someone decked the head or cylinder abit too much.

Title: Re: LT500 Spark Plug Piston Problem
Post by: GrkGuy on January 13, 2013, 09:32:46 am
yep, piston is hitting the head.
Title: Re: LT500 Spark Plug Piston Problem
Post by: Rider414 on January 13, 2013, 09:16:33 am
W
O
W
!
!
!
!
!

Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 13, 2013, 08:47:19 am
Or you have an invverted squish band. Meaning from the bores edge it gets closer to the piston as it gets closer to the curtains edge or edge of where the bowl start.
Title: Re: LT500 Spark Plug Piston Problem
Post by: Julle74 on January 13, 2013, 08:42:51 am
You have piston to head contact. Check Rod bearings and main bearings
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 13, 2013, 07:25:08 am
Not sure why there was 2 of the same picture.
Title: Re: LT500 Spark Plug Piston Problem
Post by: GrkGuy on January 12, 2013, 11:38:17 pm
whats up with that clean ring around the squish, is the piston hitting the head,
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 12, 2013, 10:12:52 pm
Sorry I took so long to reply to any posts this are some pictures that I found when PCS took the bike apart and this is what we found. MotorGeek anything? (before i bring it to you?!?!) :)
Title: Re: LT500 Spark Plug Piston Problem
Post by: Glamisrider on January 10, 2013, 10:54:05 am
Do a squish test and see how much clearance you have.

Since there is no write up on here on how to do a squish test (hint...hint), here is a link on how to do a squish test.
http://www.rb-designs.com/squish-band-test.htm

You should be .048-.052


How does the piston look? 

Has it been impacting the strap on the plug?

Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 10, 2013, 06:03:03 am
As stated before. Carb and head geometry checked.
Title: Re: LT500 Spark Plug Piston Problem
Post by: LT250RWV on January 10, 2013, 12:34:18 am
more oil going into the into the jet at 24 to 1 then 32 to 1. More oil means less gas once it compressed around the crank as the gas vapors go up in the ports  as the oil suspends out  of gas and falls  around the crank then the crank spin the oil up and throws it to lubricates rings bearings rod piston.I always heard 1 jets size  up  or down for 4 oz of oil you put in or take out.
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 09, 2013, 10:59:30 pm
So how do I this detonation problem?!?
Title: Re: LT500 Spark Plug Piston Problem
Post by: MotorGeek - Jerry Hall on January 09, 2013, 10:48:22 pm
Hey guys new to the forums, have had this problem took the motor apart and now the motor is just sitting in my house.

So what was happening is the piston is slapping the spark plug out. It is bending the plug and the bike will turn off. When I bought the bike it wasn't happening but after about 2 hours of use it started happening. What I want to do is fix the bike to sell it but I don't want the next person to buy it with problems. It's the 87 with cool head. Let me know if you guys need any more information. On the motor it also says "WEBER" on it if that means anything to you guys.

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I have never seen the piston hit the spark plug on a LT 500 unless the pieces of broken piston are hitting it.


Detonation will over heat the ground strap and sometimes burn the end off.   


Detonation will over heat the center wire and cause the center wire to expand and break the ceramic cone surrounding it.


Detonation will cause the spark plug to come loose.


Detonation will eat through the head gaskets and o-rings.


Detonation will eat away at the edges of the piston and cylinder head.
Title: Re: LT500 Spark Plug Piston Problem
Post by: PCS on January 09, 2013, 07:51:30 pm
Going from 32:1 to 24:1 will lean out the fuel.
how would increasing the oil concentration in the pre mix lean out the fuel?
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 09, 2013, 06:40:50 pm
So did we conclude that this was probably because I went from 32 to 1 to whatever I was running? Should I use only 110 fuel or what kind of of fuel should I use I just have to get some gaskets to get this think back up and started. :)
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 11:17:32 pm
Pretty white. Can't attach with my phone.
Title: Re: LT500 Spark Plug Piston Problem
Post by: El Diablo on January 06, 2013, 11:12:44 pm
PCS! Yup!

What color is the porcelin?
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 11:06:31 pm
Brian I think I know who you are!!! Pedro Sanchez ring a bell?! Porcelain looks okay not **** or anything.
Title: Re: LT500 Spark Plug Piston Problem
Post by: El Diablo on January 06, 2013, 10:53:20 pm
If I remember correctly, I had a 190 jet when I used to have my Kehin. But it all depends on engine mods. Other than the bent tip, how does the porcelin look?
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 10:02:56 pm
hey guys just opened the carb 180 and 55 jets.
Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 06, 2013, 09:13:41 pm
Im assuming flywheel and stator are in good shape and tight. Timing marks lined up. Going from 32:1 to 24:1 will lean out the fuel. Need to know what jets are in it.
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 09:06:24 pm
Throttle will be all around i usually like running wide open but sometimes putt around. El diablo im in somerton bike is in the foothills. The carb is a PWK 39. Mixing 24 to 1 but the guy said to run 32 to 1.
Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 06, 2013, 08:54:32 pm
Got to be detonation. Its rattling so bad its dropping porcelin. Jerry Hall is closest to you. Might want to get that dome checked. What are you mixing your fuel out? Look around the flat area around the carb whefe thr bowl meets up. Should tell you what size carb it is. Need to see what the internals are in it. Where exactly in the throttle position is this happening? Half throttle cruizing around. Idling or wide open?
Title: Re: LT500 Spark Plug Piston Problem
Post by: El Diablo on January 06, 2013, 08:52:22 pm
Yay! another guy in Yuma! What part of town do you live? Anyhoo, not sure if it will make any difference but try an NGK B8EGV spark plug. Who built the engine?
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 08:41:23 pm
Last picture in last post was the last spark plug the popped on me(broke nipple).
Title: Re: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 08:38:43 pm
Was running 110 because the guy told me it HAD to run race fuel. Keihin PWK (on the side it says 72RA4  TJR) not sure on jets (its been a while since i had the carb opened up) elevation im in Yuma AZ (next to Gordon Well or Glamis California) I'll upload pictures temp can range from 50 degrees to 110 degrees. Was using a BR8EG plug (the nipple came right off.) Was going to try an iridium plug but didnt want to just run through iridium plugs(BR8EIX). The first picture is the plug that got over extended.
Title: Re: LT500 Spark Plug Piston Problem
Post by: Stpltn250r on January 06, 2013, 08:18:59 pm
Detonation. What fuel are you running? Carb and jets? How is the head cut? Elevation and temp?
Title: LT500 Spark Plug Piston Problem
Post by: MrMendo2 on January 06, 2013, 08:07:58 pm
Hey guys new to the forums, have had this problem took the motor apart and now the motor is just sitting in my house.

So what was happening is the piston is slapping the spark plug out. It is bending the plug and the bike will turn off. When I bought the bike it wasn't happening but after about 2 hours of use it started happening. What I want to do is fix the bike to sell it but I don't want the next person to buy it with problems. It's the 87 with cool head. Let me know if you guys need any more information. On the motor it also says "WEBER" on it if that means anything to you guys.

 <1>