Racing MotoGP, WSBK, BSB, AMA, F1, WRC, DTM, NASCAR, etc...

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 59 (permalink) Old 07-02-2008, 02:01 PM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Race report LMS 28-29 of June.

Once a year I have my own personal Christmas and pack up to do a week end of racing at my "local" track some 260 kms away.
Last year I had a complete seizure and I was hoping for some more luck this year but wasnīt sure as the bike had been getting serious detonations on the left cylinder during the practise day I had a couple of weeks ago. Only on one cylinder though as the other one was running just perfect. Anyway we set the ignition and had another cylinder, piston etc in for the race.
I packed up and left home on Friday night or the drive down, you get a bit sentimental when you hit the road on your own so I started missing the missus and the three kids at home. I had to get a yawning from a friend so I had to take a detour so I arrived at the track at 21:45 and was worried that Iīd get a terrible parking on grass far away from everything but I got the best spot in the paddock!
Hooked up with another guy (Dennis) that has raced once on a 250 a few years back who now had rented a TSR250 and hadnīt ridden for two years. We set the yawning up, unpacked and rolled our bikes in. I threw out the matress in the back of the van and fell a sleep. As I hadnīt taped something over the windows I woke up way to early and had a hard time to fall rest anymore.

First qualifying was at 08:50 so I got up and got breakfast and met with Teddy who would be the third guy in our yawning. I have painted his RS250R but he hasnīt managed to get any stickers on the bike so I had done a few to get that “vely factoly look!” so I had that as a surprise to him and we started with that as soon as he was unpacked.

At 08:00, you are not allowed to run any bikes before that, I followed two stroke procedure and started her up to let everyone now it was time to wake up and that they are at a race track.
Got a bit of butterflies before we got out and the first session felt awkward as always but I had done a 1.07.099 wich was a full second and a half faster than last time I was at the track. Good riddance but still a fair bit too slow ( Fredrik Watz does the lap in mid 57s on a 250…)

Tanked up and choose not, what a fool, to check the pistons during the intermission to the next session. Had a good time a talked to friends. Teddy did a 1.05.4 and Dennis did a 1.06.2 on his first time on the bike.
Got out for the second practise and felt better but on the straight I heard the sound of a two stroke engine not wanting to cooperate more so I clutched it and managed to roll to the paddock, I managed to lower my time slightly to 1.07.001….while Dennis was down to 1.03.733 and Teddy 1.04.056.
Bad feeling as the spark plug was way to silver to be good and you could see aluminium coating it…get the cylinder head off and looking down the cylinder is not a pretty sight as the pistons is so detonated that you can actually see the piston ring with the piston in the cylinder….serious heat has been going on. The weird thing is that the water was running just fine with 56-58 C but the EGT was reading way off the chart as the highest temp on the seized cylinder was at 488 C and the other one was at 590 C…
For some reason that cylinder was ithe rnot getting enough fuel, sucking air trough the exhaust or the ignition was way off.
We stripped the carb and found a small piece of tank foam inside the power jet. We also checked the solenoids and they were acting the same on both cylinders. New cylinder and a used piston was thrown in. Assembled it all in time for the race and crossed my fingers.

As usual I got a fairly crap start but I managed to pass some guys on the first two laps and managed to get behind a faster guy so I felt the pace was a bit better but on lap eight I had the exact same thing happening as in the second Q and I clutched and rolled to the paddock. Clearly the foam wasnīt the problem. Setting a new personal best with 1.06.501 didnīt help much…
A bit depressing but eventually I got going and ripped the bike apart and it looked exactly the same. Left cylinder fine and the right one terrible with exactly the same pattern and a seized piston.
I had a lot of help, as usual from fellow 250 maniac Anders Kihlander (he runs 58.4 times on his Aprilia RSV250 at this track) so we checked everything we could check. Ignition, solenoids again, stripped the carbs, synchronized the power valves and carbs, checked the exhaust for cracks, checked reeds and carb mount but we just couldnīt see any major problem so we opted to run the cylinder really safe and went from a 0.7mm squish to a 1.3mm wich means the compression ratio will be very low and hence reducing the risk of detonations.

For Sunday we decided that Iīd just do four or five laps and then get in so I could check if the changes had worked.After the first session I went in and stripped the head and it all looked fie and as it should do. Nice!

For the second practise we geared the bike differently with the idea to be aable to ru second instead of first as it was just too snappy. It started terrible as I didnīt have any feeling and just tried to hard so I went in to the pit lane and sat for a minute, checked the times and my best was a 1.07.9! So bad!
Got out again ad really tried to concentrate at getting the entries right and with more speed so that I could run second as planed and it really started to feel nice and it felt much faster.
I managed to set several 1.06.5 times and lower with a best of 1.06.110. Whohooo! I had lowered my personal best with 1.8 seconds since last year.
Something positive, and the cylinder looked great so I was happy with that.
Dennis was storming to pole with a 1.01.9, second day on the bike…

I was going to start as 11th, the class is a real mix of 125GP bikes with mostly fast, young guys, some older gentlemen on 250GPs, some Aprilia RS250s, one Kwacker ZXR400 and two SV650s..
I am lousy at starting and did by my accounts fairly ok and passed Teddy on the brakes in to the first corner only for him to pass me getting in to the corner leading on to the main straight, this is my real bogey corner at this track as I really have no entry speed. Going down the straight I used the power to pass som e of the small guys on 125s.

Passing the line for the first time I had the first of the two SV650s right in sight and I was determined to get by him but I felt the clutch starting to slip a bit and when we got on the main straight were I usually can pass them with ease it got even worse so I had to start short shifting and loosing momentum. Damn!
From here on it was just a struggle and I put the nail in my own coffin on the eight lap when I saw that my AIM logger had switched off, I log the EGT so it is valuable, I used my left hand to turn it on again going down the straight when the bike just went dead, silent and no revs. Because of the problems I had experienced I thought that it had seized again! After the race I got in and stripped both heads and they both looked great….strange so I put it back together and she started like a sweat dream.
When I started recalling what must have happened I got to the conclusion that I accidently turned the ignition off when grabbing the handlebar after turning the AIM logger on! What a fucking stupid thing to do!

Anyway I am fairly pleased with the fact that I managed to run a much better pace than last year. The only problem is that I still do not know exactly what caused the melt pistons. I will raise the compression again and see what happens but it is annoying that we didnīt find the problem.
Hopefully I can do one more race this year and I will be back with more rants then!
Attached Images
File Type: jpg LMS-B-race-1.jpg (113.2 KB, 3 views)
File Type: jpg LMS-B-race-2.jpg (82.5 KB, 8 views)
File Type: jpg LMS-B-race-2008-1.jpg (167.7 KB, 2 views)


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Gustav O; 07-02-2008 at 02:05 PM.
Gustav O is offline  
Sponsored Links
Advertisement
 
post #2 of 59 (permalink) Old 07-02-2008, 02:51 PM
Resident Redneck
 
Biga's Avatar
 
Join Date: Mar 2006
Location: On This Forum
Posts: 9,793
   
Send a message via Skype™ to Biga



Expect a PM from Vale soon


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Biga is offline  
post #3 of 59 (permalink) Old 07-02-2008, 02:55 PM
Resident Redneck
 
Biga's Avatar
 
Join Date: Mar 2006
Location: On This Forum
Posts: 9,793
   
Send a message via Skype™ to Biga
Glad you had a good time racing


BTW next time go with your instincts and check pistons


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Biga is offline  
Sponsored Links
Advertisement
 
post #4 of 59 (permalink) Old 07-02-2008, 02:58 PM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by Biga View Post
Expect a PM from Vale soon
I am used to PMs bacuase of my male apperance.

Quote:
Originally Posted by Biga View Post
Glad you had a good time racing


BTW next time go with your instincts and check pistons
I know I should have checked the pistons....stupid, lazy ass!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Gustav O; 07-02-2008 at 02:58 PM. Reason: Automerged Doublepost
Gustav O is offline  
post #5 of 59 (permalink) Old 07-02-2008, 03:02 PM
Resident Redneck
 
Biga's Avatar
 
Join Date: Mar 2006
Location: On This Forum
Posts: 9,793
   
Send a message via Skype™ to Biga
Quote:
Originally Posted by Gustav O View Post


I know I should have checked the pistons....stupid, lazy ass!

I alway learn by my own mistakes


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Biga is offline  
post #6 of 59 (permalink) Old 07-02-2008, 03:06 PM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by Biga View Post
I alway learn by my own mistakes
Donīt we all?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Gustav O is offline  
post #7 of 59 (permalink) Old 07-02-2008, 03:18 PM
 
Join Date: Jun 2005
Posts: 14,712
  
Glad you had a great time, and hope you will find what causing the melting pistons.


P.S. PM sent.
valerossi is offline  
post #8 of 59 (permalink) Old 07-02-2008, 04:55 PM
7c Forever
 
Junior's Avatar
 
Join Date: Jul 2005
Location: the business end of a CAD station.
Posts: 9,879
  
what heat range plug are you running?

could consider backing it off a heat range, or double checking that both jugs are the same plug.

HAIL TO THE KING!!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Junior is offline  
post #9 of 59 (permalink) Old 07-02-2008, 08:06 PM
I dont inhale
 
vcyclenut's Avatar
 
Join Date: Oct 2005
Posts: 2,437
  
great report!!!

its amazing how much money we spend and sacrifices we make to work soo hard, lol.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
vcyclenut is offline  
post #10 of 59 (permalink) Old 07-02-2008, 09:06 PM
doomsday machine
 
shagzomatic's Avatar
 
Join Date: Jun 2006
Location: Iowa
Posts: 3,971
   
Nice (and thorough ) write-up. Always fun to read these things.


Quote:
Originally Posted by vcyclenut View Post
its amazing how much money we spend and sacrifices we make to work soo hard, lol.
Reminds me of something a CR said hanging around the pits talking to another rider at the May event in MN. The guy was joking about how he wasn't nearly as smart as our CRs...the reply went something like this: "Umm, smart? You're talking to guys who spend every last cent we have to go racing....for what? A little plaque......MAYBE."
shagzomatic is offline  
post #11 of 59 (permalink) Old 07-02-2008, 09:38 PM
7c Forever
 
Junior's Avatar
 
Join Date: Jul 2005
Location: the business end of a CAD station.
Posts: 9,879
  
oh I also want to take this opportunity to point out that it's perfectly normal for an EGT to drop like crazy when there's detonation present. Once upon a time you'd see a coolant temp rise, but modern cooling systems are good enough that they're generally able to keep up. The extra heat is getting out into the cylinder 'cause the detonation is sweeping the boundary layer off the combustion chamber and cylinder walls.... and the piston, which is why you almost ended up with a ringless piston. It's good you caught it when you did or you'd have certainly slagged that jug.

You might get away with just a Nic coating at this point.

HAIL TO THE KING!!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Junior is offline  
post #12 of 59 (permalink) Old 07-03-2008, 04:08 AM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by Junior View Post
what heat range plug are you running?

could consider backing it off a heat range, or double checking that both jugs are the same plug.
I run the standard plugs, same on both cylinders as we checked this as well.
I am still puzzled as to what happened but I will see what happens when I increase the compression ratio again.
One more thing Iīll do is clean out all stuff from the expansion chambers, especially at the stinger as there might be to much goo in there.
Iīll get som ephotos of the pistons for you.

Quote:
Originally Posted by Junior View Post
oh I also want to take this opportunity to point out that it's perfectly normal for an EGT to drop like crazy when there's detonation present. Once upon a time you'd see a coolant temp rise, but modern cooling systems are good enough that they're generally able to keep up. The extra heat is getting out into the cylinder 'cause the detonation is sweeping the boundary layer off the combustion chamber and cylinder walls.... and the piston, which is why you almost ended up with a ringless piston. It's good you caught it when you did or you'd have certainly slagged that jug.

You might get away with just a Nic coating at this point.
OK. Good to hear that confirmed from someone who knows what he talks about. EGT is not very well used in Sweden so when I talked about this to other people they didnīt know if I was wrong or right. As I have understood the EGT will increase when you lean the mixture but at a certain point it will drop again and that is probably what I saw. That cylinder was runnign at around 480-490 degrees celsius while the othe roe was at 580 degrees.
I have the two cylinders that was used in for fix. Hopefully I will only need to get rid of the pistons smeared on the walls and the he will "hone" the cylinders, maybe Iīll need new nic but I hope not.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Gustav O; 07-03-2008 at 04:08 AM. Reason: Automerged Doublepost
Gustav O is offline  
post #13 of 59 (permalink) Old 07-03-2008, 04:18 AM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by vcyclenut View Post
great report!!!

its amazing how much money we spend and sacrifices we make to work soo hard, lol.
I never count how much money I spend, unfortunately my missus does.
Itīs insane and I still run a very low budget compared to many others. I canīt even imagine the costs for the guys that race brand new 1000cc bikes and crashe them as those bikes crash so heavy compared to GP bike. One guy at this race crashed his ZX10R and it was just a pile of metal scrap, not to mention all the tires those bikes eat.

Anyway. Found a picture of me when I am looking at the bike after I turned the ignition off....
Attached Images
File Type: jpg DSC01250%20%28Large%29.JPG (127.1 KB, 3 views)


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Gustav O is offline  
post #14 of 59 (permalink) Old 07-03-2008, 07:37 AM
7c Forever
 
Junior's Avatar
 
Join Date: Jul 2005
Location: the business end of a CAD station.
Posts: 9,879
  
a little meriatic acid will de-slag cylinders more effectivly than a hone will. I've had luck with it, the yamaha coating seems to be resiliant to it. test it on the bottom of the skirt before you actually try it on a part that the ring will see tho.

HAIL TO THE KING!!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Junior is offline  
post #15 of 59 (permalink) Old 07-03-2008, 07:43 AM
7c Forever
 
Junior's Avatar
 
Join Date: Jul 2005
Location: the business end of a CAD station.
Posts: 9,879
  
oh, also on EGT's, an ignition retard can make an EGT drop, but the center section temp isn't actually dropping, just you're delaying combustion and pushing the flame further out into the pipe, so the EGT is seeing an earlier stage in the flamefront.

The placement of the probe matters a lot too, I used to always go 7" from the piston edge, and the temp that had the correct piston wash for me was ~730*c Unless ofcourse it was a ceramic coated piston (~$75/egg iirc) At which point I was able to run it up to 790*c or so.

just some food for thought. If the probe is in the divergant cone, 590 sounds awfull low, that's more typical of a center section temp, which might be what's going on.

Don't stress forgetting to turn on the logger, believe me, we've all done that.

HAIL TO THE KING!!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Junior is offline  
post #16 of 59 (permalink) Old 07-03-2008, 12:33 PM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by Junior View Post
a little meriatic acid will de-slag cylinders more effectivly than a hone will. I've had luck with it, the yamaha coating seems to be resiliant to it. test it on the bottom of the skirt before you actually try it on a part that the ring will see tho.
Iīve left it to a guy who knows what he does and he will use acid to get the aluminum away and then hone it if necessary.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by Gustav O; 07-04-2008 at 12:21 PM.
Gustav O is offline  
post #17 of 59 (permalink) Old 07-03-2008, 12:40 PM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by Junior View Post
oh, also on EGT's, an ignition retard can make an EGT drop, but the center section temp isn't actually dropping, just you're delaying combustion and pushing the flame further out into the pipe, so the EGT is seeing an earlier stage in the flamefront.

The placement of the probe matters a lot too, I used to always go 7" from the piston edge, and the temp that had the correct piston wash for me was ~730*c Unless ofcourse it was a ceramic coated piston (~$75/egg iirc) At which point I was able to run it up to 790*c or so.

just some food for thought. If the probe is in the divergant cone, 590 sounds awfull low, that's more typical of a center section temp, which might be what's going on.

Don't stress forgetting to turn on the logger, believe me, we've all done that.
I know it sounds very low to most people but I am just starting to use it and I run the bike very safe on the jetting so it is not close to being lean or perfect burn. I will measure the distance from the pipe and then take som ephotos of the pistons for you to see and maybe have an idea on what went wrong.
The weird thing is that it disapperaed ad the only things we did was rise the floater height, raise the squish and seal the EGT gauge in the pipe. Nothing major was found or adjusted...


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Gustav O is offline  
post #18 of 59 (permalink) Old 07-03-2008, 12:49 PM
Moderator
 
MV-999R's Avatar
 
Join Date: Jun 2005
Posts: 6,306
  
Great report (although i'll confess i haven't read it all) and good to see you out there racing

Too bad about the melted pistons though....

Have you tried racing a 4 stroke bike? Less problems although i know you're a 2 stroke fan....
MV-999R is offline  
post #19 of 59 (permalink) Old 07-03-2008, 02:11 PM Thread Starter
250 cc pilota.
 
Gustav O's Avatar
 
Join Date: Mar 2006
Location: Uppsala, Sweden
Posts: 2,223
  
Quote:
Originally Posted by MV-999R View Post
Great report (although i'll confess i haven't read it all) and good to see you out there racing

Too bad about the melted pistons though....

Have you tried racing a 4 stroke bike? Less problems although i know you're a 2 stroke fan....
I understand that people donīt bother to read all the ranting I do.
I did one race on my TRX850 and then bought this bike. I canīt see myself racing a fourstroke after getting used to GP bike chassis and feel. I could do with a little less machine problems though, and I hate changing tires all the time.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Gustav O is offline  
post #20 of 59 (permalink) Old 07-03-2008, 02:59 PM
7c Forever
 
Junior's Avatar
 
Join Date: Jul 2005
Location: the business end of a CAD station.
Posts: 9,879
  
Quote:
Originally Posted by Gustav O View Post
I know it sounds very low to most people but I am just starting to use it and I run the bike very safe on the jetting so it is not close to being lean or perfect burn. I will measure the distance from the pipe and then take som ephotos of the pistons for you to see and maybe have an idea on what went wrong.
The weird thing is that it disapperaed ad the only things we did was rise the floater height, raise the squish and seal the EGT gauge in the pipe. Nothing major was found or adjusted...
raising squish height is a major change. raising squish height by 0.5mm can change flame front propogation speed by 20m/s. Meaning that at 10,000rpm it's the same as moving the position of the probe by 120mm.

MV, as far as the 4-strokes go, I'm not sure how true that is. I mean how many hours do you spend race wiring the bike, how many hours do you spend doing valve checks and adjustments. Personally it takes me a full day in the shop to dissassemble, check, adjust, reassemble a 20v R1 head. Even at that it's honking and assuming stuff goes in. So figure for the sake of being fair that it's 8h to adjust valves, and you'll need to do it once a race season. I can replace a topend in a 2-stroke in ~45 minutes. I think it's 20-30 minutes for me to even change the oil in a 4-stroke. If you follow where I'm going with it. I mean I'm biased forsure, and forsure from a consumer standpoint you have to take into account taking it to the shop more often and wasting time trailering it back and forth. But if you can't maintain a 2-stroke, you sure as shit can't maintain a 4-stroke. And a mistake like moving a squish height = catastrophic failure and total loss of the engine.

That said, we all know I'm biased, and I also don't come from a gp bike 2-stroke background, I come from the world of bigger, friendlier, more forgiving 2-strokes.

HAIL TO THE KING!!

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Junior is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Sport Bike Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Motogp Catalunya Qualification Results R1biker Racing 10 06-18-2006 05:47 AM
SPOILER- Phillip Island Results pugwash Racing 8 03-07-2006 12:04 AM
WERA 6 hour endurance race at Summit Point, WV report bmfgsxr Anything Goes 10 09-24-2005 09:14 AM
MotoGP: Gibernau's report after the race... Brno GP. valerossi Racing 9 08-30-2005 02:35 AM
US Grand Prix Laguna Seca R1Nomad Media 3 07-14-2005 11:18 AM

Posting Rules  
You may post new threads
You may 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

 
For the best viewing experience please update your browser to Google Chrome