GasGas Riders Club Forum  

Go Back   GasGas Riders Club Forum > GasGas Enduro Technical Forums > Enduro Engine - 2 stroke

Enduro Engine - 2 stroke Cylinder, Piston, Tranny, Bearings, Clutch, Pipes & Silencers, etc.


Reply
 
Thread Tools Display Modes
  #21  
Old 03-27-2012, 10:59 PM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default

Quote:
Originally Posted by (F5) View Post
Or poking it into your finger! Do you really not want that experience?
I'm guessing you've been there.. How was it?


Reply With Quote


  #22  
Old 03-28-2012, 08:52 AM
GMP's Avatar
GMP GMP is offline
Senior Member
 
Join Date: Jul 2006
Location: Jefferson Twp., NJ
Posts: 7,597
Thumbs up

C-clipper is a great tool, once you use it you will never want to install clips manually again!
Reply With Quote
  #23  
Old 03-28-2012, 07:42 PM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default

I have been in dscussions with Dave (dmcca) who will be doing my head modifications. He has since signed up with this forum and will no doubt have some info to post into this thread himself. Hopefully some nice pictures as the work comes together.

So far we've decided that I will install the piston, and cylinder with the piston set with the exhaust ports at BDC. I will then take squish measurements (solder method), and calculate the trapped volue (sealing rings with grease and cc'ing with metho up to the bottom of the spark plug hole).

After this I will be sending the entire S3 cylinder and head (and insert that gives the tightest squish) to Dave to work his magic. He has a nice workshop set up and in particular is building a database for the software he uses to simulate effects on engine behaviour prior to modification. He will be taking measurements of the S3 cylinder and will be able to provide feedback how it compares to the standard cylinder and if any port changes have been made (other than cleaning up casting). So far he has taken measurements for a 2010 EC300R (NSE.ONE) and an EC250 (was this yours Lonetree? - AHH ROBKTM dbw). By running sims he will then determine the best gasket stack to meet my desired goals and then machine to spec. He also agrees with F5 (tighter is better) so we'll see what he does. The insert will also be corrected for volume to achieve whatever CR I want.

We confirmed the head and insert will both require the same amount machined off them to make sure that they seal, which will make the other 2 inserts redundant. If anyone with a S3 head wants them shoot a PM.

Dave has been really great to deal with and explains everything in nice simple terms. He's located in Australia (at the other end of the country from me) and seems to be building his business up nicely. If anyone else is thinking about going this route I wouldn't hesitate to recommend him based on my experience, or the feedback received by others who've had his work.

One last thing from Dave re the 250 he worked on: "I also mapped out the stock ignition curve and the dual map switch simply changes the entire curve by 2-3 degrees. I advanced the base timing by 2-3 degrees so that the 'wet' curve is now the same as the old 'dry' curve, and the new 'dry' curve has a little more oomph down low but still revs out fine." I may consider doing this to my bike also as I have never run the wet curve, even in the wettest conditions as a 300.
Reply With Quote
  #24  
Old 04-01-2012, 11:45 PM
(F5)'s Avatar
(F5) (F5) is offline
Gold Level Site Supporter
 
Join Date: Jul 2006
Location: Wellington New Zealand
Posts: 1,322
Default

A simple 3 deg delay? That is pretty lazy. I'd assumed they had programmed several curves & tried them in difficult situations. . . because it works so well. Either way I like the wet function & use it probably 50% of the time, like yesterday when there was some tricky sections & unseasonable wet, but obviously our rainfall is far more than Auss.


I know 2 people with ISDE models which seem to be more aggressive power delivery. Both are experienced good riders & both leave them on the wet setting.

As far as the base setting goes you may have to test to find out. I fitted a road tyre to my 200 & dyno'd it. Often running higher comp one needs to retard ign a touch. Running high comp, close squish on 1/2 Av gas & 1/2 pump gas I found that std position worked best for this older no-switch ign.

You may find with new setup that it can't take more advance without detonation. Or you may find stock setting was pretty safe so as to cope with a multitude of crap gases one might encounter so more advance may be the ticket for your bike & gas. Maybe.

My point it test test test. If you care that much about 1/10ths. The 300 has all the power I ever ask for, and occasionally a tickle more than I wanted, but that's just my inner Muppet.
Reply With Quote
  #25  
Old 04-02-2012, 12:32 AM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default

Few considerations here. I'll probably be running the same or even less compression than I am at the moment. I'll also be changing to a 250 so may be looking for some more oomph (maybe). Ultimately I'm not looking at sacrificing reliability in the chase of more power.

Don't know how much rain you've had over there lately but we have experienced a somewhat late season or as you'd call unseasonable wet too! Mud mud and more mud out. Ran it in sunshine all day long! I must admit that putting it on the pipe in these conditions is a waste of time and momentum is ones best friend.

The good news is that the arrangements with dmcca are falling into place nicely re the 250 work. I will be having him attend to the 300 head at some point too! All the suspension parts are starting to arrive, and I'm getting the extra hours up on the 300. It should only be a few weeks and there'll be some more progression with this thread.
Reply With Quote
  #26  
Old 04-06-2012, 10:58 PM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default Action time

Well the bike has close to 5000kms on it now (160hrs in total / 85hrs on current top end). I've got some time off work over Easter and the parts are all in the post for the rest of the bike so should be arriving over the next week or two. It feels like the right time to get a start on this change over.

I've spoke to Dave (dmcca) again and got his postal address sorted and informed him of the plans so all is well on that front.

I've still got to get some 2mm resin/rosin core solder as I can't be bothered twisting it up like I did last time and feel it will be quicker and easier this way. Hope to give the bike a thorough wash down Monday (stripped back to make sure the frame is clean). If time allows I might pop the pipe, drop the oil, drain the coolant and generally just get the bike ready for Tuesday.

I'm dedicating this whole day to taking measurements both of the 300 top end and the 250, and by the end of the day hope to have the 250 top end specced and ready to post by wednesday morning.

I'm hoping the C-clipper arrives so I can avoid the head aches when fitting the piston. Just out of curiosity, as I'll be just snugging everything up to set the port timing, get a squish reading on the head, and CC the trapped volume, do you think it would be safe to just slide the pin in without the clips? The bike will then be pulled back down again straight away. Or is there a big risk the pin will slide out and cause issues? Looking for feedback again

Thanks!
Reply With Quote
  #27  
Old 04-07-2012, 09:16 AM
Fred1956's Avatar
Fred1956 Fred1956 is offline
Senior Member
 
Join Date: Oct 2009
Location: NW Arkansas
Posts: 1,254
Default

Quote:
Originally Posted by Jakobi View Post
Just out of curiosity, as I'll be just snugging everything up to set the port timing, get a squish reading on the head, and CC the trapped volume, do you think it would be safe to just slide the pin in without the clips? The bike will then be pulled back down again straight away. Or is there a big risk the pin will slide out and cause issues? Looking for feedback again

Thanks!
Lack of clips for measuring everything should cause no issues- just don't get busy and forget to install them before start up !!
__________________
Fred Overstreet
2010 EC250 SixDays
2004 GasGas EC300 -Sold to a good home
2006 GasGas EC250-Sold to a good home
2006 GasGas TXT 280 Pro
Reply With Quote
  #28  
Old 04-07-2012, 04:46 PM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default

Thats what I was thinking Fred. It'll be going on to measure the squish and then the trapped volume and then the head and cylinder will both be coming off and sent off. I'll need to clean the grease from the rings and ringland anyway so probably easier to take the complete piston right off again anyway

Getting excited!
Reply With Quote
  #29  
Old 04-10-2012, 03:34 AM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default

Well its been a long day and I've been reminded why I'm not a mechanic! No issues faced. Just a lot of back and forwards measure this measure that.

I managed to measure up the current setup I was running (Stock 300 cyl, S3 Head, 1.3mm base gasket stack). It seems my squish was even larger than I remembered measuring it at last time. I did several measurements and settled on 1.95mm. The trapped volume was 23cc. Both top and bottom ring gaps measured in at 0.55mm. The piston has been warm enough to lightly glaze some oil on the underside of the dome. The top burn pattern is as expected from running a big squish (ie all over the shop). There were only a few areas where the carbon had built up and most was just a light oily coating that wiped off without much effort. I will post some pics later.

For the S3 cylinder, it appeared to be very much the same as the stock for the port locations. The casting is much cleaner as my stock has quite a lot of slop in one side on the transfers. Both cyldinders required a 1.3mm gasket stack to set the port timing, piston top flush with the exhaust port at bottom dead center.

The 250 top end with the ports timed as above and the S3 head with the black insert measured up very similar to the 300. Squish at 2.05mm. Trapped volume 16cc (however I was getting a bit mentally tired and ready for a beverage by then so it could be out by a mm. I did measure twice but still not certain so will get Dave to crunch the numbers for this one just to be safe).

After quickly doing a few numbers it seems the black insert boosts the compression ratio up big time on the 250.
S3 EC300: (23+293)/23 = CR 13.7:1
S3 EC250: (16+249)/16 = CR 16.5:1
Even if I missed a cc or two the 250 would still have a CR of 15.6:1/14.8:1

Note: Identified errors with viewing the fluid level at the base of the plug. Trapped volumes incorrect. Updates further ahead.

Pics coming soon.

Last edited by Jakobi; 04-12-2012 at 07:46 AM.
Reply With Quote
  #30  
Old 04-10-2012, 05:16 AM
Jakobi's Avatar
Jakobi Jakobi is offline
Super Moderator
 
Join Date: Oct 2010
Location: Australia
Posts: 7,844
Default

Everything cleaned up and pulled down. Nice to see no water has been causing any rust on the flywheel/stator. All gaskets lifted easily. Only had to do some minor work on the 0.3mm cylinder gasket.







Reply With Quote
Reply



Thread Tools
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
VHM aftermarket cylinder head GG27 Enduro Engine - 2 stroke 2 11-02-2009 04:15 AM
cylinder head Question? whodat Enduro Engine - 2 stroke 3 12-27-2008 12:54 PM
Cylinder Head Braces nsgasser Enduro Engine - 2 stroke 2 06-10-2008 04:52 PM
New cylinder head Kent A Enduro Engine - 2 stroke 8 05-01-2007 01:43 PM




All times are GMT -5. The time now is 01:41 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2009 - GasGasRider.org