stock cr500 top and stock custom speedchaser on the bottom
don't believe I can go thinner

have not done a squish

yOu can't hodge podge or mix and match parts to these built motors and expect anything but trouble??? I asked you about your squish weeks ago... You never answered...

I would have to say that it's a good guess that the unmatched head is making a difference because of the probable CC volume of the head is probably greater than what the Engine was designed to have on it. Do you have a way to find out what the CC volume for the 360 Engine's head should be?

Running a larger unmatched head like that can cause hot spot issues around the top rim of the cylinder itself.

Rand

I did not slap it together without asking ..
I asked one of the builders!,He said yes it would work,but ..he did not know what the compression would end up being..
Now we know...

most all of the motors were custom hand built, the builders swapped out alot of the parts to see what worked best,I have done endless hours of homework on these motors and talked to the actual builders,
I knew there was going to be a lower comp reading,I just didnt know it would be this low

yes, The head should be the same as a 350 head, I can do a cc reading on the big bore head I read the adnoh post on doing this
the 360 jug uses a .40 350 piston

At this point,I am going to do a tear down on the top half, I will get all the measurements and post what I come up with

got it apart, everything looks nice, choc brown,
anyway, the bigbore head measures about 40cc and the 360 measures about 37cc

Im going to try the 350 head on the jug and get a comp reading,I did just talk to one of the guys again,there is a chance I can get a hold of one of the orig heads

Measure the outer diameter of the dome area of the head and the inner diameter of the 360 cylinder. I don't know what the piston size variance is between the 360 and the 400 but it is probably substantial. the the dome for the 400 will be cut to a larger diameter to accommodate for the larger piston and it will leave the top edge of the cylinder exposed causing hot spots.

Rand

you are on the money, anyway,with the 350 head.. compression was right at 140 psi using the cr500 gasket

so,,Im back to the drawing board, seach for a head that will work, I have a couple of leads like I said,hope they pan out

if those don't pan out then maybe speedchaser can mill the head dome area out for you???

What happen to the head for the 360 cylinder?

I would talk to the Engine builder ask for the correct dimensions for your head to be used on that Engine something like this http://www.pilotodyssey.com/Pilothead.htm

Then have a dome made to match the exact dimensions, it only takes a slight variation from the design to make a huge impact on the performance.

I hope something will work! This custom shit is starting to drive me nuts!..LOL

here is a pic of the motor (( Internal Combustion Engine ? )), good color?



BTW,Just got my call,looks like I will have the correct head!

Yeah that cylinder is a modified 350 cylinder. Like I said on the phone if you can't get an original head from the builder then you may be able to have Trevor modify a head for you.

The other option would be as Turbo has mentioned...... have speedchaser do some custom head work for you.

And remember as Hoser mentioned,

Quote:

it only takes a slight variation from the design to make a huge impact on the performance.

Rand

I went through the other parts totes, no heads other than the 400 head for my BV 400/350 jug. Rand, the 400/350s use a 87mm piston as the starter bore.

Just an idea, how about milling a head ? Depending on the squish you have, you can set it for what you need for pump gas. Prob get a head from evil bay pretty cheap.

GREAT NEWS!
I have the correct head being shipped today, maybe even some extras for the 360 motor (( Internal Combustion Engine ? ))

I guess while Im waiting I can get a few of the other goodies installed!

Now your talking, you will be much happier with the correct head.

When you get the heads you should measure them first, make sure the bore diameter is correct, also measure them to see how many cc's this info will be helpful in the future.

Are the heads setup for race gas or pump gas or do you know?

Great news! I'm startting to get excited now!

He is getting one for race gas and one for pump. He is getting the pump gas first so he will be ready for that race.

Sounds good, I would still blue print them before installing so you know what you have you know sooner or later adnoh will need that info so he can crunch the numbers he also should make a port map.

Like gary said,Looks like im getting 2,He already took the measurements from my piston to make sure these are the correct ones
The first one I should be able to run 93 oct no problem,the second he is going to work for me depending on what the compression is on the first one
He said he would mill it down to bump the compression and dress it up nicely! {for full race }
He mentioned having a whole top end set up too.complete,,jug piston,head.all fully liquid cooled and ready to go!..LOL...I don't think I need another though

Heads
I will have both come mid week!
one full race one semi
I will crunch the numbers on them first!

More good news!
I also have my new piston set up coming for the BIG BORE motor (( Internal Combustion Engine ? ))!
so it will be coming together next week maybe
Got the egt mounted today,water temp stuff tomorrow...
also will be mounting my fluidyne radiator set up{ got ahold of the correct fill res.}


On another note
for those of you that may be interested
I have come across a bunch of big bore parts
full liquid cooled jugs and heads..These use the yz490 pistons
Comet clutches..102 and 108 c's
HRD clutches!
and MORE
I will be getting some in for sure in the next couple weeks

They will be for sale to board members at a very good price!

any questions,shoot me a text or call..828-777-5877

More details to come!

KUDA

Kuda, next time you talk to the builder or owner of the Engine you have, ask him which rod is in it. Stock or what year of 250r. I noticed in the pic of the piston of the cylinder if at TDC (Top Dead Center) there was a lot of deck. This may account for some the low comp reading. Before you install a head on it set it at TDC (Top Dead Center) and get the measurement from top of cylinder to top of piston edge and then run it to BDC and measure from the top of the cylinder to the exhaust and intake port opening. As an alternate number place a flat piec of metal across cylinder and run the piston up from BDC untill it touches the flat bar then measure down from top of cylinder to top of piston edge and measure crushed thickness of head gasket and the ID. This of couse if you have time. I know your busy. With this info I can start to figure about where you CR is Just curious. DO you know what rpm you comp reading are taken at. The cylinder look like a poloris 400 modified, any info there.

Thanks, Adnoh

Adnoh,
Both motors have 350 jugs,the 360 has a 350 sleeve the 420 has a yz 490 sleeve
This I know for sure, I may not have had the motor (( Internal Combustion Engine ? )) TDC (Top Dead Center) for that pic
Here is what I know about the 360 that I am working on now.
it uses a 350 .40+ 533p4 piston,coated witha window cut in it
custom liquid cooled jug and head
both motors use stock 350 connecting rods,although the 360 has a hot rod in it
custom built head... both the heads I have coming have different size chambers
I was told One with be good on pump gas{93} the other may require race gas{110+}
lots of port work was done to the jugs

The problem is...The original builder of the 360's was Bob Victoreno{cant get a hold of him,not sure if hes still around}
what I had planned on doing maybe is seeing if you want to take a closer look at these?
Once I have the motor (( Internal Combustion Engine ? )) together and running proper I want to start on the 420,..But if you want to take a close look at one of these motors at a time
we can make it happen, If you get a chance,give me a call and we will talk on it

As far as my time is concerned, I am loving working on these things

I feel like a kid again!!!

hoser mentioned having them blueprinted??

you up to it?
KUDA

Yes make him blueprint them he is good with these type details it would be great to document so if others wanted to build one in the future they know what needs done, we need to start documenting all the Pilot Odyssey history we can before its all lost for ever.

I may have time late in the year to take on new projects. It depends on upon getting done what I have on my plate know. I keep you advised if time allows. It will take time to do the work and I would have to have parts for about a year. The whole complete Engine, heads and exhausts would be required and all the varible parts. It does interest me to have an opertunity to look over professional Engine builders work and learn. I have been logging data from your Engine in a seperate file. I have a ton of questions that would drive the builder nuts and most likly get a wrench upside my head. What interests me about you pic and piston location is the squish. It goes against would I have done and been working on. An air cooled cylinder, I could see an application for such clearence however on the water cooled jug I find it surprising and make me ask my self why and time to refelct. Many has mentioned squish and whats the #. This may be why they ask as well other than just making sure it's not to close,in this case it may be, why so much. I will try to get my hands on a YZ piston and see what the piston crown angle, pin to crown and pin offset is. Wonder which way Yahama rolls the piston, intake or exhaust side. My first thought on the pic and the comp # is over rev which the short stroke of the ody likes and has an advantge over the pilot. Wonder if they do this to help keep it in check. Then it makes me question the timimg and heat range and LT on the pipe. See more question than ansawers. It leads me to think that it made to rev up past 8500 with a peak around 8000 and get the egts right on top end and a slughish bottom sounding like it's missing and slight stumble thu mid. I gotta know is it kinda hard to start at low cranking speed. I know its a lot of thought just from a pic and low comp number.That is just how my head works, again more questions than ansawers. When you did a crank comp check did you do a wet test just to make sure it's not a ring problem. Again just aback yard hacker no pro. Thank you for sharing this project with the board

out of space: I agree with "H" that as much documation as one can and post so it will be around for a long time. So every one keep it coming.