| PilotOdyssey.com http://www.pilotodyssey.com/PO/ |
|
| FL400 Low compression. Time to check. http://www.pilotodyssey.com/PO/viewtopic.php?f=41&t=9373 |
Page 2 of 3 |
| Author: | speedchaser [ Sun Apr 08, 2012 4:38 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
hoser wrote: MAS Racing wrote: No. Will have to talk to speed. I will look to see if I have a 47cc dome if I do I will send you can try it see what you think, if you like you can either send me your 49cc or another 47cc ? Pretty sure I had Speedchaser cut me a 47cc I doubt I will ever use it. i have some on the self let me know speed |
|
| Author: | MAS Racing [ Sun Apr 08, 2012 4:46 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Hoser, Let me know if you find it. I will need to have it lapped though. I cant do it myself. If I send you the head can you lap it? I will gladly pay the shipping. Also what is the max compression that I can go using 91 pump gas? |
|
| Author: | hoser [ Mon Apr 09, 2012 12:41 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
speedchaser wrote: hoser wrote: MAS Racing wrote: No. Will have to talk to speed. I will look to see if I have a 47cc dome if I do I will send you can try it see what you think, if you like you can either send me your 49cc or another 47cc ? Pretty sure I had Speedchaser cut me a 47cc I doubt I will ever use it. i have some on the self let me know speed Will one of your off the shelf drop into his shell without lapping if so he is probably better off buying from you when we factor in shipping his head 2x's |
|
| Author: | MAS Racing [ Mon Apr 09, 2012 6:48 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Hoser, Did you find the dome? Speed said in a PM he would lap it too. |
|
| Author: | hoser [ Mon Apr 09, 2012 7:02 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
MAS Racing wrote: Hoser, Did you find the dome? Speed said in a PM he would lap it too. Yeah I found mine I didnt realize Speedchaser had some in stock the last time I had talked to him he didnt have any if you like go ahead and get one from him? I hate to stick Speedchaser with a Pilot dome I am sure some day I will use mine where as Speed does not have a Pilot... YET! |
|
| Author: | MAS Racing [ Mon Apr 09, 2012 7:08 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Thanks Hoser, I will go ahead and send a PM to speed then. |
|
| Author: | adnoh [ Mon Apr 09, 2012 10:37 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Mas Racing, If you could would you get the measument from the exhaust port roof to the top of deck since the heads off. No big deal if you can't. just curious. Thanks Adnoh. |
|
| Author: | MAS Racing [ Mon Apr 09, 2012 11:07 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Just under 48mm. My calipers just broke so I cannot get an accurate mesurment better than that. |
|
| Author: | hoser [ Tue Apr 10, 2012 3:10 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Yeah it should be closer to 45mm try taking a piece of paper and sticking it inside the cylinder and getting a rubbing then measure it off the paper. http://www.macdizzy.com/cylinder_map.htm Make sure when your done playing to recoat the the cylinder wall with 2 stroke oil please  
|
|
| Author: | MAS Racing [ Wed Apr 11, 2012 1:23 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Hoser I can try it tomorrow if I get a chance. |
|
| Author: | MAS Racing [ Wed Apr 11, 2012 1:30 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Do you guys think that I should get a copper head gasket? I cant use just one layer of a stock gasket because my squish is good with all three pieces of the stock gasket. The copper gasket is .032" and Hoser said the stock gasket is .030". The copper is reusable. I do already have a Honda OEM head gasket though. |
|
| Author: | adnoh [ Wed Apr 11, 2012 8:17 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
that's ok Mas Racing. I was just wondering if maybe the port had been altered a little effecting your issue. I was going to run you numbers and see where it was at and what the change would be. I would hate for you to scratch you cylinder ect. You can use a straw cutting the tip at a 45 then raise the piston to the top of the port where a feller guage slides into the port and then slide the straw done to the feller guage then mark or cut it off at the deck then bench measure for a close number. Maybe a good lesson for the young wrencher. Then the apprentiace can do some math for home work. After all how many young guns can do CCR calculations. Nothing like knowing ones Engine. Then you can have a discussion with the young one on the difference and the importance between cranking compression guage reading and CR/ CCR expecially since your at a higher altitude. |
|
| Author: | MAS Racing [ Sun Apr 15, 2012 7:24 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
adnoh wrote: that's ok Mas Racing. I was just wondering if maybe the port had been altered a little effecting your issue. I was going to run you numbers and see where it was at and what the change would be. I would hate for you to scratch you cylinder ect. You can use a straw cutting the tip at a 45 then raise the piston to the top of the port where a feller guage slides into the port and then slide the straw done to the feller guage then mark or cut it off at the deck then bench measure for a close number. Maybe a good lesson for the young wrencher. Then the apprentiace can do some math for home work. After all how many young guns can do CCR calculations. Nothing like knowing ones Engine. Then you can have a discussion with the young one on the difference and the importance between cranking compression guage reading and CR/ CCR expecially since your at a higher altitude. The young one is only 10 yrs old so I don't know that she is up to doing the math on this yet but I did measure it for you anyway. She is learning a lot about this Engine though so I do appreciate any info you want to give. She is in advanced math though so she might get it. I went out and bought a cheap caliper that seems to work Ok but not great. I will get a better one later when I get a chance. I used to have really nice Sterite ones that I sold in a fit of depression after I lost my sight (along with quite a few other tools and equipment).  I got 46.44mm or 1.8280" from the exhaust port to the top of the cylinder. I sent my head to SPEED to get the 47cc dome and have it lapped. I will recheck the squish when I get it back. The calipers do seen accurate enough to do this as I checked them with my feeler gauge. |
|
| Author: | adnoh [ Mon Apr 16, 2012 10:40 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Thnaks for getting me the number. In order to get an idea of what the change will be to the compression ratio of the Engine and the cankng presure reading wll will first calculate the CCR ( corrected compression ratio) using your 46.44 and some numbers I have from previous work to draw a conclusion of the effect for fun. Your 46.44mm from exhaut open to deck using a stock base gasket puts you right around 92 degrees ATDC (after top dead center). With the speed head with the 49 cc dome and the numbers I have we can calculate the base line CCR. We will use the formula of VTDC + swept volume /VTDC. VTDC= volume at top dead center or the pisotn at TDC (Top Dead Center) and the total volume above it. The swept voulme is the amount of cc of the cylinder less piston crown volume at the point which the piston crowns edge shuts off the exhaust port. First calculate you swept volume. bore x bore x .0007854 x stroke Take you piston size which appears to be 80 mm and use that as your bore and use your 46.44 as your stroke. That will give you your swept volume For the VTDC we will use a number I have and for that, use 38 Now you can use the the change in the head to see the difference. Example would be if speed is going to fit the head with a 47cc in place of the 49cc subtract the difference for the 38 and recalculate. Also if there some decking and dome change ask speed for the decking number or the new head total cc to use. The 38 for the formula is based on a 49 cc head and stock head gasket. Post up her/your results. Then you can compare the cranking compression number at your base line CCR and the cranking compression at the new CCR number for your altitude. Then we can compare to a lower altitude numbers I have. The compariosn between CCR and cranking are not revelant other than fun facts. The rise in CCR will have an effect on your pistons thermal loading and the wave speed in the pipe at that port time opening,nothing too major just related fact. Take a pic of her/your work and post your results. |
|
| Author: | MAS Racing [ Mon Apr 16, 2012 11:26 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Ok I did ask speed and will let you know what he says. |
|
| Author: | MAS Racing [ Tue Apr 24, 2012 12:23 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Got the head back from Speed and mounted it with the 47 cc dome. It was about 142 compression with the 47cc dome up from 132 with the 49cc dome. I know it is not broken in yet so it should end up a little higher than that after break-in. The squish is 0.045"-0.046" at the intake/exhaust edges of the piston and goes down to 0.041" at the inner edge of the squich band. This is with the stock gasket with all of the black scraped off the outside. I think about 0.028" thick. A little thinner than a new stock gasket. Do you think that it would be safe to remove one layer of stock head gasket to run it with only two layers? Or should I leave it alone and use a complete stock head gasket? |
|
| Author: | hoser [ Tue Apr 24, 2012 12:27 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
MAS Racing I would go with the full gasket myself. andoh the effective distance from the top of the cylinder to the top of the exhaust port opening should be 45.68mm or 1.798 a template is used when I do the exhaust openings so they are all the same after its cut then the port bevel applied with a radius it becomes harder to take actual measurements, you can run both the as found by MAS Racing then my numbers...Attachment: hoserized exhaust.jpg [ 67.45 KiB | Viewed 1571 times ] |
|
| Author: | adnoh [ Thu Apr 26, 2012 7:03 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Great info "H" and Mas Racing. Hell month ended today so I can get back to playing around in the garage. Miss, Mas Racing can run the numbers and let us know. Kinda cool how the 2 cc change made 10 psi diff. Now we can look at the diff in CCR. |
|
| Author: | MAS Racing [ Fri Apr 27, 2012 12:11 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Speed still has not got back to me with the decking number or the new head total cc to use. He is probbibly busy. Sommer did the math on the 49cc dome for now using Hosers numbers. Swept volume 80.25 x 80.25 x 0.0007854 x 45.68= 231.05058 CCR for the 49cc dome 38 + 231.05058 / 38= 44.080278 Cranking compression at 4500" elevation for the 49cc dome = 132 psi (not broken in) |
|
| Author: | adnoh [ Fri Apr 27, 2012 10:18 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Opps back to school for her. stock is around 6.2, 44 would be rather high. The formula looks rigt the anaswer looks wrong. The CCR is off. 38+ 231.05058 = 269.05058, 269.05058/38 = 7.0802784210526315789473684210526 or 7.1 36 + 231.05058 = 267.05058, 267.05058/36 = 7.4180716666666666666666666666667 or 7.4 psi 132 at 38 cc psi 142 at 36 cc ( estimated) More math later. start looking for the coralation between the numbers. |
|
| Author: | MAS Racing [ Fri Apr 27, 2012 6:44 pm ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
I think that she divided 231.05058 by 38 and then added 38 after. |
|
| Author: | MAS Racing [ Mon May 07, 2012 1:16 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Put the cylinder and speed head on the other day. Did the leakdown test today. No leaks. Then we started putting the Pilot back together. We installed the Afastcar hoses (don't they look nice). Then we got the gas tank in. We had emptied and cleaned it during the time the cylinder was with Hoser. It had no rust and just a little gunk in the bottom that we had to clean out. We also had thoroughly cleaned out the radiator and did a leak test of the cooling system today. No leaks. Pics below.Attachment: 100_4300.jpg [ 53.69 KiB | Viewed 1524 times ] Attachment: 100_4301.jpg [ 88.03 KiB | Viewed 1524 times ] |
|
| Author: | hoser [ Mon May 07, 2012 8:24 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Are those nuts on the cylinder studs? If they are I would remove them and reinstall the Honda nuts, hard telling how the extra mass of the tall nuts is going to react when they meet the harmonics of the running Engine, you don't need them vibrating loose or tight while out riding. |
|
| Author: | MAS Racing [ Tue May 08, 2012 1:04 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
I lost the nuts that went to the cylinder so I ended up using these. I understand what you are saying about the vibration but i should not have a problem as I used high temp medium strength three bond threadlocker. I apreciate the concern though. |
|
| Author: | nitrosport_5 [ Tue May 08, 2012 1:14 am ] |
| Post subject: | Re: FL400 Low compression. Time to check. |
Very nice looking machine MAS Racing. Great work. Now you need to get it dirty 
|
|
| Page 2 of 3 | All times are UTC - 5 hours [ DST ] |
| Powered by phpBB® Forum Software © phpBB Group https://www.phpbb.com/ |
|