It was 100 psi and its now 75 psi??? 
I say "Hmmmm"...
Did you do the compression check properly?
When doing the compression check,did you keep the throttle wide open during the test?
Did you work the kick start until the needle stopped moving?
Was the gauge screwed into the spark plug tightly to prevent leaks?
Before we go any further with this...
How many CC's does the re-chamber "toroidal" head CC at? The reason I'm asking,is because I've cut MANY toroidal heads for yamaha blasters,and by looking at the depth of the cut on the other heads he's done,they look to be VERY deep,which = large CC combustion chamber. This WILL lower your compression. he states that they're "approximately 20cc's". That doesn't cut it. I can guarantee you its MUCH more that 20 CC's! The heads I cut for "Best " were 19.5 CC's. Both a "Hemi" (my favorite) and a "toroidal" (my second favorite) and I had to take ALOT of material off the entire head of the "toroidal" to get it to 19.5 CC's. My guess is the head you have is like 25 CC's + . This will cause your drop in compression! Right off the bat by looking at a picture of it (in the for sale section) I would say 27 CC's or possibly more. A stock head is 23 CC's. Did you CC it yourself to check? Its easy to do,and you will be able to get the measuring down to tenths of a CC.
If your not noticing a power increase...Hows your jetting? Thats a "Big one".
I would go back and do a compression check,and get some new readings. You may have made a mistake. If your compression is still 75 psi,swap the stock head back on and test again. That should show where the difference is.
Also... Don't be afraid to try a different compression gage. I've had a bad one before.
QUOTE..."Sorry Joe couldn't wait"
I hear ya,been there,done that....but situations like this is where I say...
A little patience goes a L-O-N-G way!
My turn around time is (literally) two corona's and hour and a half of time which includes PROPERLY CC'ing the chamber plus of course shipping time for "priority mail". Couldn't wait? Wow. Most shops give a lead time of 10 days to 2 weeks not including shipping time
(except Ken OConnor... he's quick).
Your patience has to come into play somewhere.
You still have to get that toomey pipe on on your bike. Don't start talking about swapping out a pipe that you didn't even try yet. Thats ridiculous and expensive. trust me!
If you already have the money for a different pipe to replace the toomey you still haven't even tried yet,....you had the money for my porting and head work. Think about it.
Cheaping out on porting, but already wanting to replace a pipe you have yet to tested makes no sense.
Slow down... You need to get everything "Tuned" and working in unison. Not start buying more mis-matched parts.
Your going to like that toomey. It will work well for you,if you do your part. The pipe and a properly re-chambered head will really wake up your blaster!BUT... PORTING IS KING! End of story.
If I were you,I would CC that head,and compression test with BOTH heads,and see what you come up with.
Post your findings here,so we can help. Pictures too.
Just think... by now you could have been ridng your blaster with a proven
"Aggresive Desert" ported cylinder and re-chamberd "Hemi" head".
Now you've got to fix things..
Report your findings,and lets see if we can get it dialed in. All is not lost.[/B]
Here's a 19.5 CC "toroidal" I did for Steve (Best). You can see the depth of the cut that I had to take to get that size of chamber It was quite a bit...
I say "Hmmmm"...Did you do the compression check properly?
When doing the compression check,did you keep the throttle wide open during the test?
Did you work the kick start until the needle stopped moving?
Was the gauge screwed into the spark plug tightly to prevent leaks?
Before we go any further with this...
How many CC's does the re-chamber "toroidal" head CC at? The reason I'm asking,is because I've cut MANY toroidal heads for yamaha blasters,and by looking at the depth of the cut on the other heads he's done,they look to be VERY deep,which = large CC combustion chamber. This WILL lower your compression. he states that they're "approximately 20cc's". That doesn't cut it. I can guarantee you its MUCH more that 20 CC's! The heads I cut for "Best " were 19.5 CC's. Both a "Hemi" (my favorite) and a "toroidal" (my second favorite) and I had to take ALOT of material off the entire head of the "toroidal" to get it to 19.5 CC's. My guess is the head you have is like 25 CC's + . This will cause your drop in compression! Right off the bat by looking at a picture of it (in the for sale section) I would say 27 CC's or possibly more. A stock head is 23 CC's. Did you CC it yourself to check? Its easy to do,and you will be able to get the measuring down to tenths of a CC.
If your not noticing a power increase...Hows your jetting? Thats a "Big one".
I would go back and do a compression check,and get some new readings. You may have made a mistake. If your compression is still 75 psi,swap the stock head back on and test again. That should show where the difference is.
Also... Don't be afraid to try a different compression gage. I've had a bad one before.
QUOTE..."Sorry Joe couldn't wait"
I hear ya,been there,done that....but situations like this is where I say...
A little patience goes a L-O-N-G way!
My turn around time is (literally) two corona's and hour and a half of time which includes PROPERLY CC'ing the chamber plus of course shipping time for "priority mail". Couldn't wait? Wow. Most shops give a lead time of 10 days to 2 weeks not including shipping time
(except Ken OConnor... he's quick).
Your patience has to come into play somewhere.
You still have to get that toomey pipe on on your bike. Don't start talking about swapping out a pipe that you didn't even try yet. Thats ridiculous and expensive. trust me!
If you already have the money for a different pipe to replace the toomey you still haven't even tried yet,....you had the money for my porting and head work. Think about it.
Cheaping out on porting, but already wanting to replace a pipe you have yet to tested makes no sense.
Slow down... You need to get everything "Tuned" and working in unison. Not start buying more mis-matched parts.
Your going to like that toomey. It will work well for you,if you do your part. The pipe and a properly re-chambered head will really wake up your blaster!BUT... PORTING IS KING! End of story.
If I were you,I would CC that head,and compression test with BOTH heads,and see what you come up with.
Post your findings here,so we can help. Pictures too.
Just think... by now you could have been ridng your blaster with a proven
"Aggresive Desert" ported cylinder and re-chamberd "Hemi" head".
Now you've got to fix things..
Report your findings,and lets see if we can get it dialed in. All is not lost.[/B]
Here's a 19.5 CC "toroidal" I did for Steve (Best). You can see the depth of the cut that I had to take to get that size of chamber It was quite a bit...
Last edited:
