Elroy , when you had your head shaved, how much did you take off and how much squish did you end up with? Do you have any problems with detonation now ?I originally had .035 taken off mine which left me with .075 squish. My bike would sound like ballbearings in a tin can when it was held at 5000 rpm at 1/8 throttle.I doubled up on the headgaskets and that put me at .090 squish. I was still getting some detonation at the same throttle and rpm's.Yesterday I removed the head and I could see some tiny marks on the piston crown and the head from the detonation.I took the head to my machinist friend nextdoor to my shop and had .035 taken off the squish band to basically put me back at the stock squish.I talked to Rick Ritter and I then had the head rechambered 2 deg.which he said should help with any detonation.Basically I now have a piston crown with 13 deg. and a squish band with 15 deg.I haven't had a chance to test it since yesterday But the short drive I took it on makes me think I lost a bit of hp because of widening the squich back to around the stock setting of .110.It seems strange to me that these bikes will detonate with the squish set at .075 but a lot of engines are taken down to .035 to .050 with no problems.I would like to tighten it up again but I dont want to go backwards again.My head can't take much more machining.I need to know how yours is working and what numbers you are using.

 

When I shaved my head, I actually did it twice. The first time I shaved it, it started at .110 clearance. I shaved it about .035". I came home, bolted it on and I had .075" clearance. I took it for a little test flight.(I was actually porting my motor, I just figured I'd get the head shaved while I was at it.) I got back from an impressive spin and was curious what my compression was. I tested it and found that I only had about 130lbs. I was hoping to get it up to about 150lbs. The next day I decided to get it shaved a little more to up my compression. Before I ripped the head off, I checked my clearance again. It measured .085". When I take this measurement, I take it on both sides of the piston and do this twice. I also kept all my test pieces for a later reference. When I saw that my clearance grew .010" over night, I referred back to my previous test pieces. I was right. It measured .075" one night and the next day it measured .085". I still don't know what happened but I still have my test pieces. Any how, I took it back to the shop and shaved another .020" off. Brought it back, bolted it on and had .060"(it did say .070" here but it was a type-o) clearance. However my compression still didn't go up any. I still had 130lbs compression. At the time I thought my comp. tester was defective. I later found out that it was right. I still can't figure out why my compression didn't go up after another .020" was shaved off.

As it stands now, I shaved .055" of my head which gives me .060"(did say .070" here) clearance. I carry about 130lbs compression and I run it on 93 octane gas. Mind you thou, I am still waiting for my RCR pipe and have a 34TM carb for it too. I haven't got to run this set up yet. I may end up with the same problems as you. I hope not.

The porting and head shaving made a hell of a difference even on the stock carb and pipe. I can't wait to see what it will be like with my new pieces. My quad has never acted funny and has never given me any problems. It always starts right up and never lets me down.

I don't know that your UFO or dial-a-jet have anything to do with your problems but I can say that I will stay away from them for now. Hasn't your detonation always been around 1/8 throttle? Did it have this detonation problem before these two carb mods?

 

Actually when I first had the head shaved and it was detonating really badly was with the stock carb on the bike.It also did it at about 1/8 throttle then. Then I added the second headgasket (which is about .017 thick) and the detonation was mostly gone.This was all happening in the fall whan the air temps were starting to drop.Then I installed the 34mm carb and ran it for about a week without the UFO.The detonation didnt seem to be there at the time.Then I put the UFO on the bike and got it jetted where it looked good on the EGT guage.It seemed alright then too.The ex temp was around 1000 to 1100 at 1/8 throttle which is acceptable.The plug looks good too.Then I got the pipe around the first week of January.This is also when we got our first couple of snowstorms so I couldn't really run the bike much. Then the first real time I drove it for any extended time was around the last week of Jan.I went out one afternoon for a drive and after the bike warmed up it started to detonate again. Not as badly as when I first had the head shaved, but bad enough to concern me.I also noticed the bike runs hotter with the pipe on it.
I have tried to jet it so rich that it doesn't even want to idle when hot and it will still detonate at the 1/8 throttle when the engine gets hot.

So I had the head rechambered on last Tuesday and I haven't really had a chance to test it yet. If it still detonates, I am going to put the stock pipe back on and see if it cures it. It seems to do it at 1/8 throttle right around when the engine hits 5000rpm. And this is pretty much when the engine comes "on the pipe".If I give it more throttle to bring the RPM's up it goes away but when the rpm drop back to 5000 it comes back.This alone might mean something.I also have tried to retard the timing a bit and it does help it a bit. But it rob some power too.

When will you have your bike back together and when do you expect the pipe to arrive? I'm curious to see if you have the problem too.The strange thing is that my bike did it when the only mods were ,some mild porting and polishing and had the head shaved .035.

 

In my last post, I said my clearance was .070". I meant to say .060". I fixed it now so it says .060" instead of .070". I thought I'd let you know I changed it in case you didn't notice. Sometimes my fingers are just to clumsy for this keyboard.

My pipe arrived thursday afternoon. My one mechanic called it the "tomahawk". Man, it sure is different than the stock unit.

Your detonation problem sure is baffling me. I shaved even more off my head than yours. My port job was not a light one by no means. I really opened my exhaust port up ALOT, didn't do much to the transfer ports and opened my intake up a fair amount. I did end up raising my exhaust port thou. Didn't mean to but that dremel just really liked cuting those ports. I also bored my stock carb out to a 31mm a week or two before I ported and shaved the head.

What spark plug are you running? I never use the stock B8ES. At the least I run a B8EG. I prefer running the B8EVX which is a super fine tipped electrode that is also dual platinum. their is also a B8EGV which is between these two but isn't a platinum plug. I notice better starting, better throttle response and harder acceleration with each step I go up from the stock B8ES.

I don't know when I'll have my quad together. I only took it to work a month ago because we were kind of slow at the time and I don't have heat in my Polaris shed yet. Once I got the machine completely tore down to the bare frame, we got busy again. Now I have a hard time getting the time to work on it. We don't close until 7:00 and I live over a half hour away so I don't like staying late. Ecspecially since I don't ever get to leave until well after 7:00 anyway. I hope to get it atleast running some time in the next week. I still have to come up with a silencer for my pipe because I thought I was getting one from someone else when I ordered my pipe. Now I have a pipe with no silencer. I also have to figure my jetting out but I have to get it running first. I am sure at this present rate, I won't have it completely done for a few more weeks. I hate to say it but I almost wish we would slow down a little again. that way I could ge it done sooner. Oh well, I need the paycheck more. Thank god for Yamaha's. I might actually have as many Polaris in for repairs as I do Yamaha's at the moment. That doesn't happen much. I usually have three or four Yamahas for every Polaris.