12:5:1 416

[ill_lil_romey]

I think that would be a hot setup, anyone agree? I'm thinking of going with this. But I question the reliabilty of this. What do you guys think?

Well you will HAVE to run race gas in it,,which is gonna be about $4 a gallon at the lowest..and also I've read a few times and been told by an engine builder that it could bring crank problems later down the line.

[oynot400]

It should be a trick set up. A stronger rod would be a good idea also.
Rico is right you will have to run race gas with that high of compression. I think race fuel varies in price through out the country because I am only paying $3 a gallon. :D

[ChadEXer]

With a good cam that would be real nice! But I do recommend a stronger rod also just for insurance, but with that compression you will need to run at least C-12 or C14(VP) and thats gonna set you back at least $4-5 a gallon,,,Tom recommends I run C-14 or C-14+ in mine which cost me $6.25 a gallon,,,but I wont be buying much gas anymore;)

[ill_lil_romey]

Yea I was aware of the need to run race gas at this high of a compression, but I was not aware of the stronger rod. I am rebuilding and I think that this is the way that I am going to lean towards. Sounds good to me! What companies can I look to for a stonger rod? And cost?

[ChadEXer]

I would get a Carrilo rod if I was you!! They are better than the IMS rods but are a little more expensive too!!

[Dave400ex]

That high of a Compression is really hard on your Motor. I think a great setup would be a 11.5:1. Sparks can have Pistons custom made so you could do that. Sparks also has Carrilo Rods. I think the 11.5:1 would be awesome. You would still need Race Gas, but it's not so high. Talk to Sparks about it. You may want to get a Clutch kit also.

[ChadEXer]

Warriorman, your talking about Sparks here, he runs VERY high compression in all his motors!! He has been running 15:1 in his 465's on alky,,,thats rediculous!!! I dont know if he would recommend going high to most people or he just done his bikes that way so they would be the fastest out there?? But I do agree that it will be a little bettr on the motor to go with a little lower compression,,,but If it was me I would go 12.5:1,,but we all know Im power hungry and dont pay much attention to relibility sometimes!!!

[ChadEXer]

Warriorman, your talking about Sparks here, he runs VERY high compression in all his motors!! He has been running 15:1 in his 465's on alky,,,thats rediculous!!! I dont know if he would recommend going high to most people or he just done his bikes that way so they would be the fastest out there?? But I do agree that it will be a little better on the motor to go with a little lower compression,,,but If it was me I would go 12.5:1,,but we all know Im power hungry and dont pay much attention to relibility sometimes!!!

[ill_lil_romey]

Interesting. Reliability is a big must when mx racing like I do, but I'm mechanically able. Maybe that 11:5:1 wouldn't be so bad, well actually, not bad at all, I do agree thought 12:5:1 is a lot of compression and stressfull on the motor, but it sounds sooooo swaa swAA SWEET! My budget won't allow me to rebuild every season, so leaning to the reliable side is more an option. We all know Sparks is awesome, but he's a little too steep on his pricing and the long waits, I can have JE custome make the piston 11:5:1, 12:5:1, or what ever it may be. I know I want it to be a 416 or 26 though

[Dave400ex]

Well let me know if you go with the 11.5:1 and how it works. I may consider that also.

[ill_lil_romey]

Im going to go with 11:5:1 with a full race cam. And I will be sure to post the results Warriorman! I think that that compression with a 416 or 425 bore will be a combo that is very hard to beat, especially with everything tuned to perfection.

[Sick0]

You may also have a problem with your starter, and battery. Plus you're engine will run hotter too.

[ill_lil_romey]

The engine running hot is not a prob of immediate concern, there are ways to prevent that. And as far as starting, I don't think it will be much of a problem, if there is, then Ill just get a GSX-R battery. What I am concerned about is the studs staying in place, the durability of the rod, and blowing gaskets. You never know untill you try. And besides, its a honda, I've never had a prob with modified hondas. done right. I have the choke removed on the carb also. So in the cold she might be a biyatch to start. But down here in Louisiana we don't have to worry about cold. South of the lake it rarely gets below 30

[Dave400ex]

Your starter will be fine. I would go with the GSXR Battery though. Onyot has one on his 12.5:1 463 motor and he said the battery made it start like the motor is still stock. Heat should be alright. Just make sure you change the Oil about every 5 hours and you will be ok. Air Scoops and an Oil Tank would really help. The rod would be my only concern. I would get the Oversized Head Studs from TC if I was you. They are only around $80 or so.

I would get the Oversized Head Studs from TC if I was you. They are only around $80 or so.

Man are we all brain washed or what? First time I read this I didnt even think twice about paying $80.00 for $10.00 worth of bolts LOL guess they got me trained too :D

BTW So far so good with the 11.2:1 Ross running 12.5:1 actual comp. and its not wanting as much octane as I thought it would.

[ill_lil_romey]

You not lying man 80 bucks for some bolts is just ridiculous, but hey, if it gets the job done right? I can't wait to put this thing together and see what the results are like!

[ChadEXer]

About the starting issue, talk to TC about getting a decompressor on the cam, Im not sure if its something only an engine builder would be able to do or if the do it yourselfer can do, but he put one on my bike and with my HUGE bore and 12.5:1 compression, one tap of the starter and it fires right up, matter of fact it starts better than it did stock!!! My friend has a big bore Raptor and his doesnt even want to start most of the time, and batteries dont last!!
The TC head studs are high for bolts, but man are they well worth it!!! Also you can o-ring the head to and that will nearly eliminate blown head gaskets and stuff like that!!
Also your saying since you removed your choke it will be hard to start in the cold,,well Im in the same weather as you(TX) and when it was as cold as it ever gets here, when my bike was a 416 with stock carb, it starts actually pretty easy in the cold,,the stocker has an accelerator pump that will make sure it fires right up!!!

[ill_lil_romey]

Great info Chad. I don't think I would need a decompressor, but if it ever came to that then so be it. This has been a great thread for me and i appreciate all the help and advice you guys have given me. When it really cold, 5 pumps of the throttle and a 1/4 start and it fired right up. But im concerned about it with the high compression.

[YZROOSTINYA]

with high compression it should actually start easier. when you compress air it gets hot, so if you compress it even more it will even get hotter even the motor is cold the air is still heated slightly. my 416 starts and runs beter than when it was stock. also i would suggest going with a stage 2 hotcam instead of a hrc. there half the price and made of the same material. i have one in mine and it runs great, no probs at all. alot of people intially said bad things about them and the specs being off. i think the dealers were getting it mixed up more so then the vendor. i talked with the guys there personally many times and i have a stock valve train besides the cam and about 20 hours on it now with no probs.

[oynot400]

One thing that Mike from For Dirt Only told me was if starting became a problem. Then I might need to install a decompression lever off a xr400. The parts for it are pretty cheap. I do notice it doesn't like to start the best if the motor is hot. Even with the new battery, but it will start.

[ill_lil_romey]

The cold starting issue was because of the choke being removed off the carb, but thats not a prob. It shouldn't be to hard to start when the motor is hot, like if you stall in the middle of a race or something, I guess Ill know soon. The duration and lift of the HRC cam is higher that the hotcam stage 2, and I have heard bad things about it and some good things, it's just that people have told me that the HRC kicks ***. What kind of compression are you running in that 463?

[smith]

fyi....the hrc cam comes with the same style decompressor as stock. It works great and helps with starting the higher compression motors. (aka..no need to add on later because it's already there!)

[ChadEXer]

I found out about the decompressor on mine when I asked Tom about doing a compression check, the only bad thing about it is you cant really do a compression check when troubleshooting because with the decompressor it will only read somewhere about half of your true compression when your hitting the starter, so basically a decompressor knocks your compression in half when starting the motor whick makes it start very easy!! The HRC cam is real nice, but you can get cams with very close specs that are half the price of the HRC!!!!

[YZROOSTINYA]

i have no decoompresser and i have no choke either, its about 20 degrees out. its not the easiet to start. i have to pump the carb, then hold then throttle for a sec and it usually stays running. if it stalls just repeat and hold 1/8 throttle for a sec and it idles fine then till it warms up completely

[ill_lil_romey]

Damn is the HRC cam that much? If I can find one with very close specs to it then maybe I would have to try it, but as far as the decompressor being built in I never Knew that. What about a web cam? I've heard that they make nice cams.

[ChadEXer]

I would get a TC cam! Its not the cheapest cam out there but its cheaper than the HRC,,,its about as hot as you can go without having to harden the rockers and all that other mess!!!

[YZROOSTINYA]

hrc 350-395

hotcam 125-145

[Dave400ex]

Yes we are all brain washed because when Arens said his LT arms will be under $600 I was like well there only $600. That is still a lot of money.
Chad if I get a TC Cam could I have like a local mechanic rig up the decompressor? If it helps it start better then I want to have it. I have enough problems with it starting in the cold now, and sometimes when it's really hot. I do want to get the GSXR battery and bigger battery cables, but it sounds like keeping the decompressor is the way to go.
Get the TC Cam. They are from $180 to $210. Heck I may have to go call TC about this now. lol

[ChadEXer]

Yeah you would have to call TC because i dont know much about it,,,we talked about it shortly but I have no idea how its done or whats involved!!! Anything from an engine builder is expensive,,,TC is one of the cheapest and his stuff is still high!!! He wants $325 for a Lectron setup for alky when I can get one from Fast by Gast for $250,,,,but I will still probably spend the little extra because I would like for Tom to know exactly whats on my bike in case something happens!!!

[ill_lil_romey]

I wouldn't mind getting a TC cam, but I do not like to put different products from many different companies on my bike you know. If you get all the components from one companie they have been tested together and tuned to work to perfection and in sink with each other. I was thinking of a white brothers full race cam.

wanna buy a bridge? :)

MAny of the so called builders and sales co (WB)products are not special at all cause they buy them from the same place you can.

[Evan]

Ive had the 12.5 416 and loved it, would do it again in a heart beat. I also had the 13:1 425 and would not do it again. I had engine failures with both setups but niether was due to too high of compression. I had no trouble turning my motor over with stock battery. Although I did have a FCR39 if that made any difference. I had a Sparks cam and love it too, just needs stiffer valve springs as with any high lift cam. It was a drop in too, I dont know about the others I belive u have to press on some peice onto the cam, and heard of some coming off. If it was me I wouldnt take that risk. Supposedly the WB track cam, the TC cam, and the GT cam I belive it is, are all the same cam. Do some searching to find out more. Remember any cam that has been rewelded, you will need hardend rockers. As long as its drop in you wont need rockers. I would like to see how a HRC cam compares to other cams, I mean if its good enough for honda.....BTW I dont know if anyone knew this, but Sparks sat down with honda and designed his cams, and most of his stuff so that they would work well. You might also want to look at where a cam performs best ie upper or lower rpms, for MX you need a cam for mid-upper, cams designate where the power comes in, like porting and pipes on 2 strokes. Hope this helps some.