tri z 250 cool head and vforce 3 install pics

[pcs]

ever since i decided to build up my tri z, ive found that some of the info about parts is a bit sketchy or not easily found i figured ill help others that come along and have question on certain parts by posting pics up of what i buy and maybe ill save them time.
here are pics of the part #'s direct of the v force cage that is going into my tri z and pics of the cool head i purchased and a few side by side of the parts they are replacing. 165976165977165978

[pcs]

here are pics of the head, i went with the pump gas dome for now since the cylinder isnt ported.

[Jcormode]

Nice parts cheif who did the head?

[pcs]

i ordered the head like that, its a pump gas dome.

[pcs]

got it from off road innovation

[Mosh]

Nice parts cheif who did the head?



got it from off road innovation

The heads were produced by Corey Sprock back in 2006-2007 and the first runs were all plain aluminum. Later another member here (Honda250sx) took some of the natural aluminum heads and anodized them for Sprock.
You can read up on the development here.

http://www.3wheelerworld.com/showthread.php/55804-SPROCK-TRI-Z-COOLHEADS-DONE.Test-results-and-more-new-pics



here are pics of the head, i went with the pump gas dome for now since the cylinder isnt ported.

During the initial design it was thought that the first runs of domes would yield different performance gains. Once the heads made it into the field for further reports, it was found that the "pump gas" domes were barely that. Unless you have your exhaust bridge raised to lower compression, or you re-chamber the "pump gas" dome you have, more than likely you will find that even with 94 octane fuel you may have some pinging or detonation. In most cases, if you make no alterations and run that dome as it sets, you will need a minimum of 50-50 93 octane and 110 race fuel to avoid detonation.
Any domes higher in compression and squish, or shall I say smaller in CC's than Sprock's "pump gas" dome designation, were significantly high on the compression chart and will require 100% race fuel. It has been my experience that the Z does not like tight compression without significant squish changes and dome alterations, a science which Yamahondaman had nailed down packed, but unfortunately those secrets went with him when he passed away. (Most on this forum would consider him the king of Tri-Z horsepower gains) Yamahondaman that is.

The VF3 reeds were also developed / found through Sprock a few years later during big bore Z development, when another rider not on forums, shared the info with Sprock and I, that the 2006 KX125 used the same mounting area as a Z jug and was later refined through Moto Tasanari aka V Force, to be altered slightly to fit the Z engine specs. Those work well with or without the factory Boost Bottle IMO.
Before then, some members found that WR 250 cages fit the Z in which you could get them in the VF2 design before the 3's came along.

There is loads of history on this forum about the Z and parts being altered/made to fit.

[pcs]

thx for the added info mosh, according to offroad, they also mention that people who had ran the pump gas dome still had to mix in race gas, which is what i do anyways.

[christph]

Yeah, thanks for the history Mosh. I wish I have known the "pump dome" was really a 50/50 dome, it would have saved me some grief. I did a lot of mods all at once so I had trouble figuring out what the problem was. Now it runs great--much better than I thought a Z was capable of.

[Rigaman]

Does anyone have info on how to modify the pump gas dome to make it run on pump gas? How much power would be lost?

Also.. Do you use a special head gasket with the cool head?

[Just-Tri-It]

Mosh, are you saying that with either of the domes that come with it, there are still mods that need to be done to the dome for it to run 93 successfully and not have detonations?

[3 Wheel Drive]

Does anyone have info on how to modify the pump gas dome to make it run on pump gas? How much power would be lost?

Also.. Do you use a special head gasket with the cool head?


You can save yourself some time and $$$$ by just using your OEM stock head, right? Keep the high compression domes for when you want to run 112 octane... IMO. One day they may not be so readily available?

I was going to track down a pump dome but decided not to cause my stock one works fine. The cool heads use rubber re-usable o-rings, no need to keep paying for new gaskets if you use them.

[Rigaman]

But if I switch from a stock cylinder to a cool head, I will have to keep changing head gaskets when I put the stock head on.

I would much rather have a good dome that I can use for pump gas, and another for race fuel.

[badass350x]

Looking good buddy, I guess this explains why you were not at invasion 2013????

Dean

[Bryan Raffa]

got any pic's of the bottom of the cyl,,, when it was off? last I knew cory had blank domes!

[pcs]

yes it does badass350x: took to long to get parts in. i was hoping to at least have the reeds and the carb in but they were shipped via usps and they are horrible! got a pwk keihin and a swinger in the works now
the cool head does not run a head gasket, it uses o rings as mentioned above and any of the domes can be machined down to reduce compression.not much of an issue or difficult to have done.i have also seen people run a thicker base gasket too. i personally dont run straight gas 91 bc it has ethanol in it and ethanol likes to pull moisture from the atmosphere and when it combines with water it will separate from the pre mix and when that fuel goes in to the motor it provides no lubrication for the motor. race gas do not have ethanol and doesnt have this issue.

[badass350x]

Going to need some mods on that swinger huh?

[pcs]

just took quick measurements with the stock one still on and they seem to match up, just need to cut out the center section to clear the engine, im going to try and slide in the stock axle assembly into a round 35mm carrier, if it doesnt work then ill just get a stock rear axle set up off a banshee and run that with a quadzilla rear shock (swaps with a banshee) bc it has a remote ressi i can mount in the stock location so i can keep the stock gas tank for now. its about a plus 6 in swinger. found the swinger for $100, its from metal tech in phx,az and a chromoly version

[Mosh]

Does anyone have info on how to modify the pump gas dome to make it run on pump gas? How much power would be lost?

Also.. Do you use a special head gasket with the cool head?


Mosh, are you saying that with either of the domes that come with it, there are still mods that need to be done to the dome for it to run 93 successfully and not have detonations?

Yes, in most cases the pump gas dome will require a 50-50 mix of race fuel. I agree with PCS, that if you can afford it race fuel, it is much better than regular premium.

Supposedly Sprock is making a round of new domes that are relieved to drop down to regular 93 octane. I currently have a modified one that he cut I am working with testing/tuning now. It seems to be working well, but I am still testing it.

As far as losing power from cutting the dome, IMO you won't notice it on most applications. Once your squish and compression get too high, you actually will lose performance. So by getting those numbers down to ideal levels you will most likely gain a little power or at least top end revs. You may lose some bottom end torque, which IMO the Z is ok with bottom end anyway.

Compare those pics that PCS posted of the dome..IMO the squish band should be turned down around .020" and where the dome starts to taper towards the plug area, those edges should be laid back at least .030" to give it a little larger chamber towards the plug area. I am not a machinist, nor do I pretend to be, but I do know a little about engines and that is what I would do with the dome.
On a Z I feel that compression should be kept at 175psi and the squish should be kept at .055" or higher, but no lower. If you don't know what squish is or how to measure it, do a google search. Until Sprock gets the domes made, you could contact Jason Hall and see if he can rechamber them or any other machinist local with a lathe should be able to modify the areas for you relatively cheap.

[JasonB]

thanks for posting that up, im sure some of the tri-z guys will benefit from it!

also I have had two swingers done by metal tech, great guys! I love my +6 swingers they did for me

[pcs]

ive learned plenty from other members here so i feel i should help the 3 wheeler community when i can

[tri-Z ripper]

i will be following this thread for sure! $100 for a 6+ swinger, did you steal it? lol :)

[pcs]

tri z ripper: funny that a different member said the same thing about me buying an 85 r for $200. just looking around for parts and looking around everywhere to fine a good deal.ill make a separate thread for the swinger, ill try and get lots of pics posted

[christph]

I've got nearly all the parts Sprock made for the Z, the cool head, manifold, V-Force, hi-flow impeller, and clutch basket. It took a while to get the engine figured out but now I am very happy with it. Frankly, I didn't think a Z could perform this good. Here are some of the stats on my engine. I have Sprock's race gas dome in it. I checked the squish band clearance using the solder test and it measures .043. The compression is 190-95 psi. With this configuration I run 75/25 race gas to pump gas (110 Sunoco purple mixed with 93 pump). I've done some testing and it actually likes the 75/25 mix better than straight race gas. It also runs surprisingly cool. I've got Engine Ice in it and Sprock's hi-flow impeller and it runs around 180 degrees. In the future I hope to get a better pipe for it. Right now I'm running a DG. Here are some pictures.

166101166099166100

[pcs]

im heading in a similar direction as you are chris, i wanted to run less compression bc when i dune i ride hard for longer periods of time and i ride in the az summer which you know how that is so want to keep chances of pre ignition down. i usually run 1 gal of purple gas to 2 gal 91 mixed at 32:1 but with this head ill try 1:1 purple gas to 91. only other thing i dont like running intake spacers, i like how yours looks and the extra shine it adds to the motor however. im running the stock boot. only took about 3 mins in hot water and the 39 pwk slip right in.

[christph]

You may want to give a reed spacer a chance--it is not just bling. In fact, I was shocked how much it improved the performance of my engine. Since you are running the stock manifold with the boost bottle you might not get the same results, but then again they aren't that expensive. As I think you know, I added a boost port to my cylinder and got it flowing much better. Even with the V-Force it didn't feel like it was living up to its potential. The engine felt choked up. Then I installed the spacer and WOW, it really boosted its performance. Now, I don't give all or even most of the credit to the spacer. I think with the added boost port and the capacity to flow more air, the V-Force just needed more room in the intake to operate at maximum flow. Either it was too close to the boost ports or perhaps the reeds were being limited in their actuation by the relatively small intake of the Z. Whatever the explanation, the results speak for themselves. Here is a thread I started about it: http://www.3wheelerworld.com/showthread.php/154045-TRI-Z-likes-Reed-Spacer?highlight=tri-z+likes+reed+spacer

[volfan537240]

How much was the head? That site has no prices.

[christph]

I think I paid $220 for mine. For that you get the head, a dome of your choice, and a gasket set. I ordered a couple gasket sets because they are only 12 bucks. If you want the other dome (only two available I believe, pump and race) I think they are around $30 each. Greg, the owner, is good to work with. Sometimes Sprock is slow with getting him parts but that is just something you have to accept. I'm just glad he is making them.

[pcs]

the domes available come in 20,22,24 cc suppose to race gas,50:50, and pump gas versions

[ktmcrasher]

I'd love a cool head but don't know where to buy one & what dome to use on 98 octane uk fuel

[christph]

the domes available come in 20,22,24 cc suppose to race gas,50:50, and pump gas versions

Last time I talked with Greg at Off-Road Innovations he said there were only two domes available, pump and 50/50 (which is the race dome).

[christph]

I'd love a cool head but don't know where to buy one & what dome to use on 98 octane uk fuel

You can get them through Greg at Off-Road Innovation. You might be able to use a pump dome with 98 octane. Here is the link: http://www.off-roadinnovation.com/yamaha_tri_z_parts_ytz250.html

[pcs]

maybe that is all he had available? but i remember he said their were 3 domes
KTM: if greg doesnt have them, check out this site as well
http://www.cosmicquads.com/8401.html
dont procrastinate if you want one bc sprock only makes a few at a time then you have to wait till the next batch comes out.