steve125

LIFETIME SPONSOR
Oct 19, 2000
1,252
0
Troy776 if bottom end power is important to you then go with the 02yz125,with mods the honda will run with the yam from 8k to peak but below that the Honda is no match for it.:eek: Mike t i would guess at least a 3-4hp drop from the crank to the rear wheel.:D xtreameair125 the newer hondas do run better than the 99..if moneys tight try a 00yz125 it's as fast if not faster than any of the new bikes:eek: nc514 the new 01-02 delta will work fine just be sure to match the manifold hole to the new reed block:cool: tom 125 i doubt the 02 boot will fit:scream: joe p 81 the 144 mod on the yz runs well and you'll have a tough time decideing on which bike to ride, the fun factor is the same.
 
Feb 25, 2001
394
1
Just out of curiousity what do you do for a living Steve125 ? seems like you have alot of $$$$ to put parts into your bike like they are 2 dollar play toys. Seems like your building a monster. Do you race in your area ? I do some Ultra series races up near your way in Va.
 

steve125

LIFETIME SPONSOR
Oct 19, 2000
1,252
0
Yes it may seem like i spend alot of $$$, but i have alot of good friends "in the industry" so those good deals allow me to test alot of products;) Pete Payne of HDR helps out alot too.
 

NC514

Member
Oct 20, 2001
64
0
I hope there aren't any kickbacks

Stece125,for myself and the rest of the DRN forum readers, we rely on the info that knowledgeable people like yourself provide. I'm looking forward to hearing your findings on the PRO CIRCUIT pipe/silencer setup on your 02 CR125. We just want good honest findings that's all. I have a hard time relying on magazines. I believe it was the December issue of DIRT BIKE, They did a pipe test of PRO CIRCUIT and FmF pipes. It was a waste of paper. The caption under the 02 CR125 about each pipe, exact wording flipped around about. The only difference, PC caption add a few spicy adjectives to catch your eye more, Oh.. and a picture for the PC pipe! The article just confused me more. I would like to thank you for all the insight you have given the readers on bikes.
 

Sage

dirtbike riding roadracer
Mar 28, 2001
621
0
Originally posted by steve125
if bottom end power is important to you then go with the 02yz125,with mods the honda will run with the yam from 8k to peak but below that the Honda is no match for it

Steve, are these engines stock with just bolt on's? does the Yamaha have more compression than the Honda? Both the YZ & CR engines are very close in design, I'm just wondering what makes YZ go. Port timing, cylinder pressure??
 

XtremeAir125

Member
Jul 5, 2001
120
0
Steve125- I'm confused about you mentioning the 00yz125 reed manifold. i plan on selling my 99 CR125 and getting a 00 CR125. I checked out Yamaha's microfeche www.yamahaoftroy.com and noticed the whole intake (reed valve, reeds, stopper, etc) were like $50. Would I need that whole kit to bolt it up to a 00 CR125? Would it work for a 00 CR125 or only on the 01-02 like you mentioned? I'm kinda clueless here but what do you mean by the reed manifold and cage? Is it the whole reed assembly? I wanted to mirror your gains on the 00 CR125 like you did with a 02. Were the 00 YZ125 reeds you used in yer experiment carbon fiber? Also, would the DeltaForce reeds work too on a 00 CR125 to get 1 extra hp? Sorry for the long post.

Ryan
 

NO HAND

~SPONSOR~
Jun 21, 2000
1,198
0
XtremeAir125, If you want to step up to a 00, you might want to know what are the flaws on that bike in the first place. For that new cylinder model year (00), they had a serious mismatch between the cylinder and cases. Eric fixes that by enlarging the cylinder transfers to match the cases and the stock 01 has the mismatch fixed. The 00 cylinder has the rear transfers that are misaligned and Eric redirects to flow more towards the center of the piston, that was also corrected on the stock 01. It's very cool the way Eric uses epoxy to shape the transfer flow pattern. The v-force does make a big improvement on the 00 also, It's a good product for us cr125 owners. The 00 has a large intake manifold compared to 02. You might not have to tamper with it as much as you will have to fix the cylinder. The reed manifold is the rubber tube between the carb and the cylinder. The reed cage (what you bold the reeds on) is hiding between the cylinder (oops actually crankcase) and that manifold. Manifolds are interchangeable between cr125's What fits on your 99 will fit on the 02 and vice verca.
Originally posted by EricGorr
Honda updated the cases in 2001 making the upper corners leading to the transfers wider and smoother. In 2002 they modifyed the design of the intake skirt of the cylinder for less restrictive flow through the reed valve.
I'm guessing that the next move will be to shroud the crank like the KTM and the new YZ85.
Taken from: (Link)
 

XtremeAir125

Member
Jul 5, 2001
120
0
Ok, I have a question for Steve125/Marcus/NO HAND- Just today I found out that I got a job at my local Honda motorcycle dealership. I'm selling my 99 CR125 on E-Bay right now, and when I do finally sell it. I plan on taking the money and paying off of what's left on my bike payment. When I do that, my next bike will definately be a 2002 CR125. Will this outta the way, im still kinda not sure what the reed manifold is. I checked out www.yamahaoftroy.com and went to the 2000 YZ125 parts microfeche. Is the reed manifold part number 5ET-13565-00-00 JOINT, CARBURETOR...#6 on the parts microfeche. OR #8 90450-51070-00 HOSE CLAMP ASSY? Sorry for being a tard but I have no clue. I read on Steve125 first post about using 00YZ125 reeds and the manifold....are the stock reeds from a 00 carbon fiber? And when Steve125 mentioned drilled to fit YZ manifold and drilled to fit YZ reeds, does that mean I'd have to drill the reeds into the cage to fit? I'm still a little confused here....sorry fellas. Now if I order the Delta 2 Reed assembly, I'd have to cut pieces away of the rubber? Sorry for the long post, but building an ultimate CR125 is my goal. How about a 02CR250 airboot and the 38mm carb on the 02CR125? More Power? Thanks guys and sorry for this way-to-long post. Take care!

Ryan
 

NO HAND

~SPONSOR~
Jun 21, 2000
1,198
0
Congratulation on the new job! Well, I'd better leave Steeve and Marcus explain the best mods for a 02cr125 because they have a 02 and did some testing already. A reed manifold is the rubber boot between the carb and reeds. see part #9. (click for the diagram) You will need to cut some rubber on the manifold if you use the v-force. It's the only way it will fit. (click for v-force instructions). the stock reeds from a 00 are carbon fiber. To fit the yz reed and manif, Steeve probably drilled the manifold #9 and reed cage #5 to line up with the crankcase mounting holes. We're talking about the 4 holes in the corners to hold onto the engine, not the reed petals. I wonder if he still suggests that mod for a 02. The airboot and 38 was good for 00-01, It remains to be seen if it's good also for the 02.
 

NO HAND

~SPONSOR~
Jun 21, 2000
1,198
0
O.K. I've been studying very carefully Marcus and Steve 125's posts and I'll try to give you my guess of the recommended mods. For 02 he says the air boot is large enough so fitting the 02cr250 boot to the 125 won't be worth it. First, get the head done by Eric to prevent detonation (just head work is very cheap) or run 2 head gaskets. Get a 7mm spacer for the power-valve to correct the blow-bown timing problem(Click Link).

For a mid-top powerband: it would be: Latest version 02 v-force (it has a large back-plate now 31/38mm), The intake manifold from a 00yz125 is 32/37mm so you wouldn't have to hog out too much to make it fit. You could buy the 00cr125 manifold at 29/32mm which is almost 10$ cheaper and cut the inside to fit the v-force cage back-plate (not 01 the hole is offset). Keep your stock 02 manifold in case you wan't to switch to a low-mid powerband. A 38mm carb would be next. If you are using a 38 mikuni you will have no problem fitting it. If you have a Keihin, you will need to buy the 99cr125 manifold instead of the 00. It's the only way it will fit. That's about it.

Low-mid powerband: Leave the carb and manifold alone. Get some Boyesen power reeds (resin, cheap). Or maybe the v-force on the low tension setting would be even better. They help low end because they are softer than carbon fiber. Get the cometic thin base gasket, The stock porting is very agressive and suited for mid-top and the thin base gasket will retard timing a bit. Next is a Vertex piston for Husky 00125cr the absence of lightening holes increase crankcase pressure. Last, a shorty silencer adds some low-end snap. That's my guess. How about other's guess?
 
Last edited:

NO HAND

~SPONSOR~
Jun 21, 2000
1,198
0
I still have to figure what combination would give more, better power everywhere.
 
Last edited:

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
Seb you are a good learner:) Its not easy remembering all these combinations,basically top end engines require big holes(this is over simplifying)big manifold holes,big ports/big carbs, the downside to this is on low throttle/rpm the airflow velocity will be poor(think blowing down a drainpipe vs a straw)so low end power/responce suffers.For low end we need smaller holes to keep airflow high but this may restict at high rpms.

What does all this mean to the 02 Cr-the 02 Cr has small carb/manifold and exhaust manifold BUT large ports-mismatch of needs.

Option 1- for low end, lower cylinder upto 1mm depending on needs(mod head to suit something like 6-7mm squish width,2 degree angle ,clearance 1mm)this gives the CR a good match of carb/ports/manifolds.A vforce will help all engines-maybe try the low tension setting.Husky piston.Shorty silencer.7mm powervalve spacer

Option 2 -top end GP spec engine-00 v force with manifold hogged out to suit(the 02 manifold will actually fit a mikuni 39mm carb, unlike the 01)remove reed spacer to fit mukuni carb(as its larger from end to end)the airboot side will fit the 39mm carb but its a tight squeeze.I would get eric to drop the lower corners of the exhaust port for more overrev.I would use a piston with a window and maybe lightening holes around the wrist pin area(basicaly like std but not std).A doma silencer(large exit bore)maybe a top end focused front pipe.7mm powervalve spacer.Mod head for narrower squish band maybe 5mm with a 3 degree angle and 1.1mm clearance.

Most of this info is learnt from erics mods over the years and his book.I would be interested in erics/richs/petes assesment on these mods but i think they are letting the students learn rather than be spoon fed(and quite right too:) )
 

jake949

~SPONSOR~
Mar 7, 2000
245
0
thin base gasket and 3 head gaskets?

in order to run the husky piston you need to use two head gaskets or race fuel. But i was wondering if a person used a cometic thin gasket to lower the ports and then used three gaskets if that would work? the thin base gasket is the same thickness as the head gasket right?? I do know that that is kinda of a stone age approach, but Eric is back logged a month on his work and i have a freind that might really like that done to his bike if you can do it.
 

Jay-R

Member
Nov 27, 2001
133
0
I don't know about three head gaskets, but right now I am running the Husky piston with the thin base gasket and one head gasket. I am running 50/50 mixture of 110 octane and 93 octane. I like how my bike runs, but I have been told that I am loosing some top end hit with only one head gasket. I would like to hear reccomendations on the set up with one head gasket versus two head gaskets. I may switch to two head gaskets, but I am not sure if I need to.
 

marcusgunby

LIFETIME SPONSOR
Jan 9, 2000
6,450
2
You can run 3 head gaskets and the cometic base gasket as a stop gap-no problem.Jay try the 2 head gaskets -you may like the feel of less comp.
 

XtremeAir125

Member
Jul 5, 2001
120
0
Steve125- You say you're using the 00 Delta, what part # is that on V-force's website? Cause if i figure I buy the newer Delta's I would have to cut around and make it fit, I don't feel comfortable when it comes to cutting and wasting $130. Thanks!

Ryan
 

steve125

LIFETIME SPONSOR
Oct 19, 2000
1,252
0
The Delta valve i ended up likeing the best for the 02 cr125 was the one for the 01cr #V2M01A. Match up the rubber manifold and your set.
 

NO HAND

~SPONSOR~
Jun 21, 2000
1,198
0
Originally posted by steve125
The Delta valve i ended up likeing the best for the 02 cr125 was the one for the 01cr #V2M01A. Match up the rubber manifold and your set.
Hi Steve, I'm surprised to hear that about the 01 v-force, because in 01 the manifold was offset to the left and v-force made a backplate that is offset to match the manifold. Now if you use the the offset 01 v-force with the 02 (centered opening) manifold you must get a bind of some sort in the flow. Maybe that's the black secret of the 01 power; compared to other years...:confused:. What was your impressions of the difference between the 00 and 01 v-force?

Originally posted by XtremeAir125
Steve125- You say you're using the 00 Delta, what part # is that on V-force's website? Cause if i figure I buy the newer Delta's I would have to cut around and make it fit, I don't feel comfortable when it comes to cutting and wasting $130. Thanks! Ryan
It's very easy to cut if you use an x-acto knike and you put the manifold in the freezer a few hours before. When frozen, you can cut the rubber easily and it leaves a smooth finish even better than original. When you get it, post here and we can help you through.
 
Last edited:

steve125

LIFETIME SPONSOR
Oct 19, 2000
1,252
0
No Hand,I like the offset idea of the 01 Delta verses the straight open hole of the 00 delta. Since in either case the manifold from the 02 needs quite a bit of grinding to match either valve,i feel the offset will help straighten the flow into the engine cases. In very much in the same way a RAD valve opens up the left side and then restricts the right side of it's valve to straighten the flow,both the 01cr and 02 yz125 Delta valves are similar to this and i think the theory is a sound one. Both the 01 and 00 cr Deltas offer a area increase once the manifold is matched to the reed cage and this is where the HP increase mainly comes from.
 
Last edited:

Top Bottom