CT ProX head to Mugen cyl. help please.......

[k10seibel]

Anyone have a CT ProX "PRO CROSS" head laying around or just off your motor currently??
I'm looking to have someone take a piece of white copy paper and scratch etch the bottom deck surface of one for comparison. I have this '85 CR Mugen cylinder that I'd like to adapt to my "Mugen 250R trike". I don't have the matching Mugen head for it, but the matching Mugen CR head has a two spigot top anyway. I got this cylinder kind of on the cheap and want to make it work with a ATC/TRX single spigot head. The Mugen head is much larger like the contemporary o-ring heads of today. Thus I'm thinking a CT, Allan Knowles, Pro Cross head might just be the ticket. I called CT, but as I thought they won't confirm. ESR looks like it too may work, but I think Allen's heads look more like the Mugen cast original style. Billet might not look quite right here on this old school vintage project.
Any help is greatly appreciated.
BTW, anyone with a true '85-'86 ATC/TRX Mugen top end kit & willing to sell.....I've got your money chest here waiting.


http://i425.photobucket.com/albums/pp334/k10seibel/May2010-Dec2010.jpg

[2-330s]

k10 i have the head off my sparks motor. i can do one beter for you if you want to meet me in madison. i'm working in deforest and get off at 3 let me know?

[k10seibel]

Oh wow that's awesome.
I'm not sure of my schedule for tomorrow, though. I'm "on call" so to speak. A real drag. If you don't mind PM me with your phone # and I'd be happy to give ya a shout. Or feel free to call me (608) 235-1103 anytime. I really appreciate the help!
Small world too!
Thanks again.
-Andy

[wild250rman]

wonder if an older CR 500 head would work?

[k10seibel]

I've wondered that too.
I'm thinking anything can BE made to work. I just thought it'd be nice not to do a lot of machine work. But will if necessary.
Using an older modified head of the period would have the right old school look anyway......

[wild250rman]

once you get it up and running could you tell us how it runs compared to a standard cylinder. good luck on your search.

[wild250rman]

looking at an old post from December 09 and black sheep had a pic of a complete mugen cylinder don,t know if it was his or just a random pic.

[k10seibel]

Yep, Black Sheep posted a pic of the '85-'86 ATC/TRX 250R Mugen kit. I mentioned having a money chest waiting for any interested seller. (LOL) Love to have that kit too. Very RARE!

[Rich250RRacer]

Since that's a CR cylinder and set up for the ATAC system, won't the extra volume in the exhaust chamber have an impact on the way it runs without the rest of the ATAC system? I think you are going to see something quite different in terms of power delivery because of this, whether postive or negative. Also, what do you plan on using for an exhaust flange?

[pdxbigfoot]

A head off a 86 CR500 in my hands right now if you need it for reference.
LMK

[troybilt]

Pics for reference... goodluck Andy!

http://i74.photobucket.com/albums/i260/robltc/untitled-1.jpg
http://i74.photobucket.com/albums/i260/robltc/dsc5026.jpg
http://i74.photobucket.com/albums/i260/robltc/dsc5020.jpg
http://i74.photobucket.com/albums/i260/robltc/dsc5005q.jpg
http://i74.photobucket.com/albums/i260/robltc/DSC00946.jpg

[C-LEIGH RACING]

Lets see a pic of the top of that cylinder so we can see the stud spacing, CR250R head might work.
Neil

[wild250rman]

k10 could you or someone else give us a little history lesson here on the mugen cylinders who ran them what type of performance or any other info. definetally an interesting piece.

[rsss396]

cr500's have 7 studs they wont be a option

[C-LEIGH RACING]

Originally posted by rsss396
cr500's have 7 studs they wont be a option


Yes they do & are 8 X 10mm step studs & MAN are they bugger bears to get out.

I aint saying no names, but know somebody gona need some handle bar hooks on their hand just to hold on after they get something back.
Neil

[Rich250RRacer]

Originally posted by troybilt
Pics for reference... goodluck Andy!

http://i74.photobucket.com/albums/i260/robltc/untitled-1.jpg
http://i74.photobucket.com/albums/i260/robltc/dsc5026.jpg
http://i74.photobucket.com/albums/i260/robltc/dsc5020.jpg
http://i74.photobucket.com/albums/i260/robltc/dsc5005q.jpg
http://i74.photobucket.com/albums/i260/robltc/DSC00946.jpg

So were there two different Mugen 250R cylinders? The one in the 4th pic is different from the cylinder on the right (250R cylinder I presume) in the 5th pic.

[troybilt]

Pics 1 and 5 are 250r cylinders, the pics 2-4 are CR Mugens... as I understand it.

[J.B.]

I know who posted the pic originally, but does anyone know who owns that bronze looking gem? I'd love some more pics of it.

[k10seibel]

The top Mugen pic Troy posted was purchased off Ebay by Richard K. a great guy on the 3 wheeler sites, and it's for the '85-'86 ATC/TRX 250Rs. I've inquired about it's possible sale and don't know of any other photos, but there may be more over at 3WW. The second pictured top end kit is for an early '80s ('81-'82??) CR 250's. That one won't work without extreme work, and debauchery to the kit's originality. The third side by side Mugen kits are Peter B's OEM '85 ATAC CR Mugen (left) and '85-'86 ATC/TRX Mugen (right) jugs. He's from the UK and owner of this phenomenal stash of parts. http://www.offroadvintage.com/
Need OEM R parts..... he's your guy!
He has done the leg work for the exhaust flange (lower pics). As for the power delivery without the external '85 ATAC mechanism... These were poor set ups from what I've heard, and many were disconnected and set aside (tossed) with the addition of aftermarket pipes (thus the OEM change in '86). I personally have no proof of performance or experience with the ATAC cylinders, but if and when I get this running I'll divulge the pros & cons when I have a clearer picture.
Thanks to all here.


http://i425.photobucket.com/albums/pp334/k10seibel/PeterBexhaustflange3.jpg


http://i425.photobucket.com/albums/pp334/k10seibel/PeterBexhaustflange2.jpg


http://i425.photobucket.com/albums/pp334/k10seibel/PeterBexhaustflange1.jpg

[2-330s]

sorry i missed your reply. i'm off tomorrow but will be working friday. saturday i will be in deerfeild running horses with my wife. sunday i will be with my buddies racing in fort atkinson. i'll call you tonight after we get done eating.

[TLR-Online]

Hey Andy,

Is the exhaust flange just an aftermarket TRX250R flange that was modified?

[k10seibel]

Originally posted by 2-330s
sorry i missed your reply. i'm off tomorrow but will be working friday. saturday i will be in deerfeild running horses with my wife. sunday i will be with my buddies racing in fort atkinson. i'll call you tonight after we get done eating.

Sorry my mail box was full. Look forward to chatting.

I need to make a correction from about Troy's first posted picture of the ATC/TRX Mugen cylinder kit. Richard K from 3WW sold it a while back. I just found out tonight. Oh well, it found a VERY loving home.

[k10seibel]

Originally posted by TLR-Online
Hey Andy,

Is the exhaust flange just an aftermarket TRX250R flange that was modified?

I believe so. Looks like the ones offered via the aftermarket and on eBay. Looks relatively easy enough??? I'll find out more soon. Emailed Pete today.

[TLR-Online]

Originally posted by k10seibel
I believe so. Looks like the ones offered via the aftermarket and on eBay. Looks relatively easy enough??? I'll find out more soon. Emailed Pete today.

Thats what it looked like to me... Are you planning to port the inside of it? I think your cylinder has a 46.5mm exhaust opening, where the stock TRX has a 42mm opening.

I cant wait to see this cylinder on your trike!

[k10seibel]

Originally posted by wild250rman
k10 could you or someone else give us a little history lesson here on the mugen cylinders who ran them what type of performance or any other info. definetally an interesting piece.

I really don't have a back story on Mugen, as far as ATV use goes... I believe I read in one of my old magazines that Steve Wright ran one after Team Honda dissolved. I don't remember for sure, could of been Marty Heart. I'd have to go back and look. Team Honda of America didn't use Mugen stuff that I'm aware. Mugen offered their (gold) version of front and rear suspension for the '85-'86 ATC 250R. I've found both suspension kits in NOS form and am looking to give the motor a touch of Mugen at a some what down to earth price. A NOS ATC/TRX '85-'86 top end kit can go for over several thousand $$. VERY RARE!! From what I'm told, possibly only 100 were made. Each cylinder has a stamp build # on the under side of the intake. My particular '85 CR Mugen cylinder is #52. A reliable source said he's never seen or heard of a ATC/TRX number over mid 90's (I f memory serves me 98), thus the assumption of a 100 built.
Here's a couple cool sights to check out with more info. Enjoy!


http://www.mugencross.com/mugenbutton.htm http://mugen125.tripod.com/mugenhistory.htm


http://www.mugencross.com/mugenbutton.htm

[wild250rman]

thanks for that info interesting. will keep my eyes open. may have seen one in the past but didn't know what it's value was

[pilotpete]

Originally posted by k10seibel
Sorry my mail box was full. Look forward to chatting.

I need to make a correction from about Troy's first posted picture of the ATC/TRX Mugen cylinder kit. Richard K from 3WW sold it a while back. I just found out tonight. Oh well, it found a VERY loving home.
Oh yes the cylinder went to a loving home ....not me but know where it went :rolleyes: :rolleyes:
Yes that flange is just one off ebay that i cut down, trick is to find a 85 CR exhaust gasket and line 2 of the holes up, mark up the outside and cut the rest off also need to drill a hole so everything lines up.....
as for the Mugen cylinders not tried any of them yet will be this year if i get the time........looking at them i would say the CR cylinder would be faster as it has slightly bigger ports and bigger cooling jacket.....

[MANIAK 88R]

I ran one of these cylinders for quite awhile. At the time, I didn't know what it was. I had a hell of a time finding parts for it. I ended up using a wiseco piston for an '84 CR to get the ports to line up. Now that I've had the prox for awhile, I can still say that the mugen was my favorite. I had the version with the tapered exhaust cavity. I thought it was an atac for a long time but then I got schooled. Unfortunately after I sold it with my 86 trike and it still resides on that bike. It just stares at me laughing every time I see it.

[k10seibel]

Hey guys, just thought I'd update the Mugen search.
I recently acquired an '85 ATC with the correct ATC/ TRX Mugen jug. The bike also has a Jemco pipe and Dellorto carb.
This will finish off the Mugen build perfectly. Someday I'll still get the '85 CR Mugen cylinder all set up for a comparison.

I drove from WI to KS (over 850 miles one way) to get it. Saved at least $400 in gas with the Neon.....(LOL)
Back home in about 21 hours. Sadly not much left of my weekend to tinker with it. My wife says it's time to spend more time with the kids....(LOL)



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[pilotpete]

congrats Andy you found one.....if you get a chance check what number it is???
found you a nice 86 harness by the way :D :D :D :D

[k10seibel]

OK, Pete will do..
Cool, thanks so much!
Talk to ya soon.

[danhung11]

Congrats Andy! Where in the heck was this hiding? Don't tell me Manhattan...

It would have been pretty funny if you were stopped by Hwy Patrol or something, the look on their face would have been priceless. :D

[k10seibel]

Dan, it was posted up for sale over at 3WW. The seller found it in a corner of a guys garage and swung a deal on it. Knowing the cylinder was different looking he thought he could make a buck or two turning the trike for sale. I think he was pleasantly surprised at the fan fair and fuss made over it after posting it and only owning it for a week. It was located in western Kansas. I'll see if I can't get the engine pulled this weekend and get the # off the jug. I'm selectively stripping the carcass of this trike and parting out anything extra, that I don't need.
Thanks guys!
-Andy

[wild250rman]

give us plenty of pics of the cylinder, head and piston when you open her up.

[profab250R]

that is the sickest thing i have ever seen! never even knew these things existed. but its all for vanity. nice find!

[Motofool250r]

definately found a rare gem in atv/atc history there

[Honda 250r 001]

GAH! Some people have all the luck! Nice find man!