Anyone tried a XR70 head yet?

CMaDillac · 2004-03-25

If anyone has tried out an xr70 head on their unit yet, let me know how it works.

G

· #2 · Mar 25, 2004

If you are going to do that then just go with a Honda Trail Bikes Head. I have one and it is great. I finally got it jetted after waiting on a backordered jet. I plan to dyno it sometime this week.

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Dezmo

· #3 · Mar 25, 2004

I'm running a ported head off a 98 XR70 with a 75cc cyl and a 20mm carb, it hangs with the stock head 88s...would prob be faster if I wasnt such a fat git

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JL

· #4 · Mar 25, 2004

One of my buddies has one in his z. It seems to work really good.

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Jetster220

· #5 · Mar 25, 2004

I second the TrailBikes head, I put it on mine where I had been running ported 50 head, and it was like adding a BB all over again. It screams like a banshee now.

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Xtreme-Racing-Ron

· #6 · Mar 25, 2004

A ported 70 head works really well too. We've A-B'ed our bikes with both ported 70's and Kitaco Ultra's, and the results are impressive. PRC uses ported 70 heads on his 14 HP killer engines too. They're definitely a good option if done right.

~Ron

Xtreme Racing 50s

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SkinDonor

· #7 · Mar 25, 2004

yes HRC heads from TB or E-11 or E-22 heads are the way to go and most are availible with race cams . these heads rip and are the only way to go when you don't own the bank.

They do require higher compression pistons though because of the combustion chamber size .

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Xtreme-Racing-Ron

· #8 · Mar 25, 2004

I've been using a Dragon 52mm mini-dome with them, but Jim says he stays with a flat-top and has great results too. I've never tried one with a flat-top, but it seems to me compression would drop a lot (not questioning Jim's work because I know he's a very smart man!).

~Ron

Xtreme Racing 50s

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SkinDonor

· #9 · Mar 25, 2004

I use the Kitaco 13:1 52 mm piston works great

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Xtreme-Racing-Ron

· #10 · Mar 25, 2004

SkinDonor said:
I use the Kitaco 13:1 52 mm piston works great

With a 70 head? I tired one once, but it hit the dome unless I double stacked head gaskets, then the plug wouldn't go in. I called Jim to see what he thought and he started laughing at me saying "I told you it wouldn't work without machining it down". That's when I searched and found that Dragon piston on your buddy's site (Dr. ATV)

where it said it's specifically for 70 heads for this application. Been running them every since.

That's my story and I'm sticking with it! :lol:

~Ron

Xtreme Racing 50s

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Jetster220

· #11 · Mar 25, 2004

Either you guys know the compresion ratio on the TB head with their piston.

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G

· #12 · Mar 25, 2004

I have been told 13:1 for TB head.

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SkinDonor

· #13 · Mar 25, 2004

Opps yah our stroke is 49.5 which alows the 13:1 kitaco piston to work . how about 11:1 probaly much better .

TB claims to be 13:1

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tjay

· #14 · Mar 26, 2004

I have been doing alot of testing, and hopefully soon I can get the results of some different pistons/setups including dyno results posted. Vince I have a setup for your motor that you will love.

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CMaDillac

Discussion Starter · #15 · Mar 26, 2004

.

Cool deal, I acually already have an xr70 head on my bike but i just wanted to see what everyone else has tried. I have a 04 xr70 head that has been ported and cut to fit a kitaco ultra head piston. Talk about compression. I have to run a washer on the spark plug cause if I dont the piston will hit the plug. He had to cut a lot out around the sides of the dome to fit the piston and it barely fits. Runs pretty good too. Smokes the stock head 88cc.

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weedracer

· #16 · Mar 26, 2004

alot a the companys out there are selling 70 heads and calling them something else just to make you pay more $$$$$$

just make shure your running the right piston pin hight so you wont have the prob of the piston hitting the spark plug

the japs are smart people they like to spend less $$$$ and make more $$$$ so a little FYI 50's 70's engines all fit the same parts even the new 90cc honda 4wheeler has the same block as a 50

its been the same block since the stone age the only thing thay changed is they went from points to cdi

so don't let after market companys take advantage of you

ps. never by any thing chinese ( they make happy meal toys and we all know how well built they are :roll: )

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