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XR cylinder base/ head gasket alignment dowels, w/ holes.

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Hey guys, anyone know for sure what location alignment dowels had the holes drilled midway in? Two dowels at base gasket, and two are at head gasket, two at cam tower. I think the factory used two drilled dowels per engine. Where should they be? Anyone looked into this? THANKS!

Edited by scabio

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Thanks. Bike Bandit shows different part numbers for the base gasket dowels than the other four, but no sign of the holes in pictures. I just dug a base gasket dowel out of a possibly virgin XR80 and there is no hole. I have no idea the function of a hole in any dowel... has anyone thought of this?

 

Thanks again!

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Geeez, just look at the cases, the base of the cylinder, the top of the cylinder and the head.

Grab some dowels and slide them in the holes that they fit in and install the cylinder and head with no gaskets. "test fit"

Be aware... Most? People guerrillaize the dowels when removing them so the are more than likely not round any more. They should always slide in WITHOUT being forced in any way!

(Coat with some light Grease when installing them so they won't corrode/rust after final assembly)

use the longest dowels that fit without causing a gap in the base gasket and head gasket areas, that way when you do install gaskets,

There won't be a interference fit on the length of the dowels.

Sometimes you just have to try it yourself and figure out what works...

OR:

You you can buy a factory, OEM Honda shop manual on E-Bay and read it first. It will have pitchers and stuff to show you the easy way to disassembly and re-assemble.

Get it done and go for a ride already, K? Your burning daylight!

Lol

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LOL! Thanks... yep, burning daylight. I'm making a cheaper version of my 107cc 12HP bike for Texas Mini GP club racing on 1/2 mile go kart tracks (about 9 turns, average track). So this one is 115 Trail Bike piston kit- a hindrance due to crappy squish and low top ring. I prefer Arias Pistons that Powroll used to sell for related reasons. Anyway, a lot of guys get 10.0 to 10.3 HP from 115 kits, and it's all about the details. Holes in dowels (they are all the same outer dimension, length) is just one of the details. If it matters, somehow, let's find out about it and get it right. Back to the 115 at hand- we'll see what the Yoshimura cam does that I'm replacing the crap TB cam with. It doesn't require sinking valves for overlap clearance or valve guide shortening, unlike my 107's. Should be good for the heavy rider that owns the bike. Will report, but target is over 11 on 115 kit bike. 11.5 would be good... and with a really wide torque curve. Thanks again for your attention.

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Geeez, just look at the cases, the base of the cylinder, the top of the cylinder and the head.

Grab some dowels and slide them in the holes that they fit in and install the cylinder and head with no gaskets. "test fit"

Be aware... Most? People guerrillaize the dowels when removing them so the are more than likely not round any more. They should always slide in WITHOUT being forced in any way!

(Coat with some light Grease when installing them so they won't corrode/rust after final assembly)

use the longest dowels that fit without causing a gap in the base gasket and head gasket areas, that way when you do install gaskets,

There won't be a interference fit on the length of the dowels.

Sometimes you just have to try it yourself and figure out what works...

OR:

You you can buy a factory, OEM Honda shop manual on E-Bay and read it first. It will have pitchers and stuff to show you the easy way to disassembly and re-assemble.

Get it done and go for a ride already, K? Your burning daylight!

Lol

 

The test fit described above is  the way to make sure you have good dowels of the proper length. Better than discovering an oil leak or head gasket leak after the rebuild.

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