Dot head conversion parts needed?

[Upshotknothole]

Considering finally swapping the head on my 91 1100 engine to a dot head I have sitting on a shelf. Anything I need other than a head gasket? Currently have RS38s on the bike, which intakes should I use? I've searched the forum, but other than it being an easy swap, haven't seen what is actually required.

My other question is I haven't run a tappet head in years, gotta check them every 3K miles right? Just preparing myself for frequently dropping the engine in my 7/11.

[Roger P.]

Dot head is screw and locknut on forked rockers, not shims. You will need the dot head inlet rubbers to match the ports. They are different parts numbers to other boilers. I ordered mine along with the head they came off of from that auction site. I also have RS38's on my bike and need to set up the accelerator pump. Other than that, it rips! 89 slingshot cams really wake up this motor. I had to renew the o-rings on the inlet rubbers. I liberated some for our stock. I needed #130 o-rings, but managed to make #129 work. Get yourself a heat gun to soften up the inlet rubbers. You'll be swearing if you don't, then you'll swear some more when you heat them up and they pop in easy like.

 

Now waiting to see if I have managed to procure a 1216 block. It's an addiction.

[george 1100]

You don't need to drop engine. If you take carbies off you can slip it off the back

[Gixer1460]

2 hours ago, george 1100 said:

You don't need to drop engine. If you take carbies off you can slip it off the back

And if you do it this way - a dab of ATV sealant on the 'mickey mouse' seals etc helps stick em in place whilst squeezing through the gaps!

[Upshotknothole]

Thanks, never even thought of pulling the carbs to get the valve cover off the back.

 

So all I need is the following...

Dot head

Inlets and appropriate O rings for the dot head

Head gasket

Should I plan on booking dyno time again after I get the head swapped? It was dyno tuned previously when the RS38s were installed.

 

Now I just need to find time to clean the garage and go through that dot head and make sure it's in good shape and start ordering any needed parts.

[Gixer1460]

You may have to trim the ignition timing due to the compression hike. And a couple of points up on the mains MAY be required to cool thing down a bit!

[Upshotknothole]

4 hours ago, Gixer1460 said:

You may have to trim the ignition timing due to the compression hike. And a couple of points up on the mains MAY be required to cool thing down a bit!

Thanks, not sure if it has a stock ignition or an aftermarket ignition advancer on it currently. I'll make sure it doesn't have an old +5 on it or anything crazy like that.

[george 1100]

Comp will go from 10:1 to 11.3:1 

[boilerdude]

Jesus. Check what? Check the valves every 3k miles? Really?

[Upshotknothole]

30 minutes ago, boilerdude said:

Jesus. Check what? Check the valves every 3k miles? Really?

That's what I read years ago with the tappet (screw and lock nut) heads was the valve interval, been doing it that way ever since. I always thought it was a bit excessive, but compared to some high tuned dirt bikes with 1K mile valve intervals, I didn't question it too much. What is it supposed to be?

[dupersunc]

Yep  i'm pretty sure 3000 miles is the recomended service interval valve clearnce check on a lock nut adjusted oil boiler.

[jonny1bump]

It really does depend on head work too and how much valve seats have being taken to limit. I had head taken way to far adjusting clearance every 500 mile.

My m / l head conversion which ray cut seats for me has lost 1/2 thou in ridiculous amount hours of use but i had also hard welded rockers, etc, etc all makes difference including oil.

Valve clearances normally close, as valve hammers into head unless using bad oil, long storage times and worn cams etc, etc.

Basically really depends on what you done to engine so very difficult question to answer.