It was good to see that the brothers made it over to see you Thursday before the hunt. They're good buddies of mine and I planted your stuff into their heads a couple months back. Rodney is still thinking 98"/level B' but still leaning with his current exhaust. Brian? He'll make his decision when he drops the bike off but still thinking intake/exhaust/PCV/cams. I tell him the power vision would be cool Told them to let me know when they bring the bikes up as I want to make the trip with them. They're pretty pumped .....

 

The heads have 85cc chambers and we used pistons we had made with a +2 dome

 

This is really our standard 107" kit with a slight bump in compression and our Level B heads. With the kit you have the choice of TW-555 or TW-777 cams, and with our heads we will set the compression where needed so the price would essentially be the same as our standard pricing which is listed at www.fuelmotousa.com/107.htm

As far as the throttle body, I would still recommend using the stock 50mm unit on builds making less than 125 Hp or so, as you can see in this example it made better HP/Tq all the way up to 5000 RPM with the stock 50mm, the 54mm only made 3 more HP above 5K
so it is tough to justify the cost only for high HP gains especially when it makes less Tq below 5K

Stock 50mm TB (FM porting) Vs 54mm TB

 

Bump. You guys at FM keep figuring out ways to take my future money . What is the max build you recommend before any crank work/or potential reliability issues? I am 100% set on a FM 107 upon getting home from Iraq, just figuring how much extra work to put into it (heads, ported TB, etc).

Thank you in advance and keep up the great work.

 

The stock crank should hold up without issue as long as the bike is driven properly, we have built many of these combinations that have made well into the 120's for torque no problem. Shock load is the biggest consideration, dropping the clutch, holeshots, burnouts, and worn compensators are hardest on the crank.

We have done some testing for a few plug manufacturers and our conclusion was if you are looking for additional gains from spark plugs you are looking the the wrong direction, however there are difference in durability one plug to the next as some are more resistant to damge from detonation and such.

 

The last charts we posted were with our standard 107 kit w/ TW-777 cams, and Level B head service, we just set the compression at 10.5 instead of the standard 10.25. We can setup your heads to the compression you specify, this is included in our Level B head service.

 

Jamie I don't know much about engine building, so I'm wondering how much of an effect will a higher compression ratio have on the crank, after a certain amount of compression is it necessary to have a stronger crank, or does it matter?

 

Jamie - Do you have a graph of the TW-777 cam with stock heads in the FM107 package to compare with the TW-555 cam?

I won't be doing the level B heads and wanted to see the difference between the cams with stock heads.

Thanks

 

Do believe they do on there website

 

Where at? I must be missing it if they do. I see some 103 tests with Level B heads in the camshaft area but nothing (yet) showing the FM107 kit with the TW-777 and stock heads.

Thanks for the help if I missed it.