best big bore kit for xr100

[Ryno454]

For those of you running bige bore kits in an xr100 what kits are you running and what carb combination? What is the most dependable and reliable kit? As well as cam recommendation

[GMAN255]

Depending on your budget, needs, and engine building skills..

There is only one choice for a inexpensive bolt on kit- the BBR 120. Add a real cam (as your funds allow) Web 68/69 or MegaCycle 129x6 and KW HD valve springs, be sure to check all your clearances- Maxim exhaust valve lift, with out sinking the valves or valve guide mods is .285") figger about $200 upgrade in addition to $230ish kit price= $430 Kit will still have a low 10.5:1 CR.

Carbs on the cheep!

24mm 200x ATC
24mm CRF150F
26mm XR200

These will bolt on the stock intake and air box boot. Use the stock XR200 or CRF150F throttle and cable. and/or the CR85 throttle and cable.

I've been testing/running a PWK 28 from a KX100 on my- far from stock BBR kit! 35 pj, JJH, 115 mj.

With all the mods above- the XR100 might just crack double digits for HP#'s

For about $600-700 budget op for a supper head 115 kit from Kitaco or Takegawa- will be solid in the teens for HP#'s as hot as you can get with out adding a stroker crank.

[Ryno454]

Is the Web cam worth the upgrade? Or should i just stick with the new bbr cam.

[GMAN255]

Yes and No.. I have degree the BBR cam, and - yes- any REAL performance cam will out perform the BBR Stick. Will it turn your lil 120 kit into a fire breathing Monster- No! It will help with mid and over rev with the right carb and pipe. Is it worth additional $200- only if you want the most performance possible from you BBR kit.

The big HP restriction on the XR100 engines are the stock small valves- Hence the Big Valve Heads on the market-Kitaco, Takegawa, Upshift and Daytona. Throw out a search- If you haven't already.

[ga705]

threw out a search and didnt come up with much so i am learning from what you are saying gman255 haha ..looking into a bore kit for my 100 also ..assuming im just gonna not get too fancy and go with the bbr120 kit and maybe a lightened flywheel ...xr200 carb......keep the stock exhaust or should i put something else on ?

[fireman_343]

Gman knows his stuff!!

I use to run a BBR120 kit with 68/69 web cam, kitaco valve springs and HD cam chain, lightened flywheel, 24mm round slide carb, custom exhaust (1.25" dia pipe), and it put out 10.3hp! Haha

I really liked the BBR kit, but since it is in my roadrace NSR/NSF, I wanted a little more mid and top end... So, I robbed a bank and got the Takegawa 124cc stroker stage 3 kit! And it is a BEAST!!
If you want cheap, good power, the BBR kit with a few other mods will do ya right! If you want that fire breathing monster, then get a stroker kit with super head and roller cam!! It's a lot of fun!!

[KenNoNotThatOne]

Yes and No.. I have degree the BBR cam, and - yes- any REAL performance cam will out perform the BBR Stick. Will it turn your lil 120 kit into a fire breathing Monster- No! It will help with mid and over rev with the right carb and pipe. Is it worth additional $200- only if you want the most performance possible from you BBR kit.

The big HP restriction on the XR100 engines are the stock small valves- Hence the Big Valve Heads on the market-Kitaco, Takegawa, Upshift and Daytona. Throw out a search- If you haven't already.

Yep. I verified the BBR and TB 120 kits' cam profiles. Per the manufacturers...they are stock, NO GAIN. I think they are worried about valve interference and/or effective compression ratio's...
For my 2001, I went with the TB 120 basic kit from TBolt and a Hot Cams stage 1 (Amazon). Additionally, I went with heavier Web Cams valve springs (to combat float) and Barnett clutch springs (to reduce slippage heat), and a jet kit. The bike came with an FMF PowerCore4. I do my own work. I call the result good, not phenomenal. I'll wager a bigger cam and carb would get me happier, but the cost almost doubles. Then there's associated headwork costs, and even more HEAT. This is a concern, as me and my kid ride in the SoCal deserts. I still don't think it would ever be "badass". I have SCOURED the boards for the consensus on the "sweet spot" for these mods. In the end, I decided 450 was my rational spending limit, or I'd sell and start looking for a used TTR150.
Keep up the good work,
Ken