First cafe build with stutter in the engine

[PM650]

Hi:

I am a new member. At age 64 I decided to build a cafe racer and now at 66 it is about 95% finished. The bike was built from 3 parts bikes, two of wich were basket cases (but had titled frames) and one with no title and a bent frame but having a good engine. I farmed out paint job and the engine work (honing, and valve job) but did the rest myself with a lot of help from cafefill. I made the seat using the original seat pan and mounted the agm battery horizontally under the seat along with some electrics. Some of the electrics are also located in the seat hump. Cafefill gave me a good deal on an xs750 tank which, to me, is a better look. Another friend happened to have a Kerker exhaust still in the wrapping. The jury is still out on the Kerker as I get a stutter at about 4000 rpm in the top two gears. I've been bugging 5 twins with questions and it looks like the first step is to replace the pods with UNIs. One problem is that I'm 6' 5" and 275 pounds (yes, I do manage to scrunch myself onto the bike, rearsets and all!) and that load is part of the problem--guys a lot lighter than me have ridden it and not experienced the problem. It is hoped that a few jetting and needle changes, etc will clear up the problem. I intend to add a fork brace and some graphics and welcome any suggestions. The bike was built with minimalism in mind. My stable of bikes also includes a BMW r1200r, a 1976 cb400f, a 1967 Harley Sprint, a suzuki 650single (for my wife), and a Ninja 250 for my daughter. PM650

 

[Dakota_Lew]

Nice bike man! I too am 6 foot 5 and 270 , some how scrunch myself on to rear sets. I had a blip when I was tuning my 650 and I re-jetted it to run a little on the rich side. Other then that your past me already on the question. Either way its always the tall guys that like the cafes sweet ride man!

 

[5twins]

Yes, very nicely done. Yes, you will want a fork brace and maybe even an abbreviated front fender of some sort. You'll immediately see what I mean if you ever get caught in the rain, lol.

Most of us change our gearing slightly and I would suggest that for you as well if you haven't done so already. You can't gear the bike too high or you'll kill it's "fun factor". Although it doesn't seem like much, I feel one tooth down in the rear (to a 33T) is the ideal set-up with an 18" rear wheel. It is well matched to this engine's power output, will reduce the revs by a few hundred at highway speeds, but won't rob much of the lower gears "lunge".