Need Direction on Hobbit Project

My Hobbit runs a little funky with its new setup. What do I mean by funky?

I'll take you through a ride.

It starts easily, one turn of the engine, with the choke on. Once running, choke still on, it misfires every few seconds. This it does like clockwork. I leave the choke on from take off til 10mph and then I can turn it off. Without the choke on for take I have to feather the throttle through bogging til 10mph. Now I'm cruising down the street. Riding at a consistent speed is finicky, but the engine fires smoothy. I can accelerate without bogging and wind out to WOT. Stopping is a little scary. As I slow down so do rpms until I'm at an almost full stop the rpms increase trying to keep the bike moving. Once completely stopped I flip the choke back on to keep the bike from dying.

If I turn the choke off with the bike running on its stand it will rev out then slowly die.

I've replaced all gaskets and seals and timed the bike to perfection.

My setup;

polini kit (exhaust matched to pipe)

Mikuni VM18 (95 main)

Stock notched variator

MLM Peoples Pipe

boyesen reeds

stock head

15k springs

I've never changed my condenser. Could that be an issue?

Re: Need Direction on Hobbit Project

Emil Kniemel /

15k springs are wayyyyyyy to cray.

jk. i know you mean 1.5.

Re: Need Direction on Hobbit Project

sit and spin all day long!

Re: Need Direction on Hobbit Project

Derick Soland /

how much have you ran the carb, may need to be cleaned out, take the spark plug out and watch the consistency of the spark, if its consistent you have a fuel issue (carb) it it isn't consistent you have an electric problem, stator, points, maybe condensor doubt it, just trace it back from spark plug to magneto

Re: Need Direction on Hobbit Project

Dealing with a similar situation now,

96 main

boysen carbon reeds

phbg 21

mm destroyer pipe

tjt variator

dr 70cc

was idling good earlier now just having issues, choke helps but I went through and had the mix set damn good for a hot minute. now all the sudden idle issues. I pulled the plug and checked spark which upon observation was kinda dancing around on the electrode, not firing hard on one spot. I made sure the coil was grounded as this was my last problem. Coil screws were a little loose creating a sketchy ground. So not sure what is going on now.

Re: Need Direction on Hobbit Project

I put the carb on this past Spring. Its still very clean on the inside.

Hey jon, I went over my bike again after a few rides the head started leaking but not really bad. You can make out where gas and oil are passingby the gasket. I'm always getting head leaks and I don't know why. anyway. I went over the bike again and replaced some hose clamps for my intake and set the timing. Now it idles without choke. IT dies if choke is on now. Except now it runs poorly fires everytime but its not firing smoothly. The bike takes about a city block of WOT before it shows any response. But when it does, hold on tight.

Re: Need Direction on Hobbit Project

Fix the head leak by making both mating surfaces flat. Tape sandpaper to a flat surface trick. Make sure your torqing your head enough also but do not snap a stud. Then rejet.

Re: Need Direction on Hobbit Project

should I do the same to the head surface of the cylinder?

Re: Need Direction on Hobbit Project

Downhill Harvey (OFMC) /

^^^I do.

Re: Need Direction on Hobbit Project

alright I'll do the head and if I get another leak I'll do the cylinder.

what grit is everyone using?

Re: Need Direction on Hobbit Project

Downhill Harvey (OFMC) /

Start with 400, then up to 1000.

Re: Need Direction on Hobbit Project

Just solved my idle shitty running issues. The phbg21 had come loose on the intake and was making it lean as fudge. I would definitely be checking for air leaks if I were you.

Re: Need Direction on Hobbit Project

I went up to 600 grit, not 1k. Obviously not going to hurt anything ! but I started at ~240. Seemed really rough but you can see the spots somewhat. I used a marker and marked the head all over the mating surface, but then I used wd40 as a wet-sand agent. That wd erased the perm marker - so maybe dont use any wet agent, just dry sand it and use a marker to see where your spots are. once you dont have any spots that do not get sanded work your way up to your 1k sandpaper. I got a piece of glass from a local window store free. he said he would cut it but I said don't bother!

lettuce know!

Re: Need Direction on Hobbit Project

thanks for the advice. I'll try it out today and post back here.

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