Starting issue

[skiracer]

I am having a problem starting my 76 175 GS with a Mikuni carb.  When the motor is cold, it takes 15-20 kicks to get it started... every time.   If I stop riding for five or ten minutes, it I have to use the choke, and 3 or 4 kicks to start it.  New plug, good gas.... any suggestions?  Thanks, James

[chicagojerry]

i bet your pilot jet is clogged. did you leave any old gas in the bowl? chi jer

[SouthRider]

Every bike I ever rode with a Mikuni had the same problem (even new). Probably because most of them are reed valve bikes & it's hard to get a good draw across the choke circuit by kicking.

Huskies are notorious for it - we always just lean them over to force them to flood a little when cold. The old wives tale was that by pumping the choke lever several times it would flick a little fuel into the circuit & help. It never seemed to work for me.

But - thinking about it - for a piston port engine like yours Jerry is probably right.

Also make sure your air filter is clean & not over oiled and that you didn't leave a shop rag in the exhaust port last time you had the pipe off...... (can't tell you how many times I found this when a customer would bring a bike in that wouldn't run).

Is the motoplat getting old? Nice fat blue spark? Plug gap correct? Coil has a good ground? Decent compression?

_____________________________________________________________________________________

"We the willing, led by the unknowing, are doing the impossible, for the ungrateful. We have done so much, for so long, with so little, that we are now qualified to do almost anything, with nothing."

1972 Penton Berkshire 100
1983 Husqvarna 250 XC
2011 Jayco 31.5 RLDS
2009 Chevy 2500 HD Duramax

[Rain Man]

If it idles after it warms up, its not the pilot jet.  If your using the choke after its warmed up to get it fired again, it sounds like a lean condition. make sure the carb  and maniflod are tight. Also the slide in the carb hanging up will make it start hard. ( just a little open )
I'm not gonna tell you to check your valve adjustment !!:D
 Too many variables to bench fix...

Raymond
 Down East Pentons

[454MRW]

Have the crank seals been replaced in the past few years? Typical Penton syndrome is that push starting works, but kicking doesn't indicating a low vacuum at kicking speed. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R

[brian kirby]

Sounds like the pilot jet is too small or the Motoplat is weak.

Brian

[G Ellis]

Weak motoplat I agree with Brian. Take the plug out and as you are kicking it over, call me crazy. I hold onto the plug and see how hard it bites. This is the true way I check for good spark. Been doing this for years, maybe this is what is wrong with me.[:0][:0]

[brian kirby]

Ha! Gary, I am so chicken of getting bit I wont even hold a good plug cap with my fingers while I kick it over, I hold it with insulated extended pliers!

Brian

[joe novak]

and that is another reason I always prefer the Bing carb with the trickle feature.   Rarely ever needed to use the choke unless a cold Ohio Winter day.   joe

[skiracer]

Thanks guys!  Fresh gas, good air cleaner, good compression, no rags....  NO I am not going to hold the plug while kicking...... I think I will start with the pilot jet.  I will work on it after doing a little shoveling!!!  Jl

[Rain Man]

your gonna do more than just a little shoveling today Mr.
 I let my wife sleep in this morning, she's gonna be busy all day.
 I got about 27" of snow right now. Looks like tomorrows rides out:(

Raymond
 Down East Pentons

[Dale Sonnenschein]

Jim, my penton 250 had the same problem. I put a bigger pilot jet and now it usually starts after a few kicks.

74 puch 175 SD
73 Husky 360 WR/RT
76 Husky WR360
75 Penton 250
10 ktm 250xc
02 bmw r1150r

[brian kirby]

Mikuni's will run well with a really lean pilot jet, but they will be very hard to start. When I took the Bing off my Can-Am 175 I had a 30 pilot in the Mikuni and it ran great when it was warm, but absolutely would not start cold unless I laid the bike over to flood the carb. The good thing about the Mikuni is once you get it dialed in you never have to spend another cent on it, unlike the Bing, which requires yearly parts replacement to keep it working if you ride it much. Those Bing parts, many times, cost more than a complete new Mikuni.

Brian

[Gordon Brennan]

I have a Bing on a Husky and my Penton. I have an Amal on an Ossa. All three have ticklers and all three start great; one or two kicks. I have a Yamaha with a Mikuni that, when cold, you can kick forever with the choke on and it will start at some point. But if I lean it over until fuel comes out of the overflow, the bike will start in two or three kicks and run forever.
I would try that first James.
I agree with Brian, as far as parts go. The Bing parts wear out fast and are expensive to replace. But for some reason, I keep buying them.

[skiracer]

I agree 100% with you guys on the Mikuni's!  That is why I have one on the bike.  The performance is so much better than the stock Bing.  I will go up a couple of numbers on the pilot jet to see what happens.  Thanks again everyone for your input, I really appreciate it!  Jl