my 85 honda 70

[skidoo99]

well, ive been able to get some good info from you all in putting this trike together. im having some issues with getting it to run right tho. this thing is a finicky little sucker. complete rebuild kit with all new jets and gaskets and i was able to get the carb to stop leaking and with some time behind a screwdriver adjusting jets i was able to get it to idle ok. the problem is i cant get full throttle out of it or even half. it spits and sputters and backfires. it seems to go ok when i walk next to it, without a load.

i have replaced the cylinder head and top end as well as all new guts in the aircleaner.
could the motor be out of time and still run half decent. maybe a tooth off?

thanks for any input

[skidoo99]

having trouble uploading pics but i think i got one on there

[skidoo99]

nope thats not it

[tri again]

So it starts and idles but won't rev?
Valve timing off by a tooth seems to work ok in a Chevy 350
but not sure about a 70.
Can you get the search key to work?
I'm sure someone had been through it before and the search key should pop up
years of suggestions.

I have a 90 that has a spring loaded spark advance plate behind the
points and it got stuck in the advance position.
Took me 2 weeks to figure it out.
Not sure if yours is points or cdi or even where the spark advance comes from.

Hopefully yours is an easy fix.

[ovhonda1]

Not trying to hijack this thread, but I too am having the same difficulty with my 70. Mine is an 83, ebay CDI, new plug, new OEM carb (very clean after many , many cleanings), moved the needle up and down, 58 main, 38 pilot. Idles great. Any gas, dies out. Fuel lines clean, etc. I have searched and read every thread that I can find and I feel that I have done everything that is possible. I get great spark. Only thing I haven't checked is a clogged muffler. Will do that tonight. SkiDoo, I am in the same boat as you and i cannot figure it out either.

[oldtime3wheeler]

Are you guyas running the stock air box set-up? Do they seem to run any better with the choke on?

[ovhonda1]

yes and yes on both questions.

[MIK6]

I had a 70 do the same thing. It needed a top end rebuild..

MIK6/ Mike

[ovhonda1]

That is my thought. I checked the compression and I am at 122. That is low I know, but i have read that they should run fine on that compression. Is this true? If not, i will have to do the top end.

[oldtime3wheeler]

I think it should run on 122. Check to see if the gasket between the carb and the intake or the gasket between the intake and the motor are good. You could have a air leak.

[yamaha driver]

i dont think 122 is low for that small cylinder. i mean my old yamaha 125 ran at 55 lbs?? and the piston was in great conditin same with the rings.

I would check for air leaks, use some carb cleaner and spray around all the gaskets and see if the idle changes

[ovhonda1]

Will give that a try. In the meantime, I am going to take the carb off again and soak it in cleaner for a couple of days to make sure that it is clean through and through. The gasket on the manifold to the head is old so there may be a leak there. Hope that is it. Thanks for the replies. Will keep posted.

[yamaha driver]

dont just soak it use an aircompressor and BLOW it out. sometimes there is dirt in the passages that only air can get out

[oldtime3wheeler]

I would replace the 2 gaskets. Also check the screen in the petcock to make sure that is clean. If you have cleaned that carb that much I would bet its an air leak somewhere around the intake.

[ovhonda1]

Yeah it is a brand new OEM carb from DRATV. I cannot imagine there being anything in it, but who knows. I will get some new intake gaskets and try it as well. I wanna ride this thing and I am getting a little frustrated. I have walked away for the night to re-group the senses and will start again tomorrow night. thanks again.

[ovhonda1]

No leaks. Cleaned and blew out all passages in carb again. Moved needle up and down. Did plug chops best I could because it dies under load. Plug shows black and dry on recommended needle setting (4th). Will run great at idle. Revs great after idling for about 30 seconds and the bogs out almost like it is not getting enough gas. It will run with the choke on but I know that is not how I want it to run. I am running the stock 58 main. Should I move up a size and see if that helps it get more fuel? Beginning to think that the cdi I bought may not be programmed correctly for this machine. Spark looks good to me. It will jump from the tip to the metal and different plugs, but it is not a dark blue spark. Maybe that is the problem. Emailed the guy from ebay-wait for his response.

[skidoo99]

well, i think our problems are pretty different. i can get mine to start and idle great off choke. with any throttle it will die. sometimes, you can slowly increase the throttle and it will begin to rev, then stumbles and farts and pops and dies. this is a brand new top end with 150 psi. complete carb kit and checked the exhaust and it is free and clear. im thinking maybe it could be a spark issue? kinda sounds like the spark is cutting out?

[ovhonda1]

Mine is doing the same thing. Idles off choke, rev it and it does what yours does. I have a CDI on mine and I seem to be getting good spark. Does yours rev well after idling for a bit? It seems that mine is running out of gas at higher RPMS.

[skidoo99]

well i just replaced the spark plug and nothing seemed better. i had it idling for a while and like before with any throttle increase it spits and dies. when i slowly rev it and play with choke back and forth i can get wide open throttle no problem, then it goes back to idle and runs great there. i did replace the filter in the petcock so that is new. i have my needle set in the middle groove. if i were to lower it to the 4th, would that add more fuel only for idle?

[oldtime3wheeler]

What is your air/fuel screw set at?

[skidoo99]

i started it at 2 1/2 turns out, but it dosent make much difference where it is

[oldtime3wheeler]

Has it been doing this since the rebuild? Sounds like it may be out of time.

[skidoo99]

yes it has been. i didnt think it could idle that well if it were out of time. i dont have a manual so i just winged it and thought it was good. anyone know where to get the 70 manual here. theres one on here but its a couple other trikes with it

[skidoo99]

got a copy of the manual and found out i was correct on timing

[ovhonda1]

Great Skidoo! Hope that you get it right. I am still in trouble with the CDI set up. No timing adjustment there. Gonna try to jet bigger and see if that helps i guess.

[skidoo99]

keep me posted, i think im going to put it in the corner and stack things on top of it. cant take much more of this aggrevation!!

[oldtime3wheeler]

skidoo99 you used new gaskets right? Maybe you have a head gasket leak? Once it heats up does it sputter then?

[briano]

Maybe a points problem. I messed with one of my 70s for a couple nights after work, tried swapping carbs with a good running one and the problem was the same as yours. Put in new points and it runs like a top.

[skidoo99]

haha havent been on in a bit but foudn the problem. the points were staying closed. adjusted them and she runs like a top. wish i saw your post briano on the 15th. thanks for all the info guys. now that i can ride it i found that i need a new chain. had so much play i could roll it off the rear sprocket even adjusted all the way. anyone have a good idea on where to get a good chain sprocket combo? good quality? thanks so much