Yet another Joe Hunt / Triumph starting question

[burndoubt]

so I thought today was the day. 1968 Triumph Bonneville fully rebuilt, Joe Hunt magneto first time starting it. I set up the magneto, following the directions and the English 101 video to the letter. I got a sputter out of the first few kicks, and now i get nothing but an occasional backfire mostly through the pipes, and once through the carbs. The only thing I haven't done is cut down the cam screw. It didn't seem like I needed to, but I don't know for sure. Can anyone tell me if there is an easy way to figure out if I need to do this, or any info? I have read all the threads, and tried all I know. Any help is appreciated

[belltown]

I had this problem also, make sure for one that you are on the correct timming mark, there is a top dead center, and a 38 degree one also, very easy to set timing up on the wrong one! Second make sure you valves are not sticking, or that you push rods are on the rockers correctly, other than that I don't know what to tell you, hope this helps!

[jcarter78]

I bet if you cut that screw down you'll have no more problems. Same shit happened with mine.

[Tony the torch]

just check the timing, if it is out of time then you should have cut the screw down.
did you strobe time it or just guess at it?

[burndoubt]

Originally Posted by Tony the torch

just check the timing, if it is out of time then you should have cut the screw down.
did you strobe time it or just guess at it?

Haven't got it to run yet. This is the first time I am starting it. I used the TDC tool and set the magneto up on the 38 degree BTDC mark. Now if I set it back to 38 BTDC the points should be just opening the same as when I installed it correct? If not, then it is slipping and I need to cut the bolt down. I have read 1/4 inch is enough to cut, is this correct? Thanks for the help.

[Tony the torch]

you don't have to have the engine running to strobe time it, all you need to do is unscrew the plugs out of the head, clamp the plugs on the outside of the head with a spring clamp and hook a timing light to either wire and kick the motor over it will fire the light and you can line up your timing marks on you stator the same way you strobe time the bike with the points ignition.
on a 68 and later Triumph there is a line on the stator and a pointer in the timing window of the primary cover. on the earlier years you can scribe a line on the stator when the engine is at 38 BTDC by using the crank pin. or put a degree wheel on it with a pointer

[burndoubt]

Thanks for the help guys! My timing did indeed slip. I ended up cutting the tip off the screw, reset the timing, and she fired right up. Now, I need to work on the carb tuning, and I should be able to road test it this week!

[bhead1968]

...that damn screw...it'll get you every time.... hey Tony why dont you make a shit load of these allen screws cut to the correct length and sell them! Ha!...you'd think the folks at Joe hunt would've done something by now. I've found the exact screw at my local true value hardware and got a few extra...

[Alchemy79]

I'm gunna hop on this thread.... I can't figure this damned timing out to save my life. I got a copy of 101 and followed it exactly, I had to use the plunger to find TDC, and a degree wheel to find 38* BTDC (engine's a 66 T120).... Set the mag at the proper .0015 gap at 38* BTDC. Plugs are @ .18. Points are at .15. I replaced the hex dive that seems to be terribly rounded out, & cut down the screw about 1/4" (it did seem to bite the tapper down a little tighter than before)... Strobed the marks and it appears to be firing properly in time. She starts first kick and idles fine. But there is absolutly no "get up and go". The bike is very sluggish and will not go over 40 mph. sounds like the timing is retarded right? It is misfiring/backfiring and the pipes are glowing red still. wtf? Is it possible that I strobed the timing to the tdc mark? Would it fire at all if it was strobed on that mark?

[ckunsman89]

I think you have answered your own question. sounds like you are on the right track. Retarded timing will allow an engine to run, but cause it to over heat, and spit, spudder, and make no power.

[Alchemy79]

So just go through the steps again? I put a late model primary cover on today. With the window and pointer. All i gotta do is find 38* BTDC and mark the rotor @ that little pointer right? Thats the mark I need to strobe.... Sounds obvious....I'm learnin....

[canuck19]

Yeah thats pretty much it. If your rotor has no marks on it, you can use the crank notch locating tool to find TDC and 38 BTDC. This video covers it really well.

http://www.youtube.com/watch?v=P-f5G...yer_embedded#!

[Alchemy79]

Thanks fellas. back to the drawing board I go....

[Alchemy79]

Another on subject question.... Does anyone have a easy way (any way for that matter) of getting the tappered hex drive off of the camshaft? Or at least loosened up enough to turn it for adjustment? That puppy is on there pretty good and I know its gotta be turned a little to the left....

[Tony the torch]

Originally Posted by Alchemy79

Another on subject question.... Does anyone have a easy way (any way for that matter) of getting the tappered hex drive off of the camshaft? Or at least loosened up enough to turn it for adjustment? That puppy is on there pretty good and I know its gotta be turned a little to the left....

the easy way is to remove the 1/4" retaining bolt and with the plugs still in the head put a wrench on the hex drive and turn it, it will start to turn the engine until it come up on compression then it will break loose.

[Alchemy79]

Thanks Tony. Sounds like a plan. I already managed to strip the hex head outta the retaining bolt and was lucky enough to get the thing out with a screw extractor (after trying 3 different types). I just didn't want to crank away at it and REALLY mess something up.

[Tony the torch]

those things round off real easily, that is why we buy so many replacements from Hunt at $5 each

[backwithabang]

OK, I'm having the same situation here. Explain this screw cutting down thing. the supplied screw was too long, it maxed out and I still had mega play in the hex drive therefore it wasn't turning the mag, no spark.

I used a screw that was shorter off my xs650 that was the same thread and it caught and tightened that thing good. I now have good spark. Did the 38 bftdc, set the plugs to 18-19 gap, and the old cellophane on the mag to right before breaking.

All I can do is get the thing to blow smoke out of my velocity stacks and pop now and then. The compression is somewhat nuts (750 head on a 68 bonnie bottom) The sweet spot on the kickstart will actually just hold on a kick attempt and I move the whole bike . (I'm 190 6'2").. Also had a plug loosely in the other day as I was rebuilding my kickstart. I gave it a kick and it flew across my garage about 8-10 feet and stuck in the drywall. It actually stripped the bottom two threads right off the plug upon ejection.

It just doesn't seem right to me. I'm of course going to retime and check everything for the next three days relentlessly until it works, but any advice would be welcome

[Tony the torch]

how did you put a 10 bolt 750 head and cylinders on a 650 bottom end? the rod and pistons are completely different

[backwithabang]

I will state this once again. it's how it came when I bought it.. heres some pics..

I count 8 bolts plus two in the middle kind of horizontal on the head, I dont know if they count. some local old guy triumph guy here said he thought they made one 68 with a compatible bolt pattern. And he knows some cray shit he's a walking parts number book

http://i1127.photobucket.com/albums/...6/fad3dab8.jpg

http://i1127.photobucket.com/albums/...6/72802d19.jpg

http://i1127.photobucket.com/albums/...6/055704e8.jpg

and the beast in full
http://i1127.photobucket.com/albums/...6/c9013e20.jpg

all I can say is that it has been an adventure. the cases are clearly 68 with the numbers, dual carbs.. the exhaust manifolds have the characteristics of the 750 head because they are quite smaller than the standard OD of a 650 exhaust and required some shimming with exhaust repair tape to get on temporarily until I figure out what the hell Im doing with this bastard of a chop. I have no idea what that front end is from, seems japanese. I do have a springer for it waiting on the sidelines (i figured it's so obscene I may as well go with the period)

it also has both timing gaps which I wasn't quite sure was present in 68's I thought it just had the one tdc gap.

it's registered as merely a 71 triumph with the aftermarket amen frame number, and to make it even more odd, it was previously owned by a member of Fishbone. If that is unfamiliar..all black ska punk funk 80s band. watch back to the beach and they do the bird is the word with pee wee herman and a song with annette funicello