Hello all,

After a few busy months at college I finally have the time to start getting the Venox on the road again. I dropped out the engine and split the crankcases and I think I found the problem with the third gear slipping. The right hand selector fork was not selecting third gear properly and the there was wear on one side of the fork. I have just received the two new gears and selector fork and all of the seals and gaskets to put the engine back together. I will be doing this with the help of a local mechanic as I don't want to make a mistake and having spent so much money on parts it would be a shame not to get the job done properly.

Has anyone put the crankcase back together before? Any tips or problems encountered that it might be helpful to know about before starting the job? I left the crankshaft in the upper half of the case which is turned upside down at the moment and will put in the new gears first. I don't know is it easier to put the crankcase back together upside down or right-side up. It might be difficult to line up the gear shafts etc.


I'm going to hopefully modify the back of the bike as soon as we get the engine back together. I'm thinking of doing a single seat conversion by chopping up the back of the bike a bit and getting a sissy bar made up.

I'll keep you all posted as to the progress.


Mark :okthumb:

Great to hear an update !
Do not think anyone here so far has posted doing what your talking about... successfully.

If its not to much trouble could you post pics as you do the rebuild ?
Might be of great help to others.

I'll do my best George.

I have a few taken and saved on my Dad's laptop of the disassembly of the engine and I'll try to put them up at the weekend when I'm back in Cork.

I'm going to a wedding on Saturday but will try to post up a bit more information on Sunday evening.

Mark

:old: I have neve split the cases on a Venox but be very careful and when you get to the heads be extra careful the is funky system they have starting with the plugs in the ends of the cams and torque evenly and in steps

Hello all,

Good news and bad news.

The good news is that the gearbox is back together and seems to be functioning correctly and selecting properly when worked by hand.

The bad news is that my local mechanic started and finished the work last night before I had a chance to call up with my camera. I thought he was going to wait for me to help with the work on Friday but he started the job last night as he had a few hours to spare. Sorry to everyone waiting on pictures of the gearbox etc.

I am going to ask him for help reassembling the rest of the engine as well just to be on the safe side so hopefully I can get pictures of putting back on the cylinder heads and cams etc. This work should be done on Friday.

Thanks for the advice Pops. I'll make sure to take good care.

I have two problems resulting from my brother being a tad heavy-handed during disassembly. He broke one of the bolts that stick out of the cylinder head that the exhaust clamps sit onto. The threaded bit has broken off leaving a metal shaft/stump. Anyone any ideas how to go about replacing this? I don't think it screws out as it appears to be an integral part of the cylinder which could be a big expensive problem. I might try angle-grinding it off and drilling a new hole and tapping it for a new bolt.

The second problem is that he also snapped one of the bolts that hold down the U-shaped cam-shaft holders. The bottom half of the bolt has stuck inside and may need to be drilled and tapped again. These problems may take us a while to sort but hopefully we can come up with a solution.

I'll leave you all know how it's going.


Mark

OUCH....
sorry I do not have an answer...

Getting those two problems sorted by an engineer/machinist who can rebore the holes and thread new ones and fit a new exhaust bolt.

It's going to take a few days by the time he gets around to doing it.

I'll keep you posted.

Mark

The mechanic hit some other snags putting the back cylinder back together.
When putting back in the cams they were very, very tight and wouldn't turn by hand at all even when only torqued down a small bit and without the chain on.

The cams are marked ' R in' and 'R ex' and are in the right places and the front cylinder are marked 'F in' and 'F ex'. The front cams turn by hand without any problem.

We tried changing the cam retainers between the two cylinders in case they were mixed up but without success. The rear cam requires a lot of force to turn even when not torqued down. This would lead to severe scoring of the cams and probably seizure of the engine before long. Has anyone any info on what might be causing this? There is enough valve clearance so this isn't causing the problem. They weren't this tight on disassembly as there is no scoring on them at the moment.

Any help appreciated.

Thanks

Mark :help:

There is also another problem somewhere in the rear cylinder as when compression was checked, the front cylinder was reading 160 and the back was only reading 100.

Problem with the pistons or rings maybe? It'll all have to come apart again. :furious:

I feel like giving up now...

Mark

You know what they say - 'Never give up', it will come right in the end

:old: The low compression leads me to think the valves are to tight, and when you rotate the cam your pushing on the valve springs. There has to be free play on the valve clearance. THose bolts can be drilled out with a left handed drill if you are carefull. Helicoils should work fine there if you do not eat up the side of the hole. ALuminum is the easiest to helicoil. and as the helicoils are Stainless Steel they are stronger. Every cam tower bolt in my race bike was done ahead of time so would not have to worry at the track when in a hurry. ALso when locating the cams on a venox and the cam towers extreme care should be used to get them to locate and seat good. Another thing that will make it hard to turn is the cam chain tensioner. Migh have to be taken off and backed off.

Like pops said, sticking valves kind of match the symptoms (low compression and tight cam-shafts) - if you take the camshafts out of the way again and use the butt of a screwdriver you should be able to easily depress the valves with your body-weight and have them pop back up under spring pressure. If they don't move freely then the cams won't turn freely either.

Hello all,


Things going from bad to worse.

We found the root of the problem with the bad compression. The rear cylinder had started to seize up. The rings were stuck and had started to score the sides of the cylinder. The cylinder is now being taken to another engine specialist to see can it be salvaged. I can get a new piston and rings from the UK if the cylinder walls are fixable but if not, that is the end of the Venox as we know it.

I saw in one of the other threads someone had mentioned dropping another engine into the Venox frame. Does anyone know did this work and what engine was used? It would be a shame to bin the bike as the rest of it is in very good condition. I would even consider putting an inline-4 in if it would fit and getting a custom exhaust made up. We're waiting to hear back from the engine guy but I should know next week.

Hope you all had a good weekend.

Mark

not good news, although that doesn't explain the tight cams ???

Is the cylinder body not replacable on the Venox? Or are they too expensive?

Engine replacement might be the best solution by the sounds of it but I have no idea what might or might not fit. I'm sure pops or obx will have a better handle on this.

tony_dt has the venox in question (was geekonabike's).
Last I ''heard'' it still was a project yet to be done (or not).

It works out way too expensive to replace the cylinder body. It would be about £700 or $1400 and that price is before postage from the UK which would be quite expensive due to the weight of the items. I know we hasn't sorted out the tight cams yet but there is no point in continuing without trying to sort that issue first.

I'm heading off on a trip around France with my girlfriend on the ZZR1100 in a few weeks and I'm trying to get the Venox sorted before I go. Looking forward to the French trip. They have great roads and fantastic scenery and it's a very biker friendly country. We should rack up a good few thousand miles in two weeks which will hopefully be trouble free. I haven't had any mechanical problems with the ZZR in the two years that I've owned it so fingers crossed.

Mark

Sorry to hear about your bad luck with the Venox. I think I would cry if mine went down like that.

:old: Do you have insurance brokers over there that migh lead you to one form a wreck. ALso Honda 250 Magnas are the same. I do not think there is enough fame for a inline four. You can use one with a bad bottom end also.

I've never seen another Kymco on the road over here Pops and I don't think they are that popular in the UK either. Honda Magna 250s are also few and far between. They are all American or Japanese imports as the main dealers don't seem to sell them from new. I've searched Ebay for the last few months but haven't come across anything that's suitable.

I've just ordered the new piston and rings and two new head gaskets as both cylinders heads have to be removed to take it to the engine guy who will skim the cylinder body to try and smooth it out as best he can.

That's the last bit of expenditure. If we can't get it back together after this the search for another v-twin engine begins! It started as a project but the costs have really started to add up. We still haven't sorted the problem with the cams but will look at them again after we have replaced the piston and rings and check that compression is good on the rear cylinder.

I'll keep you all posted.

Mark

On your Cams what may have happened is that the cam caps may have been over tightened. These are aluminum and will splay a bit if over tightened. I see this a bunch on the Yamaha racing singles we work on (as they have very little cam caps) but it can happen to any bike. If this is the case it is not too bad to fix. A machineshop line bores the head and caps and all is good. Typically this is not an expensive thing, and is better than buying a new head.