New one here ...... probably brat/cafe build

[nuke]

Hi there folks. I'm new to the forum and let me just say that you have a great forum!
I'm reading it from more than a month (when I've got my '81 XS400SE) and there is a lot of helpful information. Unfortunately, here in Bulgaria there are not a lot of these machines and there is not a big choice, so this is what I was able to get.


Without wanting to bother you, I'll post the work process here, not so much, because some miracle will be done from me, but moreover that it might be helpful for someone, as you guys are helping me, while reading the threads. And finally, because I'm old, to suit me as a reminder what to do.

Current condition of the machine:
- starting - cold start - full choke and 1-2 kicks on the kick starter; hot start - no choke and 1 kick.
- front brake not working. Dismounted and tried to move the cylinder even with a vise, no success.
- forks - quite easy for me (close to 100kg) to compress them to the end. Probably the springs will have to be changed.
- chain and sprockets - no visible service in the past 1-2 years. Spots of rust on the chain

- oil changed (almost fully black). The oil strainer was never cleaned. The oil filter was changed .... probably before an year.
- air filters - my favourite part
-left; -right;

Known problems:
- apparently changing the air filters - I'll use universal, conical 54mm and will remove the filter box
- oil leak from under the exhaust pipe on the left cylinder. Unable to determine were exactly as the engine was a bit oily. Now it is cleaned and will see where the leak is. Probably the gasket of the camshaft's cover or the gasket of the head.
- dirty sparks
-left; -right
- compression - 130psi on both cylinders, a bit lower than the low limit

Near future To-Do list:
- Change air filters - ordered universal, conical filters, waiting for the delivery
- Cleaning the oil system - ordered Bardahl engine flush. Will do 2 flushes.
- Dismount the oil pan and clean it. Will see the status of crankshaft.
- Change gaskets of the camshaft' cover and of the head. Will use the chance the check the valves and pistons. Hopefully, I'll not find anymore copper wires and/or zip ties.
- Open the forks, change the oil and any rubber rings. Probably will change the springs.
- Purchase new chain and sprockets. I think to add +2 on the back side, for a bit more bite on acceleration.
- New tyres - almost sure that will be HEIDENAU K 33 3/0 on front and AVON Safety Mileage MKII AM7 5.00 on the rear.
- New exhaust pipes and mufflers - going 2-2 with EMGO short muffler or something similar.

A bit distant future To-Do list:
- Cut the frame after the rear shocks for a brat style seat. My wife needs a place, too.
- Dismount everything and sand blast the frame, powder coating after this. Have to decide the colour.
- Sand blasting the wheels and powder coating them, too. Have to decide the colour.
- Sand blast and powder coat the gas tank. Have to decide the colour.
- New speed gauge. Need to find it.
- Oil temp gauge in place of the oil filler cap. Need to find it.

Ideas:
- Front brake system conversion - going for Arashi floating 320mm brake disk, R1 calliper and some kind of master cylinder, which i'm not sure yet. Probably R1 again.
- Lower the front end - as far as I've read, I've to add spacer with the length that I want to lower to the rebound spring and cut the half of the length from the compression spring, so I have a bit of preload.
- Change rear shocks. One is leaked. Not sure what to get, as didn't had the time for them.

A lot of things to do and not so much time to work on the machine. Only weekends and not every one - the wife becomes jealous!
Surely, I've missed something important, but ... as said, I'm an old guy

Sorry for the loooooooooong post. Didn't had the idea to make it so long. It happened somehow!

 

[spectra]

Welcome and looks like a good start.

Looks like someone swapped exhaust on it.

 

[xschris]

I would stick to stock intake and exhaust if at all possible. Pods on carbs and emgo shorties are about the worst performing setup to be run.

 

[nuke]

Hi again.
I've been able to steal an hour yesterday and did the air filters job.
Removed the stock box and installed temporary chrome conical filters. Will need some filtering element while working on the engine. What will be the final variant, I'm still not sure. Had to reinstall the bracket for the battery as I don't have new one. Thinking to put some small battery and to eliminate the electrical starter as an option.
One pic:


Aaaaaaaaand apparently someone was digging in the fuse box!


@spectra, thanks Yep, I saw that too. It's quite inconvenient. The pipes are exactly under the oil drain bolt and under one of the bolts of the oil strainer. It was quite difficult to unscrew them and following screwing them back.

@xschriss, thanks for the info. I've supposed that the EMGO will not do anything to help the backpressure, but I didn't knew about the pods. However, I'm searching visual appearance and the stock box is not the prettiest one. Of course, I do not want to make a bike that doesn't work, but loosing a horse or two or even 5 will not change the overall feel of the bike for me. I'm riding '08 ZX-10R at the moment and this bike ...... well it's not a match
It's little bike that will be used for cruising around and will put a smile on my face without driving with zilions km/h

 

[NewHavenMike]

You will feel a 2hp difference on a bike that barely has 30hp to begin with. I took my sisters GSXR600 for a ride once, it was fun and pretty fast, but it didnt feel the same. It felt way too easy to ride and had no soul. What I like about my 360 is that I can rev out 5 gears and still be cruising at 50mph.

 

[nuke]

Back again. It's been a while, not working on the bike and not getting time to sit in front of the PC for reading, writing.

@NewHavenMike, you are right. The bike doesn't feel the same, at all, and the thing that I like is exactly as written by you - revving the bike and not exceeding 100km/h. This Saturday was the official opening of the motorcycle season in my town and I was with the "big" bike. Revving it on 2nd, I was past 140km/h. The "little" one gives different pleasure.
Additionally, I intend to put +2 on the rear sprocket to help a bit on the acceleration (I don't need high speeds with the XS400). Any observation how it works with +2 on the back?

On the technical side, it's quite nice to have a classic-kind of a bike. The engine is ready for removal with just 1 hour of dismounting and disconnecting elements. The bikes that I've used to work on, need almost an hour for taking only the plastics around the engine!


While removing the chain, I've remove the front sprocket and I'm seeing such kind of wear for a first time. The teeth have wear not on the "acceleration" side, but on the "engine braking" side. Any ideas, except the obvious - a lot of engine braking?


Before dismounting everything flushed the engine twice with Bardahl engine flush. The first oil, brand new which I've put in the engine before a week, was quite black. The second flush, the oil working only for the time of the flush - 15-20 minutes, was relatively clean. Now I'm waiting all the gaskets to arrive and will open and clean the crankcase, the cover of the head and the head. Will post pictures from what's inside (before and after).

Outside of the engine works, the forks are now lowered with 56mm and the bike is almost horizontal.

(sorry for the dark photo, but it was a bit late and take in mind that the ground is not horizontal )
Now I've to think of a way to shorten the forks. I've read here to put a spacer on the rebound spring and cut half the length from the compression spring. A friend of mine is telling that only sure way to lower them is to cut the fork (the piston part). Any ideas and opinions will be hugely appreciated.
Additionally, it's very, very soft. Lowered in this way, when I sit and push the front it hits the triplet.
Is a new stiffer spring the only way to deal with this issue?
Is it an option to change the rear shocks from 320mm to 340-350mm, so the front will not be lowered so much?

 

[NewHavenMike]

That drive sprocket does look like it needs to be replaced. I believe your rear sprocket is a 38 or 39 tooth. My XS360 has a 40 tooth, so you can easily get one of those and gain teeth on the back. If you check out JT Sprockets, you can see whats available. My ratio is 16/40. I bought a new set of 17/38 because I do use my bike at highway speeds, but I havent installed it yet and dont know if I will...

The front shocks you may be able to use a heavier oil and make some spacers to gain more preload on the springs. I do not know where you can find new springs for the front, unless you find a set from another bike that has the same diameter forks.

 

[xschris]

That sprocket is bad. Very worn. Always replace both sprockets at the same time as well as the chain. For every tooth you add to the front sprocket it will drop your rpm's by about 500. For every tooth you add to the rear it will add 250. Stock xs400's with 16" rear with 120/90 tire run 16-37 sprockets. I run 17-37 for better highway rpm's.

 

[nuke]

Hi again. It's been a while ..... more than a month
But, a lot of things are done.
The engine is removed and opened entirely.
Here some pics of it. To be honest, things doesn't look very good.
Probably never cleaned around the front sprocket and below:

The back and the right side were .... OK, let's say:


The circuit breakers, apparently, have been tuned. It would have been if they were not (look on the bolts):


The cover of the head and the camshaft were looking OK:


A lot of carbon on the head and the valves. Obviously, not a very good burning:


and a lot of carbon on the pistons:


Finally, the crankshaft and the transmission were OK:



I've tried to dismount the valves, in order to clean them and the head and to ....... (I don't know the english term), pass the valves and the beds. Bought a bracket, but the bracket opened and not the valves, so the head went to a shop.


The gap on the first and second compression segments was out of the acceptable and new ones are ordered.
The cylinders are on the limit ....... to be honest a bit off the limit +0,04mm, but I'll try with just a very light honing (only to keep the oil on the walls) and new segments. If it doesn't work as it should be, I'll go on first repair size +0,25. I've found new (not OEM) piston set in the german ebay for "only" 260 Euros.

All the "rubber" elements are ordered. I'm not sure for the names, but according to Google translate they should be as in Bulgarian - semerings. However, in the parts catalog they were named "joint spy".

That's all for today. I have to get up from the PC, but I'll get back soon, as things are moving forward a lot more then the last month.